xref: /petsc/src/mat/impls/aij/seq/aij.c (revision bfe80ac4a46d58cb7760074b25f5e81b2f541d8a)
1 /*
2     Defines the basic matrix operations for the AIJ (compressed row)
3   matrix storage format.
4 */
5 
6 #include <../src/mat/impls/aij/seq/aij.h> /*I "petscmat.h" I*/
7 #include <petscblaslapack.h>
8 #include <petscbt.h>
9 #include <petsc/private/kernels/blocktranspose.h>
10 
11 /* defines MatSetValues_Seq_Hash(), MatAssemblyEnd_Seq_Hash(), MatSetUp_Seq_Hash() */
12 #define TYPE AIJ
13 #define TYPE_BS
14 #include "../src/mat/impls/aij/seq/seqhashmatsetvalues.h"
15 #include "../src/mat/impls/aij/seq/seqhashmat.h"
16 #undef TYPE
17 #undef TYPE_BS
18 
19 static PetscErrorCode MatSeqAIJSetTypeFromOptions(Mat A)
20 {
21   PetscBool flg;
22   char      type[256];
23 
24   PetscFunctionBegin;
25   PetscObjectOptionsBegin((PetscObject)A);
26   PetscCall(PetscOptionsFList("-mat_seqaij_type", "Matrix SeqAIJ type", "MatSeqAIJSetType", MatSeqAIJList, "seqaij", type, 256, &flg));
27   if (flg) PetscCall(MatSeqAIJSetType(A, type));
28   PetscOptionsEnd();
29   PetscFunctionReturn(PETSC_SUCCESS);
30 }
31 
32 static PetscErrorCode MatGetColumnReductions_SeqAIJ(Mat A, PetscInt type, PetscReal *reductions)
33 {
34   PetscInt    i, m, n;
35   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)A->data;
36 
37   PetscFunctionBegin;
38   PetscCall(MatGetSize(A, &m, &n));
39   PetscCall(PetscArrayzero(reductions, n));
40   if (type == NORM_2) {
41     for (i = 0; i < aij->i[m]; i++) reductions[aij->j[i]] += PetscAbsScalar(aij->a[i] * aij->a[i]);
42   } else if (type == NORM_1) {
43     for (i = 0; i < aij->i[m]; i++) reductions[aij->j[i]] += PetscAbsScalar(aij->a[i]);
44   } else if (type == NORM_INFINITY) {
45     for (i = 0; i < aij->i[m]; i++) reductions[aij->j[i]] = PetscMax(PetscAbsScalar(aij->a[i]), reductions[aij->j[i]]);
46   } else if (type == REDUCTION_SUM_REALPART || type == REDUCTION_MEAN_REALPART) {
47     for (i = 0; i < aij->i[m]; i++) reductions[aij->j[i]] += PetscRealPart(aij->a[i]);
48   } else if (type == REDUCTION_SUM_IMAGINARYPART || type == REDUCTION_MEAN_IMAGINARYPART) {
49     for (i = 0; i < aij->i[m]; i++) reductions[aij->j[i]] += PetscImaginaryPart(aij->a[i]);
50   } else SETERRQ(PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "Unknown reduction type");
51 
52   if (type == NORM_2) {
53     for (i = 0; i < n; i++) reductions[i] = PetscSqrtReal(reductions[i]);
54   } else if (type == REDUCTION_MEAN_REALPART || type == REDUCTION_MEAN_IMAGINARYPART) {
55     for (i = 0; i < n; i++) reductions[i] /= m;
56   }
57   PetscFunctionReturn(PETSC_SUCCESS);
58 }
59 
60 static PetscErrorCode MatFindOffBlockDiagonalEntries_SeqAIJ(Mat A, IS *is)
61 {
62   Mat_SeqAIJ     *a = (Mat_SeqAIJ *)A->data;
63   PetscInt        i, m = A->rmap->n, cnt = 0, bs = A->rmap->bs;
64   const PetscInt *jj = a->j, *ii = a->i;
65   PetscInt       *rows;
66 
67   PetscFunctionBegin;
68   for (i = 0; i < m; i++) {
69     if ((ii[i] != ii[i + 1]) && ((jj[ii[i]] < bs * (i / bs)) || (jj[ii[i + 1] - 1] > bs * ((i + bs) / bs) - 1))) cnt++;
70   }
71   PetscCall(PetscMalloc1(cnt, &rows));
72   cnt = 0;
73   for (i = 0; i < m; i++) {
74     if ((ii[i] != ii[i + 1]) && ((jj[ii[i]] < bs * (i / bs)) || (jj[ii[i + 1] - 1] > bs * ((i + bs) / bs) - 1))) {
75       rows[cnt] = i;
76       cnt++;
77     }
78   }
79   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, cnt, rows, PETSC_OWN_POINTER, is));
80   PetscFunctionReturn(PETSC_SUCCESS);
81 }
82 
83 PetscErrorCode MatFindZeroDiagonals_SeqAIJ_Private(Mat A, PetscInt *nrows, PetscInt **zrows)
84 {
85   Mat_SeqAIJ      *a = (Mat_SeqAIJ *)A->data;
86   const MatScalar *aa;
87   PetscInt         i, m = A->rmap->n, cnt = 0;
88   const PetscInt  *ii = a->i, *jj = a->j, *diag;
89   PetscInt        *rows;
90 
91   PetscFunctionBegin;
92   PetscCall(MatSeqAIJGetArrayRead(A, &aa));
93   PetscCall(MatMarkDiagonal_SeqAIJ(A));
94   diag = a->diag;
95   for (i = 0; i < m; i++) {
96     if ((diag[i] >= ii[i + 1]) || (jj[diag[i]] != i) || (aa[diag[i]] == 0.0)) cnt++;
97   }
98   PetscCall(PetscMalloc1(cnt, &rows));
99   cnt = 0;
100   for (i = 0; i < m; i++) {
101     if ((diag[i] >= ii[i + 1]) || (jj[diag[i]] != i) || (aa[diag[i]] == 0.0)) rows[cnt++] = i;
102   }
103   *nrows = cnt;
104   *zrows = rows;
105   PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
106   PetscFunctionReturn(PETSC_SUCCESS);
107 }
108 
109 static PetscErrorCode MatFindZeroDiagonals_SeqAIJ(Mat A, IS *zrows)
110 {
111   PetscInt nrows, *rows;
112 
113   PetscFunctionBegin;
114   *zrows = NULL;
115   PetscCall(MatFindZeroDiagonals_SeqAIJ_Private(A, &nrows, &rows));
116   PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)A), nrows, rows, PETSC_OWN_POINTER, zrows));
117   PetscFunctionReturn(PETSC_SUCCESS);
118 }
119 
120 static PetscErrorCode MatFindNonzeroRows_SeqAIJ(Mat A, IS *keptrows)
121 {
122   Mat_SeqAIJ      *a = (Mat_SeqAIJ *)A->data;
123   const MatScalar *aa;
124   PetscInt         m = A->rmap->n, cnt = 0;
125   const PetscInt  *ii;
126   PetscInt         n, i, j, *rows;
127 
128   PetscFunctionBegin;
129   PetscCall(MatSeqAIJGetArrayRead(A, &aa));
130   *keptrows = NULL;
131   ii        = a->i;
132   for (i = 0; i < m; i++) {
133     n = ii[i + 1] - ii[i];
134     if (!n) {
135       cnt++;
136       goto ok1;
137     }
138     for (j = ii[i]; j < ii[i + 1]; j++) {
139       if (aa[j] != 0.0) goto ok1;
140     }
141     cnt++;
142   ok1:;
143   }
144   if (!cnt) {
145     PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
146     PetscFunctionReturn(PETSC_SUCCESS);
147   }
148   PetscCall(PetscMalloc1(A->rmap->n - cnt, &rows));
149   cnt = 0;
150   for (i = 0; i < m; i++) {
151     n = ii[i + 1] - ii[i];
152     if (!n) continue;
153     for (j = ii[i]; j < ii[i + 1]; j++) {
154       if (aa[j] != 0.0) {
155         rows[cnt++] = i;
156         break;
157       }
158     }
159   }
160   PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
161   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, cnt, rows, PETSC_OWN_POINTER, keptrows));
162   PetscFunctionReturn(PETSC_SUCCESS);
163 }
164 
165 PetscErrorCode MatDiagonalSet_SeqAIJ(Mat Y, Vec D, InsertMode is)
166 {
167   Mat_SeqAIJ        *aij = (Mat_SeqAIJ *)Y->data;
168   PetscInt           i, m = Y->rmap->n;
169   const PetscInt    *diag;
170   MatScalar         *aa;
171   const PetscScalar *v;
172   PetscBool          missing;
173 
174   PetscFunctionBegin;
175   if (Y->assembled) {
176     PetscCall(MatMissingDiagonal_SeqAIJ(Y, &missing, NULL));
177     if (!missing) {
178       diag = aij->diag;
179       PetscCall(VecGetArrayRead(D, &v));
180       PetscCall(MatSeqAIJGetArray(Y, &aa));
181       if (is == INSERT_VALUES) {
182         for (i = 0; i < m; i++) aa[diag[i]] = v[i];
183       } else {
184         for (i = 0; i < m; i++) aa[diag[i]] += v[i];
185       }
186       PetscCall(MatSeqAIJRestoreArray(Y, &aa));
187       PetscCall(VecRestoreArrayRead(D, &v));
188       PetscFunctionReturn(PETSC_SUCCESS);
189     }
190     PetscCall(MatSeqAIJInvalidateDiagonal(Y));
191   }
192   PetscCall(MatDiagonalSet_Default(Y, D, is));
193   PetscFunctionReturn(PETSC_SUCCESS);
194 }
195 
196 PetscErrorCode MatGetRowIJ_SeqAIJ(Mat A, PetscInt oshift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *m, const PetscInt *ia[], const PetscInt *ja[], PetscBool *done)
197 {
198   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
199   PetscInt    i, ishift;
200 
201   PetscFunctionBegin;
202   if (m) *m = A->rmap->n;
203   if (!ia) PetscFunctionReturn(PETSC_SUCCESS);
204   ishift = 0;
205   if (symmetric && A->structurally_symmetric != PETSC_BOOL3_TRUE) {
206     PetscCall(MatToSymmetricIJ_SeqAIJ(A->rmap->n, a->i, a->j, PETSC_TRUE, ishift, oshift, (PetscInt **)ia, (PetscInt **)ja));
207   } else if (oshift == 1) {
208     PetscInt *tia;
209     PetscInt  nz = a->i[A->rmap->n];
210     /* malloc space and  add 1 to i and j indices */
211     PetscCall(PetscMalloc1(A->rmap->n + 1, &tia));
212     for (i = 0; i < A->rmap->n + 1; i++) tia[i] = a->i[i] + 1;
213     *ia = tia;
214     if (ja) {
215       PetscInt *tja;
216       PetscCall(PetscMalloc1(nz + 1, &tja));
217       for (i = 0; i < nz; i++) tja[i] = a->j[i] + 1;
218       *ja = tja;
219     }
220   } else {
221     *ia = a->i;
222     if (ja) *ja = a->j;
223   }
224   PetscFunctionReturn(PETSC_SUCCESS);
225 }
226 
227 PetscErrorCode MatRestoreRowIJ_SeqAIJ(Mat A, PetscInt oshift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *n, const PetscInt *ia[], const PetscInt *ja[], PetscBool *done)
228 {
229   PetscFunctionBegin;
230   if (!ia) PetscFunctionReturn(PETSC_SUCCESS);
231   if ((symmetric && A->structurally_symmetric != PETSC_BOOL3_TRUE) || oshift == 1) {
232     PetscCall(PetscFree(*ia));
233     if (ja) PetscCall(PetscFree(*ja));
234   }
235   PetscFunctionReturn(PETSC_SUCCESS);
236 }
237 
238 PetscErrorCode MatGetColumnIJ_SeqAIJ(Mat A, PetscInt oshift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *nn, const PetscInt *ia[], const PetscInt *ja[], PetscBool *done)
239 {
240   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
241   PetscInt    i, *collengths, *cia, *cja, n = A->cmap->n, m = A->rmap->n;
242   PetscInt    nz = a->i[m], row, *jj, mr, col;
243 
244   PetscFunctionBegin;
245   *nn = n;
246   if (!ia) PetscFunctionReturn(PETSC_SUCCESS);
247   if (symmetric) {
248     PetscCall(MatToSymmetricIJ_SeqAIJ(A->rmap->n, a->i, a->j, PETSC_TRUE, 0, oshift, (PetscInt **)ia, (PetscInt **)ja));
249   } else {
250     PetscCall(PetscCalloc1(n, &collengths));
251     PetscCall(PetscMalloc1(n + 1, &cia));
252     PetscCall(PetscMalloc1(nz, &cja));
253     jj = a->j;
254     for (i = 0; i < nz; i++) collengths[jj[i]]++;
255     cia[0] = oshift;
256     for (i = 0; i < n; i++) cia[i + 1] = cia[i] + collengths[i];
257     PetscCall(PetscArrayzero(collengths, n));
258     jj = a->j;
259     for (row = 0; row < m; row++) {
260       mr = a->i[row + 1] - a->i[row];
261       for (i = 0; i < mr; i++) {
262         col = *jj++;
263 
264         cja[cia[col] + collengths[col]++ - oshift] = row + oshift;
265       }
266     }
267     PetscCall(PetscFree(collengths));
268     *ia = cia;
269     *ja = cja;
270   }
271   PetscFunctionReturn(PETSC_SUCCESS);
272 }
273 
274 PetscErrorCode MatRestoreColumnIJ_SeqAIJ(Mat A, PetscInt oshift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *n, const PetscInt *ia[], const PetscInt *ja[], PetscBool *done)
275 {
276   PetscFunctionBegin;
277   if (!ia) PetscFunctionReturn(PETSC_SUCCESS);
278 
279   PetscCall(PetscFree(*ia));
280   PetscCall(PetscFree(*ja));
281   PetscFunctionReturn(PETSC_SUCCESS);
282 }
283 
284 /*
285  MatGetColumnIJ_SeqAIJ_Color() and MatRestoreColumnIJ_SeqAIJ_Color() are customized from
286  MatGetColumnIJ_SeqAIJ() and MatRestoreColumnIJ_SeqAIJ() by adding an output
287  spidx[], index of a->a, to be used in MatTransposeColoringCreate_SeqAIJ() and MatFDColoringCreate_SeqXAIJ()
288 */
289 PetscErrorCode MatGetColumnIJ_SeqAIJ_Color(Mat A, PetscInt oshift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *nn, const PetscInt *ia[], const PetscInt *ja[], PetscInt *spidx[], PetscBool *done)
290 {
291   Mat_SeqAIJ     *a = (Mat_SeqAIJ *)A->data;
292   PetscInt        i, *collengths, *cia, *cja, n = A->cmap->n, m = A->rmap->n;
293   PetscInt        nz = a->i[m], row, mr, col, tmp;
294   PetscInt       *cspidx;
295   const PetscInt *jj;
296 
297   PetscFunctionBegin;
298   *nn = n;
299   if (!ia) PetscFunctionReturn(PETSC_SUCCESS);
300 
301   PetscCall(PetscCalloc1(n, &collengths));
302   PetscCall(PetscMalloc1(n + 1, &cia));
303   PetscCall(PetscMalloc1(nz, &cja));
304   PetscCall(PetscMalloc1(nz, &cspidx));
305   jj = a->j;
306   for (i = 0; i < nz; i++) collengths[jj[i]]++;
307   cia[0] = oshift;
308   for (i = 0; i < n; i++) cia[i + 1] = cia[i] + collengths[i];
309   PetscCall(PetscArrayzero(collengths, n));
310   jj = a->j;
311   for (row = 0; row < m; row++) {
312     mr = a->i[row + 1] - a->i[row];
313     for (i = 0; i < mr; i++) {
314       col         = *jj++;
315       tmp         = cia[col] + collengths[col]++ - oshift;
316       cspidx[tmp] = a->i[row] + i; /* index of a->j */
317       cja[tmp]    = row + oshift;
318     }
319   }
320   PetscCall(PetscFree(collengths));
321   *ia    = cia;
322   *ja    = cja;
323   *spidx = cspidx;
324   PetscFunctionReturn(PETSC_SUCCESS);
325 }
326 
327 PetscErrorCode MatRestoreColumnIJ_SeqAIJ_Color(Mat A, PetscInt oshift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *n, const PetscInt *ia[], const PetscInt *ja[], PetscInt *spidx[], PetscBool *done)
328 {
329   PetscFunctionBegin;
330   PetscCall(MatRestoreColumnIJ_SeqAIJ(A, oshift, symmetric, inodecompressed, n, ia, ja, done));
331   PetscCall(PetscFree(*spidx));
332   PetscFunctionReturn(PETSC_SUCCESS);
333 }
334 
335 static PetscErrorCode MatSetValuesRow_SeqAIJ(Mat A, PetscInt row, const PetscScalar v[])
336 {
337   Mat_SeqAIJ  *a  = (Mat_SeqAIJ *)A->data;
338   PetscInt    *ai = a->i;
339   PetscScalar *aa;
340 
341   PetscFunctionBegin;
342   PetscCall(MatSeqAIJGetArray(A, &aa));
343   PetscCall(PetscArraycpy(aa + ai[row], v, ai[row + 1] - ai[row]));
344   PetscCall(MatSeqAIJRestoreArray(A, &aa));
345   PetscFunctionReturn(PETSC_SUCCESS);
346 }
347 
348 /*
349     MatSeqAIJSetValuesLocalFast - An optimized version of MatSetValuesLocal() for SeqAIJ matrices with several assumptions
350 
351       -   a single row of values is set with each call
352       -   no row or column indices are negative or (in error) larger than the number of rows or columns
353       -   the values are always added to the matrix, not set
354       -   no new locations are introduced in the nonzero structure of the matrix
355 
356      This does NOT assume the global column indices are sorted
357 
358 */
359 
360 #include <petsc/private/isimpl.h>
361 PetscErrorCode MatSeqAIJSetValuesLocalFast(Mat A, PetscInt m, const PetscInt im[], PetscInt n, const PetscInt in[], const PetscScalar v[], InsertMode is)
362 {
363   Mat_SeqAIJ     *a = (Mat_SeqAIJ *)A->data;
364   PetscInt        low, high, t, row, nrow, i, col, l;
365   const PetscInt *rp, *ai = a->i, *ailen = a->ilen, *aj = a->j;
366   PetscInt        lastcol = -1;
367   MatScalar      *ap, value, *aa;
368   const PetscInt *ridx = A->rmap->mapping->indices, *cidx = A->cmap->mapping->indices;
369 
370   PetscFunctionBegin;
371   PetscCall(MatSeqAIJGetArray(A, &aa));
372   row  = ridx[im[0]];
373   rp   = aj + ai[row];
374   ap   = aa + ai[row];
375   nrow = ailen[row];
376   low  = 0;
377   high = nrow;
378   for (l = 0; l < n; l++) { /* loop over added columns */
379     col   = cidx[in[l]];
380     value = v[l];
381 
382     if (col <= lastcol) low = 0;
383     else high = nrow;
384     lastcol = col;
385     while (high - low > 5) {
386       t = (low + high) / 2;
387       if (rp[t] > col) high = t;
388       else low = t;
389     }
390     for (i = low; i < high; i++) {
391       if (rp[i] == col) {
392         ap[i] += value;
393         low = i + 1;
394         break;
395       }
396     }
397   }
398   PetscCall(MatSeqAIJRestoreArray(A, &aa));
399   return PETSC_SUCCESS;
400 }
401 
402 PetscErrorCode MatSetValues_SeqAIJ(Mat A, PetscInt m, const PetscInt im[], PetscInt n, const PetscInt in[], const PetscScalar v[], InsertMode is)
403 {
404   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
405   PetscInt   *rp, k, low, high, t, ii, row, nrow, i, col, l, rmax, N;
406   PetscInt   *imax = a->imax, *ai = a->i, *ailen = a->ilen;
407   PetscInt   *aj = a->j, nonew = a->nonew, lastcol = -1;
408   MatScalar  *ap = NULL, value = 0.0, *aa;
409   PetscBool   ignorezeroentries = a->ignorezeroentries;
410   PetscBool   roworiented       = a->roworiented;
411 
412   PetscFunctionBegin;
413   PetscCall(MatSeqAIJGetArray(A, &aa));
414   for (k = 0; k < m; k++) { /* loop over added rows */
415     row = im[k];
416     if (row < 0) continue;
417     PetscCheck(row < A->rmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Row too large: row %" PetscInt_FMT " max %" PetscInt_FMT, row, A->rmap->n - 1);
418     rp = PetscSafePointerPlusOffset(aj, ai[row]);
419     if (!A->structure_only) ap = PetscSafePointerPlusOffset(aa, ai[row]);
420     rmax = imax[row];
421     nrow = ailen[row];
422     low  = 0;
423     high = nrow;
424     for (l = 0; l < n; l++) { /* loop over added columns */
425       if (in[l] < 0) continue;
426       PetscCheck(in[l] < A->cmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Column too large: col %" PetscInt_FMT " max %" PetscInt_FMT, in[l], A->cmap->n - 1);
427       col = in[l];
428       if (v && !A->structure_only) value = roworiented ? v[l + k * n] : v[k + l * m];
429       if (!A->structure_only && value == 0.0 && ignorezeroentries && is == ADD_VALUES && row != col) continue;
430 
431       if (col <= lastcol) low = 0;
432       else high = nrow;
433       lastcol = col;
434       while (high - low > 5) {
435         t = (low + high) / 2;
436         if (rp[t] > col) high = t;
437         else low = t;
438       }
439       for (i = low; i < high; i++) {
440         if (rp[i] > col) break;
441         if (rp[i] == col) {
442           if (!A->structure_only) {
443             if (is == ADD_VALUES) {
444               ap[i] += value;
445               (void)PetscLogFlops(1.0);
446             } else ap[i] = value;
447           }
448           low = i + 1;
449           goto noinsert;
450         }
451       }
452       if (value == 0.0 && ignorezeroentries && row != col) goto noinsert;
453       if (nonew == 1) goto noinsert;
454       PetscCheck(nonew != -1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Inserting a new nonzero at (%" PetscInt_FMT ",%" PetscInt_FMT ") in the matrix", row, col);
455       if (A->structure_only) {
456         MatSeqXAIJReallocateAIJ_structure_only(A, A->rmap->n, 1, nrow, row, col, rmax, ai, aj, rp, imax, nonew, MatScalar);
457       } else {
458         MatSeqXAIJReallocateAIJ(A, A->rmap->n, 1, nrow, row, col, rmax, aa, ai, aj, rp, ap, imax, nonew, MatScalar);
459       }
460       N = nrow++ - 1;
461       a->nz++;
462       high++;
463       /* shift up all the later entries in this row */
464       PetscCall(PetscArraymove(rp + i + 1, rp + i, N - i + 1));
465       rp[i] = col;
466       if (!A->structure_only) {
467         PetscCall(PetscArraymove(ap + i + 1, ap + i, N - i + 1));
468         ap[i] = value;
469       }
470       low = i + 1;
471     noinsert:;
472     }
473     ailen[row] = nrow;
474   }
475   PetscCall(MatSeqAIJRestoreArray(A, &aa));
476   PetscFunctionReturn(PETSC_SUCCESS);
477 }
478 
479 static PetscErrorCode MatSetValues_SeqAIJ_SortedFullNoPreallocation(Mat A, PetscInt m, const PetscInt im[], PetscInt n, const PetscInt in[], const PetscScalar v[], InsertMode is)
480 {
481   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
482   PetscInt   *rp, k, row;
483   PetscInt   *ai = a->i;
484   PetscInt   *aj = a->j;
485   MatScalar  *aa, *ap;
486 
487   PetscFunctionBegin;
488   PetscCheck(!A->was_assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot call on assembled matrix.");
489   PetscCheck(m * n + a->nz <= a->maxnz, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Number of entries in matrix will be larger than maximum nonzeros allocated for %" PetscInt_FMT " in MatSeqAIJSetTotalPreallocation()", a->maxnz);
490 
491   PetscCall(MatSeqAIJGetArray(A, &aa));
492   for (k = 0; k < m; k++) { /* loop over added rows */
493     row = im[k];
494     rp  = aj + ai[row];
495     ap  = PetscSafePointerPlusOffset(aa, ai[row]);
496 
497     PetscCall(PetscMemcpy(rp, in, n * sizeof(PetscInt)));
498     if (!A->structure_only) {
499       if (v) {
500         PetscCall(PetscMemcpy(ap, v, n * sizeof(PetscScalar)));
501         v += n;
502       } else {
503         PetscCall(PetscMemzero(ap, n * sizeof(PetscScalar)));
504       }
505     }
506     a->ilen[row]  = n;
507     a->imax[row]  = n;
508     a->i[row + 1] = a->i[row] + n;
509     a->nz += n;
510   }
511   PetscCall(MatSeqAIJRestoreArray(A, &aa));
512   PetscFunctionReturn(PETSC_SUCCESS);
513 }
514 
515 /*@
516   MatSeqAIJSetTotalPreallocation - Sets an upper bound on the total number of expected nonzeros in the matrix.
517 
518   Input Parameters:
519 + A       - the `MATSEQAIJ` matrix
520 - nztotal - bound on the number of nonzeros
521 
522   Level: advanced
523 
524   Notes:
525   This can be called if you will be provided the matrix row by row (from row zero) with sorted column indices for each row.
526   Simply call `MatSetValues()` after this call to provide the matrix entries in the usual manner. This matrix may be used
527   as always with multiple matrix assemblies.
