xref: /petsc/src/mat/impls/shell/shell.c (revision 2de926d82d823da29bdda0ecdcb77fc7c15bee72)
1 /*
2    This provides a simple shell for Fortran (and C programmers) to
3   create a very simple matrix class for use with KSP without coding
4   much of anything.
5 */
6 
7 #include <../src/mat/impls/shell/shell.h> /*I "petscmat.h" I*/
8 
9 /*
10      Store and scale values on zeroed rows
11      xx = [x_1, 0], 0 on zeroed columns
12 */
13 static PetscErrorCode MatShellPreZeroRight(Mat A, Vec x, Vec *xx)
14 {
15   Mat_Shell *shell = (Mat_Shell *)A->data;
16 
17   PetscFunctionBegin;
18   *xx = x;
19   if (shell->zrows) {
20     PetscCall(VecSet(shell->zvals_w, 0.0));
21     PetscCall(VecScatterBegin(shell->zvals_sct_c, x, shell->zvals_w, INSERT_VALUES, SCATTER_FORWARD));
22     PetscCall(VecScatterEnd(shell->zvals_sct_c, x, shell->zvals_w, INSERT_VALUES, SCATTER_FORWARD));
23     PetscCall(VecPointwiseMult(shell->zvals_w, shell->zvals_w, shell->zvals));
24   }
25   if (shell->zcols) {
26     if (!shell->right_work) PetscCall(MatCreateVecs(A, &shell->right_work, NULL));
27     PetscCall(VecCopy(x, shell->right_work));
28     PetscCall(VecISSet(shell->right_work, shell->zcols, 0.0));
29     *xx = shell->right_work;
30   }
31   PetscFunctionReturn(PETSC_SUCCESS);
32 }
33 
34 /* Insert properly diagonally scaled values stored in MatShellPreZeroRight */
35 static PetscErrorCode MatShellPostZeroLeft(Mat A, Vec x)
36 {
37   Mat_Shell *shell = (Mat_Shell *)A->data;
38 
39   PetscFunctionBegin;
40   if (shell->zrows) {
41     PetscCall(VecScatterBegin(shell->zvals_sct_r, shell->zvals_w, x, INSERT_VALUES, SCATTER_REVERSE));
42     PetscCall(VecScatterEnd(shell->zvals_sct_r, shell->zvals_w, x, INSERT_VALUES, SCATTER_REVERSE));
43   }
44   PetscFunctionReturn(PETSC_SUCCESS);
45 }
46 
47 /*
48      Store and scale values on zeroed rows
49      xx = [x_1, 0], 0 on zeroed rows
50 */
51 static PetscErrorCode MatShellPreZeroLeft(Mat A, Vec x, Vec *xx)
52 {
53   Mat_Shell *shell = (Mat_Shell *)A->data;
54 
55   PetscFunctionBegin;
56   *xx = NULL;
57   if (!shell->zrows) {
58     *xx = x;
59   } else {
60     if (!shell->left_work) PetscCall(MatCreateVecs(A, NULL, &shell->left_work));
61     PetscCall(VecCopy(x, shell->left_work));
62     PetscCall(VecSet(shell->zvals_w, 0.0));
63     PetscCall(VecScatterBegin(shell->zvals_sct_r, shell->zvals_w, shell->left_work, INSERT_VALUES, SCATTER_REVERSE));
64     PetscCall(VecScatterEnd(shell->zvals_sct_r, shell->zvals_w, shell->left_work, INSERT_VALUES, SCATTER_REVERSE));
65     PetscCall(VecScatterBegin(shell->zvals_sct_r, x, shell->zvals_w, INSERT_VALUES, SCATTER_FORWARD));
66     PetscCall(VecScatterEnd(shell->zvals_sct_r, x, shell->zvals_w, INSERT_VALUES, SCATTER_FORWARD));
67     PetscCall(VecPointwiseMult(shell->zvals_w, shell->zvals_w, shell->zvals));
68     *xx = shell->left_work;
69   }
70   PetscFunctionReturn(PETSC_SUCCESS);
71 }
72 
73 /* Zero zero-columns contributions, sum contributions from properly scaled values stored in MatShellPreZeroLeft */
74 static PetscErrorCode MatShellPostZeroRight(Mat A, Vec x)
75 {
76   Mat_Shell *shell = (Mat_Shell *)A->data;
77 
78   PetscFunctionBegin;
79   if (shell->zcols) PetscCall(VecISSet(x, shell->zcols, 0.0));
80   if (shell->zrows) {
81     PetscCall(VecScatterBegin(shell->zvals_sct_c, shell->zvals_w, x, ADD_VALUES, SCATTER_REVERSE));
82     PetscCall(VecScatterEnd(shell->zvals_sct_c, shell->zvals_w, x, ADD_VALUES, SCATTER_REVERSE));
83   }
84   PetscFunctionReturn(PETSC_SUCCESS);
85 }
86 
87 /*
88       xx = diag(left)*x
89 */
90 static PetscErrorCode MatShellPreScaleLeft(Mat A, Vec x, Vec *xx, PetscBool conjugate)