528 
529 .seealso: [](ch_matrices), `Mat`, `MatSetOption()`, `MAT_SORTED_FULL`, `MatSetValues()`, `MatSeqAIJSetPreallocation()`
530 @*/
531 PetscErrorCode MatSeqAIJSetTotalPreallocation(Mat A, PetscInt nztotal)
532 {
533   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
534 
535   PetscFunctionBegin;
536   PetscCall(PetscLayoutSetUp(A->rmap));
537   PetscCall(PetscLayoutSetUp(A->cmap));
538   a->maxnz = nztotal;
539   if (!a->imax) { PetscCall(PetscMalloc1(A->rmap->n, &a->imax)); }
540   if (!a->ilen) {
541     PetscCall(PetscMalloc1(A->rmap->n, &a->ilen));
542   } else {
543     PetscCall(PetscMemzero(a->ilen, A->rmap->n * sizeof(PetscInt)));
544   }
545 
546   /* allocate the matrix space */
547   PetscCall(PetscShmgetAllocateArray(A->rmap->n + 1, sizeof(PetscInt), (void **)&a->i));
548   PetscCall(PetscShmgetAllocateArray(nztotal, sizeof(PetscInt), (void **)&a->j));
549   a->free_ij = PETSC_TRUE;
550   if (A->structure_only) {
551     a->free_a = PETSC_FALSE;
552   } else {
553     PetscCall(PetscShmgetAllocateArray(nztotal, sizeof(PetscScalar), (void **)&a->a));
554     a->free_a = PETSC_TRUE;
555   }
556   a->i[0]           = 0;
557   A->ops->setvalues = MatSetValues_SeqAIJ_SortedFullNoPreallocation;
558   A->preallocated   = PETSC_TRUE;
559   PetscFunctionReturn(PETSC_SUCCESS);
560 }
561 
562 static PetscErrorCode MatSetValues_SeqAIJ_SortedFull(Mat A, PetscInt m, const PetscInt im[], PetscInt n, const PetscInt in[], const PetscScalar v[], InsertMode is)
563 {
564   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
565   PetscInt   *rp, k, row;
566   PetscInt   *ai = a->i, *ailen = a->ilen;
567   PetscInt   *aj = a->j;
568   MatScalar  *aa, *ap;
569 
570   PetscFunctionBegin;
571   PetscCall(MatSeqAIJGetArray(A, &aa));
572   for (k = 0; k < m; k++) { /* loop over added rows */
573     row = im[k];
574     PetscCheck(n <= a->imax[row], PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Preallocation for row %" PetscInt_FMT " does not match number of columns provided", n);
575     rp = aj + ai[row];
576     ap = aa + ai[row];
577     if (!A->was_assembled) PetscCall(PetscMemcpy(rp, in, n * sizeof(PetscInt)));
578     if (!A->structure_only) {
579       if (v) {
580         PetscCall(PetscMemcpy(ap, v, n * sizeof(PetscScalar)));
581         v += n;
582       } else {
583         PetscCall(PetscMemzero(ap, n * sizeof(PetscScalar)));
584       }
585     }
586     ailen[row] = n;
587     a->nz += n;
588   }
589   PetscCall(MatSeqAIJRestoreArray(A, &aa));
590   PetscFunctionReturn(PETSC_SUCCESS);
591 }
592 
593 static PetscErrorCode MatGetValues_SeqAIJ(Mat A, PetscInt m, const PetscInt im[], PetscInt n, const PetscInt in[], PetscScalar v[])
594 {
595   Mat_SeqAIJ      *a = (Mat_SeqAIJ *)A->data;
596   PetscInt        *rp, k, low, high, t, row, nrow, i, col, l, *aj = a->j;
597   PetscInt        *ai = a->i, *ailen = a->ilen;
598   const MatScalar *ap, *aa;
599 
600   PetscFunctionBegin;
601   PetscCall(MatSeqAIJGetArrayRead(A, &aa));
602   for (k = 0; k < m; k++) { /* loop over rows */
603     row = im[k];
604     if (row < 0) {
605       v += n;
606       continue;
607     } /* negative row */
608     PetscCheck(row < A->rmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Row too large: row %" PetscInt_FMT " max %" PetscInt_FMT, row, A->rmap->n - 1);
609     rp   = PetscSafePointerPlusOffset(aj, ai[row]);
610     ap   = PetscSafePointerPlusOffset(aa, ai[row]);
611     nrow = ailen[row];
612     for (l = 0; l < n; l++) { /* loop over columns */
613       if (in[l] < 0) {
614         v++;
615         continue;
616       } /* negative column */
617       PetscCheck(in[l] < A->cmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Column too large: col %" PetscInt_FMT " max %" PetscInt_FMT, in[l], A->cmap->n - 1);
618       col  = in[l];
619       high = nrow;
620       low  = 0; /* assume unsorted */
621       while (high - low > 5) {
622         t = (low + high) / 2;
623         if (rp[t] > col) high = t;
624         else low = t;
625       }
626       for (i = low; i < high; i++) {
627         if (rp[i] > col) break;
628         if (rp[i] == col) {
629           *v++ = ap[i];
630           goto finished;
631         }
632       }
633       *v++ = 0.0;
634     finished:;
635     }
636   }
637   PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
638   PetscFunctionReturn(PETSC_SUCCESS);
639 }
640 
641 static PetscErrorCode MatView_SeqAIJ_Binary(Mat mat, PetscViewer viewer)
642 {
643   Mat_SeqAIJ        *A = (Mat_SeqAIJ *)mat->data;
644   const PetscScalar *av;
645   PetscInt           header[4], M, N, m, nz, i;
646   PetscInt          *rowlens;
647 
648   PetscFunctionBegin;
649   PetscCall(PetscViewerSetUp(viewer));
650 
651   M  = mat->rmap->N;
652   N  = mat->cmap->N;
653   m  = mat->rmap->n;
654   nz = A->nz;
655 
656   /* write matrix header */
657   header[0] = MAT_FILE_CLASSID;
658   header[1] = M;
659   header[2] = N;
660   header[3] = nz;
661   PetscCall(PetscViewerBinaryWrite(viewer, header, 4, PETSC_INT));
662 
663   /* fill in and store row lengths */
664   PetscCall(PetscMalloc1(m, &rowlens));
665   for (i = 0; i < m; i++) rowlens[i] = A->i[i + 1] - A->i[i];
666   if (PetscDefined(USE_DEBUG)) {
667     PetscInt mnz = 0;
668 
669     for (i = 0; i < m; i++) mnz += rowlens[i];
670     PetscCheck(nz == mnz, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Row lens %" PetscInt_FMT " do not sum to nz %" PetscInt_FMT, mnz, nz);
671   }
672   PetscCall(PetscViewerBinaryWrite(viewer, rowlens, m, PETSC_INT));
673   PetscCall(PetscFree(rowlens));
674   /* store column indices */
675   PetscCall(PetscViewerBinaryWrite(viewer, A->j, nz, PETSC_INT));
676   /* store nonzero values */
677   PetscCall(MatSeqAIJGetArrayRead(mat, &av));
678   PetscCall(PetscViewerBinaryWrite(viewer, av, nz, PETSC_SCALAR));
679   PetscCall(MatSeqAIJRestoreArrayRead(mat, &av));
680 
681   /* write block size option to the viewer's .info file */
682   PetscCall(MatView_Binary_BlockSizes(mat, viewer));
683   PetscFunctionReturn(PETSC_SUCCESS);
684 }
685 
686 static PetscErrorCode MatView_SeqAIJ_ASCII_structonly(Mat A, PetscViewer viewer)
687 {
688   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
689   PetscInt    i, k, m = A->rmap->N;
690 
691   PetscFunctionBegin;
692   PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
693   for (i = 0; i < m; i++) {
694     PetscCall(PetscViewerASCIIPrintf(viewer, "row %" PetscInt_FMT ":", i));
695     for (k = a->i[i]; k < a->i[i + 1]; k++) PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ") ", a->j[k]));
696     PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
697   }
698   PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
699   PetscFunctionReturn(PETSC_SUCCESS);
700 }
701 
702 extern PetscErrorCode MatSeqAIJFactorInfo_Matlab(Mat, PetscViewer);
703 
704 static PetscErrorCode MatView_SeqAIJ_ASCII(Mat A, PetscViewer viewer)
705 {
706   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
707   const PetscScalar *av;
708   PetscInt           i, j, m = A->rmap->n;
709   const char        *name;
710   PetscViewerFormat  format;
711 
712   PetscFunctionBegin;
713   if (A->structure_only) {
714     PetscCall(MatView_SeqAIJ_ASCII_structonly(A, viewer));
715     PetscFunctionReturn(PETSC_SUCCESS);
716   }
717 
718   PetscCall(PetscViewerGetFormat(viewer, &format));
719   // By petsc's rule, even PETSC_VIEWER_ASCII_INFO_DETAIL doesn't print matrix entries
720   if (format == PETSC_VIEWER_ASCII_FACTOR_INFO || format == PETSC_VIEWER_ASCII_INFO || format == PETSC_VIEWER_ASCII_INFO_DETAIL) PetscFunctionReturn(PETSC_SUCCESS);
721 
722   /* trigger copy to CPU if needed */
723   PetscCall(MatSeqAIJGetArrayRead(A, &av));
724   PetscCall(MatSeqAIJRestoreArrayRead(A, &av));
725   if (format == PETSC_VIEWER_ASCII_MATLAB) {
726     PetscInt nofinalvalue = 0;
727     if (m && ((a->i[m] == a->i[m - 1]) || (a->j[a->nz - 1] != A->cmap->n - 1))) {
728       /* Need a dummy value to ensure the dimension of the matrix. */
729       nofinalvalue = 1;
730     }
731     PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
732     PetscCall(PetscViewerASCIIPrintf(viewer, "%% Size = %" PetscInt_FMT " %" PetscInt_FMT " \n", m, A->cmap->n));
733     PetscCall(PetscViewerASCIIPrintf(viewer, "%% Nonzeros = %" PetscInt_FMT " \n", a->nz));
734 #if defined(PETSC_USE_COMPLEX)
735     PetscCall(PetscViewerASCIIPrintf(viewer, "zzz = zeros(%" PetscInt_FMT ",4);\n", a->nz + nofinalvalue));
736 #else
737     PetscCall(PetscViewerASCIIPrintf(viewer, "zzz = zeros(%" PetscInt_FMT ",3);\n", a->nz + nofinalvalue));
738 #endif
739     PetscCall(PetscViewerASCIIPrintf(viewer, "zzz = [\n"));
740 
741     for (i = 0; i < m; i++) {
742       for (j = a->i[i]; j < a->i[i + 1]; j++) {
743 #if defined(PETSC_USE_COMPLEX)
744         PetscCall(PetscViewerASCIIPrintf(viewer, "%" PetscInt_FMT " %" PetscInt_FMT "  %18.16e %18.16e\n", i + 1, a->j[j] + 1, (double)PetscRealPart(a->a[j]), (double)PetscImaginaryPart(a->a[j])));
745 #else
746         PetscCall(PetscViewerASCIIPrintf(viewer, "%" PetscInt_FMT " %" PetscInt_FMT "  %18.16e\n", i + 1, a->j[j] + 1, (double)a->a[j]));
747 #endif
748       }
749     }
750     if (nofinalvalue) {
751 #if defined(PETSC_USE_COMPLEX)
752       PetscCall(PetscViewerASCIIPrintf(viewer, "%" PetscInt_FMT " %" PetscInt_FMT "  %18.16e %18.16e\n", m, A->cmap->n, 0., 0.));
753 #else
754       PetscCall(PetscViewerASCIIPrintf(viewer, "%" PetscInt_FMT " %" PetscInt_FMT "  %18.16e\n", m, A->cmap->n, 0.0));
755 #endif
756     }
757     PetscCall(PetscObjectGetName((PetscObject)A, &name));
758     PetscCall(PetscViewerASCIIPrintf(viewer, "];\n %s = spconvert(zzz);\n", name));
759     PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
760   } else if (format == PETSC_VIEWER_ASCII_COMMON) {
761     PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
762     for (i = 0; i < m; i++) {
763       PetscCall(PetscViewerASCIIPrintf(viewer, "row %" PetscInt_FMT ":", i));
764       for (j = a->i[i]; j < a->i[i + 1]; j++) {
765 #if defined(PETSC_USE_COMPLEX)
766         if (PetscImaginaryPart(a->a[j]) > 0.0 && PetscRealPart(a->a[j]) != 0.0) {
767           PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g + %g i)", a->j[j], (double)PetscRealPart(a->a[j]), (double)PetscImaginaryPart(a->a[j])));
768         } else if (PetscImaginaryPart(a->a[j]) < 0.0 && PetscRealPart(a->a[j]) != 0.0) {
769           PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g - %g i)", a->j[j], (double)PetscRealPart(a->a[j]), (double)-PetscImaginaryPart(a->a[j])));
770         } else if (PetscRealPart(a->a[j]) != 0.0) {
771           PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g) ", a->j[j], (double)PetscRealPart(a->a[j])));
772         }
773 #else
774         if (a->a[j] != 0.0) PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g) ", a->j[j], (double)a->a[j]));
775 #endif
776       }
777       PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
778     }
779     PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
780   } else if (format == PETSC_VIEWER_ASCII_SYMMODU) {
781     PetscInt nzd = 0, fshift = 1, *sptr;
782     PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
783     PetscCall(PetscMalloc1(m + 1, &sptr));
784     for (i = 0; i < m; i++) {
785       sptr[i] = nzd + 1;
786       for (j = a->i[i]; j < a->i[i + 1]; j++) {
787         if (a->j[j] >= i) {
788 #if defined(PETSC_USE_COMPLEX)
789           if (PetscImaginaryPart(a->a[j]) != 0.0 || PetscRealPart(a->a[j]) != 0.0) nzd++;
790 #else
791           if (a->a[j] != 0.0) nzd++;
792 #endif
793         }
794       }
795     }
796     sptr[m] = nzd + 1;
797     PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT " %" PetscInt_FMT "\n\n", m, nzd));
798     for (i = 0; i < m + 1; i += 6) {
799       if (i + 4 < m) {
800         PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT "\n", sptr[i], sptr[i + 1], sptr[i + 2], sptr[i + 3], sptr[i + 4], sptr[i + 5]));
801       } else if (i + 3 < m) {
802         PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT "\n", sptr[i], sptr[i + 1], sptr[i + 2], sptr[i + 3], sptr[i + 4]));
803       } else if (i + 2 < m) {
804         PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT "\n", sptr[i], sptr[i + 1], sptr[i + 2], sptr[i + 3]));
805       } else if (i + 1 < m) {
806         PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT "\n", sptr[i], sptr[i + 1], sptr[i + 2]));
807       } else if (i < m) {
808         PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT " %" PetscInt_FMT "\n", sptr[i], sptr[i + 1]));
809       } else {
810         PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT "\n", sptr[i]));
811       }
812     }
813     PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
814     PetscCall(PetscFree(sptr));
815     for (i = 0; i < m; i++) {
816       for (j = a->i[i]; j < a->i[i + 1]; j++) {
817         if (a->j[j] >= i) PetscCall(PetscViewerASCIIPrintf(viewer, " %" PetscInt_FMT " ", a->j[j] + fshift));
818       }
819       PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
820     }
821     PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
822     for (i = 0; i < m; i++) {
823       for (j = a->i[i]; j < a->i[i + 1]; j++) {
824         if (a->j[j] >= i) {
825 #if defined(PETSC_USE_COMPLEX)
826           if (PetscImaginaryPart(a->a[j]) != 0.0 || PetscRealPart(a->a[j]) != 0.0) PetscCall(PetscViewerASCIIPrintf(viewer, " %18.16e %18.16e ", (double)PetscRealPart(a->a[j]), (double)PetscImaginaryPart(a->a[j])));
827 #else
828           if (a->a[j] != 0.0) PetscCall(PetscViewerASCIIPrintf(viewer, " %18.16e ", (double)a->a[j]));
829 #endif
830         }
831       }
832       PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
833     }
834     PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
835   } else if (format == PETSC_VIEWER_ASCII_DENSE) {
836     PetscInt    cnt = 0, jcnt;
837     PetscScalar value;
838 #if defined(PETSC_USE_COMPLEX)
839     PetscBool realonly = PETSC_TRUE;
840 
841     for (i = 0; i < a->i[m]; i++) {
842       if (PetscImaginaryPart(a->a[i]) != 0.0) {
843         realonly = PETSC_FALSE;
844         break;
845       }
846     }
847 #endif
848 
849     PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
850     for (i = 0; i < m; i++) {
851       jcnt = 0;
852       for (j = 0; j < A->cmap->n; j++) {
853         if (jcnt < a->i[i + 1] - a->i[i] && j == a->j[cnt]) {
854           value = a->a[cnt++];
855           jcnt++;
856         } else {
857           value = 0.0;
858         }
859 #if defined(PETSC_USE_COMPLEX)
860         if (realonly) {
861           PetscCall(PetscViewerASCIIPrintf(viewer, " %7.5e ", (double)PetscRealPart(value)));
862         } else {
863           PetscCall(PetscViewerASCIIPrintf(viewer, " %7.5e+%7.5e i ", (double)PetscRealPart(value), (double)PetscImaginaryPart(value)));
864         }
865 #else
866         PetscCall(PetscViewerASCIIPrintf(viewer, " %7.5e ", (double)value));
867 #endif
868       }
869       PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
870     }
871     PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
872   } else if (format == PETSC_VIEWER_ASCII_MATRIXMARKET) {
873     PetscInt fshift = 1;
874     PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
875 #if defined(PETSC_USE_COMPLEX)
876     PetscCall(PetscViewerASCIIPrintf(viewer, "%%%%MatrixMarket matrix coordinate complex general\n"));
877 #else
878     PetscCall(PetscViewerASCIIPrintf(viewer, "%%%%MatrixMarket matrix coordinate real general\n"));
879 #endif
880     PetscCall(PetscViewerASCIIPrintf(viewer, "%" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT "\n", m, A->cmap->n, a->nz));
881     for (i = 0; i < m; i++) {
882       for (j = a->i[i]; j < a->i[i + 1]; j++) {
883 #if defined(PETSC_USE_COMPLEX)
884         PetscCall(PetscViewerASCIIPrintf(viewer, "%" PetscInt_FMT " %" PetscInt_FMT " %g %g\n", i + fshift, a->j[j] + fshift, (double)PetscRealPart(a->a[j]), (double)PetscImaginaryPart(a->a[j])));
885 #else
886         PetscCall(PetscViewerASCIIPrintf(viewer, "%" PetscInt_FMT " %" PetscInt_FMT " %g\n", i + fshift, a->j[j] + fshift, (double)a->a[j]));
887 #endif
888       }
889     }
890     PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
891   } else {
892     PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
893     if (A->factortype) {
894       for (i = 0; i < m; i++) {
895         PetscCall(PetscViewerASCIIPrintf(viewer, "row %" PetscInt_FMT ":", i));
896         /* L part */
897         for (j = a->i[i]; j < a->i[i + 1]; j++) {
898 #if defined(PETSC_USE_COMPLEX)
899           if (PetscImaginaryPart(a->a[j]) > 0.0) {
900             PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g + %g i)", a->j[j], (double)PetscRealPart(a->a[j]), (double)PetscImaginaryPart(a->a[j])));
901           } else if (PetscImaginaryPart(a->a[j]) < 0.0) {
902             PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g - %g i)", a->j[j], (double)PetscRealPart(a->a[j]), (double)(-PetscImaginaryPart(a->a[j]))));
903           } else {
904             PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g) ", a->j[j], (double)PetscRealPart(a->a[j])));
905           }
906 #else
907           PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g) ", a->j[j], (double)a->a[j]));
908 #endif
909         }
910         /* diagonal */
911         j = a->diag[i];
912 #if defined(PETSC_USE_COMPLEX)
913         if (PetscImaginaryPart(a->a[j]) > 0.0) {
914           PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g + %g i)", a->j[j], (double)PetscRealPart(1 / a->a[j]), (double)PetscImaginaryPart(1 / a->a[j])));
915         } else if (PetscImaginaryPart(a->a[j]) < 0.0) {
916           PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g - %g i)", a->j[j], (double)PetscRealPart(1 / a->a[j]), (double)(-PetscImaginaryPart(1 / a->a[j]))));
917         } else {
918           PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g) ", a->j[j], (double)PetscRealPart(1 / a->a[j])));
919         }
920 #else
921         PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g) ", a->j[j], (double)(1 / a->a[j])));
922 #endif
923 
924         /* U part */
925         for (j = a->diag[i + 1] + 1; j < a->diag[i]; j++) {
926 #if defined(PETSC_USE_COMPLEX)
927           if (PetscImaginaryPart(a->a[j]) > 0.0) {
928             PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g + %g i)", a->j[j], (double)PetscRealPart(a->a[j]), (double)PetscImaginaryPart(a->a[j])));
929           } else if (PetscImaginaryPart(a->a[j]) < 0.0) {
930             PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g - %g i)", a->j[j], (double)PetscRealPart(a->a[j]), (double)(-PetscImaginaryPart(a->a[j]))));
931           } else {
932             PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g) ", a->j[j], (double)PetscRealPart(a->a[j])));
933           }
934 #else
935           PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g) ", a->j[j], (double)a->a[j]));
936 #endif
937         }
938         PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
939       }
940     } else {
941       for (i = 0; i < m; i++) {
942         PetscCall(PetscViewerASCIIPrintf(viewer, "row %" PetscInt_FMT ":", i));
943         for (j = a->i[i]; j < a->i[i + 1]; j++) {
944 #if defined(PETSC_USE_COMPLEX)
945           if (PetscImaginaryPart(a->a[j]) > 0.0) {
946             PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g + %g i)", a->j[j], (double)PetscRealPart(a->a[j]), (double)PetscImaginaryPart(a->a[j])));
947           } else if (PetscImaginaryPart(a->a[j]) < 0.0) {
948             PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g - %g i)", a->j[j], (double)PetscRealPart(a->a[j]), (double)-PetscImaginaryPart(a->a[j])));
949           } else {
950             PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g) ", a->j[j], (double)PetscRealPart(a->a[j])));
951           }
952 #else
953           PetscCall(PetscViewerASCIIPrintf(viewer, " (%" PetscInt_FMT ", %g) ", a->j[j], (double)a->a[j]));
954 #endif
955         }
956         PetscCall(PetscViewerASCIIPrintf(viewer, "\n"));
957       }
958     }
959     PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
960   }
961   PetscCall(PetscViewerFlush(viewer));
962   PetscFunctionReturn(PETSC_SUCCESS);
963 }
964 
965 #include <petscdraw.h>
966 static PetscErrorCode MatView_SeqAIJ_Draw_Zoom(PetscDraw draw, void *Aa)
967 {
968   Mat                A = (Mat)Aa;
969   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
970   PetscInt           i, j, m = A->rmap->n;
971   int                color;
972   PetscReal          xl, yl, xr, yr, x_l, x_r, y_l, y_r;
973   PetscViewer        viewer;
974   PetscViewerFormat  format;
975   const PetscScalar *aa;
976 
977   PetscFunctionBegin;
978   PetscCall(PetscObjectQuery((PetscObject)A, "Zoomviewer", (PetscObject *)&viewer));
979   PetscCall(PetscViewerGetFormat(viewer, &format));
980   PetscCall(PetscDrawGetCoordinates(draw, &xl, &yl, &xr, &yr));
981 
982   /* loop over matrix elements drawing boxes */
983   PetscCall(MatSeqAIJGetArrayRead(A, &aa));
984   if (format != PETSC_VIEWER_DRAW_CONTOUR) {
985     PetscDrawCollectiveBegin(draw);
986     /* Blue for negative, Cyan for zero and  Red for positive */
987     color = PETSC_DRAW_BLUE;
988     for (i = 0; i < m; i++) {
989       y_l = m - i - 1.0;
990       y_r = y_l + 1.0;
991       for (j = a->i[i]; j < a->i[i + 1]; j++) {
992         x_l = a->j[j];
993         x_r = x_l + 1.0;
994         if (PetscRealPart(aa[j]) >= 0.) continue;
995         PetscCall(PetscDrawRectangle(draw, x_l, y_l, x_r, y_r, color, color, color, color));
996       }
997     }
998     color = PETSC_DRAW_CYAN;
999     for (i = 0; i < m; i++) {
1000       y_l = m - i - 1.0;
1001       y_r = y_l + 1.0;
1002       for (j = a->i[i]; j < a->i[i + 1]; j++) {
1003         x_l = a->j[j];
1004         x_r = x_l + 1.0;
1005         if (aa[j] != 0.) continue;
1006         PetscCall(PetscDrawRectangle(draw, x_l, y_l, x_r, y_r, color, color, color, color));
1007       }
1008     }
1009     color = PETSC_DRAW_RED;
1010     for (i = 0; i < m; i++) {
1011       y_l = m - i - 1.0;
1012       y_r = y_l + 1.0;
1013       for (j = a->i[i]; j < a->i[i + 1]; j++) {
1014         x_l = a->j[j];
1015         x_r = x_l + 1.0;
1016         if (PetscRealPart(aa[j]) <= 0.) continue;
1017         PetscCall(PetscDrawRectangle(draw, x_l, y_l, x_r, y_r, color, color, color, color));
1018       }
1019     }
1020     PetscDrawCollectiveEnd(draw);
1021   } else {
1022     /* use contour shading to indicate magnitude of values */
1023     /* first determine max of all nonzero values */
1024     PetscReal minv = 0.0, maxv = 0.0;
1025     PetscInt  nz = a->nz, count = 0;
1026     PetscDraw popup;
1027 
1028     for (i = 0; i < nz; i++) {
1029       if (PetscAbsScalar(aa[i]) > maxv) maxv = PetscAbsScalar(aa[i]);
1030     }
1031     if (minv >= maxv) maxv = minv + PETSC_SMALL;
1032     PetscCall(PetscDrawGetPopup(draw, &popup));
1033     PetscCall(PetscDrawScalePopup(popup, minv, maxv));
1034 
1035     PetscDrawCollectiveBegin(draw);
1036     for (i = 0; i < m; i++) {
1037       y_l = m - i - 1.0;
1038       y_r = y_l + 1.0;
1039       for (j = a->i[i]; j < a->i[i + 1]; j++) {
1040         x_l   = a->j[j];
1041         x_r   = x_l + 1.0;
1042         color = PetscDrawRealToColor(PetscAbsScalar(aa[count]), minv, maxv);
1043         PetscCall(PetscDrawRectangle(draw, x_l, y_l, x_r, y_r, color, color, color, color));
1044         count++;
1045       }
1046     }
1047     PetscDrawCollectiveEnd(draw);
1048   }
1049   PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
1050   PetscFunctionReturn(PETSC_SUCCESS);
1051 }
1052 
1053 #include <petscdraw.h>
1054 static PetscErrorCode MatView_SeqAIJ_Draw(Mat A, PetscViewer viewer)
1055 {
1056   PetscDraw draw;
1057   PetscReal xr, yr, xl, yl, h, w;
1058   PetscBool isnull;
1059 
1060   PetscFunctionBegin;
1061   PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
1062   PetscCall(PetscDrawIsNull(draw, &isnull));
1063   if (isnull) PetscFunctionReturn(PETSC_SUCCESS);
1064 
1065   xr = A->cmap->n;
1066   yr = A->rmap->n;
1067   h  = yr / 10.0;
1068   w  = xr / 10.0;
1069   xr += w;
1070   yr += h;
1071   xl = -w;
1072   yl = -h;
1073   PetscCall(PetscDrawSetCoordinates(draw, xl, yl, xr, yr));
1074   PetscCall(PetscObjectCompose((PetscObject)A, "Zoomviewer", (PetscObject)viewer));
1075   PetscCall(PetscDrawZoom(draw, MatView_SeqAIJ_Draw_Zoom, A));
1076   PetscCall(PetscObjectCompose((PetscObject)A, "Zoomviewer", NULL));
1077   PetscCall(PetscDrawSave(draw));
1078   PetscFunctionReturn(PETSC_SUCCESS);
1079 }
1080 
1081 PetscErrorCode MatView_SeqAIJ(Mat A, PetscViewer viewer)
1082 {
1083   PetscBool iascii, isbinary, isdraw;
1084 
1085   PetscFunctionBegin;
1086   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii));
1087   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
1088   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
1089   if (iascii) PetscCall(MatView_SeqAIJ_ASCII(A, viewer));
1090   else if (isbinary) PetscCall(MatView_SeqAIJ_Binary(A, viewer));
1091   else if (isdraw) PetscCall(MatView_SeqAIJ_Draw(A, viewer));
1092   PetscCall(MatView_SeqAIJ_Inode(A, viewer));
1093   PetscFunctionReturn(PETSC_SUCCESS);
1094 }
1095 
1096 PetscErrorCode MatAssemblyEnd_SeqAIJ(Mat A, MatAssemblyType mode)
1097 {
1098   Mat_SeqAIJ *a      = (Mat_SeqAIJ *)A->data;
1099   PetscInt    fshift = 0, i, *ai = a->i, *aj = a->j, *imax = a->imax;
1100   PetscInt    m = A->rmap->n, *ip, N, *ailen = a->ilen, rmax = 0, n;
1101   MatScalar  *aa    = a->a, *ap;
1102   PetscReal   ratio = 0.6;
1103 
1104   PetscFunctionBegin;
1105   if (mode == MAT_FLUSH_ASSEMBLY) PetscFunctionReturn(PETSC_SUCCESS);
1106   PetscCall(MatSeqAIJInvalidateDiagonal(A));
1107   if (A->was_assembled && A->ass_nonzerostate == A->nonzerostate) {
1108     /* we need to respect users asking to use or not the inodes routine in between matrix assemblies */
1109     PetscCall(MatAssemblyEnd_SeqAIJ_Inode(A, mode));
1110     PetscFunctionReturn(PETSC_SUCCESS);
1111   }
1112 
1113   if (m) rmax = ailen[0]; /* determine row with most nonzeros */
1114   for (i = 1; i < m; i++) {
1115     /* move each row back by the amount of empty slots (fshift) before it*/
1116     fshift += imax[i - 1] - ailen[i - 1];
1117     rmax = PetscMax(rmax, ailen[i]);
1118     if (fshift) {
1119       ip = aj + ai[i];
1120       ap = aa + ai[i];
1121       N  = ailen[i];
1122       PetscCall(PetscArraymove(ip - fshift, ip, N));
1123       if (!A->structure_only) PetscCall(PetscArraymove(ap - fshift, ap, N));
1124     }
1125     ai[i] = ai[i - 1] + ailen[i - 1];
1126   }
1127   if (m) {
1128     fshift += imax[m - 1] - ailen[m - 1];
1129     ai[m] = ai[m - 1] + ailen[m - 1];
1130   }
1131   /* reset ilen and imax for each row */
1132   a->nonzerorowcnt = 0;
1133   if (A->structure_only) {
1134     PetscCall(PetscFree(a->imax));
1135     PetscCall(PetscFree(a->ilen));
1136   } else { /* !A->structure_only */
1137     for (i = 0; i < m; i++) {
1138       ailen[i] = imax[i] = ai[i + 1] - ai[i];
1139       a->nonzerorowcnt += ((ai[i + 1] - ai[i]) > 0);
1140     }
1141   }
1142   a->nz = ai[m];
1143   PetscCheck(!fshift || a->nounused != -1, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Unused space detected in matrix: %" PetscInt_FMT " X %" PetscInt_FMT ", %" PetscInt_FMT " unneeded", m, A->cmap->n, fshift);
1144   PetscCall(MatMarkDiagonal_SeqAIJ(A)); // since diagonal info is used a lot, it is helpful to set them up at the end of assembly
1145   a->diagonaldense = PETSC_TRUE;
1146   n                = PetscMin(A->rmap->n, A->cmap->n);
1147   for (i = 0; i < n; i++) {
1148     if (a->diag[i] >= ai[i + 1]) {
1149       a->diagonaldense = PETSC_FALSE;
1150       break;
1151     }
1152   }
1153   PetscCall(PetscInfo(A, "Matrix size: %" PetscInt_FMT " X %" PetscInt_FMT "; storage space: %" PetscInt_FMT " unneeded,%" PetscInt_FMT " used\n", m, A->cmap->n, fshift, a->nz));
1154   PetscCall(PetscInfo(A, "Number of mallocs during MatSetValues() is %" PetscInt_FMT "\n", a->reallocs));
1155   PetscCall(PetscInfo(A, "Maximum nonzeros in any row is %" PetscInt_FMT "\n", rmax));
1156 
1157   A->info.mallocs += a->reallocs;
1158   a->reallocs         = 0;
1159   A->info.nz_unneeded = (PetscReal)fshift;
1160   a->rmax             = rmax;
1161 
1162   if (!A->structure_only) PetscCall(MatCheckCompressedRow(A, a->nonzerorowcnt, &a->compressedrow, a->i, m, ratio));
1163   PetscCall(MatAssemblyEnd_SeqAIJ_Inode(A, mode));
1164   PetscFunctionReturn(PETSC_SUCCESS);
1165 }
1166 
1167 static PetscErrorCode MatRealPart_SeqAIJ(Mat A)
1168 {
1169   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
1170   PetscInt    i, nz = a->nz;
1171   MatScalar  *aa;
1172 
1173   PetscFunctionBegin;
1174   PetscCall(MatSeqAIJGetArray(A, &aa));
1175   for (i = 0; i < nz; i++) aa[i] = PetscRealPart(aa[i]);
1176   PetscCall(MatSeqAIJRestoreArray(A, &aa));
1177   PetscCall(MatSeqAIJInvalidateDiagonal(A));
1178   PetscFunctionReturn(PETSC_SUCCESS);
1179 }
1180 
1181 static PetscErrorCode MatImaginaryPart_SeqAIJ(Mat A)
1182 {
1183   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
1184   PetscInt    i, nz = a->nz;
1185   MatScalar  *aa;
1186 
1187   PetscFunctionBegin;
1188   PetscCall(MatSeqAIJGetArray(A, &aa));
1189   for (i = 0; i < nz; i++) aa[i] = PetscImaginaryPart(aa[i]);
1190   PetscCall(MatSeqAIJRestoreArray(A, &aa));
1191   PetscCall(MatSeqAIJInvalidateDiagonal(A));
1192   PetscFunctionReturn(PETSC_SUCCESS);
1193 }
1194 
1195 PetscErrorCode MatZeroEntries_SeqAIJ(Mat A)
1196 {
1197   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
1198   MatScalar  *aa;
1199 
1200   PetscFunctionBegin;
1201   PetscCall(MatSeqAIJGetArrayWrite(A, &aa));
1202   PetscCall(PetscArrayzero(aa, a->i[A->rmap->n]));
1203   PetscCall(MatSeqAIJRestoreArrayWrite(A, &aa));
1204   PetscCall(MatSeqAIJInvalidateDiagonal(A));
1205   PetscFunctionReturn(PETSC_SUCCESS);
1206 }
1207 
1208 static PetscErrorCode MatReset_SeqAIJ(Mat A)
1209 {
1210   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
1211 
1212   PetscFunctionBegin;
1213   if (A->hash_active) {
1214     A->ops[0] = a->cops;
1215     PetscCall(PetscHMapIJVDestroy(&a->ht));
1216     PetscCall(PetscFree(a->dnz));
1217     A->hash_active = PETSC_FALSE;
1218   }
1219 
1220   PetscCall(PetscLogObjectState((PetscObject)A, "Rows=%" PetscInt_FMT ", Cols=%" PetscInt_FMT ", NZ=%" PetscInt_FMT, A->rmap->n, A->cmap->n, a->nz));
1221   PetscCall(MatSeqXAIJFreeAIJ(A, &a->a, &a->j, &a->i));
1222   PetscCall(ISDestroy(&a->row));
1223   PetscCall(ISDestroy(&a->col));
1224   PetscCall(PetscFree(a->diag));
1225   PetscCall(PetscFree(a->ibdiag));
1226   PetscCall(PetscFree(a->imax));
1227   PetscCall(PetscFree(a->ilen));
1228   PetscCall(PetscFree(a->ipre));
1229   PetscCall(PetscFree3(a->idiag, a->mdiag, a->ssor_work));
1230   PetscCall(PetscFree(a->solve_work));
1231   PetscCall(ISDestroy(&a->icol));
1232   PetscCall(PetscFree(a->saved_values));
1233   PetscCall(PetscFree2(a->compressedrow.i, a->compressedrow.rindex));
1234   PetscCall(MatDestroy_SeqAIJ_Inode(A));
1235   PetscFunctionReturn(PETSC_SUCCESS);
1236 }
1237 
1238 static PetscErrorCode MatResetHash_SeqAIJ(Mat A)
1239 {
1240   PetscFunctionBegin;
1241   PetscCall(MatReset_SeqAIJ(A));
1242   PetscCall(MatCreate_SeqAIJ_Inode(A));
1243   PetscCall(MatSetUp_Seq_Hash(A));
1244   A->nonzerostate++;
1245   PetscFunctionReturn(PETSC_SUCCESS);
1246 }
1247 
1248 PetscErrorCode MatDestroy_SeqAIJ(Mat A)
1249 {
1250   PetscFunctionBegin;
1251   PetscCall(MatReset_SeqAIJ(A));
1252   PetscCall(PetscFree(A->data));
1253 
1254   /* MatMatMultNumeric_SeqAIJ_SeqAIJ_Sorted may allocate this.
1255      That function is so heavily used (sometimes in an hidden way through multnumeric function pointers)
1256      that is hard to properly add this data to the MatProduct data. We free it here to avoid
1257      users reusing the matrix object with different data to incur in obscure segmentation faults
1258      due to different matrix sizes */
1259   PetscCall(PetscObjectCompose((PetscObject)A, "__PETSc__ab_dense", NULL));
1260 
1261   PetscCall(PetscObjectChangeTypeName((PetscObject)A, NULL));
1262   PetscCall(PetscObjectComposeFunction((PetscObject)A, "PetscMatlabEnginePut_C", NULL));
1263   PetscCall(PetscObjectComposeFunction((PetscObject)A, "PetscMatlabEngineGet_C", NULL));
1264   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatSeqAIJSetColumnIndices_C", NULL));
1265   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatStoreValues_C", NULL));
1266   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatRetrieveValues_C", NULL));
1267   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_seqsbaij_C", NULL));
1268   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_seqbaij_C", NULL));
1269   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_seqaijperm_C", NULL));
1270   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_seqaijsell_C", NULL));
1271 #if defined(PETSC_HAVE_MKL_SPARSE)
1272   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_seqaijmkl_C", NULL));
1273 #endif
1274 #if defined(PETSC_HAVE_CUDA)
1275   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_seqaijcusparse_C", NULL));
1276   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_seqaijcusparse_seqaij_C", NULL));
1277   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_seqaij_seqaijcusparse_C", NULL));
1278 #endif
1279 #if defined(PETSC_HAVE_HIP)
1280   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_seqaijhipsparse_C", NULL));
1281   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_seqaijhipsparse_seqaij_C", NULL));
1282   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_seqaij_seqaijhipsparse_C", NULL));
1283 #endif
1284 #if defined(PETSC_HAVE_KOKKOS_KERNELS)
1285   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_seqaijkokkos_C", NULL));
1286 #endif
1287   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_seqaijcrl_C", NULL));
1288 #if defined(PETSC_HAVE_ELEMENTAL)
1289   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_elemental_C", NULL));
1290 #endif
1291 #if defined(PETSC_HAVE_SCALAPACK)
1292   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_scalapack_C", NULL));
1293 #endif
1294 #if defined(PETSC_HAVE_HYPRE)
1295   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_hypre_C", NULL));
1296   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_transpose_seqaij_seqaij_C", NULL));
1297 #endif
1298   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_seqdense_C", NULL));
1299   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_seqsell_C", NULL));
1300   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_is_C", NULL));
1301   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatIsTranspose_C", NULL));
1302   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatIsHermitianTranspose_C", NULL));
1303   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatSeqAIJSetPreallocation_C", NULL));
1304   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatResetPreallocation_C", NULL));
1305   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatResetHash_C", NULL));
1306   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatSeqAIJSetPreallocationCSR_C", NULL));
1307   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatReorderForNonzeroDiagonal_C", NULL));
1308   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_is_seqaij_C", NULL));
1309   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_seqdense_seqaij_C", NULL));
1310   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_seqaij_seqaij_C", NULL));
1311   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatSeqAIJKron_C", NULL));
1312   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatSetPreallocationCOO_C", NULL));
1313   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatSetValuesCOO_C", NULL));
1314   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatFactorGetSolverType_C", NULL));
1315   /* these calls do not belong here: the subclasses Duplicate/Destroy are wrong */
1316   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaijsell_seqaij_C", NULL));
1317   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaijperm_seqaij_C", NULL));
1318   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_seqaij_seqaijviennacl_C", NULL));
1319   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_seqaijviennacl_seqdense_C", NULL));
1320   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_seqaijviennacl_seqaij_C", NULL));
1321   PetscFunctionReturn(PETSC_SUCCESS);
1322 }
1323 
1324 PetscErrorCode MatSetOption_SeqAIJ(Mat A, MatOption op, PetscBool flg)
1325 {
1326   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
1327 
1328   PetscFunctionBegin;
1329   switch (op) {
1330   case MAT_ROW_ORIENTED:
1331     a->roworiented = flg;
1332     break;
1333   case MAT_KEEP_NONZERO_PATTERN:
1334     a->keepnonzeropattern = flg;
1335     break;
1336   case MAT_NEW_NONZERO_LOCATIONS:
1337     a->nonew = (flg ? 0 : 1);
1338     break;
1339   case MAT_NEW_NONZERO_LOCATION_ERR:
1340     a->nonew = (flg ? -1 : 0);
1341     break;
1342   case MAT_NEW_NONZERO_ALLOCATION_ERR:
1343     a->nonew = (flg ? -2 : 0);
1344     break;
1345   case MAT_UNUSED_NONZERO_LOCATION_ERR:
1346     a->nounused = (flg ? -1 : 0);
1347     break;
1348   case MAT_IGNORE_ZERO_ENTRIES:
1349     a->ignorezeroentries = flg;
1350     break;
1351   case MAT_USE_INODES:
1352     PetscCall(MatSetOption_SeqAIJ_Inode(A, MAT_USE_INODES, flg));
1353     break;
1354   case MAT_SUBMAT_SINGLEIS:
1355     A->submat_singleis = flg;
1356     break;
1357   case MAT_SORTED_FULL:
1358     if (flg) A->ops->setvalues = MatSetValues_SeqAIJ_SortedFull;
1359     else A->ops->setvalues = MatSetValues_SeqAIJ;
1360     break;
1361   case MAT_FORM_EXPLICIT_TRANSPOSE:
1362     A->form_explicit_transpose = flg;
1363     break;
1364   default:
1365     break;
1366   }
1367   PetscFunctionReturn(PETSC_SUCCESS);
1368 }
1369 
1370 static PetscErrorCode MatGetDiagonal_SeqAIJ(Mat A, Vec v)
1371 {
1372   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
1373   PetscInt           i, j, n, *ai = a->i, *aj = a->j;
1374   PetscScalar       *x;
1375   const PetscScalar *aa;
1376 
1377   PetscFunctionBegin;
1378   PetscCall(VecGetLocalSize(v, &n));
1379   PetscCheck(n == A->rmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Nonconforming matrix and vector");
1380   PetscCall(MatSeqAIJGetArrayRead(A, &aa));
1381   if (A->factortype == MAT_FACTOR_ILU || A->factortype == MAT_FACTOR_LU) {
1382     PetscInt *diag = a->diag;
1383     PetscCall(VecGetArrayWrite(v, &x));
1384     for (i = 0; i < n; i++) x[i] = 1.0 / aa[diag[i]];
1385     PetscCall(VecRestoreArrayWrite(v, &x));
1386     PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
1387     PetscFunctionReturn(PETSC_SUCCESS);
1388   }
1389 
1390   PetscCall(VecGetArrayWrite(v, &x));
1391   for (i = 0; i < n; i++) {
1392     x[i] = 0.0;
1393     for (j = ai[i]; j < ai[i + 1]; j++) {
1394       if (aj[j] == i) {
1395         x[i] = aa[j];
1396         break;
1397       }
1398     }
1399   }
1400   PetscCall(VecRestoreArrayWrite(v, &x));
1401   PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
1402   PetscFunctionReturn(PETSC_SUCCESS);
1403 }
1404 
1405 #include <../src/mat/impls/aij/seq/ftn-kernels/fmult.h>
1406 PetscErrorCode MatMultTransposeAdd_SeqAIJ(Mat A, Vec xx, Vec zz, Vec yy)
1407 {
1408   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
1409   const MatScalar   *aa;
1410   PetscScalar       *y;
1411   const PetscScalar *x;
1412   PetscInt           m = A->rmap->n;
1413 #if !defined(PETSC_USE_FORTRAN_KERNEL_MULTTRANSPOSEAIJ)
1414   const MatScalar  *v;
1415   PetscScalar       alpha;
1416   PetscInt          n, i, j;
1417   const PetscInt   *idx, *ii, *ridx = NULL;
1418   Mat_CompressedRow cprow    = a->compressedrow;
1419   PetscBool         usecprow = cprow.use;
1420 #endif
1421 
1422   PetscFunctionBegin;
1423   if (zz != yy) PetscCall(VecCopy(zz, yy));
1424   PetscCall(VecGetArrayRead(xx, &x));
1425   PetscCall(VecGetArray(yy, &y));
1426   PetscCall(MatSeqAIJGetArrayRead(A, &aa));
1427 
1428 #if defined(PETSC_USE_FORTRAN_KERNEL_MULTTRANSPOSEAIJ)
1429   fortranmulttransposeaddaij_(&m, x, a->i, a->j, aa, y);
1430 #else
1431   if (usecprow) {
1432     m    = cprow.nrows;
1433     ii   = cprow.i;
1434     ridx = cprow.rindex;
1435   } else {
1436     ii = a->i;
1437   }
1438   for (i = 0; i < m; i++) {
1439     idx = a->j + ii[i];
1440     v   = aa + ii[i];
1441     n   = ii[i + 1] - ii[i];
1442     if (usecprow) {
1443       alpha = x[ridx[i]];
1444     } else {
1445       alpha = x[i];
1446     }
1447     for (j = 0; j < n; j++) y[idx[j]] += alpha * v[j];
1448   }
1449 #endif
1450   PetscCall(PetscLogFlops(2.0 * a->nz));
1451   PetscCall(VecRestoreArrayRead(xx, &x));
1452   PetscCall(VecRestoreArray(yy, &y));
1453   PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
1454   PetscFunctionReturn(PETSC_SUCCESS);
1455 }
1456 
1457 PetscErrorCode MatMultTranspose_SeqAIJ(Mat A, Vec xx, Vec yy)
1458 {
1459   PetscFunctionBegin;
1460   PetscCall(VecSet(yy, 0.0));
1461   PetscCall(MatMultTransposeAdd_SeqAIJ(A, xx, yy, yy));
1462   PetscFunctionReturn(PETSC_SUCCESS);
1463 }
1464 
1465 #include <../src/mat/impls/aij/seq/ftn-kernels/fmult.h>
1466 
1467 PetscErrorCode MatMult_SeqAIJ(Mat A, Vec xx, Vec yy)
1468 {
1469   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
1470   PetscScalar       *y;
1471   const PetscScalar *x;
1472   const MatScalar   *a_a;
1473   PetscInt           m = A->rmap->n;
1474   const PetscInt    *ii, *ridx = NULL;
1475   PetscBool          usecprow = a->compressedrow.use;
1476 
1477 #if defined(PETSC_HAVE_PRAGMA_DISJOINT)
1478   #pragma disjoint(*x, *y, *aa)
1479 #endif
1480 
1481   PetscFunctionBegin;
1482   if (a->inode.use && a->inode.checked) {
1483     PetscCall(MatMult_SeqAIJ_Inode(A, xx, yy));
1484     PetscFunctionReturn(PETSC_SUCCESS);
1485   }
1486   PetscCall(MatSeqAIJGetArrayRead(A, &a_a));
1487   PetscCall(VecGetArrayRead(xx, &x));
1488   PetscCall(VecGetArray(yy, &y));
1489   ii = a->i;
1490   if (usecprow) { /* use compressed row format */
1491     PetscCall(PetscArrayzero(y, m));
1492     m    = a->compressedrow.nrows;
1493     ii   = a->compressedrow.i;
1494     ridx = a->compressedrow.rindex;
1495     PetscPragmaUseOMPKernels(parallel for)
1496     for (PetscInt i = 0; i < m; i++) {
1497       PetscInt           n   = ii[i + 1] - ii[i];
1498       const PetscInt    *aj  = a->j + ii[i];
1499       const PetscScalar *aa  = a_a + ii[i];
1500       PetscScalar        sum = 0.0;
1501       PetscSparseDensePlusDot(sum, x, aa, aj, n);
1502       /* for (j=0; j<n; j++) sum += (*aa++)*x[*aj++]; */
1503       y[*ridx++] = sum;
1504     }
1505   } else { /* do not use compressed row format */
1506 #if defined(PETSC_USE_FORTRAN_KERNEL_MULTAIJ)
1507     fortranmultaij_(&m, x, ii, a->j, a_a, y);
1508 #else
1509     PetscPragmaUseOMPKernels(parallel for)
1510     for (PetscInt i = 0; i < m; i++) {
1511       PetscInt           n   = ii[i + 1] - ii[i];
1512       const PetscInt    *aj  = a->j + ii[i];
1513       const PetscScalar *aa  = a_a + ii[i];
1514       PetscScalar        sum = 0.0;
1515       PetscSparseDensePlusDot(sum, x, aa, aj, n);
1516       y[i] = sum;
1517     }
1518 #endif
1519   }
1520   PetscCall(PetscLogFlops(2.0 * a->nz - a->nonzerorowcnt));
1521   PetscCall(VecRestoreArrayRead(xx, &x));
1522   PetscCall(VecRestoreArray(yy, &y));
1523   PetscCall(MatSeqAIJRestoreArrayRead(A, &a_a));
1524   PetscFunctionReturn(PETSC_SUCCESS);
1525 }
1526 
1527 // HACK!!!!! Used by src/mat/tests/ex170.c
1528 PETSC_EXTERN PetscErrorCode MatMultMax_SeqAIJ(Mat A, Vec xx, Vec yy)
1529 {
1530   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
1531   PetscScalar       *y;
1532   const PetscScalar *x;
1533   const MatScalar   *aa, *a_a;
1534   PetscInt           m = A->rmap->n;
1535   const PetscInt    *aj, *ii, *ridx   = NULL;
1536   PetscInt           n, i, nonzerorow = 0;
1537   PetscScalar        sum;
1538   PetscBool          usecprow = a->compressedrow.use;
1539 
1540 #if defined(PETSC_HAVE_PRAGMA_DISJOINT)
1541   #pragma disjoint(*x, *y, *aa)
1542 #endif
1543 
1544   PetscFunctionBegin;
1545   PetscCall(MatSeqAIJGetArrayRead(A, &a_a));
1546   PetscCall(VecGetArrayRead(xx, &x));
1547   PetscCall(VecGetArray(yy, &y));
1548   if (usecprow) { /* use compressed row format */
1549     m    = a->compressedrow.nrows;
1550     ii   = a->compressedrow.i;
1551     ridx = a->compressedrow.rindex;
1552     for (i = 0; i < m; i++) {
1553       n   = ii[i + 1] - ii[i];
1554       aj  = a->j + ii[i];
1555       aa  = a_a + ii[i];
1556       sum = 0.0;
1557       nonzerorow += (n > 0);
1558       PetscSparseDenseMaxDot(sum, x, aa, aj, n);
1559       /* for (j=0; j<n; j++) sum += (*aa++)*x[*aj++]; */
1560       y[*ridx++] = sum;
1561     }
1562   } else { /* do not use compressed row format */
1563     ii = a->i;
1564     for (i = 0; i < m; i++) {
1565       n   = ii[i + 1] - ii[i];
1566       aj  = a->j + ii[i];
1567       aa  = a_a + ii[i];
1568       sum = 0.0;
1569       nonzerorow += (n > 0);
1570       PetscSparseDenseMaxDot(sum, x, aa, aj, n);
1571       y[i] = sum;
1572     }
1573   }
1574   PetscCall(PetscLogFlops(2.0 * a->nz - nonzerorow));
1575   PetscCall(VecRestoreArrayRead(xx, &x));
1576   PetscCall(VecRestoreArray(yy, &y));
1577   PetscCall(MatSeqAIJRestoreArrayRead(A, &a_a));
1578   PetscFunctionReturn(PETSC_SUCCESS);
1579 }
1580 
1581 // HACK!!!!! Used by src/mat/tests/ex170.c
1582 PETSC_EXTERN PetscErrorCode MatMultAddMax_SeqAIJ(Mat A, Vec xx, Vec yy, Vec zz)
1583 {
1584   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
1585   PetscScalar       *y, *z;
1586   const PetscScalar *x;
1587   const MatScalar   *aa, *a_a;
1588   PetscInt           m = A->rmap->n, *aj, *ii;
1589   PetscInt           n, i, *ridx = NULL;
1590   PetscScalar        sum;
1591   PetscBool          usecprow = a->compressedrow.use;
1592 
1593   PetscFunctionBegin;
1594   PetscCall(MatSeqAIJGetArrayRead(A, &a_a));
1595   PetscCall(VecGetArrayRead(xx, &x));
1596   PetscCall(VecGetArrayPair(yy, zz, &y, &z));
1597   if (usecprow) { /* use compressed row format */
1598     if (zz != yy) PetscCall(PetscArraycpy(z, y, m));
1599     m    = a->compressedrow.nrows;
1600     ii   = a->compressedrow.i;
1601     ridx = a->compressedrow.rindex;
1602     for (i = 0; i < m; i++) {
1603       n   = ii[i + 1] - ii[i];
1604       aj  = a->j + ii[i];
1605       aa  = a_a + ii[i];
1606       sum = y[*ridx];
1607       PetscSparseDenseMaxDot(sum, x, aa, aj, n);
1608       z[*ridx++] = sum;
1609     }
1610   } else { /* do not use compressed row format */
1611     ii = a->i;
1612     for (i = 0; i < m; i++) {
1613       n   = ii[i + 1] - ii[i];
1614       aj  = a->j + ii[i];
1615       aa  = a_a + ii[i];
1616       sum = y[i];
1617       PetscSparseDenseMaxDot(sum, x, aa, aj, n);
1618       z[i] = sum;
1619     }
1620   }
1621   PetscCall(PetscLogFlops(2.0 * a->nz));
1622   PetscCall(VecRestoreArrayRead(xx, &x));
1623   PetscCall(VecRestoreArrayPair(yy, zz, &y, &z));
1624   PetscCall(MatSeqAIJRestoreArrayRead(A, &a_a));
1625   PetscFunctionReturn(PETSC_SUCCESS);
1626 }
1627 
1628 #include <../src/mat/impls/aij/seq/ftn-kernels/fmultadd.h>
1629 PetscErrorCode MatMultAdd_SeqAIJ(Mat A, Vec xx, Vec yy, Vec zz)
1630 {
1631   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
1632   PetscScalar       *y, *z;
1633   const PetscScalar *x;
1634   const MatScalar   *a_a;
1635   const PetscInt    *ii, *ridx = NULL;
1636   PetscInt           m        = A->rmap->n;
1637   PetscBool          usecprow = a->compressedrow.use;
1638 
1639   PetscFunctionBegin;
1640   if (a->inode.use && a->inode.checked) {
1641     PetscCall(MatMultAdd_SeqAIJ_Inode(A, xx, yy, zz));
1642     PetscFunctionReturn(PETSC_SUCCESS);
1643   }
1644   PetscCall(MatSeqAIJGetArrayRead(A, &a_a));
1645   PetscCall(VecGetArrayRead(xx, &x));
1646   PetscCall(VecGetArrayPair(yy, zz, &y, &z));
1647   if (usecprow) { /* use compressed row format */
1648     if (zz != yy) PetscCall(PetscArraycpy(z, y, m));
1649     m    = a->compressedrow.nrows;
1650     ii   = a->compressedrow.i;
1651     ridx = a->compressedrow.rindex;
1652     for (PetscInt i = 0; i < m; i++) {
1653       PetscInt           n   = ii[i + 1] - ii[i];
1654       const PetscInt    *aj  = a->j + ii[i];
1655       const PetscScalar *aa  = a_a + ii[i];
1656       PetscScalar        sum = y[*ridx];
1657       PetscSparseDensePlusDot(sum, x, aa, aj, n);
1658       z[*ridx++] = sum;
1659     }
1660   } else { /* do not use compressed row format */
1661     ii = a->i;
1662 #if defined(PETSC_USE_FORTRAN_KERNEL_MULTADDAIJ)
1663     fortranmultaddaij_(&m, x, ii, a->j, a_a, y, z);
1664 #else
1665     PetscPragmaUseOMPKernels(parallel for)
1666     for (PetscInt i = 0; i < m; i++) {
1667       PetscInt           n   = ii[i + 1] - ii[i];
1668       const PetscInt    *aj  = a->j + ii[i];
1669       const PetscScalar *aa  = a_a + ii[i];
1670       PetscScalar        sum = y[i];
1671       PetscSparseDensePlusDot(sum, x, aa, aj, n);
1672       z[i] = sum;
1673     }
1674 #endif
1675   }
1676   PetscCall(PetscLogFlops(2.0 * a->nz));
1677   PetscCall(VecRestoreArrayRead(xx, &x));
1678   PetscCall(VecRestoreArrayPair(yy, zz, &y, &z));
1679   PetscCall(MatSeqAIJRestoreArrayRead(A, &a_a));
1680   PetscFunctionReturn(PETSC_SUCCESS);
1681 }
1682 
1683 /*
1684      Adds diagonal pointers to sparse matrix nonzero structure.
1685 */
1686 PetscErrorCode MatMarkDiagonal_SeqAIJ(Mat A)
1687 {
1688   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
1689   PetscInt    i, j, m = A->rmap->n;
1690   PetscBool   alreadySet = PETSC_TRUE;
1691 
1692   PetscFunctionBegin;
1693   if (!a->diag) {
1694     PetscCall(PetscMalloc1(m, &a->diag));
1695     alreadySet = PETSC_FALSE;
1696   }
1697   for (i = 0; i < A->rmap->n; i++) {
1698     /* If A's diagonal is already correctly set, this fast track enables cheap and repeated MatMarkDiagonal_SeqAIJ() calls */
1699     if (alreadySet) {
1700       PetscInt pos = a->diag[i];
1701       if (pos >= a->i[i] && pos < a->i[i + 1] && a->j[pos] == i) continue;
1702     }
1703 
1704     a->diag[i] = a->i[i + 1];
1705     for (j = a->i[i]; j < a->i[i + 1]; j++) {
1706       if (a->j[j] == i) {
1707         a->diag[i] = j;
1708         break;
1709       }
1710     }
1711   }
1712   PetscFunctionReturn(PETSC_SUCCESS);
1713 }
1714 
1715 static PetscErrorCode MatShift_SeqAIJ(Mat A, PetscScalar v)
1716 {
1717   Mat_SeqAIJ     *a    = (Mat_SeqAIJ *)A->data;
1718   const PetscInt *diag = (const PetscInt *)a->diag;
1719   const PetscInt *ii   = (const PetscInt *)a->i;
1720   PetscInt        i, *mdiag = NULL;
1721   PetscInt        cnt = 0; /* how many diagonals are missing */
1722 
1723   PetscFunctionBegin;
1724   if (!A->preallocated || !a->nz) {
1725     PetscCall(MatSeqAIJSetPreallocation(A, 1, NULL));
1726     PetscCall(MatShift_Basic(A, v));
1727     PetscFunctionReturn(PETSC_SUCCESS);
1728   }
1729 
1730   if (a->diagonaldense) {
1731     cnt = 0;
1732   } else {
1733     PetscCall(PetscCalloc1(A->rmap->n, &mdiag));
1734     for (i = 0; i < A->rmap->n; i++) {
1735       if (i < A->cmap->n && diag[i] >= ii[i + 1]) { /* 'out of range' rows never have diagonals */
1736         cnt++;
1737         mdiag[i] = 1;
1738       }
1739     }
1740   }
1741   if (!cnt) {
1742     PetscCall(MatShift_Basic(A, v));
1743   } else {
1744     PetscScalar       *olda = a->a; /* preserve pointers to current matrix nonzeros structure and values */
1745     PetscInt          *oldj = a->j, *oldi = a->i;
1746     PetscBool          free_a = a->free_a, free_ij = a->free_ij;
1747     const PetscScalar *Aa;
1748 
1749     PetscCall(MatSeqAIJGetArrayRead(A, &Aa)); // sync the host
1750     PetscCall(MatSeqAIJRestoreArrayRead(A, &Aa));
1751 
1752     a->a = NULL;
1753     a->j = NULL;
1754     a->i = NULL;
1755     /* increase the values in imax for each row where a diagonal is being inserted then reallocate the matrix data structures */
1756     for (i = 0; i < PetscMin(A->rmap->n, A->cmap->n); i++) a->imax[i] += mdiag[i];
1757     PetscCall(MatSeqAIJSetPreallocation_SeqAIJ(A, 0, a->imax));
1758 
1759     /* copy old values into new matrix data structure */
1760     for (i = 0; i < A->rmap->n; i++) {
1761       PetscCall(MatSetValues(A, 1, &i, a->imax[i] - mdiag[i], &oldj[oldi[i]], &olda[oldi[i]], ADD_VALUES));
1762       if (i < A->cmap->n) PetscCall(MatSetValue(A, i, i, v, ADD_VALUES));
1763     }
1764     PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
1765     PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
1766     if (free_a) PetscCall(PetscShmgetDeallocateArray((void **)&olda));
1767     if (free_ij) PetscCall(PetscShmgetDeallocateArray((void **)&oldj));
1768     if (free_ij) PetscCall(PetscShmgetDeallocateArray((void **)&oldi));
1769   }
1770   PetscCall(PetscFree(mdiag));
1771   a->diagonaldense = PETSC_TRUE;
1772   PetscFunctionReturn(PETSC_SUCCESS);
1773 }
1774 
1775 /*
1776      Checks for missing diagonals
1777 */
1778 PetscErrorCode MatMissingDiagonal_SeqAIJ(Mat A, PetscBool *missing, PetscInt *d)
1779 {
1780   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
1781   PetscInt   *diag, *ii = a->i, i;
1782 
1783   PetscFunctionBegin;
1784   *missing = PETSC_FALSE;
1785   if (A->rmap->n > 0 && !ii) {
1786     *missing = PETSC_TRUE;
1787     if (d) *d = 0;
1788     PetscCall(PetscInfo(A, "Matrix has no entries therefore is missing diagonal\n"));
1789   } else {
1790     PetscInt n;
1791     n    = PetscMin(A->rmap->n, A->cmap->n);
1792     diag = a->diag;
1793     for (i = 0; i < n; i++) {
1794       if (diag[i] >= ii[i + 1]) {
1795         *missing = PETSC_TRUE;
1796         if (d) *d = i;
1797         PetscCall(PetscInfo(A, "Matrix is missing diagonal number %" PetscInt_FMT "\n", i));
1798         break;
1799       }
1800     }
1801   }
1802   PetscFunctionReturn(PETSC_SUCCESS);
1803 }
1804 
1805 #include <petscblaslapack.h>
1806 #include <petsc/private/kernels/blockinvert.h>
1807 
1808 /*
1809     Note that values is allocated externally by the PC and then passed into this routine
1810 */
1811 static PetscErrorCode MatInvertVariableBlockDiagonal_SeqAIJ(Mat A, PetscInt nblocks, const PetscInt *bsizes, PetscScalar *diag)
1812 {
1813   PetscInt        n = A->rmap->n, i, ncnt = 0, *indx, j, bsizemax = 0, *v_pivots;
1814   PetscBool       allowzeropivot, zeropivotdetected = PETSC_FALSE;
1815   const PetscReal shift = 0.0;
1816   PetscInt        ipvt[5];
1817   PetscCount      flops = 0;
1818   PetscScalar     work[25], *v_work;
1819 
1820   PetscFunctionBegin;
1821   allowzeropivot = PetscNot(A->erroriffailure);
1822   for (i = 0; i < nblocks; i++) ncnt += bsizes[i];
1823   PetscCheck(ncnt == n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Total blocksizes %" PetscInt_FMT " doesn't match number matrix rows %" PetscInt_FMT, ncnt, n);
1824   for (i = 0; i < nblocks; i++) bsizemax = PetscMax(bsizemax, bsizes[i]);
1825   PetscCall(PetscMalloc1(bsizemax, &indx));
1826   if (bsizemax > 7) PetscCall(PetscMalloc2(bsizemax, &v_work, bsizemax, &v_pivots));
1827   ncnt = 0;
1828   for (i = 0; i < nblocks; i++) {
1829     for (j = 0; j < bsizes[i]; j++) indx[j] = ncnt + j;
1830     PetscCall(MatGetValues(A, bsizes[i], indx, bsizes[i], indx, diag));
1831     switch (bsizes[i]) {
1832     case 1:
1833       *diag = 1.0 / (*diag);
1834       break;
1835     case 2:
1836       PetscCall(PetscKernel_A_gets_inverse_A_2(diag, shift, allowzeropivot, &zeropivotdetected));
1837       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
1838       PetscCall(PetscKernel_A_gets_transpose_A_2(diag));
1839       break;
1840     case 3:
1841       PetscCall(PetscKernel_A_gets_inverse_A_3(diag, shift, allowzeropivot, &zeropivotdetected));
1842       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
1843       PetscCall(PetscKernel_A_gets_transpose_A_3(diag));
1844       break;
1845     case 4:
1846       PetscCall(PetscKernel_A_gets_inverse_A_4(diag, shift, allowzeropivot, &zeropivotdetected));
1847       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
1848       PetscCall(PetscKernel_A_gets_transpose_A_4(diag));
1849       break;
1850     case 5:
1851       PetscCall(PetscKernel_A_gets_inverse_A_5(diag, ipvt, work, shift, allowzeropivot, &zeropivotdetected));
1852       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
1853       PetscCall(PetscKernel_A_gets_transpose_A_5(diag));
1854       break;
1855     case 6:
1856       PetscCall(PetscKernel_A_gets_inverse_A_6(diag, shift, allowzeropivot, &zeropivotdetected));
1857       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
1858       PetscCall(PetscKernel_A_gets_transpose_A_6(diag));
1859       break;
1860     case 7:
1861       PetscCall(PetscKernel_A_gets_inverse_A_7(diag, shift, allowzeropivot, &zeropivotdetected));
1862       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
1863       PetscCall(PetscKernel_A_gets_transpose_A_7(diag));
1864       break;
1865     default:
1866       PetscCall(PetscKernel_A_gets_inverse_A(bsizes[i], diag, v_pivots, v_work, allowzeropivot, &zeropivotdetected));
1867       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
1868       PetscCall(PetscKernel_A_gets_transpose_A_N(diag, bsizes[i]));
1869     }
1870     ncnt += bsizes[i];
1871     diag += bsizes[i] * bsizes[i];
1872     flops += 2 * PetscPowInt64(bsizes[i], 3) / 3;
1873   }
1874   PetscCall(PetscLogFlops(flops));
1875   if (bsizemax > 7) PetscCall(PetscFree2(v_work, v_pivots));
1876   PetscCall(PetscFree(indx));
1877   PetscFunctionReturn(PETSC_SUCCESS);
1878 }
1879 
1880 /*
1881    Negative shift indicates do not generate an error if there is a zero diagonal, just invert it anyways
1882 */
1883 static PetscErrorCode MatInvertDiagonal_SeqAIJ(Mat A, PetscScalar omega, PetscScalar fshift)
1884 {
1885   Mat_SeqAIJ      *a = (Mat_SeqAIJ *)A->data;
1886   PetscInt         i, *diag, m = A->rmap->n;
1887   const MatScalar *v;
1888   PetscScalar     *idiag, *mdiag;
1889 
1890   PetscFunctionBegin;
1891   if (a->idiagvalid) PetscFunctionReturn(PETSC_SUCCESS);
1892   PetscCall(MatMarkDiagonal_SeqAIJ(A));
1893   diag = a->diag;
1894   if (!a->idiag) { PetscCall(PetscMalloc3(m, &a->idiag, m, &a->mdiag, m, &a->ssor_work)); }
1895 
1896   mdiag = a->mdiag;
1897   idiag = a->idiag;
1898   PetscCall(MatSeqAIJGetArrayRead(A, &v));
1899   if (omega == 1.0 && PetscRealPart(fshift) <= 0.0) {
1900     for (i = 0; i < m; i++) {
1901       mdiag[i] = v[diag[i]];
1902       if (!PetscAbsScalar(mdiag[i])) { /* zero diagonal */
1903         if (PetscRealPart(fshift)) {
1904           PetscCall(PetscInfo(A, "Zero diagonal on row %" PetscInt_FMT "\n", i));
1905           A->factorerrortype             = MAT_FACTOR_NUMERIC_ZEROPIVOT;
1906           A->factorerror_zeropivot_value = 0.0;
1907           A->factorerror_zeropivot_row   = i;
1908         } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Zero diagonal on row %" PetscInt_FMT, i);
1909       }
1910       idiag[i] = 1.0 / v[diag[i]];
1911     }
1912     PetscCall(PetscLogFlops(m));
1913   } else {
1914     for (i = 0; i < m; i++) {
1915       mdiag[i] = v[diag[i]];
1916       idiag[i] = omega / (fshift + v[diag[i]]);
1917     }
1918     PetscCall(PetscLogFlops(2.0 * m));
1919   }
1920   a->idiagvalid = PETSC_TRUE;
1921   PetscCall(MatSeqAIJRestoreArrayRead(A, &v));
1922   PetscFunctionReturn(PETSC_SUCCESS);
1923 }
1924 
1925 PetscErrorCode MatSOR_SeqAIJ(Mat A, Vec bb, PetscReal omega, MatSORType flag, PetscReal fshift, PetscInt its, PetscInt lits, Vec xx)
1926 {
1927   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
1928   PetscScalar       *x, d, sum, *t, scale;
1929   const MatScalar   *v, *idiag = NULL, *mdiag, *aa;
1930   const PetscScalar *b, *bs, *xb, *ts;
1931   PetscInt           n, m = A->rmap->n, i;
1932   const PetscInt    *idx, *diag;
1933 
1934   PetscFunctionBegin;
1935   if (a->inode.use && a->inode.checked && omega == 1.0 && fshift == 0.0) {
1936     PetscCall(MatSOR_SeqAIJ_Inode(A, bb, omega, flag, fshift, its, lits, xx));
1937     PetscFunctionReturn(PETSC_SUCCESS);
1938   }
1939   its = its * lits;
1940 
1941   if (fshift != a->fshift || omega != a->omega) a->idiagvalid = PETSC_FALSE; /* must recompute idiag[] */
1942   if (!a->idiagvalid) PetscCall(MatInvertDiagonal_SeqAIJ(A, omega, fshift));
1943   a->fshift = fshift;
1944   a->omega  = omega;
1945 
1946   diag  = a->diag;
1947   t     = a->ssor_work;
1948   idiag = a->idiag;
1949   mdiag = a->mdiag;
1950 
1951   PetscCall(MatSeqAIJGetArrayRead(A, &aa));
1952   PetscCall(VecGetArray(xx, &x));
1953   PetscCall(VecGetArrayRead(bb, &b));
1954   /* We count flops by assuming the upper triangular and lower triangular parts have the same number of nonzeros */
1955   if (flag == SOR_APPLY_UPPER) {
1956     /* apply (U + D/omega) to the vector */
1957     bs = b;
1958     for (i = 0; i < m; i++) {
1959       d   = fshift + mdiag[i];
1960       n   = a->i[i + 1] - diag[i] - 1;
1961       idx = a->j + diag[i] + 1;
1962       v   = aa + diag[i] + 1;
1963       sum = b[i] * d / omega;
1964       PetscSparseDensePlusDot(sum, bs, v, idx, n);
1965       x[i] = sum;
1966     }
1967     PetscCall(VecRestoreArray(xx, &x));
1968     PetscCall(VecRestoreArrayRead(bb, &b));
1969     PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
1970     PetscCall(PetscLogFlops(a->nz));
1971     PetscFunctionReturn(PETSC_SUCCESS);
1972   }
1973 
1974   PetscCheck(flag != SOR_APPLY_LOWER, PETSC_COMM_SELF, PETSC_ERR_SUP, "SOR_APPLY_LOWER is not implemented");
1975   if (flag & SOR_EISENSTAT) {
1976     /* Let  A = L + U + D; where L is lower triangular,
1977     U is upper triangular, E = D/omega; This routine applies
1978 
1979             (L + E)^{-1} A (U + E)^{-1}
1980 
1981     to a vector efficiently using Eisenstat's trick.
1982     */
1983     scale = (2.0 / omega) - 1.0;
1984 
1985     /*  x = (E + U)^{-1} b */
1986     for (i = m - 1; i >= 0; i--) {
1987       n   = a->i[i + 1] - diag[i] - 1;
1988       idx = a->j + diag[i] + 1;
1989       v   = aa + diag[i] + 1;
1990       sum = b[i];
1991       PetscSparseDenseMinusDot(sum, x, v, idx, n);
1992       x[i] = sum * idiag[i];
1993     }
1994 
1995     /*  t = b - (2*E - D)x */
1996     v = aa;
1997     for (i = 0; i < m; i++) t[i] = b[i] - scale * (v[*diag++]) * x[i];
1998 
1999     /*  t = (E + L)^{-1}t */
2000     ts   = t;
2001     diag = a->diag;
2002     for (i = 0; i < m; i++) {
2003       n   = diag[i] - a->i[i];
2004       idx = a->j + a->i[i];
2005       v   = aa + a->i[i];
2006       sum = t[i];
2007       PetscSparseDenseMinusDot(sum, ts, v, idx, n);
2008       t[i] = sum * idiag[i];
2009       /*  x = x + t */
2010       x[i] += t[i];
2011     }
2012 
2013     PetscCall(PetscLogFlops(6.0 * m - 1 + 2.0 * a->nz));
2014     PetscCall(VecRestoreArray(xx, &x));
2015     PetscCall(VecRestoreArrayRead(bb, &b));
2016     PetscFunctionReturn(PETSC_SUCCESS);
2017   }
2018   if (flag & SOR_ZERO_INITIAL_GUESS) {
2019     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP) {
2020       for (i = 0; i < m; i++) {
2021         n   = diag[i] - a->i[i];
2022         idx = a->j + a->i[i];
2023         v   = aa + a->i[i];
2024         sum = b[i];
2025         PetscSparseDenseMinusDot(sum, x, v, idx, n);
2026         t[i] = sum;
2027         x[i] = sum * idiag[i];
2028       }
2029       xb = t;
2030       PetscCall(PetscLogFlops(a->nz));
2031     } else xb = b;
2032     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP) {
2033       for (i = m - 1; i >= 0; i--) {
2034         n   = a->i[i + 1] - diag[i] - 1;
2035         idx = a->j + diag[i] + 1;
2036         v   = aa + diag[i] + 1;
2037         sum = xb[i];
2038         PetscSparseDenseMinusDot(sum, x, v, idx, n);
2039         if (xb == b) {
2040           x[i] = sum * idiag[i];
2041         } else {
2042           x[i] = (1 - omega) * x[i] + sum * idiag[i]; /* omega in idiag */
2043         }
2044       }
2045       PetscCall(PetscLogFlops(a->nz)); /* assumes 1/2 in upper */
2046     }
2047     its--;
2048   }
2049   while (its--) {
2050     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP) {
2051       for (i = 0; i < m; i++) {
2052         /* lower */
2053         n   = diag[i] - a->i[i];
2054         idx = a->j + a->i[i];
2055         v   = aa + a->i[i];
2056         sum = b[i];
2057         PetscSparseDenseMinusDot(sum, x, v, idx, n);
2058         t[i] = sum; /* save application of the lower-triangular part */
2059         /* upper */
2060         n   = a->i[i + 1] - diag[i] - 1;
2061         idx = a->j + diag[i] + 1;
2062         v   = aa + diag[i] + 1;
2063         PetscSparseDenseMinusDot(sum, x, v, idx, n);
2064         x[i] = (1. - omega) * x[i] + sum * idiag[i]; /* omega in idiag */
2065       }
2066       xb = t;
2067       PetscCall(PetscLogFlops(2.0 * a->nz));
2068     } else xb = b;
2069     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP) {
2070       for (i = m - 1; i >= 0; i--) {
2071         sum = xb[i];
2072         if (xb == b) {
2073           /* whole matrix (no checkpointing available) */
2074           n   = a->i[i + 1] - a->i[i];
2075           idx = a->j + a->i[i];
2076           v   = aa + a->i[i];
2077           PetscSparseDenseMinusDot(sum, x, v, idx, n);
2078           x[i] = (1. - omega) * x[i] + (sum + mdiag[i] * x[i]) * idiag[i];
2079         } else { /* lower-triangular part has been saved, so only apply upper-triangular */
2080           n   = a->i[i + 1] - diag[i] - 1;
2081           idx = a->j + diag[i] + 1;
2082           v   = aa + diag[i] + 1;
2083           PetscSparseDenseMinusDot(sum, x, v, idx, n);
2084           x[i] = (1. - omega) * x[i] + sum * idiag[i]; /* omega in idiag */
2085         }
2086       }
2087       if (xb == b) {
2088         PetscCall(PetscLogFlops(2.0 * a->nz));
2089       } else {
2090         PetscCall(PetscLogFlops(a->nz)); /* assumes 1/2 in upper */
2091       }
2092     }
2093   }
2094   PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
2095   PetscCall(VecRestoreArray(xx, &x));
2096   PetscCall(VecRestoreArrayRead(bb, &b));
2097   PetscFunctionReturn(PETSC_SUCCESS);
2098 }
2099 
2100 static PetscErrorCode MatGetInfo_SeqAIJ(Mat A, MatInfoType flag, MatInfo *info)
2101 {
2102   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
2103 
2104   PetscFunctionBegin;
2105   info->block_size   = 1.0;
2106   info->nz_allocated = a->maxnz;
2107   info->nz_used      = a->nz;
2108   info->nz_unneeded  = (a->maxnz - a->nz);
2109   info->assemblies   = A->num_ass;
2110   info->mallocs      = A->info.mallocs;
2111   info->memory       = 0; /* REVIEW ME */
2112   if (A->factortype) {
2113     info->fill_ratio_given  = A->info.fill_ratio_given;
2114     info->fill_ratio_needed = A->info.fill_ratio_needed;
2115     info->factor_mallocs    = A->info.factor_mallocs;
2116   } else {
2117     info->fill_ratio_given  = 0;
2118     info->fill_ratio_needed = 0;
2119     info->factor_mallocs    = 0;
2120   }
2121   PetscFunctionReturn(PETSC_SUCCESS);
2122 }
2123 
2124 static PetscErrorCode MatZeroRows_SeqAIJ(Mat A, PetscInt N, const PetscInt rows[], PetscScalar diag, Vec x, Vec b)
2125 {
2126   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
2127   PetscInt           i, m = A->rmap->n - 1;
2128   const PetscScalar *xx;
2129   PetscScalar       *bb, *aa;
2130   PetscInt           d = 0;
2131 
2132   PetscFunctionBegin;
2133   if (x && b) {
2134     PetscCall(VecGetArrayRead(x, &xx));
2135     PetscCall(VecGetArray(b, &bb));
2136     for (i = 0; i < N; i++) {
2137       PetscCheck(rows[i] >= 0 && rows[i] <= m, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "row %" PetscInt_FMT " out of range", rows[i]);
2138       if (rows[i] >= A->cmap->n) continue;
2139       bb[rows[i]] = diag * xx[rows[i]];
2140     }
2141     PetscCall(VecRestoreArrayRead(x, &xx));
2142     PetscCall(VecRestoreArray(b, &bb));
2143   }
2144 
2145   PetscCall(MatSeqAIJGetArray(A, &aa));
2146   if (a->keepnonzeropattern) {
2147     for (i = 0; i < N; i++) {
2148       PetscCheck(rows[i] >= 0 && rows[i] <= m, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "row %" PetscInt_FMT " out of range", rows[i]);
2149       PetscCall(PetscArrayzero(&aa[a->i[rows[i]]], a->ilen[rows[i]]));
2150     }
2151     if (diag != 0.0) {
2152       for (i = 0; i < N; i++) {
2153         d = rows[i];
2154         if (rows[i] >= A->cmap->n) continue;
2155         PetscCheck(a->diag[d] < a->i[d + 1], PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Matrix is missing diagonal entry in the zeroed row %" PetscInt_FMT, d);
2156       }
2157       for (i = 0; i < N; i++) {
2158         if (rows[i] >= A->cmap->n) continue;
2159         aa[a->diag[rows[i]]] = diag;
2160       }
2161     }
2162   } else {
2163     if (diag != 0.0) {
2164       for (i = 0; i < N; i++) {
2165         PetscCheck(rows[i] >= 0 && rows[i] <= m, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "row %" PetscInt_FMT " out of range", rows[i]);
2166         if (a->ilen[rows[i]] > 0) {
2167           if (rows[i] >= A->cmap->n) {
2168             a->ilen[rows[i]] = 0;
2169           } else {
2170             a->ilen[rows[i]]    = 1;
2171             aa[a->i[rows[i]]]   = diag;
2172             a->j[a->i[rows[i]]] = rows[i];
2173           }
2174         } else if (rows[i] < A->cmap->n) { /* in case row was completely empty */
2175           PetscCall(MatSetValues_SeqAIJ(A, 1, &rows[i], 1, &rows[i], &diag, INSERT_VALUES));
2176         }
2177       }
2178     } else {
2179       for (i = 0; i < N; i++) {
2180         PetscCheck(rows[i] >= 0 && rows[i] <= m, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "row %" PetscInt_FMT " out of range", rows[i]);
2181         a->ilen[rows[i]] = 0;
2182       }
2183     }
2184     A->nonzerostate++;
2185   }
2186   PetscCall(MatSeqAIJRestoreArray(A, &aa));
2187   PetscUseTypeMethod(A, assemblyend, MAT_FINAL_ASSEMBLY);
2188   PetscFunctionReturn(PETSC_SUCCESS);
2189 }
2190 
2191 static PetscErrorCode MatZeroRowsColumns_SeqAIJ(Mat A, PetscInt N, const PetscInt rows[], PetscScalar diag, Vec x, Vec b)
2192 {
2193   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
2194   PetscInt           i, j, m = A->rmap->n - 1, d = 0;
2195   PetscBool          missing, *zeroed, vecs = PETSC_FALSE;
2196   const PetscScalar *xx;
2197   PetscScalar       *bb, *aa;
2198 
2199   PetscFunctionBegin;
2200   if (!N) PetscFunctionReturn(PETSC_SUCCESS);
2201   PetscCall(MatSeqAIJGetArray(A, &aa));
2202   if (x && b) {
2203     PetscCall(VecGetArrayRead(x, &xx));
2204     PetscCall(VecGetArray(b, &bb));
2205     vecs = PETSC_TRUE;
2206   }
2207   PetscCall(PetscCalloc1(A->rmap->n, &zeroed));
2208   for (i = 0; i < N; i++) {
2209     PetscCheck(rows[i] >= 0 && rows[i] <= m, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "row %" PetscInt_FMT " out of range", rows[i]);
2210     PetscCall(PetscArrayzero(PetscSafePointerPlusOffset(aa, a->i[rows[i]]), a->ilen[rows[i]]));
2211 
2212     zeroed[rows[i]] = PETSC_TRUE;
2213   }
2214   for (i = 0; i < A->rmap->n; i++) {
2215     if (!zeroed[i]) {
2216       for (j = a->i[i]; j < a->i[i + 1]; j++) {
2217         if (a->j[j] < A->rmap->n && zeroed[a->j[j]]) {
2218           if (vecs) bb[i] -= aa[j] * xx[a->j[j]];
2219           aa[j] = 0.0;
2220         }
2221       }
2222     } else if (vecs && i < A->cmap->N) bb[i] = diag * xx[i];
2223   }
2224   if (x && b) {
2225     PetscCall(VecRestoreArrayRead(x, &xx));
2226     PetscCall(VecRestoreArray(b, &bb));
2227   }
2228   PetscCall(PetscFree(zeroed));
2229   if (diag != 0.0) {
2230     PetscCall(MatMissingDiagonal_SeqAIJ(A, &missing, &d));
2231     if (missing) {
2232       for (i = 0; i < N; i++) {
2233         if (rows[i] >= A->cmap->N) continue;
2234         PetscCheck(!a->nonew || rows[i] < d, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Matrix is missing diagonal entry in row %" PetscInt_FMT " (%" PetscInt_FMT ")", d, rows[i]);
2235         PetscCall(MatSetValues_SeqAIJ(A, 1, &rows[i], 1, &rows[i], &diag, INSERT_VALUES));
2236       }
2237     } else {
2238       for (i = 0; i < N; i++) aa[a->diag[rows[i]]] = diag;
2239     }
2240   }
2241   PetscCall(MatSeqAIJRestoreArray(A, &aa));
2242   PetscUseTypeMethod(A, assemblyend, MAT_FINAL_ASSEMBLY);
2243   PetscFunctionReturn(PETSC_SUCCESS);
2244 }
2245 
2246 PetscErrorCode MatGetRow_SeqAIJ(Mat A, PetscInt row, PetscInt *nz, PetscInt **idx, PetscScalar **v)
2247 {
2248   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
2249   const PetscScalar *aa;
2250 
2251   PetscFunctionBegin;
2252   PetscCall(MatSeqAIJGetArrayRead(A, &aa));
2253   *nz = a->i[row + 1] - a->i[row];
2254   if (v) *v = PetscSafePointerPlusOffset((PetscScalar *)aa, a->i[row]);
2255   if (idx) {
2256     if (*nz && a->j) *idx = a->j + a->i[row];
2257     else *idx = NULL;
2258   }
2259   PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
2260   PetscFunctionReturn(PETSC_SUCCESS);
2261 }
2262 
2263 PetscErrorCode MatRestoreRow_SeqAIJ(Mat A, PetscInt row, PetscInt *nz, PetscInt **idx, PetscScalar **v)
2264 {
2265   PetscFunctionBegin;
2266   PetscFunctionReturn(PETSC_SUCCESS);
2267 }
2268 
2269 static PetscErrorCode MatNorm_SeqAIJ(Mat A, NormType type, PetscReal *nrm)
2270 {
2271   Mat_SeqAIJ      *a = (Mat_SeqAIJ *)A->data;
2272   const MatScalar *v;
2273   PetscReal        sum = 0.0;
2274   PetscInt         i, j;
2275 
2276   PetscFunctionBegin;
2277   PetscCall(MatSeqAIJGetArrayRead(A, &v));
2278   if (type == NORM_FROBENIUS) {
2279 #if defined(PETSC_USE_REAL___FP16)
2280     PetscBLASInt one = 1, nz = a->nz;
2281     PetscCallBLAS("BLASnrm2", *nrm = BLASnrm2_(&nz, v, &one));
2282 #else
2283     for (i = 0; i < a->nz; i++) {
2284       sum += PetscRealPart(PetscConj(*v) * (*v));
2285       v++;
2286     }
2287     *nrm = PetscSqrtReal(sum);
2288 #endif
2289     PetscCall(PetscLogFlops(2.0 * a->nz));
2290   } else if (type == NORM_1) {
2291     PetscReal *tmp;
2292     PetscInt  *jj = a->j;
2293     PetscCall(PetscCalloc1(A->cmap->n + 1, &tmp));
2294     *nrm = 0.0;
2295     for (j = 0; j < a->nz; j++) {
2296       tmp[*jj++] += PetscAbsScalar(*v);
2297       v++;
2298     }
2299     for (j = 0; j < A->cmap->n; j++) {
2300       if (tmp[j] > *nrm) *nrm = tmp[j];
2301     }
2302     PetscCall(PetscFree(tmp));
2303     PetscCall(PetscLogFlops(PetscMax(a->nz - 1, 0)));
2304   } else if (type == NORM_INFINITY) {
2305     *nrm = 0.0;
2306     for (j = 0; j < A->rmap->n; j++) {
2307       const PetscScalar *v2 = PetscSafePointerPlusOffset(v, a->i[j]);
2308       sum                   = 0.0;
2309       for (i = 0; i < a->i[j + 1] - a->i[j]; i++) {
2310         sum += PetscAbsScalar(*v2);
2311         v2++;
2312       }
2313       if (sum > *nrm) *nrm = sum;
2314     }
2315     PetscCall(PetscLogFlops(PetscMax(a->nz - 1, 0)));
2316   } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "No support for two norm");
2317   PetscCall(MatSeqAIJRestoreArrayRead(A, &v));
2318   PetscFunctionReturn(PETSC_SUCCESS);
2319 }
2320 
2321 static PetscErrorCode MatIsTranspose_SeqAIJ(Mat A, Mat B, PetscReal tol, PetscBool *f)
2322 {
2323   Mat_SeqAIJ      *aij = (Mat_SeqAIJ *)A->data, *bij = (Mat_SeqAIJ *)B->data;
2324   PetscInt        *adx, *bdx, *aii, *bii, *aptr, *bptr;
2325   const MatScalar *va, *vb;
2326   PetscInt         ma, na, mb, nb, i;
2327 
2328   PetscFunctionBegin;
2329   PetscCall(MatGetSize(A, &ma, &na));
2330   PetscCall(MatGetSize(B, &mb, &nb));
2331   if (ma != nb || na != mb) {
2332     *f = PETSC_FALSE;
2333     PetscFunctionReturn(PETSC_SUCCESS);
2334   }
2335   PetscCall(MatSeqAIJGetArrayRead(A, &va));
2336   PetscCall(MatSeqAIJGetArrayRead(B, &vb));
2337   aii = aij->i;
2338   bii = bij->i;
2339   adx = aij->j;
2340   bdx = bij->j;
2341   PetscCall(PetscMalloc1(ma, &aptr));
2342   PetscCall(PetscMalloc1(mb, &bptr));
2343   for (i = 0; i < ma; i++) aptr[i] = aii[i];
2344   for (i = 0; i < mb; i++) bptr[i] = bii[i];
2345 
2346   *f = PETSC_TRUE;
2347   for (i = 0; i < ma; i++) {
2348     while (aptr[i] < aii[i + 1]) {
2349       PetscInt    idc, idr;
2350       PetscScalar vc, vr;
2351       /* column/row index/value */
2352       idc = adx[aptr[i]];
2353       idr = bdx[bptr[idc]];
2354       vc  = va[aptr[i]];
2355       vr  = vb[bptr[idc]];
2356       if (i != idr || PetscAbsScalar(vc - vr) > tol) {
2357         *f = PETSC_FALSE;
2358         goto done;
2359       } else {
2360         aptr[i]++;
2361         if (B || i != idc) bptr[idc]++;
2362       }
2363     }
2364   }
2365 done:
2366   PetscCall(PetscFree(aptr));
2367   PetscCall(PetscFree(bptr));
2368   PetscCall(MatSeqAIJRestoreArrayRead(A, &va));
2369   PetscCall(MatSeqAIJRestoreArrayRead(B, &vb));
2370   PetscFunctionReturn(PETSC_SUCCESS);
2371 }
2372 
2373 static PetscErrorCode MatIsHermitianTranspose_SeqAIJ(Mat A, Mat B, PetscReal tol, PetscBool *f)
2374 {
2375   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)A->data, *bij = (Mat_SeqAIJ *)B->data;
2376   PetscInt   *adx, *bdx, *aii, *bii, *aptr, *bptr;
2377   MatScalar  *va, *vb;
2378   PetscInt    ma, na, mb, nb, i;
2379 
2380   PetscFunctionBegin;
2381   PetscCall(MatGetSize(A, &ma, &na));
2382   PetscCall(MatGetSize(B, &mb, &nb));
2383   if (ma != nb || na != mb) {
2384     *f = PETSC_FALSE;
2385     PetscFunctionReturn(PETSC_SUCCESS);
2386   }
2387   aii = aij->i;
2388   bii = bij->i;
2389   adx = aij->j;
2390   bdx = bij->j;
2391   va  = aij->a;
2392   vb  = bij->a;
2393   PetscCall(PetscMalloc1(ma, &aptr));
2394   PetscCall(PetscMalloc1(mb, &bptr));
2395   for (i = 0; i < ma; i++) aptr[i] = aii[i];
2396   for (i = 0; i < mb; i++) bptr[i] = bii[i];
2397 
2398   *f = PETSC_TRUE;
2399   for (i = 0; i < ma; i++) {
2400     while (aptr[i] < aii[i + 1]) {
2401       PetscInt    idc, idr;
2402       PetscScalar vc, vr;
2403       /* column/row index/value */
2404       idc = adx[aptr[i]];
2405       idr = bdx[bptr[idc]];
2406       vc  = va[aptr[i]];
2407       vr  = vb[bptr[idc]];
2408       if (i != idr || PetscAbsScalar(vc - PetscConj(vr)) > tol) {
2409         *f = PETSC_FALSE;
2410         goto done;
2411       } else {
2412         aptr[i]++;
2413         if (B || i != idc) bptr[idc]++;
2414       }
2415     }
2416   }
2417 done:
2418   PetscCall(PetscFree(aptr));
2419   PetscCall(PetscFree(bptr));
2420   PetscFunctionReturn(PETSC_SUCCESS);
2421 }
2422 
2423 PetscErrorCode MatDiagonalScale_SeqAIJ(Mat A, Vec ll, Vec rr)
2424 {
2425   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
2426   const PetscScalar *l, *r;
2427   PetscScalar        x;
2428   MatScalar         *v;
2429   PetscInt           i, j, m = A->rmap->n, n = A->cmap->n, M, nz = a->nz;
2430   const PetscInt    *jj;
2431 
2432   PetscFunctionBegin;
2433   if (ll) {
2434     /* The local size is used so that VecMPI can be passed to this routine
2435        by MatDiagonalScale_MPIAIJ */
2436     PetscCall(VecGetLocalSize(ll, &m));
2437     PetscCheck(m == A->rmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Left scaling vector wrong length");
2438     PetscCall(VecGetArrayRead(ll, &l));
2439     PetscCall(MatSeqAIJGetArray(A, &v));
2440     for (i = 0; i < m; i++) {
2441       x = l[i];
2442       M = a->i[i + 1] - a->i[i];
2443       for (j = 0; j < M; j++) (*v++) *= x;
2444     }
2445     PetscCall(VecRestoreArrayRead(ll, &l));
2446     PetscCall(PetscLogFlops(nz));
2447     PetscCall(MatSeqAIJRestoreArray(A, &v));
2448   }
2449   if (rr) {
2450     PetscCall(VecGetLocalSize(rr, &n));
2451     PetscCheck(n == A->cmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Right scaling vector wrong length");
2452     PetscCall(VecGetArrayRead(rr, &r));
2453     PetscCall(MatSeqAIJGetArray(A, &v));
2454     jj = a->j;
2455     for (i = 0; i < nz; i++) (*v++) *= r[*jj++];
2456     PetscCall(MatSeqAIJRestoreArray(A, &v));
2457     PetscCall(VecRestoreArrayRead(rr, &r));
2458     PetscCall(PetscLogFlops(nz));
2459   }
2460   PetscCall(MatSeqAIJInvalidateDiagonal(A));
2461   PetscFunctionReturn(PETSC_SUCCESS);
2462 }
2463 
2464 PetscErrorCode MatCreateSubMatrix_SeqAIJ(Mat A, IS isrow, IS iscol, PetscInt csize, MatReuse scall, Mat *B)
2465 {
2466   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data, *c;
2467   PetscInt          *smap, i, k, kstart, kend, oldcols = A->cmap->n, *lens;
2468   PetscInt           row, mat_i, *mat_j, tcol, first, step, *mat_ilen, sum, lensi;
2469   const PetscInt    *irow, *icol;
2470   const PetscScalar *aa;
2471   PetscInt           nrows, ncols;
2472   PetscInt          *starts, *j_new, *i_new, *aj = a->j, *ai = a->i, ii, *ailen = a->ilen;
2473   MatScalar         *a_new, *mat_a, *c_a;
2474   Mat                C;
2475   PetscBool          stride;
2476 
2477   PetscFunctionBegin;
2478   PetscCall(ISGetIndices(isrow, &irow));
2479   PetscCall(ISGetLocalSize(isrow, &nrows));
2480   PetscCall(ISGetLocalSize(iscol, &ncols));
2481 
2482   PetscCall(PetscObjectTypeCompare((PetscObject)iscol, ISSTRIDE, &stride));
2483   if (stride) {
2484     PetscCall(ISStrideGetInfo(iscol, &first, &step));
2485   } else {
2486     first = 0;
2487     step  = 0;
2488   }
2489   if (stride && step == 1) {
2490     /* special case of contiguous rows */
2491     PetscCall(PetscMalloc2(nrows, &lens, nrows, &starts));
2492     /* loop over new rows determining lens and starting points */
2493     for (i = 0; i < nrows; i++) {
2494       kstart    = ai[irow[i]];
2495       kend      = kstart + ailen[irow[i]];
2496       starts[i] = kstart;
2497       for (k = kstart; k < kend; k++) {
2498         if (aj[k] >= first) {
2499           starts[i] = k;
2500           break;
2501         }
2502       }
2503       sum = 0;
2504       while (k < kend) {
2505         if (aj[k++] >= first + ncols) break;
2506         sum++;
2507       }
2508       lens[i] = sum;
2509     }
2510     /* create submatrix */
2511     if (scall == MAT_REUSE_MATRIX) {
2512       PetscInt n_cols, n_rows;
2513       PetscCall(MatGetSize(*B, &n_rows, &n_cols));
2514       PetscCheck(n_rows == nrows && n_cols == ncols, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Reused submatrix wrong size");
2515       PetscCall(MatZeroEntries(*B));
2516       C = *B;
2517     } else {
2518       PetscInt rbs, cbs;
2519       PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &C));
2520       PetscCall(MatSetSizes(C, nrows, ncols, PETSC_DETERMINE, PETSC_DETERMINE));
2521       PetscCall(ISGetBlockSize(isrow, &rbs));
2522       PetscCall(ISGetBlockSize(iscol, &cbs));
2523       PetscCall(MatSetBlockSizes(C, rbs, cbs));
2524       PetscCall(MatSetType(C, ((PetscObject)A)->type_name));
2525       PetscCall(MatSeqAIJSetPreallocation_SeqAIJ(C, 0, lens));
2526     }
2527     c = (Mat_SeqAIJ *)C->data;
2528 
2529     /* loop over rows inserting into submatrix */
2530     PetscCall(MatSeqAIJGetArrayWrite(C, &a_new)); // Not 'a_new = c->a-new', since that raw usage ignores offload state of C
2531     j_new = c->j;
2532     i_new = c->i;
2533     PetscCall(MatSeqAIJGetArrayRead(A, &aa));
2534     for (i = 0; i < nrows; i++) {
2535       ii    = starts[i];
2536       lensi = lens[i];
2537       if (lensi) {
2538         for (k = 0; k < lensi; k++) *j_new++ = aj[ii + k] - first;
2539         PetscCall(PetscArraycpy(a_new, aa + starts[i], lensi));
2540         a_new += lensi;
2541       }
2542       i_new[i + 1] = i_new[i] + lensi;
2543       c->ilen[i]   = lensi;
2544     }
2545     PetscCall(MatSeqAIJRestoreArrayWrite(C, &a_new)); // Set C's offload state properly
2546     PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
2547     PetscCall(PetscFree2(lens, starts));
2548   } else {
2549     PetscCall(ISGetIndices(iscol, &icol));
2550     PetscCall(PetscCalloc1(oldcols, &smap));
2551     PetscCall(PetscMalloc1(1 + nrows, &lens));
2552     for (i = 0; i < ncols; i++) {
2553       PetscCheck(icol[i] < oldcols, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Requesting column beyond largest column icol[%" PetscInt_FMT "] %" PetscInt_FMT " >= A->cmap->n %" PetscInt_FMT, i, icol[i], oldcols);
2554       smap[icol[i]] = i + 1;
2555     }
2556 
2557     /* determine lens of each row */
2558     for (i = 0; i < nrows; i++) {
2559       kstart  = ai[irow[i]];
2560       kend    = kstart + a->ilen[irow[i]];
2561       lens[i] = 0;
2562       for (k = kstart; k < kend; k++) {
2563         if (smap[aj[k]]) lens[i]++;
2564       }
2565     }
2566     /* Create and fill new matrix */
2567     if (scall == MAT_REUSE_MATRIX) {
2568       PetscBool equal;
2569 
2570       c = (Mat_SeqAIJ *)((*B)->data);
2571       PetscCheck((*B)->rmap->n == nrows && (*B)->cmap->n == ncols, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Cannot reuse matrix. wrong size");
2572       PetscCall(PetscArraycmp(c->ilen, lens, (*B)->rmap->n, &equal));
2573       PetscCheck(equal, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Cannot reuse matrix. wrong number of nonzeros");
2574       PetscCall(PetscArrayzero(c->ilen, (*B)->rmap->n));
2575       C = *B;
2576     } else {
2577       PetscInt rbs, cbs;
2578       PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &C));
2579       PetscCall(MatSetSizes(C, nrows, ncols, PETSC_DETERMINE, PETSC_DETERMINE));
2580       PetscCall(ISGetBlockSize(isrow, &rbs));
2581       PetscCall(ISGetBlockSize(iscol, &cbs));
2582       if (rbs > 1 || cbs > 1) PetscCall(MatSetBlockSizes(C, rbs, cbs));
2583       PetscCall(MatSetType(C, ((PetscObject)A)->type_name));
2584       PetscCall(MatSeqAIJSetPreallocation_SeqAIJ(C, 0, lens));
2585     }
2586     PetscCall(MatSeqAIJGetArrayRead(A, &aa));
2587 
2588     c = (Mat_SeqAIJ *)C->data;
2589     PetscCall(MatSeqAIJGetArrayWrite(C, &c_a)); // Not 'c->a', since that raw usage ignores offload state of C
2590     for (i = 0; i < nrows; i++) {
2591       row      = irow[i];
2592       kstart   = ai[row];
2593       kend     = kstart + a->ilen[row];
2594       mat_i    = c->i[i];
2595       mat_j    = PetscSafePointerPlusOffset(c->j, mat_i);
2596       mat_a    = PetscSafePointerPlusOffset(c_a, mat_i);
2597       mat_ilen = c->ilen + i;
2598       for (k = kstart; k < kend; k++) {
2599         if ((tcol = smap[a->j[k]])) {
2600           *mat_j++ = tcol - 1;
2601           *mat_a++ = aa[k];
2602           (*mat_ilen)++;
2603         }
2604       }
2605     }
2606     PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
2607     /* Free work space */
2608     PetscCall(ISRestoreIndices(iscol, &icol));
2609     PetscCall(PetscFree(smap));
2610     PetscCall(PetscFree(lens));
2611     /* sort */
2612     for (i = 0; i < nrows; i++) {
2613       PetscInt ilen;
2614 
2615       mat_i = c->i[i];
2616       mat_j = PetscSafePointerPlusOffset(c->j, mat_i);
2617       mat_a = PetscSafePointerPlusOffset(c_a, mat_i);
2618       ilen  = c->ilen[i];
2619       PetscCall(PetscSortIntWithScalarArray(ilen, mat_j, mat_a));
2620     }
2621     PetscCall(MatSeqAIJRestoreArrayWrite(C, &c_a));
2622   }
2623 #if defined(PETSC_HAVE_DEVICE)
2624   PetscCall(MatBindToCPU(C, A->boundtocpu));
2625 #endif
2626   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
2627   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
2628 
2629   PetscCall(ISRestoreIndices(isrow, &irow));
2630   *B = C;
2631   PetscFunctionReturn(PETSC_SUCCESS);
2632 }
2633 
2634 static PetscErrorCode MatGetMultiProcBlock_SeqAIJ(Mat mat, MPI_Comm subComm, MatReuse scall, Mat *subMat)
2635 {
2636   Mat B;
2637 
2638   PetscFunctionBegin;
2639   if (scall == MAT_INITIAL_MATRIX) {
2640     PetscCall(MatCreate(subComm, &B));
2641     PetscCall(MatSetSizes(B, mat->rmap->n, mat->cmap->n, mat->rmap->n, mat->cmap->n));
2642     PetscCall(MatSetBlockSizesFromMats(B, mat, mat));
2643     PetscCall(MatSetType(B, MATSEQAIJ));
2644     PetscCall(MatDuplicateNoCreate_SeqAIJ(B, mat, MAT_COPY_VALUES, PETSC_TRUE));
2645     *subMat = B;
2646   } else {
2647     PetscCall(MatCopy_SeqAIJ(mat, *subMat, SAME_NONZERO_PATTERN));
2648   }
2649   PetscFunctionReturn(PETSC_SUCCESS);
2650 }
2651 
2652 static PetscErrorCode MatILUFactor_SeqAIJ(Mat inA, IS row, IS col, const MatFactorInfo *info)
2653 {
2654   Mat_SeqAIJ *a = (Mat_SeqAIJ *)inA->data;
2655   Mat         outA;
2656   PetscBool   row_identity, col_identity;
2657 
2658   PetscFunctionBegin;
2659   PetscCheck(info->levels == 0, PETSC_COMM_SELF, PETSC_ERR_SUP, "Only levels=0 supported for in-place ilu");
2660 
2661   PetscCall(ISIdentity(row, &row_identity));
2662   PetscCall(ISIdentity(col, &col_identity));
2663 
2664   outA             = inA;
2665   outA->factortype = MAT_FACTOR_LU;
2666   PetscCall(PetscFree(inA->solvertype));
2667   PetscCall(PetscStrallocpy(MATSOLVERPETSC, &inA->solvertype));
2668 
2669   PetscCall(PetscObjectReference((PetscObject)row));
2670   PetscCall(ISDestroy(&a->row));
2671 
2672   a->row = row;
2673 
2674   PetscCall(PetscObjectReference((PetscObject)col));
2675   PetscCall(ISDestroy(&a->col));
2676 
2677   a->col = col;
2678 
2679   /* Create the inverse permutation so that it can be used in MatLUFactorNumeric() */
2680   PetscCall(ISDestroy(&a->icol));
2681   PetscCall(ISInvertPermutation(col, PETSC_DECIDE, &a->icol));
2682 
2683   if (!a->solve_work) { /* this matrix may have been factored before */
2684     PetscCall(PetscMalloc1(inA->rmap->n + 1, &a->solve_work));
2685   }
2686 
2687   PetscCall(MatMarkDiagonal_SeqAIJ(inA));
2688   if (row_identity && col_identity) {
2689     PetscCall(MatLUFactorNumeric_SeqAIJ_inplace(outA, inA, info));
2690   } else {
2691     PetscCall(MatLUFactorNumeric_SeqAIJ_InplaceWithPerm(outA, inA, info));
2692   }
2693   PetscFunctionReturn(PETSC_SUCCESS);
2694 }
2695 
2696 PetscErrorCode MatScale_SeqAIJ(Mat inA, PetscScalar alpha)
2697 {
2698   Mat_SeqAIJ  *a = (Mat_SeqAIJ *)inA->data;
2699   PetscScalar *v;
2700   PetscBLASInt one = 1, bnz;
2701 
2702   PetscFunctionBegin;
2703   PetscCall(MatSeqAIJGetArray(inA, &v));
2704   PetscCall(PetscBLASIntCast(a->nz, &bnz));
2705   PetscCallBLAS("BLASscal", BLASscal_(&bnz, &alpha, v, &one));
2706   PetscCall(PetscLogFlops(a->nz));
2707   PetscCall(MatSeqAIJRestoreArray(inA, &v));
2708   PetscCall(MatSeqAIJInvalidateDiagonal(inA));
2709   PetscFunctionReturn(PETSC_SUCCESS);
2710 }
2711 
2712 PetscErrorCode MatDestroySubMatrix_Private(Mat_SubSppt *submatj)
2713 {
2714   PetscInt i;
2715 
2716   PetscFunctionBegin;
2717   if (!submatj->id) { /* delete data that are linked only to submats[id=0] */
2718     PetscCall(PetscFree4(submatj->sbuf1, submatj->ptr, submatj->tmp, submatj->ctr));
2719 
2720     for (i = 0; i < submatj->nrqr; ++i) PetscCall(PetscFree(submatj->sbuf2[i]));
2721     PetscCall(PetscFree3(submatj->sbuf2, submatj->req_size, submatj->req_source1));
2722 
2723     if (submatj->rbuf1) {
2724       PetscCall(PetscFree(submatj->rbuf1[0]));
2725       PetscCall(PetscFree(submatj->rbuf1));
2726     }
2727 
2728     for (i = 0; i < submatj->nrqs; ++i) PetscCall(PetscFree(submatj->rbuf3[i]));
2729     PetscCall(PetscFree3(submatj->req_source2, submatj->rbuf2, submatj->rbuf3));
2730     PetscCall(PetscFree(submatj->pa));
2731   }
2732 
2733 #if defined(PETSC_USE_CTABLE)
2734   PetscCall(PetscHMapIDestroy(&submatj->rmap));
2735   if (submatj->cmap_loc) PetscCall(PetscFree(submatj->cmap_loc));
2736   PetscCall(PetscFree(submatj->rmap_loc));
2737 #else
2738   PetscCall(PetscFree(submatj->rmap));
2739 #endif
2740 
2741   if (!submatj->allcolumns) {
2742 #if defined(PETSC_USE_CTABLE)
2743     PetscCall(PetscHMapIDestroy(&submatj->cmap));
2744 #else
2745     PetscCall(PetscFree(submatj->cmap));
2746 #endif
2747   }
2748   PetscCall(PetscFree(submatj->row2proc));
2749 
2750   PetscCall(PetscFree(submatj));
2751   PetscFunctionReturn(PETSC_SUCCESS);
2752 }
2753 
2754 PetscErrorCode MatDestroySubMatrix_SeqAIJ(Mat C)
2755 {
2756   Mat_SeqAIJ  *c       = (Mat_SeqAIJ *)C->data;
2757   Mat_SubSppt *submatj = c->submatis1;
2758 
2759   PetscFunctionBegin;
2760   PetscCall((*submatj->destroy)(C));
2761   PetscCall(MatDestroySubMatrix_Private(submatj));
2762   PetscFunctionReturn(PETSC_SUCCESS);
2763 }
2764 
2765 /* Note this has code duplication with MatDestroySubMatrices_SeqBAIJ() */
2766 static PetscErrorCode MatDestroySubMatrices_SeqAIJ(PetscInt n, Mat *mat[])
2767 {
2768   PetscInt     i;
2769   Mat          C;
2770   Mat_SeqAIJ  *c;
2771   Mat_SubSppt *submatj;
2772 
2773   PetscFunctionBegin;
2774   for (i = 0; i < n; i++) {
2775     C       = (*mat)[i];
2776     c       = (Mat_SeqAIJ *)C->data;
2777     submatj = c->submatis1;
2778     if (submatj) {
2779       if (--((PetscObject)C)->refct <= 0) {
2780         PetscCall(PetscFree(C->factorprefix));
2781         PetscCall((*submatj->destroy)(C));
2782         PetscCall(MatDestroySubMatrix_Private(submatj));
2783         PetscCall(PetscFree(C->defaultvectype));
2784         PetscCall(PetscFree(C->defaultrandtype));
2785         PetscCall(PetscLayoutDestroy(&C->rmap));
2786         PetscCall(PetscLayoutDestroy(&C->cmap));
2787         PetscCall(PetscHeaderDestroy(&C));
2788       }
2789     } else {
2790       PetscCall(MatDestroy(&C));
2791     }
2792   }
2793 
2794   /* Destroy Dummy submatrices created for reuse */
2795   PetscCall(MatDestroySubMatrices_Dummy(n, mat));
2796 
2797   PetscCall(PetscFree(*mat));
2798   PetscFunctionReturn(PETSC_SUCCESS);
2799 }
2800 
2801 static PetscErrorCode MatCreateSubMatrices_SeqAIJ(Mat A, PetscInt n, const IS irow[], const IS icol[], MatReuse scall, Mat *B[])
2802 {
2803   PetscInt i;
2804 
2805   PetscFunctionBegin;
2806   if (scall == MAT_INITIAL_MATRIX) PetscCall(PetscCalloc1(n + 1, B));
2807 
2808   for (i = 0; i < n; i++) PetscCall(MatCreateSubMatrix_SeqAIJ(A, irow[i], icol[i], PETSC_DECIDE, scall, &(*B)[i]));
2809   PetscFunctionReturn(PETSC_SUCCESS);
2810 }
2811 
2812 static PetscErrorCode MatIncreaseOverlap_SeqAIJ(Mat A, PetscInt is_max, IS is[], PetscInt ov)
2813 {
2814   Mat_SeqAIJ     *a = (Mat_SeqAIJ *)A->data;
2815   PetscInt        row, i, j, k, l, ll, m, n, *nidx, isz, val;
2816   const PetscInt *idx;
2817   PetscInt        start, end, *ai, *aj, bs = A->rmap->bs == A->cmap->bs ? A->rmap->bs : 1;
2818   PetscBT         table;
2819 
2820   PetscFunctionBegin;
2821   m  = A->rmap->n / bs;
2822   ai = a->i;
2823   aj = a->j;
2824 
2825   PetscCheck(ov >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "illegal negative overlap value used");
2826 
2827   PetscCall(PetscMalloc1(m + 1, &nidx));
2828   PetscCall(PetscBTCreate(m, &table));
2829 
2830   for (i = 0; i < is_max; i++) {
2831     /* Initialize the two local arrays */
2832     isz = 0;
2833     PetscCall(PetscBTMemzero(m, table));
2834 
2835     /* Extract the indices, assume there can be duplicate entries */
2836     PetscCall(ISGetIndices(is[i], &idx));
2837     PetscCall(ISGetLocalSize(is[i], &n));
2838 
2839     if (bs > 1) {
2840       /* Enter these into the temp arrays. I.e., mark table[row], enter row into new index */
2841       for (j = 0; j < n; ++j) {
2842         if (!PetscBTLookupSet(table, idx[j] / bs)) nidx[isz++] = idx[j] / bs;
2843       }
2844       PetscCall(ISRestoreIndices(is[i], &idx));
2845       PetscCall(ISDestroy(&is[i]));
2846 
2847       k = 0;
2848       for (j = 0; j < ov; j++) { /* for each overlap */
2849         n = isz;
2850         for (; k < n; k++) { /* do only those rows in nidx[k], which are not done yet */
2851           for (ll = 0; ll < bs; ll++) {
2852             row   = bs * nidx[k] + ll;
2853             start = ai[row];
2854             end   = ai[row + 1];
2855             for (l = start; l < end; l++) {
2856               val = aj[l] / bs;
2857               if (!PetscBTLookupSet(table, val)) nidx[isz++] = val;
2858             }
2859           }
2860         }
2861       }
2862       PetscCall(ISCreateBlock(PETSC_COMM_SELF, bs, isz, nidx, PETSC_COPY_VALUES, is + i));
2863     } else {
2864       /* Enter these into the temp arrays. I.e., mark table[row], enter row into new index */
2865       for (j = 0; j < n; ++j) {
2866         if (!PetscBTLookupSet(table, idx[j])) nidx[isz++] = idx[j];
2867       }
2868       PetscCall(ISRestoreIndices(is[i], &idx));
2869       PetscCall(ISDestroy(&is[i]));
2870 
2871       k = 0;
2872       for (j = 0; j < ov; j++) { /* for each overlap */
2873         n = isz;
2874         for (; k < n; k++) { /* do only those rows in nidx[k], which are not done yet */
2875           row   = nidx[k];
2876           start = ai[row];
2877           end   = ai[row + 1];
2878           for (l = start; l < end; l++) {
2879             val = aj[l];
2880             if (!PetscBTLookupSet(table, val)) nidx[isz++] = val;
2881           }
2882         }
2883       }
2884       PetscCall(ISCreateGeneral(PETSC_COMM_SELF, isz, nidx, PETSC_COPY_VALUES, is + i));
2885     }
2886   }
2887   PetscCall(PetscBTDestroy(&table));
2888   PetscCall(PetscFree(nidx));
2889   PetscFunctionReturn(PETSC_SUCCESS);
2890 }
2891 
2892 static PetscErrorCode MatPermute_SeqAIJ(Mat A, IS rowp, IS colp, Mat *B)
2893 {
2894   Mat_SeqAIJ     *a = (Mat_SeqAIJ *)A->data;
2895   PetscInt        i, nz = 0, m = A->rmap->n, n = A->cmap->n;
2896   const PetscInt *row, *col;
2897   PetscInt       *cnew, j, *lens;
2898   IS              icolp, irowp;
2899   PetscInt       *cwork = NULL;
2900   PetscScalar    *vwork = NULL;
2901 
2902   PetscFunctionBegin;
2903   PetscCall(ISInvertPermutation(rowp, PETSC_DECIDE, &irowp));
2904   PetscCall(ISGetIndices(irowp, &row));
2905   PetscCall(ISInvertPermutation(colp, PETSC_DECIDE, &icolp));
2906   PetscCall(ISGetIndices(icolp, &col));
2907 
2908   /* determine lengths of permuted rows */
2909   PetscCall(PetscMalloc1(m + 1, &lens));
2910   for (i = 0; i < m; i++) lens[row[i]] = a->i[i + 1] - a->i[i];
2911   PetscCall(MatCreate(PetscObjectComm((PetscObject)A), B));
2912   PetscCall(MatSetSizes(*B, m, n, m, n));
2913   PetscCall(MatSetBlockSizesFromMats(*B, A, A));
2914   PetscCall(MatSetType(*B, ((PetscObject)A)->type_name));
2915   PetscCall(MatSeqAIJSetPreallocation_SeqAIJ(*B, 0, lens));
2916   PetscCall(PetscFree(lens));
2917 
2918   PetscCall(PetscMalloc1(n, &cnew));
2919   for (i = 0; i < m; i++) {
2920     PetscCall(MatGetRow_SeqAIJ(A, i, &nz, &cwork, &vwork));
2921     for (j = 0; j < nz; j++) cnew[j] = col[cwork[j]];
2922     PetscCall(MatSetValues_SeqAIJ(*B, 1, &row[i], nz, cnew, vwork, INSERT_VALUES));
2923     PetscCall(MatRestoreRow_SeqAIJ(A, i, &nz, &cwork, &vwork));
2924   }
2925   PetscCall(PetscFree(cnew));
2926 
2927   (*B)->assembled = PETSC_FALSE;
2928 
2929 #if defined(PETSC_HAVE_DEVICE)
2930   PetscCall(MatBindToCPU(*B, A->boundtocpu));
2931 #endif
2932   PetscCall(MatAssemblyBegin(*B, MAT_FINAL_ASSEMBLY));
2933   PetscCall(MatAssemblyEnd(*B, MAT_FINAL_ASSEMBLY));
2934   PetscCall(ISRestoreIndices(irowp, &row));
2935   PetscCall(ISRestoreIndices(icolp, &col));
2936   PetscCall(ISDestroy(&irowp));
2937   PetscCall(ISDestroy(&icolp));
2938   if (rowp == colp) PetscCall(MatPropagateSymmetryOptions(A, *B));
2939   PetscFunctionReturn(PETSC_SUCCESS);
2940 }
2941 
2942 PetscErrorCode MatCopy_SeqAIJ(Mat A, Mat B, MatStructure str)
2943 {
2944   PetscFunctionBegin;
2945   /* If the two matrices have the same copy implementation, use fast copy. */
2946   if (str == SAME_NONZERO_PATTERN && (A->ops->copy == B->ops->copy)) {
2947     Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
2948     Mat_SeqAIJ        *b = (Mat_SeqAIJ *)B->data;
2949     const PetscScalar *aa;
2950 
2951     PetscCall(MatSeqAIJGetArrayRead(A, &aa));
2952     PetscCheck(a->i[A->rmap->n] == b->i[B->rmap->n], PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Number of nonzeros in two matrices are different %" PetscInt_FMT " != %" PetscInt_FMT, a->i[A->rmap->n], b->i[B->rmap->n]);
2953     PetscCall(PetscArraycpy(b->a, aa, a->i[A->rmap->n]));
2954     PetscCall(PetscObjectStateIncrease((PetscObject)B));
2955     PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
2956   } else {
2957     PetscCall(MatCopy_Basic(A, B, str));
2958   }
2959   PetscFunctionReturn(PETSC_SUCCESS);
2960 }
2961 
2962 PETSC_INTERN PetscErrorCode MatSeqAIJGetArray_SeqAIJ(Mat A, PetscScalar *array[])
2963 {
2964   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
2965 
2966   PetscFunctionBegin;
2967   *array = a->a;
2968   PetscFunctionReturn(PETSC_SUCCESS);
2969 }
2970 
2971 PETSC_INTERN PetscErrorCode MatSeqAIJRestoreArray_SeqAIJ(Mat A, PetscScalar *array[])
2972 {
2973   PetscFunctionBegin;
2974   *array = NULL;
2975   PetscFunctionReturn(PETSC_SUCCESS);
2976 }
2977 
2978 /*
2979    Computes the number of nonzeros per row needed for preallocation when X and Y
2980    have different nonzero structure.
2981 */
2982 PetscErrorCode MatAXPYGetPreallocation_SeqX_private(PetscInt m, const PetscInt *xi, const PetscInt *xj, const PetscInt *yi, const PetscInt *yj, PetscInt *nnz)
2983 {
2984   PetscInt i, j, k, nzx, nzy;
2985 
2986   PetscFunctionBegin;
2987   /* Set the number of nonzeros in the new matrix */
2988   for (i = 0; i < m; i++) {
2989     const PetscInt *xjj = PetscSafePointerPlusOffset(xj, xi[i]), *yjj = PetscSafePointerPlusOffset(yj, yi[i]);
2990     nzx    = xi[i + 1] - xi[i];
2991     nzy    = yi[i + 1] - yi[i];
2992     nnz[i] = 0;
2993     for (j = 0, k = 0; j < nzx; j++) {                  /* Point in X */
2994       for (; k < nzy && yjj[k] < xjj[j]; k++) nnz[i]++; /* Catch up to X */
2995       if (k < nzy && yjj[k] == xjj[j]) k++;             /* Skip duplicate */
2996       nnz[i]++;
2997     }
2998     for (; k < nzy; k++) nnz[i]++;
2999   }
3000   PetscFunctionReturn(PETSC_SUCCESS);
3001 }
3002 
3003 PetscErrorCode MatAXPYGetPreallocation_SeqAIJ(Mat Y, Mat X, PetscInt *nnz)
3004 {
3005   PetscInt    m = Y->rmap->N;
3006   Mat_SeqAIJ *x = (Mat_SeqAIJ *)X->data;
3007   Mat_SeqAIJ *y = (Mat_SeqAIJ *)Y->data;
3008 
3009   PetscFunctionBegin;
3010   /* Set the number of nonzeros in the new matrix */
3011   PetscCall(MatAXPYGetPreallocation_SeqX_private(m, x->i, x->j, y->i, y->j, nnz));
3012   PetscFunctionReturn(PETSC_SUCCESS);
3013 }
3014 
3015 PetscErrorCode MatAXPY_SeqAIJ(Mat Y, PetscScalar a, Mat X, MatStructure str)
3016 {
3017   Mat_SeqAIJ *x = (Mat_SeqAIJ *)X->data, *y = (Mat_SeqAIJ *)Y->data;
3018 
3019   PetscFunctionBegin;
3020   if (str == UNKNOWN_NONZERO_PATTERN || (PetscDefined(USE_DEBUG) && str == SAME_NONZERO_PATTERN)) {
3021     PetscBool e = x->nz == y->nz ? PETSC_TRUE : PETSC_FALSE;
3022     if (e) {
3023       PetscCall(PetscArraycmp(x->i, y->i, Y->rmap->n + 1, &e));
3024       if (e) {
3025         PetscCall(PetscArraycmp(x->j, y->j, y->nz, &e));
3026         if (e) str = SAME_NONZERO_PATTERN;
3027       }
3028     }
3029     if (!e) PetscCheck(str != SAME_NONZERO_PATTERN, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MatStructure is not SAME_NONZERO_PATTERN");
3030   }
3031   if (str == SAME_NONZERO_PATTERN) {
3032     const PetscScalar *xa;
3033     PetscScalar       *ya, alpha = a;
3034     PetscBLASInt       one = 1, bnz;
3035 
3036     PetscCall(PetscBLASIntCast(x->nz, &bnz));
3037     PetscCall(MatSeqAIJGetArray(Y, &ya));
3038     PetscCall(MatSeqAIJGetArrayRead(X, &xa));
3039     PetscCallBLAS("BLASaxpy", BLASaxpy_(&bnz, &alpha, xa, &one, ya, &one));
3040     PetscCall(MatSeqAIJRestoreArrayRead(X, &xa));
3041     PetscCall(MatSeqAIJRestoreArray(Y, &ya));
3042     PetscCall(PetscLogFlops(2.0 * bnz));
3043     PetscCall(MatSeqAIJInvalidateDiagonal(Y));
3044     PetscCall(PetscObjectStateIncrease((PetscObject)Y));
3045   } else if (str == SUBSET_NONZERO_PATTERN) { /* nonzeros of X is a subset of Y's */
3046     PetscCall(MatAXPY_Basic(Y, a, X, str));
3047   } else {
3048     Mat       B;
3049     PetscInt *nnz;
3050     PetscCall(PetscMalloc1(Y->rmap->N, &nnz));
3051     PetscCall(MatCreate(PetscObjectComm((PetscObject)Y), &B));
3052     PetscCall(PetscObjectSetName((PetscObject)B, ((PetscObject)Y)->name));
3053     PetscCall(MatSetLayouts(B, Y->rmap, Y->cmap));
3054     PetscCall(MatSetType(B, ((PetscObject)Y)->type_name));
3055     PetscCall(MatAXPYGetPreallocation_SeqAIJ(Y, X, nnz));
3056     PetscCall(MatSeqAIJSetPreallocation(B, 0, nnz));
3057     PetscCall(MatAXPY_BasicWithPreallocation(B, Y, a, X, str));
3058     PetscCall(MatHeaderMerge(Y, &B));
3059     PetscCall(MatSeqAIJCheckInode(Y));
3060     PetscCall(PetscFree(nnz));
3061   }
3062   PetscFunctionReturn(PETSC_SUCCESS);
3063 }
3064 
3065 PETSC_INTERN PetscErrorCode MatConjugate_SeqAIJ(Mat mat)
3066 {
3067 #if defined(PETSC_USE_COMPLEX)
3068   Mat_SeqAIJ  *aij = (Mat_SeqAIJ *)mat->data;
3069   PetscInt     i, nz;
3070   PetscScalar *a;
3071 
3072   PetscFunctionBegin;
3073   nz = aij->nz;
3074   PetscCall(MatSeqAIJGetArray(mat, &a));
3075   for (i = 0; i < nz; i++) a[i] = PetscConj(a[i]);
3076   PetscCall(MatSeqAIJRestoreArray(mat, &a));
3077 #else
3078   PetscFunctionBegin;
3079 #endif
3080   PetscFunctionReturn(PETSC_SUCCESS);
3081 }
3082 
3083 static PetscErrorCode MatGetRowMaxAbs_SeqAIJ(Mat A, Vec v, PetscInt idx[])
3084 {
3085   Mat_SeqAIJ      *a = (Mat_SeqAIJ *)A->data;
3086   PetscInt         i, j, m = A->rmap->n, *ai, *aj, ncols, n;
3087   PetscReal        atmp;
3088   PetscScalar     *x;
3089   const MatScalar *aa, *av;
3090 
3091   PetscFunctionBegin;
3092   PetscCheck(!A->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3093   PetscCall(MatSeqAIJGetArrayRead(A, &av));
3094   aa = av;
3095   ai = a->i;
3096   aj = a->j;
3097 
3098   PetscCall(VecGetArrayWrite(v, &x));
3099   PetscCall(VecGetLocalSize(v, &n));
3100   PetscCheck(n == A->rmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Nonconforming matrix and vector");
3101   for (i = 0; i < m; i++) {
3102     ncols = ai[1] - ai[0];
3103     ai++;
3104     x[i] = 0;
3105     for (j = 0; j < ncols; j++) {
3106       atmp = PetscAbsScalar(*aa);
3107       if (PetscAbsScalar(x[i]) < atmp) {
3108         x[i] = atmp;
3109         if (idx) idx[i] = *aj;
3110       }
3111       aa++;
3112       aj++;
3113     }
3114   }
3115   PetscCall(VecRestoreArrayWrite(v, &x));
3116   PetscCall(MatSeqAIJRestoreArrayRead(A, &av));
3117   PetscFunctionReturn(PETSC_SUCCESS);
3118 }
3119 
3120 static PetscErrorCode MatGetRowSumAbs_SeqAIJ(Mat A, Vec v)
3121 {
3122   Mat_SeqAIJ      *a = (Mat_SeqAIJ *)A->data;
3123   PetscInt         i, j, m = A->rmap->n, *ai, ncols, n;
3124   PetscScalar     *x;
3125   const MatScalar *aa, *av;
3126 
3127   PetscFunctionBegin;
3128   PetscCheck(!A->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3129   PetscCall(MatSeqAIJGetArrayRead(A, &av));
3130   aa = av;
3131   ai = a->i;
3132 
3133   PetscCall(VecGetArrayWrite(v, &x));
3134   PetscCall(VecGetLocalSize(v, &n));
3135   PetscCheck(n == A->rmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Nonconforming matrix and vector");
3136   for (i = 0; i < m; i++) {
3137     ncols = ai[1] - ai[0];
3138     ai++;
3139     x[i] = 0;
3140     for (j = 0; j < ncols; j++) {
3141       x[i] += PetscAbsScalar(*aa);
3142       aa++;
3143     }
3144   }
3145   PetscCall(VecRestoreArrayWrite(v, &x));
3146   PetscCall(MatSeqAIJRestoreArrayRead(A, &av));
3147   PetscFunctionReturn(PETSC_SUCCESS);
3148 }
3149 
3150 static PetscErrorCode MatGetRowMax_SeqAIJ(Mat A, Vec v, PetscInt idx[])
3151 {
3152   Mat_SeqAIJ      *a = (Mat_SeqAIJ *)A->data;
3153   PetscInt         i, j, m = A->rmap->n, *ai, *aj, ncols, n;
3154   PetscScalar     *x;
3155   const MatScalar *aa, *av;
3156 
3157   PetscFunctionBegin;
3158   PetscCheck(!A->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3159   PetscCall(MatSeqAIJGetArrayRead(A, &av));
3160   aa = av;
3161   ai = a->i;
3162   aj = a->j;
3163 
3164   PetscCall(VecGetArrayWrite(v, &x));
3165   PetscCall(VecGetLocalSize(v, &n));
3166   PetscCheck(n == A->rmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Nonconforming matrix and vector");
3167   for (i = 0; i < m; i++) {
3168     ncols = ai[1] - ai[0];
3169     ai++;
3170     if (ncols == A->cmap->n) { /* row is dense */
3171       x[i] = *aa;
3172       if (idx) idx[i] = 0;
3173     } else { /* row is sparse so already KNOW maximum is 0.0 or higher */
3174       x[i] = 0.0;
3175       if (idx) {
3176         for (j = 0; j < ncols; j++) { /* find first implicit 0.0 in the row */
3177           if (aj[j] > j) {
3178             idx[i] = j;
3179             break;
3180           }
3181         }
3182         /* in case first implicit 0.0 in the row occurs at ncols-th column */
3183         if (j == ncols && j < A->cmap->n) idx[i] = j;
3184       }
3185     }
3186     for (j = 0; j < ncols; j++) {
3187       if (PetscRealPart(x[i]) < PetscRealPart(*aa)) {
3188         x[i] = *aa;
3189         if (idx) idx[i] = *aj;
3190       }
3191       aa++;
3192       aj++;
3193     }
3194   }
3195   PetscCall(VecRestoreArrayWrite(v, &x));
3196   PetscCall(MatSeqAIJRestoreArrayRead(A, &av));
3197   PetscFunctionReturn(PETSC_SUCCESS);
3198 }
3199 
3200 static PetscErrorCode MatGetRowMinAbs_SeqAIJ(Mat A, Vec v, PetscInt idx[])
3201 {
3202   Mat_SeqAIJ      *a = (Mat_SeqAIJ *)A->data;
3203   PetscInt         i, j, m = A->rmap->n, *ai, *aj, ncols, n;
3204   PetscScalar     *x;
3205   const MatScalar *aa, *av;
3206 
3207   PetscFunctionBegin;
3208   PetscCall(MatSeqAIJGetArrayRead(A, &av));
3209   aa = av;
3210   ai = a->i;
3211   aj = a->j;
3212 
3213   PetscCall(VecGetArrayWrite(v, &x));
3214   PetscCall(VecGetLocalSize(v, &n));
3215   PetscCheck(n == m, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Nonconforming matrix and vector, %" PetscInt_FMT " vs. %" PetscInt_FMT " rows", m, n);
3216   for (i = 0; i < m; i++) {
3217     ncols = ai[1] - ai[0];
3218     ai++;
3219     if (ncols == A->cmap->n) { /* row is dense */
3220       x[i] = *aa;
3221       if (idx) idx[i] = 0;
3222     } else { /* row is sparse so already KNOW minimum is 0.0 or higher */
3223       x[i] = 0.0;
3224       if (idx) { /* find first implicit 0.0 in the row */
3225         for (j = 0; j < ncols; j++) {
3226           if (aj[j] > j) {
3227             idx[i] = j;
3228             break;
3229           }
3230         }
3231         /* in case first implicit 0.0 in the row occurs at ncols-th column */
3232         if (j == ncols && j < A->cmap->n) idx[i] = j;
3233       }
3234     }
3235     for (j = 0; j < ncols; j++) {
3236       if (PetscAbsScalar(x[i]) > PetscAbsScalar(*aa)) {
3237         x[i] = *aa;
3238         if (idx) idx[i] = *aj;
3239       }
3240       aa++;
3241       aj++;
3242     }
3243   }
3244   PetscCall(VecRestoreArrayWrite(v, &x));
3245   PetscCall(MatSeqAIJRestoreArrayRead(A, &av));
3246   PetscFunctionReturn(PETSC_SUCCESS);
3247 }
3248 
3249 static PetscErrorCode MatGetRowMin_SeqAIJ(Mat A, Vec v, PetscInt idx[])
3250 {
3251   Mat_SeqAIJ      *a = (Mat_SeqAIJ *)A->data;
3252   PetscInt         i, j, m = A->rmap->n, ncols, n;
3253   const PetscInt  *ai, *aj;
3254   PetscScalar     *x;
3255   const MatScalar *aa, *av;
3256 
3257   PetscFunctionBegin;
3258   PetscCheck(!A->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3259   PetscCall(MatSeqAIJGetArrayRead(A, &av));
3260   aa = av;
3261   ai = a->i;
3262   aj = a->j;
3263 
3264   PetscCall(VecGetArrayWrite(v, &x));
3265   PetscCall(VecGetLocalSize(v, &n));
3266   PetscCheck(n == m, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Nonconforming matrix and vector");
3267   for (i = 0; i < m; i++) {
3268     ncols = ai[1] - ai[0];
3269     ai++;
3270     if (ncols == A->cmap->n) { /* row is dense */
3271       x[i] = *aa;
3272       if (idx) idx[i] = 0;
3273     } else { /* row is sparse so already KNOW minimum is 0.0 or lower */
3274       x[i] = 0.0;
3275       if (idx) { /* find first implicit 0.0 in the row */
3276         for (j = 0; j < ncols; j++) {
3277           if (aj[j] > j) {
3278             idx[i] = j;
3279             break;
3280           }
3281         }
3282         /* in case first implicit 0.0 in the row occurs at ncols-th column */
3283         if (j == ncols && j < A->cmap->n) idx[i] = j;
3284       }
3285     }
3286     for (j = 0; j < ncols; j++) {
3287       if (PetscRealPart(x[i]) > PetscRealPart(*aa)) {
3288         x[i] = *aa;
3289         if (idx) idx[i] = *aj;
3290       }
3291       aa++;
3292       aj++;
3293     }
3294   }
3295   PetscCall(VecRestoreArrayWrite(v, &x));
3296   PetscCall(MatSeqAIJRestoreArrayRead(A, &av));
3297   PetscFunctionReturn(PETSC_SUCCESS);
3298 }
3299 
3300 static PetscErrorCode MatInvertBlockDiagonal_SeqAIJ(Mat A, const PetscScalar **values)
3301 {
3302   Mat_SeqAIJ     *a = (Mat_SeqAIJ *)A->data;
3303   PetscInt        i, bs = A->rmap->bs, mbs = A->rmap->n / bs, ipvt[5], bs2 = bs * bs, *v_pivots, ij[7], *IJ, j;
3304   MatScalar      *diag, work[25], *v_work;
3305   const PetscReal shift = 0.0;
3306   PetscBool       allowzeropivot, zeropivotdetected = PETSC_FALSE;
3307 
3308   PetscFunctionBegin;
3309   allowzeropivot = PetscNot(A->erroriffailure);
3310   if (a->ibdiagvalid) {
3311     if (values) *values = a->ibdiag;
3312     PetscFunctionReturn(PETSC_SUCCESS);
3313   }
3314   PetscCall(MatMarkDiagonal_SeqAIJ(A));
3315   if (!a->ibdiag) { PetscCall(PetscMalloc1(bs2 * mbs, &a->ibdiag)); }
3316   diag = a->ibdiag;
3317   if (values) *values = a->ibdiag;
3318   /* factor and invert each block */
3319   switch (bs) {
3320   case 1:
3321     for (i = 0; i < mbs; i++) {
3322       PetscCall(MatGetValues(A, 1, &i, 1, &i, diag + i));
3323       if (PetscAbsScalar(diag[i] + shift) < PETSC_MACHINE_EPSILON) {
3324         if (allowzeropivot) {
3325           A->factorerrortype             = MAT_FACTOR_NUMERIC_ZEROPIVOT;
3326           A->factorerror_zeropivot_value = PetscAbsScalar(diag[i]);
3327           A->factorerror_zeropivot_row   = i;
3328           PetscCall(PetscInfo(A, "Zero pivot, row %" PetscInt_FMT " pivot %g tolerance %g\n", i, (double)PetscAbsScalar(diag[i]), (double)PETSC_MACHINE_EPSILON));
3329         } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_MAT_LU_ZRPVT, "Zero pivot, row %" PetscInt_FMT " pivot %g tolerance %g", i, (double)PetscAbsScalar(diag[i]), (double)PETSC_MACHINE_EPSILON);
3330       }
3331       diag[i] = (PetscScalar)1.0 / (diag[i] + shift);
3332     }
3333     break;
3334   case 2:
3335     for (i = 0; i < mbs; i++) {
3336       ij[0] = 2 * i;
3337       ij[1] = 2 * i + 1;
3338       PetscCall(MatGetValues(A, 2, ij, 2, ij, diag));
3339       PetscCall(PetscKernel_A_gets_inverse_A_2(diag, shift, allowzeropivot, &zeropivotdetected));
3340       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
3341       PetscCall(PetscKernel_A_gets_transpose_A_2(diag));
3342       diag += 4;
3343     }
3344     break;
3345   case 3:
3346     for (i = 0; i < mbs; i++) {
3347       ij[0] = 3 * i;
3348       ij[1] = 3 * i + 1;
3349       ij[2] = 3 * i + 2;
3350       PetscCall(MatGetValues(A, 3, ij, 3, ij, diag));
3351       PetscCall(PetscKernel_A_gets_inverse_A_3(diag, shift, allowzeropivot, &zeropivotdetected));
3352       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
3353       PetscCall(PetscKernel_A_gets_transpose_A_3(diag));
3354       diag += 9;
3355     }
3356     break;
3357   case 4:
3358     for (i = 0; i < mbs; i++) {
3359       ij[0] = 4 * i;
3360       ij[1] = 4 * i + 1;
3361       ij[2] = 4 * i + 2;
3362       ij[3] = 4 * i + 3;
3363       PetscCall(MatGetValues(A, 4, ij, 4, ij, diag));
3364       PetscCall(PetscKernel_A_gets_inverse_A_4(diag, shift, allowzeropivot, &zeropivotdetected));
3365       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
3366       PetscCall(PetscKernel_A_gets_transpose_A_4(diag));
3367       diag += 16;
3368     }
3369     break;
3370   case 5:
3371     for (i = 0; i < mbs; i++) {
3372       ij[0] = 5 * i;
3373       ij[1] = 5 * i + 1;
3374       ij[2] = 5 * i + 2;
3375       ij[3] = 5 * i + 3;
3376       ij[4] = 5 * i + 4;
3377       PetscCall(MatGetValues(A, 5, ij, 5, ij, diag));
3378       PetscCall(PetscKernel_A_gets_inverse_A_5(diag, ipvt, work, shift, allowzeropivot, &zeropivotdetected));
3379       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
3380       PetscCall(PetscKernel_A_gets_transpose_A_5(diag));
3381       diag += 25;
3382     }
3383     break;
3384   case 6:
3385     for (i = 0; i < mbs; i++) {
3386       ij[0] = 6 * i;
3387       ij[1] = 6 * i + 1;
3388       ij[2] = 6 * i + 2;
3389       ij[3] = 6 * i + 3;
3390       ij[4] = 6 * i + 4;
3391       ij[5] = 6 * i + 5;
3392       PetscCall(MatGetValues(A, 6, ij, 6, ij, diag));
3393       PetscCall(PetscKernel_A_gets_inverse_A_6(diag, shift, allowzeropivot, &zeropivotdetected));
3394       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
3395       PetscCall(PetscKernel_A_gets_transpose_A_6(diag));
3396       diag += 36;
3397     }
3398     break;
3399   case 7:
3400     for (i = 0; i < mbs; i++) {
3401       ij[0] = 7 * i;
3402       ij[1] = 7 * i + 1;
3403       ij[2] = 7 * i + 2;
3404       ij[3] = 7 * i + 3;
3405       ij[4] = 7 * i + 4;
3406       ij[5] = 7 * i + 5;
3407       ij[6] = 7 * i + 6;
3408       PetscCall(MatGetValues(A, 7, ij, 7, ij, diag));
3409       PetscCall(PetscKernel_A_gets_inverse_A_7(diag, shift, allowzeropivot, &zeropivotdetected));
3410       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
3411       PetscCall(PetscKernel_A_gets_transpose_A_7(diag));
3412       diag += 49;
3413     }
3414     break;
3415   default:
3416     PetscCall(PetscMalloc3(bs, &v_work, bs, &v_pivots, bs, &IJ));
3417     for (i = 0; i < mbs; i++) {
3418       for (j = 0; j < bs; j++) IJ[j] = bs * i + j;
3419       PetscCall(MatGetValues(A, bs, IJ, bs, IJ, diag));
3420       PetscCall(PetscKernel_A_gets_inverse_A(bs, diag, v_pivots, v_work, allowzeropivot, &zeropivotdetected));
3421       if (zeropivotdetected) A->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
3422       PetscCall(PetscKernel_A_gets_transpose_A_N(diag, bs));
3423       diag += bs2;
3424     }
3425     PetscCall(PetscFree3(v_work, v_pivots, IJ));
3426   }
3427   a->ibdiagvalid = PETSC_TRUE;
3428   PetscFunctionReturn(PETSC_SUCCESS);
3429 }
3430 
3431 static PetscErrorCode MatSetRandom_SeqAIJ(Mat x, PetscRandom rctx)
3432 {
3433   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)x->data;
3434   PetscScalar a, *aa;
3435   PetscInt    m, n, i, j, col;
3436 
3437   PetscFunctionBegin;
3438   if (!x->assembled) {
3439     PetscCall(MatGetSize(x, &m, &n));
3440     for (i = 0; i < m; i++) {
3441       for (j = 0; j < aij->imax[i]; j++) {
3442         PetscCall(PetscRandomGetValue(rctx, &a));
3443         col = (PetscInt)(n * PetscRealPart(a));
3444         PetscCall(MatSetValues(x, 1, &i, 1, &col, &a, ADD_VALUES));
3445       }
3446     }
3447   } else {
3448     PetscCall(MatSeqAIJGetArrayWrite(x, &aa));
3449     for (i = 0; i < aij->nz; i++) PetscCall(PetscRandomGetValue(rctx, aa + i));
3450     PetscCall(MatSeqAIJRestoreArrayWrite(x, &aa));
3451   }
3452   PetscCall(MatAssemblyBegin(x, MAT_FINAL_ASSEMBLY));
3453   PetscCall(MatAssemblyEnd(x, MAT_FINAL_ASSEMBLY));
3454   PetscFunctionReturn(PETSC_SUCCESS);
3455 }
3456 
3457 /* Like MatSetRandom_SeqAIJ, but do not set values on columns in range of [low, high) */
3458 PetscErrorCode MatSetRandomSkipColumnRange_SeqAIJ_Private(Mat x, PetscInt low, PetscInt high, PetscRandom rctx)
3459 {
3460   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)x->data;
3461   PetscScalar a;
3462   PetscInt    m, n, i, j, col, nskip;
3463 
3464   PetscFunctionBegin;
3465   nskip = high - low;
3466   PetscCall(MatGetSize(x, &m, &n));
3467   n -= nskip; /* shrink number of columns where nonzeros can be set */
3468   for (i = 0; i < m; i++) {
3469     for (j = 0; j < aij->imax[i]; j++) {
3470       PetscCall(PetscRandomGetValue(rctx, &a));
3471       col = (PetscInt)(n * PetscRealPart(a));
3472       if (col >= low) col += nskip; /* shift col rightward to skip the hole */
3473       PetscCall(MatSetValues(x, 1, &i, 1, &col, &a, ADD_VALUES));
3474     }
3475   }
3476   PetscCall(MatAssemblyBegin(x, MAT_FINAL_ASSEMBLY));
3477   PetscCall(MatAssemblyEnd(x, MAT_FINAL_ASSEMBLY));
3478   PetscFunctionReturn(PETSC_SUCCESS);
3479 }
3480 
3481 static struct _MatOps MatOps_Values = {MatSetValues_SeqAIJ,
3482                                        MatGetRow_SeqAIJ,
3483                                        MatRestoreRow_SeqAIJ,
3484                                        MatMult_SeqAIJ,
3485                                        /*  4*/ MatMultAdd_SeqAIJ,
3486                                        MatMultTranspose_SeqAIJ,
3487                                        MatMultTransposeAdd_SeqAIJ,
3488                                        NULL,
3489                                        NULL,
3490                                        NULL,
3491                                        /* 10*/ NULL,
3492                                        MatLUFactor_SeqAIJ,
3493                                        NULL,
3494                                        MatSOR_SeqAIJ,
3495                                        MatTranspose_SeqAIJ,
3496                                        /*1 5*/ MatGetInfo_SeqAIJ,
3497                                        MatEqual_SeqAIJ,
3498                                        MatGetDiagonal_SeqAIJ,
3499                                        MatDiagonalScale_SeqAIJ,
3500                                        MatNorm_SeqAIJ,
3501                                        /* 20*/ NULL,
3502                                        MatAssemblyEnd_SeqAIJ,
3503                                        MatSetOption_SeqAIJ,
3504                                        MatZeroEntries_SeqAIJ,
3505                                        /* 24*/ MatZeroRows_SeqAIJ,
3506                                        NULL,
3507                                        NULL,
3508                                        NULL,
3509                                        NULL,
3510                                        /* 29*/ MatSetUp_Seq_Hash,
3511                                        NULL,
3512                                        NULL,
3513                                        NULL,
3514                                        NULL,
3515                                        /* 34*/ MatDuplicate_SeqAIJ,
3516                                        NULL,
3517                                        NULL,
3518                                        MatILUFactor_SeqAIJ,
3519                                        NULL,
3520                                        /* 39*/ MatAXPY_SeqAIJ,
3521                                        MatCreateSubMatrices_SeqAIJ,
3522                                        MatIncreaseOverlap_SeqAIJ,
3523                                        MatGetValues_SeqAIJ,
3524                                        MatCopy_SeqAIJ,
3525                                        /* 44*/ MatGetRowMax_SeqAIJ,
3526                                        MatScale_SeqAIJ,
3527                                        MatShift_SeqAIJ,
3528                                        MatDiagonalSet_SeqAIJ,
3529                                        MatZeroRowsColumns_SeqAIJ,
3530                                        /* 49*/ MatSetRandom_SeqAIJ,
3531                                        MatGetRowIJ_SeqAIJ,
3532                                        MatRestoreRowIJ_SeqAIJ,
3533                                        MatGetColumnIJ_SeqAIJ,
3534                                        MatRestoreColumnIJ_SeqAIJ,
3535                                        /* 54*/ MatFDColoringCreate_SeqXAIJ,
3536                                        NULL,
3537                                        NULL,
3538                                        MatPermute_SeqAIJ,
3539                                        NULL,
3540                                        /* 59*/ NULL,
3541                                        MatDestroy_SeqAIJ,
3542                                        MatView_SeqAIJ,
3543                                        NULL,
3544                                        NULL,
3545                                        /* 64*/ NULL,
3546                                        MatMatMatMultNumeric_SeqAIJ_SeqAIJ_SeqAIJ,
3547                                        NULL,
3548                                        NULL,
3549                                        NULL,
3550                                        /* 69*/ MatGetRowMaxAbs_SeqAIJ,
3551                                        MatGetRowMinAbs_SeqAIJ,
3552                                        NULL,
3553                                        NULL,
3554                                        NULL,
3555                                        /* 74*/ NULL,
3556                                        MatFDColoringApply_AIJ,
3557                                        NULL,
3558                                        NULL,
3559                                        NULL,
3560                                        /* 79*/ MatFindZeroDiagonals_SeqAIJ,
3561                                        NULL,
3562                                        NULL,
3563                                        NULL,
3564                                        MatLoad_SeqAIJ,
3565                                        /* 84*/ NULL,
3566                                        NULL,
3567                                        NULL,
3568                                        NULL,
3569                                        NULL,
3570                                        /* 89*/ NULL,
3571                                        NULL,
3572                                        MatMatMultNumeric_SeqAIJ_SeqAIJ,
3573                                        NULL,
3574                                        NULL,
3575                                        /* 94*/ MatPtAPNumeric_SeqAIJ_SeqAIJ_SparseAxpy,
3576                                        NULL,
3577                                        NULL,
3578                                        MatMatTransposeMultNumeric_SeqAIJ_SeqAIJ,
3579                                        NULL,
3580                                        /* 99*/ MatProductSetFromOptions_SeqAIJ,
3581                                        NULL,
3582                                        NULL,
3583                                        MatConjugate_SeqAIJ,
3584                                        NULL,
3585                                        /*104*/ MatSetValuesRow_SeqAIJ,
3586                                        MatRealPart_SeqAIJ,
3587                                        MatImaginaryPart_SeqAIJ,
3588                                        NULL,
3589                                        NULL,
3590                                        /*109*/ MatMatSolve_SeqAIJ,
3591                                        NULL,
3592                                        MatGetRowMin_SeqAIJ,
3593                                        NULL,
3594                                        MatMissingDiagonal_SeqAIJ,
3595                                        /*114*/ NULL,
3596                                        NULL,
3597                                        NULL,
3598                                        NULL,
3599                                        NULL,
3600                                        /*119*/ NULL,
3601                                        NULL,
3602                                        NULL,
3603                                        NULL,
3604                                        MatGetMultiProcBlock_SeqAIJ,
3605                                        /*124*/ MatFindNonzeroRows_SeqAIJ,
3606                                        MatGetColumnReductions_SeqAIJ,
3607                                        MatInvertBlockDiagonal_SeqAIJ,
3608                                        MatInvertVariableBlockDiagonal_SeqAIJ,
3609                                        NULL,
3610                                        /*129*/ NULL,
3611                                        NULL,
3612                                        NULL,
3613                                        MatTransposeMatMultNumeric_SeqAIJ_SeqAIJ,
3614                                        MatTransposeColoringCreate_SeqAIJ,
3615                                        /*134*/ MatTransColoringApplySpToDen_SeqAIJ,
3616                                        MatTransColoringApplyDenToSp_SeqAIJ,
3617                                        NULL,
3618                                        NULL,
3619                                        MatRARtNumeric_SeqAIJ_SeqAIJ,
3620                                        /*139*/ NULL,
3621                                        NULL,
3622                                        NULL,
3623                                        MatFDColoringSetUp_SeqXAIJ,
3624                                        MatFindOffBlockDiagonalEntries_SeqAIJ,
3625                                        MatCreateMPIMatConcatenateSeqMat_SeqAIJ,
3626                                        /*145*/ MatDestroySubMatrices_SeqAIJ,
3627                                        NULL,
3628                                        NULL,
3629                                        MatCreateGraph_Simple_AIJ,
3630                                        NULL,
3631                                        /*150*/ MatTransposeSymbolic_SeqAIJ,
3632                                        MatEliminateZeros_SeqAIJ,
3633                                        MatGetRowSumAbs_SeqAIJ,
3634                                        NULL,
3635                                        NULL,
3636                                        /*155*/ NULL,
3637                                        MatCopyHashToXAIJ_Seq_Hash};
3638 
3639 static PetscErrorCode MatSeqAIJSetColumnIndices_SeqAIJ(Mat mat, PetscInt *indices)
3640 {
3641   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)mat->data;
3642   PetscInt    i, nz, n;
3643 
3644   PetscFunctionBegin;
3645   nz = aij->maxnz;
3646   n  = mat->rmap->n;
3647   for (i = 0; i < nz; i++) aij->j[i] = indices[i];
3648   aij->nz = nz;
3649   for (i = 0; i < n; i++) aij->ilen[i] = aij->imax[i];
3650   PetscFunctionReturn(PETSC_SUCCESS);
3651 }
3652 
3653 /*
3654  * Given a sparse matrix with global column indices, compact it by using a local column space.
3655  * The result matrix helps saving memory in other algorithms, such as MatPtAPSymbolic_MPIAIJ_MPIAIJ_scalable()
3656  */
3657 PetscErrorCode MatSeqAIJCompactOutExtraColumns_SeqAIJ(Mat mat, ISLocalToGlobalMapping *mapping)
3658 {
3659   Mat_SeqAIJ   *aij = (Mat_SeqAIJ *)mat->data;
3660   PetscHMapI    gid1_lid1;
3661   PetscHashIter tpos;
3662   PetscInt      gid, lid, i, ec, nz = aij->nz;
3663   PetscInt     *garray, *jj = aij->j;
3664 
3665   PetscFunctionBegin;
3666   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
3667   PetscAssertPointer(mapping, 2);
3668   /* use a table */
3669   PetscCall(PetscHMapICreateWithSize(mat->rmap->n, &gid1_lid1));
3670   ec = 0;
3671   for (i = 0; i < nz; i++) {
3672     PetscInt data, gid1 = jj[i] + 1;
3673     PetscCall(PetscHMapIGetWithDefault(gid1_lid1, gid1, 0, &data));
3674     if (!data) {
3675       /* one based table */
3676       PetscCall(PetscHMapISet(gid1_lid1, gid1, ++ec));
3677     }
3678   }
3679   /* form array of columns we need */
3680   PetscCall(PetscMalloc1(ec, &garray));
3681   PetscHashIterBegin(gid1_lid1, tpos);
3682   while (!PetscHashIterAtEnd(gid1_lid1, tpos)) {
3683     PetscHashIterGetKey(gid1_lid1, tpos, gid);
3684     PetscHashIterGetVal(gid1_lid1, tpos, lid);
3685     PetscHashIterNext(gid1_lid1, tpos);
3686     gid--;
3687     lid--;
3688     garray[lid] = gid;
3689   }
3690   PetscCall(PetscSortInt(ec, garray)); /* sort, and rebuild */
3691   PetscCall(PetscHMapIClear(gid1_lid1));
3692   for (i = 0; i < ec; i++) PetscCall(PetscHMapISet(gid1_lid1, garray[i] + 1, i + 1));
3693   /* compact out the extra columns in B */
3694   for (i = 0; i < nz; i++) {
3695     PetscInt gid1 = jj[i] + 1;
3696     PetscCall(PetscHMapIGetWithDefault(gid1_lid1, gid1, 0, &lid));
3697     lid--;
3698     jj[i] = lid;
3699   }
3700   PetscCall(PetscLayoutDestroy(&mat->cmap));
3701   PetscCall(PetscHMapIDestroy(&gid1_lid1));
3702   PetscCall(PetscLayoutCreateFromSizes(PetscObjectComm((PetscObject)mat), ec, ec, 1, &mat->cmap));
3703   PetscCall(ISLocalToGlobalMappingCreate(PETSC_COMM_SELF, mat->cmap->bs, mat->cmap->n, garray, PETSC_OWN_POINTER, mapping));
3704   PetscCall(ISLocalToGlobalMappingSetType(*mapping, ISLOCALTOGLOBALMAPPINGHASH));
3705   PetscFunctionReturn(PETSC_SUCCESS);
3706 }
3707 
3708 /*@
3709   MatSeqAIJSetColumnIndices - Set the column indices for all the rows
3710   in the matrix.
3711 
3712   Input Parameters:
3713 + mat     - the `MATSEQAIJ` matrix
3714 - indices - the column indices
3715 
3716   Level: advanced
3717 
3718   Notes:
3719   This can be called if you have precomputed the nonzero structure of the
3720   matrix and want to provide it to the matrix object to improve the performance
3721   of the `MatSetValues()` operation.
3722 
3723   You MUST have set the correct numbers of nonzeros per row in the call to
3724   `MatCreateSeqAIJ()`, and the columns indices MUST be sorted.
3725 
3726   MUST be called before any calls to `MatSetValues()`
3727 
3728   The indices should start with zero, not one.
3729 
3730 .seealso: [](ch_matrices), `Mat`, `MATSEQAIJ`
3731 @*/
3732 PetscErrorCode MatSeqAIJSetColumnIndices(Mat mat, PetscInt *indices)
3733 {
3734   PetscFunctionBegin;
3735   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
3736   PetscAssertPointer(indices, 2);
3737   PetscUseMethod(mat, "MatSeqAIJSetColumnIndices_C", (Mat, PetscInt *), (mat, indices));
3738   PetscFunctionReturn(PETSC_SUCCESS);
3739 }
3740 
3741 static PetscErrorCode MatStoreValues_SeqAIJ(Mat mat)
3742 {
3743   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)mat->data;
3744   size_t      nz  = aij->i[mat->rmap->n];
3745 
3746   PetscFunctionBegin;
3747   PetscCheck(aij->nonew, PETSC_COMM_SELF, PETSC_ERR_ORDER, "Must call MatSetOption(A,MAT_NEW_NONZERO_LOCATIONS,PETSC_FALSE);first");
3748 
3749   /* allocate space for values if not already there */
3750   if (!aij->saved_values) { PetscCall(PetscMalloc1(nz + 1, &aij->saved_values)); }
3751 
3752   /* copy values over */
3753   PetscCall(PetscArraycpy(aij->saved_values, aij->a, nz));
3754   PetscFunctionReturn(PETSC_SUCCESS);
3755 }
3756 
3757 /*@
3758   MatStoreValues - Stashes a copy of the matrix values; this allows reusing of the linear part of a Jacobian, while recomputing only the
3759   nonlinear portion.
3760 
3761   Logically Collect
3762 
3763   Input Parameter:
3764 . mat - the matrix (currently only `MATAIJ` matrices support this option)
3765 
3766   Level: advanced
3767 
3768   Example Usage:
3769 .vb
3770     Using SNES
3771     Create Jacobian matrix
3772     Set linear terms into matrix
3773     Apply boundary conditions to matrix, at this time matrix must have
3774       final nonzero structure (i.e. setting the nonlinear terms and applying
3775       boundary conditions again will not change the nonzero structure
3776     MatSetOption(mat, MAT_NEW_NONZERO_LOCATIONS, PETSC_FALSE);
3777     MatStoreValues(mat);
3778     Call SNESSetJacobian() with matrix
3779     In your Jacobian routine
3780       MatRetrieveValues(mat);
3781       Set nonlinear terms in matrix
3782 
3783     Without `SNESSolve()`, i.e. when you handle nonlinear solve yourself:
3784     // build linear portion of Jacobian
3785     MatSetOption(mat, MAT_NEW_NONZERO_LOCATIONS, PETSC_FALSE);
3786     MatStoreValues(mat);
3787     loop over nonlinear iterations
3788        MatRetrieveValues(mat);
3789        // call MatSetValues(mat,...) to set nonliner portion of Jacobian
3790        // call MatAssemblyBegin/End() on matrix
3791        Solve linear system with Jacobian
3792     endloop
3793 .ve
3794 
3795   Notes:
3796   Matrix must already be assembled before calling this routine
3797   Must set the matrix option `MatSetOption`(mat,`MAT_NEW_NONZERO_LOCATIONS`,`PETSC_FALSE`); before
3798   calling this routine.
3799 
3800   When this is called multiple times it overwrites the previous set of stored values
3801   and does not allocated additional space.
3802 
3803 .seealso: [](ch_matrices), `Mat`, `MatRetrieveValues()`
3804 @*/
3805 PetscErrorCode MatStoreValues(Mat mat)
3806 {
3807   PetscFunctionBegin;
3808   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
3809   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3810   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3811   PetscUseMethod(mat, "MatStoreValues_C", (Mat), (mat));
3812   PetscFunctionReturn(PETSC_SUCCESS);
3813 }
3814 
3815 static PetscErrorCode MatRetrieveValues_SeqAIJ(Mat mat)
3816 {
3817   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)mat->data;
3818   PetscInt    nz  = aij->i[mat->rmap->n];
3819 
3820   PetscFunctionBegin;
3821   PetscCheck(aij->nonew, PETSC_COMM_SELF, PETSC_ERR_ORDER, "Must call MatSetOption(A,MAT_NEW_NONZERO_LOCATIONS,PETSC_FALSE);first");
3822   PetscCheck(aij->saved_values, PETSC_COMM_SELF, PETSC_ERR_ORDER, "Must call MatStoreValues(A);first");
3823   /* copy values over */
3824   PetscCall(PetscArraycpy(aij->a, aij->saved_values, nz));
3825   PetscFunctionReturn(PETSC_SUCCESS);
3826 }
3827 
3828 /*@
3829   MatRetrieveValues - Retrieves the copy of the matrix values that was stored with `MatStoreValues()`
3830 
3831   Logically Collect
3832 
3833   Input Parameter:
3834 . mat - the matrix (currently only `MATAIJ` matrices support this option)
3835 
3836   Level: advanced
3837 
3838 .seealso: [](ch_matrices), `Mat`, `MatStoreValues()`
3839 @*/
3840 PetscErrorCode MatRetrieveValues(Mat mat)
3841 {
3842   PetscFunctionBegin;
3843   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
3844   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3845   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3846   PetscUseMethod(mat, "MatRetrieveValues_C", (Mat), (mat));
3847   PetscFunctionReturn(PETSC_SUCCESS);
3848 }
3849 
3850 /*@
3851   MatCreateSeqAIJ - Creates a sparse matrix in `MATSEQAIJ` (compressed row) format
3852   (the default parallel PETSc format).  For good matrix assembly performance
3853   the user should preallocate the matrix storage by setting the parameter `nz`
3854   (or the array `nnz`).
3855 
3856   Collective
3857 
3858   Input Parameters:
3859 + comm - MPI communicator, set to `PETSC_COMM_SELF`
3860 . m    - number of rows
3861 . n    - number of columns
3862 . nz   - number of nonzeros per row (same for all rows)
3863 - nnz  - array containing the number of nonzeros in the various rows
3864          (possibly different for each row) or NULL
3865 
3866   Output Parameter:
3867 . A - the matrix
3868 
3869   Options Database Keys:
3870 + -mat_no_inode            - Do not use inodes
3871 - -mat_inode_limit <limit> - Sets inode limit (max limit=5)
3872 
3873   Level: intermediate
3874 
3875   Notes:
3876   It is recommend to use `MatCreateFromOptions()` instead of this routine
3877 
3878   If `nnz` is given then `nz` is ignored
3879 
3880   The `MATSEQAIJ` format, also called
3881   compressed row storage, is fully compatible with standard Fortran
3882   storage.  That is, the stored row and column indices can begin at
3883   either one (as in Fortran) or zero.
3884 
3885   Specify the preallocated storage with either `nz` or `nnz` (not both).
3886   Set `nz` = `PETSC_DEFAULT` and `nnz` = `NULL` for PETSc to control dynamic memory
3887   allocation.
3888 
3889   By default, this format uses inodes (identical nodes) when possible, to
3890   improve numerical efficiency of matrix-vector products and solves. We
3891   search for consecutive rows with the same nonzero structure, thereby
3892   reusing matrix information to achieve increased efficiency.
3893 
3894 .seealso: [](ch_matrices), `Mat`, [Sparse Matrix Creation](sec_matsparse), `MatCreate()`, `MatCreateAIJ()`, `MatSetValues()`, `MatSeqAIJSetColumnIndices()`, `MatCreateSeqAIJWithArrays()`
3895 @*/
3896 PetscErrorCode MatCreateSeqAIJ(MPI_Comm comm, PetscInt m, PetscInt n, PetscInt nz, const PetscInt nnz[], Mat *A)
3897 {
3898   PetscFunctionBegin;
3899   PetscCall(MatCreate(comm, A));
3900   PetscCall(MatSetSizes(*A, m, n, m, n));
3901   PetscCall(MatSetType(*A, MATSEQAIJ));
3902   PetscCall(MatSeqAIJSetPreallocation_SeqAIJ(*A, nz, nnz));
3903   PetscFunctionReturn(PETSC_SUCCESS);
3904 }
3905 
3906 /*@
3907   MatSeqAIJSetPreallocation - For good matrix assembly performance
3908   the user should preallocate the matrix storage by setting the parameter nz
3909   (or the array nnz).  By setting these parameters accurately, performance
3910   during matrix assembly can be increased by more than a factor of 50.
3911 
3912   Collective
3913 
3914   Input Parameters:
3915 + B   - The matrix
3916 . nz  - number of nonzeros per row (same for all rows)
3917 - nnz - array containing the number of nonzeros in the various rows
3918          (possibly different for each row) or NULL
3919 
3920   Options Database Keys:
3921 + -mat_no_inode            - Do not use inodes
3922 - -mat_inode_limit <limit> - Sets inode limit (max limit=5)
3923 
3924   Level: intermediate
3925 
3926   Notes:
3927   If `nnz` is given then `nz` is ignored
3928 
3929   The `MATSEQAIJ` format also called
3930   compressed row storage, is fully compatible with standard Fortran
3931   storage.  That is, the stored row and column indices can begin at
3932   either one (as in Fortran) or zero.  See the users' manual for details.
3933 
3934   Specify the preallocated storage with either `nz` or `nnz` (not both).
3935   Set nz = `PETSC_DEFAULT` and `nnz` = `NULL` for PETSc to control dynamic memory
3936   allocation.
3937 
3938   You can call `MatGetInfo()` to get information on how effective the preallocation was;
3939   for example the fields mallocs,nz_allocated,nz_used,nz_unneeded;
3940   You can also run with the option -info and look for messages with the string
3941   malloc in them to see if additional memory allocation was needed.
3942 
3943   Developer Notes:
3944   Use nz of `MAT_SKIP_ALLOCATION` to not allocate any space for the matrix
3945   entries or columns indices
3946 
3947   By default, this format uses inodes (identical nodes) when possible, to
3948   improve numerical efficiency of matrix-vector products and solves. We
3949   search for consecutive rows with the same nonzero structure, thereby
3950   reusing matrix information to achieve increased efficiency.
3951 
3952 .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatCreateAIJ()`, `MatSetValues()`, `MatSeqAIJSetColumnIndices()`, `MatCreateSeqAIJWithArrays()`, `MatGetInfo()`,
3953           `MatSeqAIJSetTotalPreallocation()`
3954 @*/
3955 PetscErrorCode MatSeqAIJSetPreallocation(Mat B, PetscInt nz, const PetscInt nnz[])
3956 {
3957   PetscFunctionBegin;
3958   PetscValidHeaderSpecific(B, MAT_CLASSID, 1);
3959   PetscValidType(B, 1);
3960   PetscTryMethod(B, "MatSeqAIJSetPreallocation_C", (Mat, PetscInt, const PetscInt[]), (B, nz, nnz));
3961   PetscFunctionReturn(PETSC_SUCCESS);
3962 }
3963 
3964 PetscErrorCode MatSeqAIJSetPreallocation_SeqAIJ(Mat B, PetscInt nz, const PetscInt *nnz)
3965 {
3966   Mat_SeqAIJ *b              = (Mat_SeqAIJ *)B->data;
3967   PetscBool   skipallocation = PETSC_FALSE, realalloc = PETSC_FALSE;
3968   PetscInt    i;
3969 
3970   PetscFunctionBegin;
3971   if (B->hash_active) {
3972     B->ops[0] = b->cops;
3973     PetscCall(PetscHMapIJVDestroy(&b->ht));
3974     PetscCall(PetscFree(b->dnz));
3975     B->hash_active = PETSC_FALSE;
3976   }
3977   if (nz >= 0 || nnz) realalloc = PETSC_TRUE;
3978   if (nz == MAT_SKIP_ALLOCATION) {
3979     skipallocation = PETSC_TRUE;
3980     nz             = 0;
3981   }
3982   PetscCall(PetscLayoutSetUp(B->rmap));
3983   PetscCall(PetscLayoutSetUp(B->cmap));
3984 
3985   if (nz == PETSC_DEFAULT || nz == PETSC_DECIDE) nz = 5;
3986   PetscCheck(nz >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "nz cannot be less than 0: value %" PetscInt_FMT, nz);
3987   if (nnz) {
3988     for (i = 0; i < B->rmap->n; i++) {
3989       PetscCheck(nnz[i] >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "nnz cannot be less than 0: local row %" PetscInt_FMT " value %" PetscInt_FMT, i, nnz[i]);
3990       PetscCheck(nnz[i] <= B->cmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "nnz cannot be greater than row length: local row %" PetscInt_FMT " value %" PetscInt_FMT " rowlength %" PetscInt_FMT, i, nnz[i], B->cmap->n);
3991     }
3992   }
3993 
3994   B->preallocated = PETSC_TRUE;
3995   if (!skipallocation) {
3996     if (!b->imax) { PetscCall(PetscMalloc1(B->rmap->n, &b->imax)); }
3997     if (!b->ilen) {
3998       /* b->ilen will count nonzeros in each row so far. */
3999       PetscCall(PetscCalloc1(B->rmap->n, &b->ilen));
4000     } else {
4001       PetscCall(PetscMemzero(b->ilen, B->rmap->n * sizeof(PetscInt)));
4002     }
4003     if (!b->ipre) PetscCall(PetscMalloc1(B->rmap->n, &b->ipre));
4004     if (!nnz) {
4005       if (nz == PETSC_DEFAULT || nz == PETSC_DECIDE) nz = 10;
4006       else if (nz < 0) nz = 1;
4007       nz = PetscMin(nz, B->cmap->n);
4008       for (i = 0; i < B->rmap->n; i++) b->imax[i] = nz;
4009       PetscCall(PetscIntMultError(nz, B->rmap->n, &nz));
4010     } else {
4011       PetscInt64 nz64 = 0;
4012       for (i = 0; i < B->rmap->n; i++) {
4013         b->imax[i] = nnz[i];
4014         nz64 += nnz[i];
4015       }
4016       PetscCall(PetscIntCast(nz64, &nz));
4017     }
4018 
4019     /* allocate the matrix space */
4020     PetscCall(MatSeqXAIJFreeAIJ(B, &b->a, &b->j, &b->i));
4021     PetscCall(PetscShmgetAllocateArray(nz, sizeof(PetscInt), (void **)&b->j));
4022     PetscCall(PetscShmgetAllocateArray(B->rmap->n + 1, sizeof(PetscInt), (void **)&b->i));
4023     b->free_ij = PETSC_TRUE;
4024     if (B->structure_only) {
4025       b->free_a = PETSC_FALSE;
4026     } else {
4027       PetscCall(PetscShmgetAllocateArray(nz, sizeof(PetscScalar), (void **)&b->a));
4028       b->free_a = PETSC_TRUE;
4029     }
4030     b->i[0] = 0;
4031     for (i = 1; i < B->rmap->n + 1; i++) b->i[i] = b->i[i - 1] + b->imax[i - 1];
4032   } else {
4033     b->free_a  = PETSC_FALSE;
4034     b->free_ij = PETSC_FALSE;
4035   }
4036 
4037   if (b->ipre && nnz != b->ipre && b->imax) {
4038     /* reserve user-requested sparsity */
4039     PetscCall(PetscArraycpy(b->ipre, b->imax, B->rmap->n));
4040   }
4041 
4042   b->nz               = 0;
4043   b->maxnz            = nz;
4044   B->info.nz_unneeded = (double)b->maxnz;
4045   if (realalloc) PetscCall(MatSetOption(B, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_TRUE));
4046   B->was_assembled = PETSC_FALSE;
4047   B->assembled     = PETSC_FALSE;
4048   /* We simply deem preallocation has changed nonzero state. Updating the state
4049      will give clients (like AIJKokkos) a chance to know something has happened.
4050   */
4051   B->nonzerostate++;
4052   PetscFunctionReturn(PETSC_SUCCESS);
4053 }
4054 
4055 PetscErrorCode MatResetPreallocation_SeqAIJ_Private(Mat A, PetscBool *memoryreset)
4056 {
4057   Mat_SeqAIJ *a;
4058   PetscInt    i;
4059   PetscBool   skipreset;
4060 
4061   PetscFunctionBegin;
4062   PetscValidHeaderSpecific(A, MAT_CLASSID, 1);
4063 
4064   PetscCheck(A->insertmode == NOT_SET_VALUES, PETSC_COMM_SELF, PETSC_ERR_SUP, "Cannot reset preallocation after setting some values but not yet calling MatAssemblyBegin()/MatAssemblyEnd()");
4065   if (A->num_ass == 0) PetscFunctionReturn(PETSC_SUCCESS);
4066 
4067   /* Check local size. If zero, then return */
4068   if (!A->rmap->n) PetscFunctionReturn(PETSC_SUCCESS);
4069 
4070   a = (Mat_SeqAIJ *)A->data;
4071   /* if no saved info, we error out */
4072   PetscCheck(a->ipre, PETSC_COMM_SELF, PETSC_ERR_ARG_NULL, "No saved preallocation info ");
4073 
4074   PetscCheck(a->i && a->imax && a->ilen, PETSC_COMM_SELF, PETSC_ERR_ARG_NULL, "Memory info is incomplete, and cannot reset preallocation ");
4075 
4076   PetscCall(PetscArraycmp(a->ipre, a->ilen, A->rmap->n, &skipreset));
4077   if (skipreset) PetscCall(MatZeroEntries(A));
4078   else {
4079     PetscCall(PetscArraycpy(a->imax, a->ipre, A->rmap->n));
4080     PetscCall(PetscArrayzero(a->ilen, A->rmap->n));
4081     a->i[0] = 0;
4082     for (i = 1; i < A->rmap->n + 1; i++) a->i[i] = a->i[i - 1] + a->imax[i - 1];
4083     A->preallocated     = PETSC_TRUE;
4084     a->nz               = 0;
4085     a->maxnz            = a->i[A->rmap->n];
4086     A->info.nz_unneeded = (double)a->maxnz;
4087     A->was_assembled    = PETSC_FALSE;
4088     A->assembled        = PETSC_FALSE;
4089     A->nonzerostate++;
4090     /* Log that the state of this object has changed; this will help guarantee that preconditioners get re-setup */
4091     PetscCall(PetscObjectStateIncrease((PetscObject)A));
4092   }
4093   if (memoryreset) *memoryreset = (PetscBool)!skipreset;
4094   PetscFunctionReturn(PETSC_SUCCESS);
4095 }
4096 
4097 static PetscErrorCode MatResetPreallocation_SeqAIJ(Mat A)
4098 {
4099   PetscFunctionBegin;
4100   PetscCall(MatResetPreallocation_SeqAIJ_Private(A, NULL));
4101   PetscFunctionReturn(PETSC_SUCCESS);
4102 }
4103 
4104 /*@
4105   MatSeqAIJSetPreallocationCSR - Allocates memory for a sparse sequential matrix in `MATSEQAIJ` format.
4106 
4107   Input Parameters:
4108 + B - the matrix
4109 . i - the indices into `j` for the start of each row (indices start with zero)
4110 . j - the column indices for each row (indices start with zero) these must be sorted for each row
4111 - v - optional values in the matrix, use `NULL` if not provided
4112 
4113   Level: developer
4114 
4115   Notes:
4116   The `i`,`j`,`v` values are COPIED with this routine; to avoid the copy use `MatCreateSeqAIJWithArrays()`
4117 
4118   This routine may be called multiple times with different nonzero patterns (or the same nonzero pattern). The nonzero
4119   structure will be the union of all the previous nonzero structures.
4120 
4121   Developer Notes:
4122   An optimization could be added to the implementation where it checks if the `i`, and `j` are identical to the current `i` and `j` and
4123   then just copies the `v` values directly with `PetscMemcpy()`.
4124 
4125   This routine could also take a `PetscCopyMode` argument to allow sharing the values instead of always copying them.
4126 
4127 .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatCreateSeqAIJ()`, `MatSetValues()`, `MatSeqAIJSetPreallocation()`, `MATSEQAIJ`, `MatResetPreallocation()`
4128 @*/
4129 PetscErrorCode MatSeqAIJSetPreallocationCSR(Mat B, const PetscInt i[], const PetscInt j[], const PetscScalar v[])
4130 {
4131   PetscFunctionBegin;
4132   PetscValidHeaderSpecific(B, MAT_CLASSID, 1);
4133   PetscValidType(B, 1);
4134   PetscTryMethod(B, "MatSeqAIJSetPreallocationCSR_C", (Mat, const PetscInt[], const PetscInt[], const PetscScalar[]), (B, i, j, v));
4135   PetscFunctionReturn(PETSC_SUCCESS);
4136 }
4137 
4138 static PetscErrorCode MatSeqAIJSetPreallocationCSR_SeqAIJ(Mat B, const PetscInt Ii[], const PetscInt J[], const PetscScalar v[])
4139 {
4140   PetscInt  i;
4141   PetscInt  m, n;
4142   PetscInt  nz;
4143   PetscInt *nnz;
4144 
4145   PetscFunctionBegin;
4146   PetscCheck(Ii[0] == 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Ii[0] must be 0 it is %" PetscInt_FMT, Ii[0]);
4147 
4148   PetscCall(PetscLayoutSetUp(B->rmap));
4149   PetscCall(PetscLayoutSetUp(B->cmap));
4150 
4151   PetscCall(MatGetSize(B, &m, &n));
4152   PetscCall(PetscMalloc1(m + 1, &nnz));
4153   for (i = 0; i < m; i++) {
4154     nz = Ii[i + 1] - Ii[i];
4155     PetscCheck(nz >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Local row %" PetscInt_FMT " has a negative number of columns %" PetscInt_FMT, i, nz);
4156     nnz[i] = nz;
4157   }
4158   PetscCall(MatSeqAIJSetPreallocation(B, 0, nnz));
4159   PetscCall(PetscFree(nnz));
4160 
4161   for (i = 0; i < m; i++) PetscCall(MatSetValues_SeqAIJ(B, 1, &i, Ii[i + 1] - Ii[i], J + Ii[i], PetscSafePointerPlusOffset(v, Ii[i]), INSERT_VALUES));
4162 
4163   PetscCall(MatAssemblyBegin(B, MAT_FINAL_ASSEMBLY));
4164   PetscCall(MatAssemblyEnd(B, MAT_FINAL_ASSEMBLY));
4165 
4166   PetscCall(MatSetOption(B, MAT_NEW_NONZERO_LOCATION_ERR, PETSC_TRUE));
4167   PetscFunctionReturn(PETSC_SUCCESS);
4168 }
4169 
4170 /*@
4171   MatSeqAIJKron - Computes `C`, the Kronecker product of `A` and `B`.
4172 
4173   Input Parameters:
4174 + A     - left-hand side matrix
4175 . B     - right-hand side matrix
4176 - reuse - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
4177 
4178   Output Parameter:
4179 . C - Kronecker product of `A` and `B`
4180 
4181   Level: intermediate
4182 
4183   Note:
4184   `MAT_REUSE_MATRIX` can only be used when the nonzero structure of the product matrix has not changed from that last call to `MatSeqAIJKron()`.
4185 
4186 .seealso: [](ch_matrices), `Mat`, `MatCreateSeqAIJ()`, `MATSEQAIJ`, `MATKAIJ`, `MatReuse`
4187 @*/
4188 PetscErrorCode MatSeqAIJKron(Mat A, Mat B, MatReuse reuse, Mat *C)
4189 {
4190   PetscFunctionBegin;
4191   PetscValidHeaderSpecific(A, MAT_CLASSID, 1);
4192   PetscValidType(A, 1);
4193   PetscValidHeaderSpecific(B, MAT_CLASSID, 2);
4194   PetscValidType(B, 2);
4195   PetscAssertPointer(C, 4);
4196   if (reuse == MAT_REUSE_MATRIX) {
4197     PetscValidHeaderSpecific(*C, MAT_CLASSID, 4);
4198     PetscValidType(*C, 4);
4199   }
4200   PetscTryMethod(A, "MatSeqAIJKron_C", (Mat, Mat, MatReuse, Mat *), (A, B, reuse, C));
4201   PetscFunctionReturn(PETSC_SUCCESS);
4202 }
4203 
4204 static PetscErrorCode MatSeqAIJKron_SeqAIJ(Mat A, Mat B, MatReuse reuse, Mat *C)
4205 {
4206   Mat                newmat;
4207   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data;
4208   Mat_SeqAIJ        *b = (Mat_SeqAIJ *)B->data;
4209   PetscScalar       *v;
4210   const PetscScalar *aa, *ba;
4211   PetscInt          *i, *j, m, n, p, q, nnz = 0, am = A->rmap->n, bm = B->rmap->n, an = A->cmap->n, bn = B->cmap->n;
4212   PetscBool          flg;
4213 
4214   PetscFunctionBegin;
4215   PetscCheck(!A->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
4216   PetscCheck(A->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
4217   PetscCheck(!B->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
4218   PetscCheck(B->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
4219   PetscCall(PetscObjectTypeCompare((PetscObject)B, MATSEQAIJ, &flg));
4220   PetscCheck(flg, PETSC_COMM_SELF, PETSC_ERR_SUP, "MatType %s", ((PetscObject)B)->type_name);
4221   PetscCheck(reuse == MAT_INITIAL_MATRIX || reuse == MAT_REUSE_MATRIX, PETSC_COMM_SELF, PETSC_ERR_SUP, "MatReuse %d", (int)reuse);
4222   if (reuse == MAT_INITIAL_MATRIX) {
4223     PetscCall(PetscMalloc2(am * bm + 1, &i, a->i[am] * b->i[bm], &j));
4224     PetscCall(MatCreate(PETSC_COMM_SELF, &newmat));
4225     PetscCall(MatSetSizes(newmat, am * bm, an * bn, am * bm, an * bn));
4226     PetscCall(MatSetType(newmat, MATAIJ));
4227     i[0] = 0;
4228     for (m = 0; m < am; ++m) {
4229       for (p = 0; p < bm; ++p) {
4230         i[m * bm + p + 1] = i[m * bm + p] + (a->i[m + 1] - a->i[m]) * (b->i[p + 1] - b->i[p]);
4231         for (n = a->i[m]; n < a->i[m + 1]; ++n) {
4232           for (q = b->i[p]; q < b->i[p + 1]; ++q) j[nnz++] = a->j[n] * bn + b->j[q];
4233         }
4234       }
4235     }
4236     PetscCall(MatSeqAIJSetPreallocationCSR(newmat, i, j, NULL));
4237     *C = newmat;
4238     PetscCall(PetscFree2(i, j));
4239     nnz = 0;
4240   }
4241   PetscCall(MatSeqAIJGetArray(*C, &v));
4242   PetscCall(MatSeqAIJGetArrayRead(A, &aa));
4243   PetscCall(MatSeqAIJGetArrayRead(B, &ba));
4244   for (m = 0; m < am; ++m) {
4245     for (p = 0; p < bm; ++p) {
4246       for (n = a->i[m]; n < a->i[m + 1]; ++n) {
4247         for (q = b->i[p]; q < b->i[p + 1]; ++q) v[nnz++] = aa[n] * ba[q];
4248       }
4249     }
4250   }
4251   PetscCall(MatSeqAIJRestoreArray(*C, &v));
4252   PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
4253   PetscCall(MatSeqAIJRestoreArrayRead(B, &ba));
4254   PetscFunctionReturn(PETSC_SUCCESS);
4255 }
4256 
4257 #include <../src/mat/impls/dense/seq/dense.h>
4258 #include <petsc/private/kernels/petscaxpy.h>
4259 
4260 /*
4261     Computes (B'*A')' since computing B*A directly is untenable
4262 
4263                n                       p                          p
4264         [             ]       [             ]         [                 ]
4265       m [      A      ]  *  n [       B     ]   =   m [         C       ]
4266         [             ]       [             ]         [                 ]
4267 
4268 */
4269 PetscErrorCode MatMatMultNumeric_SeqDense_SeqAIJ(Mat A, Mat B, Mat C)
4270 {
4271   Mat_SeqDense      *sub_a = (Mat_SeqDense *)A->data;
4272   Mat_SeqAIJ        *sub_b = (Mat_SeqAIJ *)B->data;
4273   Mat_SeqDense      *sub_c = (Mat_SeqDense *)C->data;
4274   PetscInt           i, j, n, m, q, p;
4275   const PetscInt    *ii, *idx;
4276   const PetscScalar *b, *a, *a_q;
4277   PetscScalar       *c, *c_q;
4278   PetscInt           clda = sub_c->lda;
4279   PetscInt           alda = sub_a->lda;
4280 
4281   PetscFunctionBegin;
4282   m = A->rmap->n;
4283   n = A->cmap->n;
4284   p = B->cmap->n;
4285   a = sub_a->v;
4286   b = sub_b->a;
4287   c = sub_c->v;
4288   if (clda == m) {
4289     PetscCall(PetscArrayzero(c, m * p));
4290   } else {
4291     for (j = 0; j < p; j++)
4292       for (i = 0; i < m; i++) c[j * clda + i] = 0.0;
4293   }
4294   ii  = sub_b->i;
4295   idx = sub_b->j;
4296   for (i = 0; i < n; i++) {
4297     q = ii[i + 1] - ii[i];
4298     while (q-- > 0) {
4299       c_q = c + clda * (*idx);
4300       a_q = a + alda * i;
4301       PetscKernelAXPY(c_q, *b, a_q, m);
4302       idx++;
4303       b++;
4304     }
4305   }
4306   PetscFunctionReturn(PETSC_SUCCESS);
4307 }
4308 
4309 PetscErrorCode MatMatMultSymbolic_SeqDense_SeqAIJ(Mat A, Mat B, PetscReal fill, Mat C)
4310 {
4311   PetscInt  m = A->rmap->n, n = B->cmap->n;
4312   PetscBool cisdense;
4313 
4314   PetscFunctionBegin;
4315   PetscCheck(A->cmap->n == B->rmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "A->cmap->n %" PetscInt_FMT " != B->rmap->n %" PetscInt_FMT, A->cmap->n, B->rmap->n);
4316   PetscCall(MatSetSizes(C, m, n, m, n));
4317   PetscCall(MatSetBlockSizesFromMats(C, A, B));
4318   PetscCall(PetscObjectTypeCompareAny((PetscObject)C, &cisdense, MATSEQDENSE, MATSEQDENSECUDA, MATSEQDENSEHIP, ""));
4319   if (!cisdense) PetscCall(MatSetType(C, MATDENSE));
4320   PetscCall(MatSetUp(C));
4321 
4322   C->ops->matmultnumeric = MatMatMultNumeric_SeqDense_SeqAIJ;
4323   PetscFunctionReturn(PETSC_SUCCESS);
4324 }
4325 
4326 /*MC
4327    MATSEQAIJ - MATSEQAIJ = "seqaij" - A matrix type to be used for sequential sparse matrices,
4328    based on compressed sparse row format.
4329 
4330    Options Database Key:
4331 . -mat_type seqaij - sets the matrix type to "seqaij" during a call to MatSetFromOptions()
4332 
4333    Level: beginner
4334 
4335    Notes:
4336     `MatSetValues()` may be called for this matrix type with a `NULL` argument for the numerical values,
4337     in this case the values associated with the rows and columns one passes in are set to zero
4338     in the matrix
4339 
4340     `MatSetOptions`(,`MAT_STRUCTURE_ONLY`,`PETSC_TRUE`) may be called for this matrix type. In this no
4341     space is allocated for the nonzero entries and any entries passed with `MatSetValues()` are ignored
4342 
4343   Developer Note:
4344     It would be nice if all matrix formats supported passing `NULL` in for the numerical values
4345 
4346 .seealso: [](ch_matrices), `Mat`, `MatCreateSeqAIJ()`, `MatSetFromOptions()`, `MatSetType()`, `MatCreate()`, `MatType`, `MATSELL`, `MATSEQSELL`, `MATMPISELL`
4347 M*/
4348 
4349 /*MC
4350    MATAIJ - MATAIJ = "aij" - A matrix type to be used for sparse matrices.
4351 
4352    This matrix type is identical to `MATSEQAIJ` when constructed with a single process communicator,
4353    and `MATMPIAIJ` otherwise.  As a result, for single process communicators,
4354    `MatSeqAIJSetPreallocation()` is supported, and similarly `MatMPIAIJSetPreallocation()` is supported
4355    for communicators controlling multiple processes.  It is recommended that you call both of
4356    the above preallocation routines for simplicity.
4357 
4358    Options Database Key:
4359 . -mat_type aij - sets the matrix type to "aij" during a call to `MatSetFromOptions()`
4360 
4361   Level: beginner
4362 
4363    Note:
4364    Subclasses include `MATAIJCUSPARSE`, `MATAIJPERM`, `MATAIJSELL`, `MATAIJMKL`, `MATAIJCRL`, and also automatically switches over to use inodes when
4365    enough exist.
4366 
4367 .seealso: [](ch_matrices), `Mat`, `MatCreateAIJ()`, `MatCreateSeqAIJ()`, `MATSEQAIJ`, `MATMPIAIJ`, `MATSELL`, `MATSEQSELL`, `MATMPISELL`
4368 M*/
4369 
4370 /*MC
4371    MATAIJCRL - MATAIJCRL = "aijcrl" - A matrix type to be used for sparse matrices.
4372 
4373    Options Database Key:
4374 . -mat_type aijcrl - sets the matrix type to "aijcrl" during a call to `MatSetFromOptions()`
4375 
4376   Level: beginner
4377 
4378    Note:
4379    This matrix type is identical to `MATSEQAIJCRL` when constructed with a single process communicator,
4380    and `MATMPIAIJCRL` otherwise.  As a result, for single process communicators,
4381    `MatSeqAIJSetPreallocation()` is supported, and similarly `MatMPIAIJSetPreallocation()` is supported
4382    for communicators controlling multiple processes.  It is recommended that you call both of
4383    the above preallocation routines for simplicity.
4384 
4385 .seealso: [](ch_matrices), `Mat`, `MatCreateMPIAIJCRL`, `MATSEQAIJCRL`, `MATMPIAIJCRL`, `MATSEQAIJCRL`, `MATMPIAIJCRL`
4386 M*/
4387 
4388 PETSC_INTERN PetscErrorCode MatConvert_SeqAIJ_SeqAIJCRL(Mat, MatType, MatReuse, Mat *);
4389 #if defined(PETSC_HAVE_ELEMENTAL)
4390 PETSC_INTERN PetscErrorCode MatConvert_SeqAIJ_Elemental(Mat, MatType, MatReuse, Mat *);
4391 #endif
4392 #if defined(PETSC_HAVE_SCALAPACK)
4393 PETSC_INTERN PetscErrorCode MatConvert_AIJ_ScaLAPACK(Mat, MatType, MatReuse, Mat *);
4394 #endif
4395 #if defined(PETSC_HAVE_HYPRE)
4396 PETSC_INTERN PetscErrorCode MatConvert_AIJ_HYPRE(Mat A, MatType, MatReuse, Mat *);
4397 #endif
4398 
4399 PETSC_EXTERN PetscErrorCode MatConvert_SeqAIJ_SeqSELL(Mat, MatType, MatReuse, Mat *);
4400 PETSC_INTERN PetscErrorCode MatConvert_XAIJ_IS(Mat, MatType, MatReuse, Mat *);
4401 PETSC_INTERN PetscErrorCode MatProductSetFromOptions_IS_XAIJ(Mat);
4402 
4403 /*@C
4404   MatSeqAIJGetArray - gives read/write access to the array where the data for a `MATSEQAIJ` matrix is stored
4405 
4406   Not Collective
4407 
4408   Input Parameter:
4409 . A - a `MATSEQAIJ` matrix
4410 
4411   Output Parameter:
4412 . array - pointer to the data
4413 
4414   Level: intermediate
4415 
4416 .seealso: [](ch_matrices), `Mat`, `MatSeqAIJRestoreArray()`
4417 @*/
4418 PetscErrorCode MatSeqAIJGetArray(Mat A, PetscScalar *array[])
4419 {
4420   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)A->data;
4421 
4422   PetscFunctionBegin;
4423   if (aij->ops->getarray) {
4424     PetscCall((*aij->ops->getarray)(A, array));
4425   } else {
4426     *array = aij->a;
4427   }
4428   PetscFunctionReturn(PETSC_SUCCESS);
4429 }
4430 
4431 /*@C
4432   MatSeqAIJRestoreArray - returns access to the array where the data for a `MATSEQAIJ` matrix is stored obtained by `MatSeqAIJGetArray()`
4433 
4434   Not Collective
4435 
4436   Input Parameters:
4437 + A     - a `MATSEQAIJ` matrix
4438 - array - pointer to the data
4439 
4440   Level: intermediate
4441 
4442 .seealso: [](ch_matrices), `Mat`, `MatSeqAIJGetArray()`
4443 @*/
4444 PetscErrorCode MatSeqAIJRestoreArray(Mat A, PetscScalar *array[])
4445 {
4446   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)A->data;
4447 
4448   PetscFunctionBegin;
4449   if (aij->ops->restorearray) {
4450     PetscCall((*aij->ops->restorearray)(A, array));
4451   } else {
4452     *array = NULL;
4453   }
4454   PetscCall(MatSeqAIJInvalidateDiagonal(A));
4455   PetscCall(PetscObjectStateIncrease((PetscObject)A));
4456   PetscFunctionReturn(PETSC_SUCCESS);
4457 }
4458 
4459 /*@C
4460   MatSeqAIJGetArrayRead - gives read-only access to the array where the data for a `MATSEQAIJ` matrix is stored
4461 
4462   Not Collective; No Fortran Support
4463 
4464   Input Parameter:
4465 . A - a `MATSEQAIJ` matrix
4466 
4467   Output Parameter:
4468 . array - pointer to the data
4469 
4470   Level: intermediate
4471 
4472 .seealso: [](ch_matrices), `Mat`, `MatSeqAIJGetArray()`, `MatSeqAIJRestoreArrayRead()`
4473 @*/
4474 PetscErrorCode MatSeqAIJGetArrayRead(Mat A, const PetscScalar *array[])
4475 {
4476   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)A->data;
4477 
4478   PetscFunctionBegin;
4479   if (aij->ops->getarrayread) {
4480     PetscCall((*aij->ops->getarrayread)(A, array));
4481   } else {
4482     *array = aij->a;
4483   }
4484   PetscFunctionReturn(PETSC_SUCCESS);
4485 }
4486 
4487 /*@C
4488   MatSeqAIJRestoreArrayRead - restore the read-only access array obtained from `MatSeqAIJGetArrayRead()`
4489 
4490   Not Collective; No Fortran Support
4491 
4492   Input Parameter:
4493 . A - a `MATSEQAIJ` matrix
4494 
4495   Output Parameter:
4496 . array - pointer to the data
4497 
4498   Level: intermediate
4499 
4500 .seealso: [](ch_matrices), `Mat`, `MatSeqAIJGetArray()`, `MatSeqAIJGetArrayRead()`
4501 @*/
4502 PetscErrorCode MatSeqAIJRestoreArrayRead(Mat A, const PetscScalar *array[])
4503 {
4504   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)A->data;
4505 
4506   PetscFunctionBegin;
4507   if (aij->ops->restorearrayread) {
4508     PetscCall((*aij->ops->restorearrayread)(A, array));
4509   } else {
4510     *array = NULL;
4511   }
4512   PetscFunctionReturn(PETSC_SUCCESS);
4513 }
4514 
4515 /*@C
4516   MatSeqAIJGetArrayWrite - gives write-only access to the array where the data for a `MATSEQAIJ` matrix is stored
4517 
4518   Not Collective; No Fortran Support
4519 
4520   Input Parameter:
4521 . A - a `MATSEQAIJ` matrix
4522 
4523   Output Parameter:
4524 . array - pointer to the data
4525 
4526   Level: intermediate
4527 
4528 .seealso: [](ch_matrices), `Mat`, `MatSeqAIJGetArray()`, `MatSeqAIJRestoreArrayRead()`
4529 @*/
4530 PetscErrorCode MatSeqAIJGetArrayWrite(Mat A, PetscScalar *array[])
4531 {
4532   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)A->data;
4533 
4534   PetscFunctionBegin;
4535   if (aij->ops->getarraywrite) {
4536     PetscCall((*aij->ops->getarraywrite)(A, array));
4537   } else {
4538     *array = aij->a;
4539   }
4540   PetscCall(MatSeqAIJInvalidateDiagonal(A));
4541   PetscCall(PetscObjectStateIncrease((PetscObject)A));
4542   PetscFunctionReturn(PETSC_SUCCESS);
4543 }
4544 
4545 /*@C
4546   MatSeqAIJRestoreArrayWrite - restore the read-only access array obtained from MatSeqAIJGetArrayRead
4547 
4548   Not Collective; No Fortran Support
4549 
4550   Input Parameter:
4551 . A - a MATSEQAIJ matrix
4552 
4553   Output Parameter:
4554 . array - pointer to the data
4555 
4556   Level: intermediate
4557 
4558 .seealso: [](ch_matrices), `Mat`, `MatSeqAIJGetArray()`, `MatSeqAIJGetArrayRead()`
4559 @*/
4560 PetscErrorCode MatSeqAIJRestoreArrayWrite(Mat A, PetscScalar *array[])
4561 {
4562   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)A->data;
4563 
4564   PetscFunctionBegin;
4565   if (aij->ops->restorearraywrite) {
4566     PetscCall((*aij->ops->restorearraywrite)(A, array));
4567   } else {
4568     *array = NULL;
4569   }
4570   PetscFunctionReturn(PETSC_SUCCESS);
4571 }
4572 
4573 /*@C
4574   MatSeqAIJGetCSRAndMemType - Get the CSR arrays and the memory type of the `MATSEQAIJ` matrix
4575 
4576   Not Collective; No Fortran Support
4577 
4578   Input Parameter:
4579 . mat - a matrix of type `MATSEQAIJ` or its subclasses
4580 
4581   Output Parameters:
4582 + i     - row map array of the matrix
4583 . j     - column index array of the matrix
4584 . a     - data array of the matrix
4585 - mtype - memory type of the arrays
4586 
4587   Level: developer
4588 
4589   Notes:
4590   Any of the output parameters can be `NULL`, in which case the corresponding value is not returned.
4591   If mat is a device matrix, the arrays are on the device. Otherwise, they are on the host.
4592 
4593   One can call this routine on a preallocated but not assembled matrix to just get the memory of the CSR underneath the matrix.
4594   If the matrix is assembled, the data array `a` is guaranteed to have the latest values of the matrix.
4595 
4596 .seealso: [](ch_matrices), `Mat`, `MatSeqAIJGetArray()`, `MatSeqAIJGetArrayRead()`
4597 @*/
4598 PetscErrorCode MatSeqAIJGetCSRAndMemType(Mat mat, const PetscInt *i[], const PetscInt *j[], PetscScalar *a[], PetscMemType *mtype)
4599 {
4600   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)mat->data;
4601 
4602   PetscFunctionBegin;
4603   PetscCheck(mat->preallocated, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "matrix is not preallocated");
4604   if (aij->ops->getcsrandmemtype) {
4605     PetscCall((*aij->ops->getcsrandmemtype)(mat, i, j, a, mtype));
4606   } else {
4607     if (i) *i = aij->i;
4608     if (j) *j = aij->j;
4609     if (a) *a = aij->a;
4610     if (mtype) *mtype = PETSC_MEMTYPE_HOST;
4611   }
4612   PetscFunctionReturn(PETSC_SUCCESS);
4613 }
4614 
4615 /*@
4616   MatSeqAIJGetMaxRowNonzeros - returns the maximum number of nonzeros in any row
4617 
4618   Not Collective
4619 
4620   Input Parameter:
4621 . A - a `MATSEQAIJ` matrix
4622 
4623   Output Parameter:
4624 . nz - the maximum number of nonzeros in any row
4625 
4626   Level: intermediate
4627 
4628 .seealso: [](ch_matrices), `Mat`, `MatSeqAIJRestoreArray()`
4629 @*/
4630 PetscErrorCode MatSeqAIJGetMaxRowNonzeros(Mat A, PetscInt *nz)
4631 {
4632   Mat_SeqAIJ *aij = (Mat_SeqAIJ *)A->data;
4633 
4634   PetscFunctionBegin;
4635   *nz = aij->rmax;
4636   PetscFunctionReturn(PETSC_SUCCESS);
4637 }
4638 
4639 static PetscErrorCode MatCOOStructDestroy_SeqAIJ(void **data)
4640 {
4641   MatCOOStruct_SeqAIJ *coo = (MatCOOStruct_SeqAIJ *)*data;
4642 
4643   PetscFunctionBegin;
4644   PetscCall(PetscFree(coo->perm));
4645   PetscCall(PetscFree(coo->jmap));
4646   PetscCall(PetscFree(coo));
4647   PetscFunctionReturn(PETSC_SUCCESS);
4648 }
4649 
4650 PetscErrorCode MatSetPreallocationCOO_SeqAIJ(Mat mat, PetscCount coo_n, PetscInt coo_i[], PetscInt coo_j[])
4651 {
4652   MPI_Comm             comm;
4653   PetscInt            *i, *j;
4654   PetscInt             M, N, row, iprev;
4655   PetscCount           k, p, q, nneg, nnz, start, end; /* Index the coo array, so use PetscCount as their type */
4656   PetscInt            *Ai;                             /* Change to PetscCount once we use it for row pointers */
4657   PetscInt            *Aj;
4658   PetscScalar         *Aa;
4659   Mat_SeqAIJ          *seqaij = (Mat_SeqAIJ *)mat->data;
4660   MatType              rtype;
4661   PetscCount          *perm, *jmap;
4662   MatCOOStruct_SeqAIJ *coo;
4663   PetscBool            isorted;
4664   PetscBool            hypre;
4665   const char          *name;
4666 
4667   PetscFunctionBegin;
4668   PetscCall(PetscObjectGetComm((PetscObject)mat, &comm));
4669   PetscCall(MatGetSize(mat, &M, &N));
4670   i = coo_i;
4671   j = coo_j;
4672   PetscCall(PetscMalloc1(coo_n, &perm));
4673 
4674   /* Ignore entries with negative row or col indices; at the same time, check if i[] is already sorted (e.g., MatConvert_AlJ_HYPRE results in this case) */
4675   isorted = PETSC_TRUE;
4676   iprev   = PETSC_INT_MIN;
4677   for (k = 0; k < coo_n; k++) {
4678     if (j[k] < 0) i[k] = -1;
4679     if (isorted) {
4680       if (i[k] < iprev) isorted = PETSC_FALSE;
4681       else iprev = i[k];
4682     }
4683     perm[k] = k;
4684   }
4685 
4686   /* Sort by row if not already */
4687   if (!isorted) PetscCall(PetscSortIntWithIntCountArrayPair(coo_n, i, j, perm));
4688 
4689   /* Advance k to the first row with a non-negative index */
4690   for (k = 0; k < coo_n; k++)
4691     if (i[k] >= 0) break;
4692   nneg = k;
4693   PetscCall(PetscMalloc1(coo_n - nneg + 1, &jmap)); /* +1 to make a CSR-like data structure. jmap[i] originally is the number of repeats for i-th nonzero */
4694   nnz = 0;                                          /* Total number of unique nonzeros to be counted */
4695   jmap++;                                           /* Inc jmap by 1 for convenience */
4696 
4697   PetscCall(PetscShmgetAllocateArray(M + 1, sizeof(PetscInt), (void **)&Ai)); /* CSR of A */
4698   PetscCall(PetscArrayzero(Ai, M + 1));
4699   PetscCall(PetscShmgetAllocateArray(coo_n - nneg, sizeof(PetscInt), (void **)&Aj)); /* We have at most coo_n-nneg unique nonzeros */
4700 
4701   PetscCall(PetscObjectGetName((PetscObject)mat, &name));
4702   PetscCall(PetscStrcmp("_internal_COO_mat_for_hypre", name, &hypre));
4703 
4704   /* In each row, sort by column, then unique column indices to get row length */
4705   Ai++;  /* Inc by 1 for convenience */
4706   q = 0; /* q-th unique nonzero, with q starting from 0 */
4707   while (k < coo_n) {
4708     PetscBool strictly_sorted; // this row is strictly sorted?
4709     PetscInt  jprev;
4710 
4711     /* get [start,end) indices for this row; also check if cols in this row are strictly sorted */
4712     row             = i[k];
4713     start           = k;
4714     jprev           = PETSC_INT_MIN;
4715     strictly_sorted = PETSC_TRUE;
4716     while (k < coo_n && i[k] == row) {
4717       if (strictly_sorted) {
4718         if (j[k] <= jprev) strictly_sorted = PETSC_FALSE;
4719         else jprev = j[k];
4720       }
4721       k++;
4722     }
4723     end = k;
4724 
4725     /* hack for HYPRE: swap min column to diag so that diagonal values will go first */
4726     if (hypre) {
4727       PetscInt  minj    = PETSC_INT_MAX;
4728       PetscBool hasdiag = PETSC_FALSE;
4729 
4730       if (strictly_sorted) { // fast path to swap the first and the diag
4731         PetscCount tmp;
4732         for (p = start; p < end; p++) {
4733           if (j[p] == row && p != start) {
4734             j[p]        = j[start]; // swap j[], so that the diagonal value will go first (manipulated by perm[])
4735             j[start]    = row;
4736             tmp         = perm[start];
4737             perm[start] = perm[p]; // also swap perm[] so we can save the call to PetscSortIntWithCountArray() below
4738             perm[p]     = tmp;
4739             break;
4740           }
4741         }
4742       } else {
4743         for (p = start; p < end; p++) {
4744           hasdiag = (PetscBool)(hasdiag || (j[p] == row));
4745           minj    = PetscMin(minj, j[p]);
4746         }
4747 
4748         if (hasdiag) {
4749           for (p = start; p < end; p++) {
4750             if (j[p] == minj) j[p] = row;
4751             else if (j[p] == row) j[p] = minj;
4752           }
4753         }
4754       }
4755     }
4756     // sort by columns in a row. perm[] indicates their original order
4757     if (!strictly_sorted) PetscCall(PetscSortIntWithCountArray(end - start, j + start, perm + start));
4758 
4759     if (strictly_sorted) { // fast path to set Aj[], jmap[], Ai[], nnz, q
4760       for (p = start; p < end; p++, q++) {
4761         Aj[q]   = j[p];
4762         jmap[q] = 1;
4763       }
4764       PetscCall(PetscIntCast(end - start, Ai + row));
4765       nnz += Ai[row]; // q is already advanced
4766     } else {
4767       /* Find number of unique col entries in this row */
4768       Aj[q]   = j[start]; /* Log the first nonzero in this row */
4769       jmap[q] = 1;        /* Number of repeats of this nonzero entry */
4770       Ai[row] = 1;
4771       nnz++;
4772 
4773       for (p = start + 1; p < end; p++) { /* Scan remaining nonzero in this row */
4774         if (j[p] != j[p - 1]) {           /* Meet a new nonzero */
4775           q++;
4776           jmap[q] = 1;
4777           Aj[q]   = j[p];
4778           Ai[row]++;
4779           nnz++;
4780         } else {
4781           jmap[q]++;
4782         }
4783       }
4784       q++; /* Move to next row and thus next unique nonzero */
4785     }
4786   }
4787 
4788   Ai--; /* Back to the beginning of Ai[] */
4789   for (k = 0; k < M; k++) Ai[k + 1] += Ai[k];
4790   jmap--; // Back to the beginning of jmap[]
4791   jmap[0] = 0;
4792   for (k = 0; k < nnz; k++) jmap[k + 1] += jmap[k];
4793 
4794   if (nnz < coo_n - nneg) { /* Reallocate with actual number of unique nonzeros */
4795     PetscCount *jmap_new;
4796     PetscInt   *Aj_new;
4797 
4798     PetscCall(PetscMalloc1(nnz + 1, &jmap_new));
4799     PetscCall(PetscArraycpy(jmap_new, jmap, nnz + 1));
4800     PetscCall(PetscFree(jmap));
4801     jmap = jmap_new;
4802 
4803     PetscCall(PetscShmgetAllocateArray(nnz, sizeof(PetscInt), (void **)&Aj_new));
4804     PetscCall(PetscArraycpy(Aj_new, Aj, nnz));
4805     PetscCall(PetscShmgetDeallocateArray((void **)&Aj));
4806     Aj = Aj_new;
4807   }
4808 
4809   if (nneg) { /* Discard heading entries with negative indices in perm[], as we'll access it from index 0 in MatSetValuesCOO */
4810     PetscCount *perm_new;
4811 
4812     PetscCall(PetscMalloc1(coo_n - nneg, &perm_new));
4813     PetscCall(PetscArraycpy(perm_new, perm + nneg, coo_n - nneg));
4814     PetscCall(PetscFree(perm));
4815     perm = perm_new;
4816   }
4817 
4818   PetscCall(MatGetRootType_Private(mat, &rtype));
4819   PetscCall(PetscShmgetAllocateArray(nnz, sizeof(PetscScalar), (void **)&Aa));
4820   PetscCall(PetscArrayzero(Aa, nnz));
4821   PetscCall(MatSetSeqAIJWithArrays_private(PETSC_COMM_SELF, M, N, Ai, Aj, Aa, rtype, mat));
4822 
4823   seqaij->free_a = seqaij->free_ij = PETSC_TRUE; /* Let newmat own Ai, Aj and Aa */
4824 
4825   // Put the COO struct in a container and then attach that to the matrix
4826   PetscCall(PetscMalloc1(1, &coo));
4827   PetscCall(PetscIntCast(nnz, &coo->nz));
4828   coo->n    = coo_n;
4829   coo->Atot = coo_n - nneg; // Annz is seqaij->nz, so no need to record that again
4830   coo->jmap = jmap;         // of length nnz+1
4831   coo->perm = perm;
4832   PetscCall(PetscObjectContainerCompose((PetscObject)mat, "__PETSc_MatCOOStruct_Host", coo, MatCOOStructDestroy_SeqAIJ));
4833   PetscFunctionReturn(PETSC_SUCCESS);
4834 }
4835 
4836 static PetscErrorCode MatSetValuesCOO_SeqAIJ(Mat A, const PetscScalar v[], InsertMode imode)
4837 {
4838   Mat_SeqAIJ          *aseq = (Mat_SeqAIJ *)A->data;
4839   PetscCount           i, j, Annz = aseq->nz;
4840   PetscCount          *perm, *jmap;
4841   PetscScalar         *Aa;
4842   PetscContainer       container;
4843   MatCOOStruct_SeqAIJ *coo;
4844 
4845   PetscFunctionBegin;
4846   PetscCall(PetscObjectQuery((PetscObject)A, "__PETSc_MatCOOStruct_Host", (PetscObject *)&container));
4847   PetscCheck(container, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Not found MatCOOStruct on this matrix");
4848   PetscCall(PetscContainerGetPointer(container, (void **)&coo));
4849   perm = coo->perm;
4850   jmap = coo->jmap;
4851   PetscCall(MatSeqAIJGetArray(A, &Aa));
4852   for (i = 0; i < Annz; i++) {
4853     PetscScalar sum = 0.0;
4854     for (j = jmap[i]; j < jmap[i + 1]; j++) sum += v[perm[j]];
4855     Aa[i] = (imode == INSERT_VALUES ? 0.0 : Aa[i]) + sum;
4856   }
4857   PetscCall(MatSeqAIJRestoreArray(A, &Aa));
4858   PetscFunctionReturn(PETSC_SUCCESS);
4859 }
4860 
4861 #if defined(PETSC_HAVE_CUDA)
4862 PETSC_INTERN PetscErrorCode MatConvert_SeqAIJ_SeqAIJCUSPARSE(Mat, MatType, MatReuse, Mat *);
4863 #endif
4864 #if defined(PETSC_HAVE_HIP)
4865 PETSC_INTERN PetscErrorCode MatConvert_SeqAIJ_SeqAIJHIPSPARSE(Mat, MatType, MatReuse, Mat *);
4866 #endif
4867 #if defined(PETSC_HAVE_KOKKOS_KERNELS)
4868 PETSC_INTERN PetscErrorCode MatConvert_SeqAIJ_SeqAIJKokkos(Mat, MatType, MatReuse, Mat *);
4869 #endif
4870 
4871 PETSC_EXTERN PetscErrorCode MatCreate_SeqAIJ(Mat B)
4872 {
4873   Mat_SeqAIJ *b;
4874   PetscMPIInt size;
4875 
4876   PetscFunctionBegin;
4877   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)B), &size));
4878   PetscCheck(size <= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Comm must be of size 1");
4879 
4880   PetscCall(PetscNew(&b));
4881 
4882   B->data   = (void *)b;
4883   B->ops[0] = MatOps_Values;
4884   if (B->sortedfull) B->ops->setvalues = MatSetValues_SeqAIJ_SortedFull;
4885 
4886   b->row                = NULL;
4887   b->col                = NULL;
4888   b->icol               = NULL;
4889   b->reallocs           = 0;
4890   b->ignorezeroentries  = PETSC_FALSE;
4891   b->roworiented        = PETSC_TRUE;
4892   b->nonew              = 0;
4893   b->diag               = NULL;
4894   b->solve_work         = NULL;
4895   B->spptr              = NULL;
4896   b->saved_values       = NULL;
4897   b->idiag              = NULL;
4898   b->mdiag              = NULL;
4899   b->ssor_work          = NULL;
4900   b->omega              = 1.0;
4901   b->fshift             = 0.0;
4902   b->idiagvalid         = PETSC_FALSE;
4903   b->ibdiagvalid        = PETSC_FALSE;
4904   b->keepnonzeropattern = PETSC_FALSE;
4905 
4906   PetscCall(PetscObjectChangeTypeName((PetscObject)B, MATSEQAIJ));
4907 #if defined(PETSC_HAVE_MATLAB)
4908   PetscCall(PetscObjectComposeFunction((PetscObject)B, "PetscMatlabEnginePut_C", MatlabEnginePut_SeqAIJ));
4909   PetscCall(PetscObjectComposeFunction((PetscObject)B, "PetscMatlabEngineGet_C", MatlabEngineGet_SeqAIJ));
4910 #endif
4911   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatSeqAIJSetColumnIndices_C", MatSeqAIJSetColumnIndices_SeqAIJ));
4912   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatStoreValues_C", MatStoreValues_SeqAIJ));
4913   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatRetrieveValues_C", MatRetrieveValues_SeqAIJ));
4914   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_seqsbaij_C", MatConvert_SeqAIJ_SeqSBAIJ));
4915   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_seqbaij_C", MatConvert_SeqAIJ_SeqBAIJ));
4916   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_seqaijperm_C", MatConvert_SeqAIJ_SeqAIJPERM));
4917   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_seqaijsell_C", MatConvert_SeqAIJ_SeqAIJSELL));
4918 #if defined(PETSC_HAVE_MKL_SPARSE)
4919   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_seqaijmkl_C", MatConvert_SeqAIJ_SeqAIJMKL));
4920 #endif
4921 #if defined(PETSC_HAVE_CUDA)
4922   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_seqaijcusparse_C", MatConvert_SeqAIJ_SeqAIJCUSPARSE));
4923   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatProductSetFromOptions_seqaijcusparse_seqaij_C", MatProductSetFromOptions_SeqAIJ));
4924   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatProductSetFromOptions_seqaij_seqaijcusparse_C", MatProductSetFromOptions_SeqAIJ));
4925 #endif
4926 #if defined(PETSC_HAVE_HIP)
4927   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_seqaijhipsparse_C", MatConvert_SeqAIJ_SeqAIJHIPSPARSE));
4928   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatProductSetFromOptions_seqaijhipsparse_seqaij_C", MatProductSetFromOptions_SeqAIJ));
4929   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatProductSetFromOptions_seqaij_seqaijhipsparse_C", MatProductSetFromOptions_SeqAIJ));
4930 #endif
4931 #if defined(PETSC_HAVE_KOKKOS_KERNELS)
4932   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_seqaijkokkos_C", MatConvert_SeqAIJ_SeqAIJKokkos));
4933 #endif
4934   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_seqaijcrl_C", MatConvert_SeqAIJ_SeqAIJCRL));
4935 #if defined(PETSC_HAVE_ELEMENTAL)
4936   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_elemental_C", MatConvert_SeqAIJ_Elemental));
4937 #endif
4938 #if defined(PETSC_HAVE_SCALAPACK)
4939   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_scalapack_C", MatConvert_AIJ_ScaLAPACK));
4940 #endif
4941 #if defined(PETSC_HAVE_HYPRE)
4942   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_hypre_C", MatConvert_AIJ_HYPRE));
4943   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatProductSetFromOptions_transpose_seqaij_seqaij_C", MatProductSetFromOptions_Transpose_AIJ_AIJ));
4944 #endif
4945   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_seqdense_C", MatConvert_SeqAIJ_SeqDense));
4946   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_seqsell_C", MatConvert_SeqAIJ_SeqSELL));
4947   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatConvert_seqaij_is_C", MatConvert_XAIJ_IS));
4948   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatIsTranspose_C", MatIsTranspose_SeqAIJ));
4949   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatIsHermitianTranspose_C", MatIsHermitianTranspose_SeqAIJ));
4950   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatSeqAIJSetPreallocation_C", MatSeqAIJSetPreallocation_SeqAIJ));
4951   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatResetPreallocation_C", MatResetPreallocation_SeqAIJ));
4952   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatResetHash_C", MatResetHash_SeqAIJ));
4953   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatSeqAIJSetPreallocationCSR_C", MatSeqAIJSetPreallocationCSR_SeqAIJ));
4954   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatReorderForNonzeroDiagonal_C", MatReorderForNonzeroDiagonal_SeqAIJ));
4955   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatProductSetFromOptions_is_seqaij_C", MatProductSetFromOptions_IS_XAIJ));
4956   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatProductSetFromOptions_seqdense_seqaij_C", MatProductSetFromOptions_SeqDense_SeqAIJ));
4957   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatProductSetFromOptions_seqaij_seqaij_C", MatProductSetFromOptions_SeqAIJ));
4958   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatSeqAIJKron_C", MatSeqAIJKron_SeqAIJ));
4959   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatSetPreallocationCOO_C", MatSetPreallocationCOO_SeqAIJ));
4960   PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatSetValuesCOO_C", MatSetValuesCOO_SeqAIJ));
4961   PetscCall(MatCreate_SeqAIJ_Inode(B));
4962   PetscCall(PetscObjectChangeTypeName((PetscObject)B, MATSEQAIJ));
4963   PetscCall(MatSeqAIJSetTypeFromOptions(B)); /* this allows changing the matrix subtype to say MATSEQAIJPERM */
4964   PetscFunctionReturn(PETSC_SUCCESS);
4965 }
4966 
4967 /*
4968     Given a matrix generated with MatGetFactor() duplicates all the information in A into C
4969 */
4970 PetscErrorCode MatDuplicateNoCreate_SeqAIJ(Mat C, Mat A, MatDuplicateOption cpvalues, PetscBool mallocmatspace)
4971 {
4972   Mat_SeqAIJ *c = (Mat_SeqAIJ *)C->data, *a = (Mat_SeqAIJ *)A->data;
4973   PetscInt    m = A->rmap->n, i;
4974 
4975   PetscFunctionBegin;
4976   PetscCheck(A->assembled || cpvalues == MAT_DO_NOT_COPY_VALUES, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot duplicate unassembled matrix");
4977 
4978   C->factortype    = A->factortype;
4979   c->row           = NULL;
4980   c->col           = NULL;
4981   c->icol          = NULL;
4982   c->reallocs      = 0;
4983   c->diagonaldense = a->diagonaldense;
4984 
4985   C->assembled = A->assembled;
4986 
4987   if (A->preallocated) {
4988     PetscCall(PetscLayoutReference(A->rmap, &C->rmap));
4989     PetscCall(PetscLayoutReference(A->cmap, &C->cmap));
4990 
4991     if (!A->hash_active) {
4992       PetscCall(PetscMalloc1(m, &c->imax));
4993       PetscCall(PetscMemcpy(c->imax, a->imax, m * sizeof(PetscInt)));
4994       PetscCall(PetscMalloc1(m, &c->ilen));
4995       PetscCall(PetscMemcpy(c->ilen, a->ilen, m * sizeof(PetscInt)));
4996 
4997       /* allocate the matrix space */
4998       if (mallocmatspace) {
4999         PetscCall(PetscShmgetAllocateArray(a->i[m], sizeof(PetscScalar), (void **)&c->a));
5000         PetscCall(PetscShmgetAllocateArray(a->i[m], sizeof(PetscInt), (void **)&c->j));
5001         PetscCall(PetscShmgetAllocateArray(m + 1, sizeof(PetscInt), (void **)&c->i));
5002         PetscCall(PetscArraycpy(c->i, a->i, m + 1));
5003         c->free_a  = PETSC_TRUE;
5004         c->free_ij = PETSC_TRUE;
5005         if (m > 0) {
5006           PetscCall(PetscArraycpy(c->j, a->j, a->i[m]));
5007           if (cpvalues == MAT_COPY_VALUES) {
5008             const PetscScalar *aa;
5009 
5010             PetscCall(MatSeqAIJGetArrayRead(A, &aa));
5011             PetscCall(PetscArraycpy(c->a, aa, a->i[m]));
5012             PetscCall(MatSeqAIJGetArrayRead(A, &aa));
5013           } else {
5014             PetscCall(PetscArrayzero(c->a, a->i[m]));
5015           }
5016         }
5017       }
5018       C->preallocated = PETSC_TRUE;
5019     } else {
5020       PetscCheck(mallocmatspace, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Cannot malloc matrix memory from a non-preallocated matrix");
5021       PetscCall(MatSetUp(C));
5022     }
5023 
5024     c->ignorezeroentries = a->ignorezeroentries;
5025     c->roworiented       = a->roworiented;
5026     c->nonew             = a->nonew;
5027     if (a->diag) {
5028       PetscCall(PetscMalloc1(m + 1, &c->diag));
5029       PetscCall(PetscMemcpy(c->diag, a->diag, m * sizeof(PetscInt)));
5030     } else c->diag = NULL;
5031 
5032     c->solve_work         = NULL;
5033     c->saved_values       = NULL;
5034     c->idiag              = NULL;
5035     c->ssor_work          = NULL;
5036     c->keepnonzeropattern = a->keepnonzeropattern;
5037 
5038     c->rmax  = a->rmax;
5039     c->nz    = a->nz;
5040     c->maxnz = a->nz; /* Since we allocate exactly the right amount */
5041 
5042     c->compressedrow.use   = a->compressedrow.use;
5043     c->compressedrow.nrows = a->compressedrow.nrows;
5044     if (a->compressedrow.use) {
5045       i = a->compressedrow.nrows;
5046       PetscCall(PetscMalloc2(i + 1, &c->compressedrow.i, i, &c->compressedrow.rindex));
5047       PetscCall(PetscArraycpy(c->compressedrow.i, a->compressedrow.i, i + 1));
5048       PetscCall(PetscArraycpy(c->compressedrow.rindex, a->compressedrow.rindex, i));
5049     } else {
5050       c->compressedrow.use    = PETSC_FALSE;
5051       c->compressedrow.i      = NULL;
5052       c->compressedrow.rindex = NULL;
5053     }
5054     c->nonzerorowcnt = a->nonzerorowcnt;
5055     C->nonzerostate  = A->nonzerostate;
5056 
5057     PetscCall(MatDuplicate_SeqAIJ_Inode(A, cpvalues, &C));
5058   }
5059   PetscCall(PetscFunctionListDuplicate(((PetscObject)A)->qlist, &((PetscObject)C)->qlist));
5060   PetscFunctionReturn(PETSC_SUCCESS);
5061 }
5062 
5063 PetscErrorCode MatDuplicate_SeqAIJ(Mat A, MatDuplicateOption cpvalues, Mat *B)
5064 {
5065   PetscFunctionBegin;
5066   PetscCall(MatCreate(PetscObjectComm((PetscObject)A), B));
5067   PetscCall(MatSetSizes(*B, A->rmap->n, A->cmap->n, A->rmap->n, A->cmap->n));
5068   if (!(A->rmap->n % A->rmap->bs) && !(A->cmap->n % A->cmap->bs)) PetscCall(MatSetBlockSizesFromMats(*B, A, A));
5069   PetscCall(MatSetType(*B, ((PetscObject)A)->type_name));
5070   PetscCall(MatDuplicateNoCreate_SeqAIJ(*B, A, cpvalues, PETSC_TRUE));
5071   PetscFunctionReturn(PETSC_SUCCESS);
5072 }
5073 
5074 PetscErrorCode MatLoad_SeqAIJ(Mat newMat, PetscViewer viewer)
5075 {
5076   PetscBool isbinary, ishdf5;
5077 
5078   PetscFunctionBegin;
5079   PetscValidHeaderSpecific(newMat, MAT_CLASSID, 1);
5080   PetscValidHeaderSpecific(viewer, PETSC_VIEWER_CLASSID, 2);
5081   /* force binary viewer to load .info file if it has not yet done so */
5082   PetscCall(PetscViewerSetUp(viewer));
5083   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
5084   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERHDF5, &ishdf5));
5085   if (isbinary) {
5086     PetscCall(MatLoad_SeqAIJ_Binary(newMat, viewer));
5087   } else if (ishdf5) {
5088 #if defined(PETSC_HAVE_HDF5)
5089     PetscCall(MatLoad_AIJ_HDF5(newMat, viewer));
5090 #else
5091     SETERRQ(PetscObjectComm((PetscObject)newMat), PETSC_ERR_SUP, "HDF5 not supported in this build.\nPlease reconfigure using --download-hdf5");
5092 #endif
5093   } else {
5094     SETERRQ(PetscObjectComm((PetscObject)newMat), PETSC_ERR_SUP, "Viewer type %s not yet supported for reading %s matrices", ((PetscObject)viewer)->type_name, ((PetscObject)newMat)->type_name);
5095   }
5096   PetscFunctionReturn(PETSC_SUCCESS);
5097 }
5098 
5099 PetscErrorCode MatLoad_SeqAIJ_Binary(Mat mat, PetscViewer viewer)
5100 {
5101   Mat_SeqAIJ *a = (Mat_SeqAIJ *)mat->data;
5102   PetscInt    header[4], *rowlens, M, N, nz, sum, rows, cols, i;
5103 
5104   PetscFunctionBegin;
5105   PetscCall(PetscViewerSetUp(viewer));
5106 
5107   /* read in matrix header */
5108   PetscCall(PetscViewerBinaryRead(viewer, header, 4, NULL, PETSC_INT));
5109   PetscCheck(header[0] == MAT_FILE_CLASSID, PETSC_COMM_SELF, PETSC_ERR_FILE_UNEXPECTED, "Not a matrix object in file");
5110   M  = header[1];
5111   N  = header[2];
5112   nz = header[3];
5113   PetscCheck(M >= 0, PetscObjectComm((PetscObject)viewer), PETSC_ERR_FILE_UNEXPECTED, "Matrix row size (%" PetscInt_FMT ") in file is negative", M);
5114   PetscCheck(N >= 0, PetscObjectComm((PetscObject)viewer), PETSC_ERR_FILE_UNEXPECTED, "Matrix column size (%" PetscInt_FMT ") in file is negative", N);
5115   PetscCheck(nz >= 0, PETSC_COMM_SELF, PETSC_ERR_FILE_UNEXPECTED, "Matrix stored in special format on disk, cannot load as SeqAIJ");
5116 
5117   /* set block sizes from the viewer's .info file */
5118   PetscCall(MatLoad_Binary_BlockSizes(mat, viewer));
5119   /* set local and global sizes if not set already */
5120   if (mat->rmap->n < 0) mat->rmap->n = M;
5121   if (mat->cmap->n < 0) mat->cmap->n = N;
5122   if (mat->rmap->N < 0) mat->rmap->N = M;
5123   if (mat->cmap->N < 0) mat->cmap->N = N;
5124   PetscCall(PetscLayoutSetUp(mat->rmap));
5125   PetscCall(PetscLayoutSetUp(mat->cmap));
5126 
5127   /* check if the matrix sizes are correct */
5128   PetscCall(MatGetSize(mat, &rows, &cols));
5129   PetscCheck(M == rows && N == cols, PETSC_COMM_SELF, PETSC_ERR_FILE_UNEXPECTED, "Matrix in file of different sizes (%" PetscInt_FMT ", %" PetscInt_FMT ") than the input matrix (%" PetscInt_FMT ", %" PetscInt_FMT ")", M, N, rows, cols);
5130 
5131   /* read in row lengths */
5132   PetscCall(PetscMalloc1(M, &rowlens));
5133   PetscCall(PetscViewerBinaryRead(viewer, rowlens, M, NULL, PETSC_INT));
5134   /* check if sum(rowlens) is same as nz */
5135   sum = 0;
5136   for (i = 0; i < M; i++) sum += rowlens[i];
5137   PetscCheck(sum == nz, PETSC_COMM_SELF, PETSC_ERR_FILE_UNEXPECTED, "Inconsistent matrix data in file: nonzeros = %" PetscInt_FMT ", sum-row-lengths = %" PetscInt_FMT, nz, sum);
5138   /* preallocate and check sizes */
5139   PetscCall(MatSeqAIJSetPreallocation_SeqAIJ(mat, 0, rowlens));
5140   PetscCall(MatGetSize(mat, &rows, &cols));
5141   PetscCheck(M == rows && N == cols, PETSC_COMM_SELF, PETSC_ERR_FILE_UNEXPECTED, "Matrix in file of different length (%" PetscInt_FMT ", %" PetscInt_FMT ") than the input matrix (%" PetscInt_FMT ", %" PetscInt_FMT ")", M, N, rows, cols);
5142   /* store row lengths */
5143   PetscCall(PetscArraycpy(a->ilen, rowlens, M));
5144   PetscCall(PetscFree(rowlens));
5145 
5146   /* fill in "i" row pointers */
5147   a->i[0] = 0;
5148   for (i = 0; i < M; i++) a->i[i + 1] = a->i[i] + a->ilen[i];
5149   /* read in "j" column indices */
5150   PetscCall(PetscViewerBinaryRead(viewer, a->j, nz, NULL, PETSC_INT));
5151   /* read in "a" nonzero values */
5152   PetscCall(PetscViewerBinaryRead(viewer, a->a, nz, NULL, PETSC_SCALAR));
5153 
5154   PetscCall(MatAssemblyBegin(mat, MAT_FINAL_ASSEMBLY));
5155   PetscCall(MatAssemblyEnd(mat, MAT_FINAL_ASSEMBLY));
5156   PetscFunctionReturn(PETSC_SUCCESS);
5157 }
5158 
5159 PetscErrorCode MatEqual_SeqAIJ(Mat A, Mat B, PetscBool *flg)
5160 {
5161   Mat_SeqAIJ        *a = (Mat_SeqAIJ *)A->data, *b = (Mat_SeqAIJ *)B->data;
5162   const PetscScalar *aa, *ba;
5163 #if defined(PETSC_USE_COMPLEX)
5164   PetscInt k;
5165 #endif
5166 
5167   PetscFunctionBegin;
5168   /* If the  matrix dimensions are not equal,or no of nonzeros */
5169   if ((A->rmap->n != B->rmap->n) || (A->cmap->n != B->cmap->n) || (a->nz != b->nz)) {
5170     *flg = PETSC_FALSE;
5171     PetscFunctionReturn(PETSC_SUCCESS);
5172   }
5173 
5174   /* if the a->i are the same */
5175   PetscCall(PetscArraycmp(a->i, b->i, A->rmap->n + 1, flg));
5176   if (!*flg) PetscFunctionReturn(PETSC_SUCCESS);
5177 
5178   /* if a->j are the same */
5179   PetscCall(PetscArraycmp(a->j, b->j, a->nz, flg));
5180   if (!*flg) PetscFunctionReturn(PETSC_SUCCESS);
5181 
5182   PetscCall(MatSeqAIJGetArrayRead(A, &aa));
5183   PetscCall(MatSeqAIJGetArrayRead(B, &ba));
5184   /* if a->a are the same */
5185 #if defined(PETSC_USE_COMPLEX)
5186   for (k = 0; k < a->nz; k++) {
5187     if (PetscRealPart(aa[k]) != PetscRealPart(ba[k]) || PetscImaginaryPart(aa[k]) != PetscImaginaryPart(ba[k])) {
5188       *flg = PETSC_FALSE;
5189       PetscFunctionReturn(PETSC_SUCCESS);
5190     }
5191   }
5192 #else
5193   PetscCall(PetscArraycmp(aa, ba, a->nz, flg));
5194 #endif
5195   PetscCall(MatSeqAIJRestoreArrayRead(A, &aa));
5196   PetscCall(MatSeqAIJRestoreArrayRead(B, &ba));
5197   PetscFunctionReturn(PETSC_SUCCESS);
5198 }
5199 
5200 /*@
5201   MatCreateSeqAIJWithArrays - Creates an sequential `MATSEQAIJ` matrix using matrix elements (in CSR format)
5202   provided by the user.
5203 
5204   Collective
5205 
5206   Input Parameters:
5207 + comm - must be an MPI communicator of size 1
5208 . m    - number of rows
5209 . n    - number of columns
5210 . i    - row indices; that is i[0] = 0, i[row] = i[row-1] + number of elements in that row of the matrix
5211 . j    - column indices
5212 - a    - matrix values
5213 
5214   Output Parameter:
5215 . mat - the matrix
5216 
5217   Level: intermediate
5218 
5219   Notes:
5220   The `i`, `j`, and `a` arrays are not copied by this routine, the user must free these arrays
5221   once the matrix is destroyed and not before
5222 
5223   You cannot set new nonzero locations into this matrix, that will generate an error.
5224 
5225   The `i` and `j` indices are 0 based
5226 
5227   The format which is used for the sparse matrix input, is equivalent to a
5228   row-major ordering.. i.e for the following matrix, the input data expected is
5229   as shown
5230 .vb
5231         1 0 0
5232         2 0 3
5233         4 5 6
5234 
5235         i =  {0,1,3,6}  [size = nrow+1  = 3+1]
5236         j =  {0,0,2,0,1,2}  [size = 6]; values must be sorted for each row
5237         v =  {1,2,3,4,5,6}  [size = 6]
5238 .ve
5239 
5240 .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatCreateAIJ()`, `MatCreateSeqAIJ()`, `MatCreateMPIAIJWithArrays()`, `MatMPIAIJSetPreallocationCSR()`
5241 @*/
5242 PetscErrorCode MatCreateSeqAIJWithArrays(MPI_Comm comm, PetscInt m, PetscInt n, PetscInt i[], PetscInt j[], PetscScalar a[], Mat *mat)
5243 {
5244   PetscInt    ii;
5245   Mat_SeqAIJ *aij;
5246   PetscInt    jj;
5247 
5248   PetscFunctionBegin;
5249   PetscCheck(m <= 0 || i[0] == 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "i (row indices) must start with 0");
5250   PetscCall(MatCreate(comm, mat));
5251   PetscCall(MatSetSizes(*mat, m, n, m, n));
5252   /* PetscCall(MatSetBlockSizes(*mat,,)); */
5253   PetscCall(MatSetType(*mat, MATSEQAIJ));
5254   PetscCall(MatSeqAIJSetPreallocation_SeqAIJ(*mat, MAT_SKIP_ALLOCATION, NULL));
5255   aij = (Mat_SeqAIJ *)(*mat)->data;
5256   PetscCall(PetscMalloc1(m, &aij->imax));
5257   PetscCall(PetscMalloc1(m, &aij->ilen));
5258 
5259   aij->i       = i;
5260   aij->j       = j;
5261   aij->a       = a;
5262   aij->nonew   = -1; /*this indicates that inserting a new value in the matrix that generates a new nonzero is an error*/
5263   aij->free_a  = PETSC_FALSE;
5264   aij->free_ij = PETSC_FALSE;
5265 
5266   for (ii = 0, aij->nonzerorowcnt = 0, aij->rmax = 0; ii < m; ii++) {
5267     aij->ilen[ii] = aij->imax[ii] = i[ii + 1] - i[ii];
5268     if (PetscDefined(USE_DEBUG)) {
5269       PetscCheck(i[ii + 1] - i[ii] >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Negative row length in i (row indices) row = %" PetscInt_FMT " length = %" PetscInt_FMT, ii, i[ii + 1] - i[ii]);
5270       for (jj = i[ii] + 1; jj < i[ii + 1]; jj++) {
5271         PetscCheck(j[jj] >= j[jj - 1], PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Column entry number %" PetscInt_FMT " (actual column %" PetscInt_FMT ") in row %" PetscInt_FMT " is not sorted", jj - i[ii], j[jj], ii);
5272         PetscCheck(j[jj] != j[jj - 1], PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Column entry number %" PetscInt_FMT " (actual column %" PetscInt_FMT ") in row %" PetscInt_FMT " is identical to previous entry", jj - i[ii], j[jj], ii);
5273       }
5274     }
5275   }
5276   if (PetscDefined(USE_DEBUG)) {
5277     for (ii = 0; ii < aij->i[m]; ii++) {
5278       PetscCheck(j[ii] >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Negative column index at location = %" PetscInt_FMT " index = %" PetscInt_FMT, ii, j[ii]);
5279       PetscCheck(j[ii] <= n - 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Column index to large at location = %" PetscInt_FMT " index = %" PetscInt_FMT " last column = %" PetscInt_FMT, ii, j[ii], n - 1);
5280     }
5281   }
5282 
5283   PetscCall(MatAssemblyBegin(*mat, MAT_FINAL_ASSEMBLY));
5284   PetscCall(MatAssemblyEnd(*mat, MAT_FINAL_ASSEMBLY));
5285   PetscFunctionReturn(PETSC_SUCCESS);
5286 }
5287 
5288 /*@
5289   MatCreateSeqAIJFromTriple - Creates an sequential `MATSEQAIJ` matrix using matrix elements (in COO format)
5290   provided by the user.
5291 
5292   Collective
5293 
5294   Input Parameters:
5295 + comm - must be an MPI communicator of size 1
5296 . m    - number of rows
5297 . n    - number of columns
5298 . i    - row indices
5299 . j    - column indices
5300 . a    - matrix values
5301 . nz   - number of nonzeros
5302 - idx  - if the `i` and `j` indices start with 1 use `PETSC_TRUE` otherwise use `PETSC_FALSE`
5303 
5304   Output Parameter:
5305 . mat - the matrix
5306 
5307   Level: intermediate
5308 
5309   Example:
5310   For the following matrix, the input data expected is as shown (using 0 based indexing)
5311 .vb
5312         1 0 0
5313         2 0 3
5314         4 5 6
5315 
5316         i =  {0,1,1,2,2,2}
5317         j =  {0,0,2,0,1,2}
5318         v =  {1,2,3,4,5,6}
5319 .ve
5320 
5321   Note:
5322   Instead of using this function, users should also consider `MatSetPreallocationCOO()` and `MatSetValuesCOO()`, which allow repeated or remote entries,
5323   and are particularly useful in iterative applications.
5324 
5325 .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatCreateAIJ()`, `MatCreateSeqAIJ()`, `MatCreateSeqAIJWithArrays()`, `MatMPIAIJSetPreallocationCSR()`, `MatSetValuesCOO()`, `MatSetPreallocationCOO()`
5326 @*/
5327 PetscErrorCode MatCreateSeqAIJFromTriple(MPI_Comm comm, PetscInt m, PetscInt n, PetscInt i[], PetscInt j[], PetscScalar a[], Mat *mat, PetscCount nz, PetscBool idx)
5328 {
5329   PetscInt ii, *nnz, one = 1, row, col;
5330 
5331   PetscFunctionBegin;
5332   PetscCall(PetscCalloc1(m, &nnz));
5333   for (ii = 0; ii < nz; ii++) nnz[i[ii] - !!idx] += 1;
5334   PetscCall(MatCreate(comm, mat));
5335   PetscCall(MatSetSizes(*mat, m, n, m, n));
5336   PetscCall(MatSetType(*mat, MATSEQAIJ));
5337   PetscCall(MatSeqAIJSetPreallocation_SeqAIJ(*mat, 0, nnz));
5338   for (ii = 0; ii < nz; ii++) {
5339     if (idx) {
5340       row = i[ii] - 1;
5341       col = j[ii] - 1;
5342     } else {
5343       row = i[ii];
5344       col = j[ii];
5345     }
5346     PetscCall(MatSetValues(*mat, one, &row, one, &col, &a[ii], ADD_VALUES));
5347   }
5348   PetscCall(MatAssemblyBegin(*mat, MAT_FINAL_ASSEMBLY));
5349   PetscCall(MatAssemblyEnd(*mat, MAT_FINAL_ASSEMBLY));
5350   PetscCall(PetscFree(nnz));
5351   PetscFunctionReturn(PETSC_SUCCESS);
5352 }
5353 
5354 PetscErrorCode MatSeqAIJInvalidateDiagonal(Mat A)
5355 {
5356   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
5357 
5358   PetscFunctionBegin;
5359   a->idiagvalid  = PETSC_FALSE;
5360   a->ibdiagvalid = PETSC_FALSE;
5361 
5362   PetscCall(MatSeqAIJInvalidateDiagonal_Inode(A));
5363   PetscFunctionReturn(PETSC_SUCCESS);
5364 }
5365 
5366 PetscErrorCode MatCreateMPIMatConcatenateSeqMat_SeqAIJ(MPI_Comm comm, Mat inmat, PetscInt n, MatReuse scall, Mat *outmat)
5367 {
5368   PetscFunctionBegin;
5369   PetscCall(MatCreateMPIMatConcatenateSeqMat_MPIAIJ(comm, inmat, n, scall, outmat));
5370   PetscFunctionReturn(PETSC_SUCCESS);
5371 }
5372 
5373 /*
5374  Permute A into C's *local* index space using rowemb,colemb.
5375  The embedding are supposed to be injections and the above implies that the range of rowemb is a subset
5376  of [0,m), colemb is in [0,n).
5377  If pattern == DIFFERENT_NONZERO_PATTERN, C is preallocated according to A.
5378  */
5379 PetscErrorCode MatSetSeqMat_SeqAIJ(Mat C, IS rowemb, IS colemb, MatStructure pattern, Mat B)
5380 {
5381   /* If making this function public, change the error returned in this function away from _PLIB. */
5382   Mat_SeqAIJ     *Baij;
5383   PetscBool       seqaij;
5384   PetscInt        m, n, *nz, i, j, count;
5385   PetscScalar     v;
5386   const PetscInt *rowindices, *colindices;
5387 
5388   PetscFunctionBegin;
5389   if (!B) PetscFunctionReturn(PETSC_SUCCESS);
5390   /* Check to make sure the target matrix (and embeddings) are compatible with C and each other. */
5391   PetscCall(PetscObjectBaseTypeCompare((PetscObject)B, MATSEQAIJ, &seqaij));
5392   PetscCheck(seqaij, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Input matrix is of wrong type");
5393   if (rowemb) {
5394     PetscCall(ISGetLocalSize(rowemb, &m));
5395     PetscCheck(m == B->rmap->n, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Row IS of size %" PetscInt_FMT " is incompatible with matrix row size %" PetscInt_FMT, m, B->rmap->n);
5396   } else {
5397     PetscCheck(C->rmap->n == B->rmap->n, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Input matrix is row-incompatible with the target matrix");
5398   }
5399   if (colemb) {
5400     PetscCall(ISGetLocalSize(colemb, &n));
5401     PetscCheck(n == B->cmap->n, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Diag col IS of size %" PetscInt_FMT " is incompatible with input matrix col size %" PetscInt_FMT, n, B->cmap->n);
5402   } else {
5403     PetscCheck(C->cmap->n == B->cmap->n, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Input matrix is col-incompatible with the target matrix");
5404   }
5405 
5406   Baij = (Mat_SeqAIJ *)B->data;
5407   if (pattern == DIFFERENT_NONZERO_PATTERN) {
5408     PetscCall(PetscMalloc1(B->rmap->n, &nz));
5409     for (i = 0; i < B->rmap->n; i++) nz[i] = Baij->i[i + 1] - Baij->i[i];
5410     PetscCall(MatSeqAIJSetPreallocation(C, 0, nz));
5411     PetscCall(PetscFree(nz));
5412   }
5413   if (pattern == SUBSET_NONZERO_PATTERN) PetscCall(MatZeroEntries(C));
5414   count      = 0;
5415   rowindices = NULL;
5416   colindices = NULL;
5417   if (rowemb) PetscCall(ISGetIndices(rowemb, &rowindices));
5418   if (colemb) PetscCall(ISGetIndices(colemb, &colindices));
5419   for (i = 0; i < B->rmap->n; i++) {
5420     PetscInt row;
5421     row = i;
5422     if (rowindices) row = rowindices[i];
5423     for (j = Baij->i[i]; j < Baij->i[i + 1]; j++) {
5424       PetscInt col;
5425       col = Baij->j[count];
5426       if (colindices) col = colindices[col];
5427       v = Baij->a[count];
5428       PetscCall(MatSetValues(C, 1, &row, 1, &col, &v, INSERT_VALUES));
5429       ++count;
5430     }
5431   }
5432   /* FIXME: set C's nonzerostate correctly. */
5433   /* Assembly for C is necessary. */
5434   C->preallocated  = PETSC_TRUE;
5435   C->assembled     = PETSC_TRUE;
5436   C->was_assembled = PETSC_FALSE;
5437   PetscFunctionReturn(PETSC_SUCCESS);
5438 }
5439 
5440 PetscErrorCode MatEliminateZeros_SeqAIJ(Mat A, PetscBool keep)
5441 {
5442   Mat_SeqAIJ *a  = (Mat_SeqAIJ *)A->data;
5443   MatScalar  *aa = a->a;
5444   PetscInt    m = A->rmap->n, fshift = 0, fshift_prev = 0, i, k;
5445   PetscInt   *ailen = a->ilen, *imax = a->imax, *ai = a->i, *aj = a->j, rmax = 0;
5446 
5447   PetscFunctionBegin;
5448   PetscCheck(A->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot eliminate zeros for unassembled matrix");
5449   if (m) rmax = ailen[0]; /* determine row with most nonzeros */
5450   for (i = 1; i <= m; i++) {
5451     /* move each nonzero entry back by the amount of zero slots (fshift) before it*/
5452     for (k = ai[i - 1]; k < ai[i]; k++) {
5453       if (aa[k] == 0 && (aj[k] != i - 1 || !keep)) fshift++;
5454       else {
5455         if (aa[k] == 0 && aj[k] == i - 1) PetscCall(PetscInfo(A, "Keep the diagonal zero at row %" PetscInt_FMT "\n", i - 1));
5456         aa[k - fshift] = aa[k];
5457         aj[k - fshift] = aj[k];
5458       }
5459     }
5460     ai[i - 1] -= fshift_prev; // safe to update ai[i-1] now since it will not be used in the next iteration
5461     fshift_prev = fshift;
5462     /* reset ilen and imax for each row */
5463     ailen[i - 1] = imax[i - 1] = ai[i] - fshift - ai[i - 1];
5464     a->nonzerorowcnt += ((ai[i] - fshift - ai[i - 1]) > 0);
5465     rmax = PetscMax(rmax, ailen[i - 1]);
5466   }
5467   if (fshift) {
5468     if (m) {
5469       ai[m] -= fshift;
5470       a->nz = ai[m];
5471     }
5472     PetscCall(PetscInfo(A, "Matrix size: %" PetscInt_FMT " X %" PetscInt_FMT "; zeros eliminated: %" PetscInt_FMT "; nonzeros left: %" PetscInt_FMT "\n", m, A->cmap->n, fshift, a->nz));
5473     A->nonzerostate++;
5474     A->info.nz_unneeded += (PetscReal)fshift;
5475     a->rmax = rmax;
5476     if (a->inode.use && a->inode.checked) PetscCall(MatSeqAIJCheckInode(A));
5477     PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
5478     PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
5479   }
5480   PetscFunctionReturn(PETSC_SUCCESS);
5481 }
5482 
5483 PetscFunctionList MatSeqAIJList = NULL;
5484 
5485 /*@
5486   MatSeqAIJSetType - Converts a `MATSEQAIJ` matrix to a subtype
5487 
5488   Collective
5489 
5490   Input Parameters:
5491 + mat    - the matrix object
5492 - matype - matrix type
5493 
5494   Options Database Key:
5495 . -mat_seqaij_type  <method> - for example seqaijcrl
5496 
5497   Level: intermediate
5498 
5499 .seealso: [](ch_matrices), `Mat`, `PCSetType()`, `VecSetType()`, `MatCreate()`, `MatType`
5500 @*/
5501 PetscErrorCode MatSeqAIJSetType(Mat mat, MatType matype)
5502 {
5503   PetscBool sametype;
5504   PetscErrorCode (*r)(Mat, MatType, MatReuse, Mat *);
5505 
5506   PetscFunctionBegin;
5507   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
5508   PetscCall(PetscObjectTypeCompare((PetscObject)mat, matype, &sametype));
5509   if (sametype) PetscFunctionReturn(PETSC_SUCCESS);
5510 
5511   PetscCall(PetscFunctionListFind(MatSeqAIJList, matype, &r));
5512   PetscCheck(r, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unknown Mat type given: %s", matype);
5513   PetscCall((*r)(mat, matype, MAT_INPLACE_MATRIX, &mat));
5514   PetscFunctionReturn(PETSC_SUCCESS);
5515 }
5516 
5517 /*@C
5518   MatSeqAIJRegister -  - Adds a new sub-matrix type for sequential `MATSEQAIJ` matrices
5519 
5520   Not Collective, No Fortran Support
5521 
5522   Input Parameters:
5523 + sname    - name of a new user-defined matrix type, for example `MATSEQAIJCRL`
5524 - function - routine to convert to subtype
5525 
5526   Level: advanced
5527 
5528   Notes:
5529   `MatSeqAIJRegister()` may be called multiple times to add several user-defined solvers.
5530 
5531   Then, your matrix can be chosen with the procedural interface at runtime via the option
5532 $     -mat_seqaij_type my_mat
5533 
5534 .seealso: [](ch_matrices), `Mat`, `MatSeqAIJRegisterAll()`
5535 @*/
5536 PetscErrorCode MatSeqAIJRegister(const char sname[], PetscErrorCode (*function)(Mat, MatType, MatReuse, Mat *))
5537 {
5538   PetscFunctionBegin;
5539   PetscCall(MatInitializePackage());
5540   PetscCall(PetscFunctionListAdd(&MatSeqAIJList, sname, function));
5541   PetscFunctionReturn(PETSC_SUCCESS);
5542 }
5543 
5544 PetscBool MatSeqAIJRegisterAllCalled = PETSC_FALSE;
5545 
5546 /*@C
5547   MatSeqAIJRegisterAll - Registers all of the matrix subtypes of `MATSSEQAIJ`
5548 
5549   Not Collective
5550 
5551   Level: advanced
5552 
5553   Note:
5554   This registers the versions of `MATSEQAIJ` for GPUs
5555 
5556 .seealso: [](ch_matrices), `Mat`, `MatRegisterAll()`, `MatSeqAIJRegister()`
5557 @*/
5558 PetscErrorCode MatSeqAIJRegisterAll(void)
5559 {
5560   PetscFunctionBegin;
5561   if (MatSeqAIJRegisterAllCalled) PetscFunctionReturn(PETSC_SUCCESS);
5562   MatSeqAIJRegisterAllCalled = PETSC_TRUE;
5563 
5564   PetscCall(MatSeqAIJRegister(MATSEQAIJCRL, MatConvert_SeqAIJ_SeqAIJCRL));
5565   PetscCall(MatSeqAIJRegister(MATSEQAIJPERM, MatConvert_SeqAIJ_SeqAIJPERM));
5566   PetscCall(MatSeqAIJRegister(MATSEQAIJSELL, MatConvert_SeqAIJ_SeqAIJSELL));
5567 #if defined(PETSC_HAVE_MKL_SPARSE)
5568   PetscCall(MatSeqAIJRegister(MATSEQAIJMKL, MatConvert_SeqAIJ_SeqAIJMKL));
5569 #endif
5570 #if defined(PETSC_HAVE_CUDA)
5571   PetscCall(MatSeqAIJRegister(MATSEQAIJCUSPARSE, MatConvert_SeqAIJ_SeqAIJCUSPARSE));
5572 #endif
5573 #if defined(PETSC_HAVE_HIP)
5574   PetscCall(MatSeqAIJRegister(MATSEQAIJHIPSPARSE, MatConvert_SeqAIJ_SeqAIJHIPSPARSE));
5575 #endif
5576 #if defined(PETSC_HAVE_KOKKOS_KERNELS)
5577   PetscCall(MatSeqAIJRegister(MATSEQAIJKOKKOS, MatConvert_SeqAIJ_SeqAIJKokkos));
5578 #endif
5579 #if defined(PETSC_HAVE_VIENNACL) && defined(PETSC_HAVE_VIENNACL_NO_CUDA)
5580   PetscCall(MatSeqAIJRegister(MATMPIAIJVIENNACL, MatConvert_SeqAIJ_SeqAIJViennaCL));
5581 #endif
5582   PetscFunctionReturn(PETSC_SUCCESS);
5583 }
5584 
5585 /*
5586     Special version for direct calls from Fortran
5587 */
5588 #if defined(PETSC_HAVE_FORTRAN_CAPS)
5589   #define matsetvaluesseqaij_ MATSETVALUESSEQAIJ
5590 #elif !defined(PETSC_HAVE_FORTRAN_UNDERSCORE)
5591   #define matsetvaluesseqaij_ matsetvaluesseqaij
5592 #endif
5593 
5594 /* Change these macros so can be used in void function */
5595 
5596 /* Change these macros so can be used in void function */
5597 /* Identical to PetscCallVoid, except it assigns to *_ierr */
5598 #undef PetscCall
5599 #define PetscCall(...) \
5600   do { \
5601     PetscErrorCode ierr_msv_mpiaij = __VA_ARGS__; \
5602     if (PetscUnlikely(ierr_msv_mpiaij)) { \
5603       *_ierr = PetscError(PETSC_COMM_SELF, __LINE__, PETSC_FUNCTION_NAME, __FILE__, ierr_msv_mpiaij, PETSC_ERROR_REPEAT, " "); \
5604       return; \
5605     } \
5606   } while (0)
5607 
5608 #undef SETERRQ
5609 #define SETERRQ(comm, ierr, ...) \
5610   do { \
5611     *_ierr = PetscError(comm, __LINE__, PETSC_FUNCTION_NAME, __FILE__, ierr, PETSC_ERROR_INITIAL, __VA_ARGS__); \
5612     return; \
5613   } while (0)
5614 
5615 PETSC_EXTERN void matsetvaluesseqaij_(Mat *AA, PetscInt *mm, const PetscInt im[], PetscInt *nn, const PetscInt in[], const PetscScalar v[], InsertMode *isis, PetscErrorCode *_ierr)
5616 {
5617   Mat         A = *AA;
5618   PetscInt    m = *mm, n = *nn;
5619   InsertMode  is = *isis;
5620   Mat_SeqAIJ *a  = (Mat_SeqAIJ *)A->data;
5621   PetscInt   *rp, k, low, high, t, ii, row, nrow, i, col, l, rmax, N;
5622   PetscInt   *imax, *ai, *ailen;
5623   PetscInt   *aj, nonew = a->nonew, lastcol = -1;
5624   MatScalar  *ap, value, *aa;
5625   PetscBool   ignorezeroentries = a->ignorezeroentries;
5626   PetscBool   roworiented       = a->roworiented;
5627 
5628   PetscFunctionBegin;
5629   MatCheckPreallocated(A, 1);
5630   imax  = a->imax;
5631   ai    = a->i;
5632   ailen = a->ilen;
5633   aj    = a->j;
5634   aa    = a->a;
5635 
5636   for (k = 0; k < m; k++) { /* loop over added rows */
5637     row = im[k];
5638     if (row < 0) continue;
5639     PetscCheck(row < A->rmap->n, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Row too large");
5640     rp   = aj + ai[row];
5641     ap   = aa + ai[row];
5642     rmax = imax[row];
5643     nrow = ailen[row];
5644     low  = 0;
5645     high = nrow;
5646     for (l = 0; l < n; l++) { /* loop over added columns */
5647       if (in[l] < 0) continue;
5648       PetscCheck(in[l] < A->cmap->n, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Column too large");
5649       col = in[l];
5650       if (roworiented) value = v[l + k * n];
5651       else value = v[k + l * m];
5652 
5653       if (value == 0.0 && ignorezeroentries && (is == ADD_VALUES)) continue;
5654 
5655       if (col <= lastcol) low = 0;
5656       else high = nrow;
5657       lastcol = col;
5658       while (high - low > 5) {
5659         t = (low + high) / 2;
5660         if (rp[t] > col) high = t;
5661         else low = t;
5662       }
5663       for (i = low; i < high; i++) {
5664         if (rp[i] > col) break;
5665         if (rp[i] == col) {
5666           if (is == ADD_VALUES) ap[i] += value;
5667           else ap[i] = value;
5668           goto noinsert;
5669         }
5670       }
5671       if (value == 0.0 && ignorezeroentries) goto noinsert;
5672       if (nonew == 1) goto noinsert;
5673       PetscCheck(nonew != -1, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Inserting a new nonzero in the matrix");
5674       MatSeqXAIJReallocateAIJ(A, A->rmap->n, 1, nrow, row, col, rmax, aa, ai, aj, rp, ap, imax, nonew, MatScalar);
5675       N = nrow++ - 1;
5676       a->nz++;
5677       high++;
5678       /* shift up all the later entries in this row */
5679       for (ii = N; ii >= i; ii--) {
5680         rp[ii + 1] = rp[ii];
5681         ap[ii + 1] = ap[ii];
5682       }
5683       rp[i] = col;
5684       ap[i] = value;
5685     noinsert:;
5686       low = i + 1;
5687     }
5688     ailen[row] = nrow;
5689   }
5690   PetscFunctionReturnVoid();
5691 }
5692 /* Undefining these here since they were redefined from their original definition above! No
5693  * other PETSc functions should be defined past this point, as it is impossible to recover the
5694  * original definitions */
5695 #undef PetscCall
5696 #undef SETERRQ
5697