91 {
92   Mat_Shell *shell = (Mat_Shell *)A->data;
93 
94   PetscFunctionBegin;
95   *xx = NULL;
96   if (!shell->left) {
97     *xx = x;
98   } else {
99     if (!shell->left_work) PetscCall(VecDuplicate(shell->left, &shell->left_work));
100     if (conjugate) { /* get arrays because there is no VecPointwiseMultConj() */
101       PetscInt           i, m;
102       const PetscScalar *d, *xarray;
103       PetscScalar       *w;
104       PetscCall(VecGetLocalSize(x, &m));
105       PetscCall(VecGetArrayRead(shell->left, &d));
106       PetscCall(VecGetArrayRead(x, &xarray));
107       PetscCall(VecGetArrayWrite(shell->left_work, &w));
108       for (i = 0; i < m; i++) w[i] = PetscConj(d[i]) * xarray[i];
109       PetscCall(VecRestoreArrayRead(shell->dshift, &d));
110       PetscCall(VecRestoreArrayRead(x, &xarray));
111       PetscCall(VecRestoreArrayWrite(shell->left_work, &w));
112     } else PetscCall(VecPointwiseMult(shell->left_work, x, shell->left));
113     *xx = shell->left_work;
114   }
115   PetscFunctionReturn(PETSC_SUCCESS);
116 }
117 
118 /*
119      xx = diag(right)*x
120 */
121 static PetscErrorCode MatShellPreScaleRight(Mat A, Vec x, Vec *xx)
122 {
123   Mat_Shell *shell = (Mat_Shell *)A->data;
124 
125   PetscFunctionBegin;
126   *xx = NULL;
127   if (!shell->right) {
128     *xx = x;
129   } else {
130     if (!shell->right_work) PetscCall(VecDuplicate(shell->right, &shell->right_work));
131     PetscCall(VecPointwiseMult(shell->right_work, x, shell->right));
132     *xx = shell->right_work;
133   }
134   PetscFunctionReturn(PETSC_SUCCESS);
135 }
136 
137 /*
138     x = diag(left)*x
139 */
140 static PetscErrorCode MatShellPostScaleLeft(Mat A, Vec x)
141 {
142   Mat_Shell *shell = (Mat_Shell *)A->data;
143 
144   PetscFunctionBegin;
145   if (shell->left) PetscCall(VecPointwiseMult(x, x, shell->left));
146   PetscFunctionReturn(PETSC_SUCCESS);
147 }
148 
149 /*
150     x = diag(right)*x
151 */
152 static PetscErrorCode MatShellPostScaleRight(Mat A, Vec x, PetscBool conjugate)
153 {
154   Mat_Shell *shell = (Mat_Shell *)A->data;
155 
156   PetscFunctionBegin;
157   if (shell->right) {
158     if (conjugate) { /* get arrays because there is no VecPointwiseMultConj() */
159       PetscInt           i, m;
160       const PetscScalar *d;
161       PetscScalar       *xarray;
162       PetscCall(VecGetLocalSize(x, &m));
163       PetscCall(VecGetArrayRead(shell->right, &d));
164       PetscCall(VecGetArray(x, &xarray));
165       for (i = 0; i < m; i++) xarray[i] = PetscConj(d[i]) * xarray[i];
166       PetscCall(VecRestoreArrayRead(shell->dshift, &d));
167       PetscCall(VecRestoreArray(x, &xarray));
168     } else PetscCall(VecPointwiseMult(x, x, shell->right));
169   }
170   PetscFunctionReturn(PETSC_SUCCESS);
171 }
172 
173 /*
174          Y = vscale*Y + diag(dshift)*X + vshift*X
175 
176          On input Y already contains A*x
177 
178          If conjugate=PETSC_TRUE then vscale, dshift, and vshift are conjugated
179 */
180 static PetscErrorCode MatShellShiftAndScale(Mat A, Vec X, Vec Y, PetscBool conjugate)
181 {
182   Mat_Shell  *shell  = (Mat_Shell *)A->data;
183   PetscScalar vscale = conjugate ? PetscConj(shell->vscale) : shell->vscale;
184   PetscScalar vshift = conjugate ? PetscConj(shell->vshift) : shell->vshift;
185 
186   PetscFunctionBegin;
187   if (shell->dshift) { /* get arrays because there is no VecPointwiseMultAdd() */
188     PetscInt           i, m;
189     const PetscScalar *x, *d;
190     PetscScalar       *y;
191     PetscCall(VecGetLocalSize(X, &m));
192     PetscCall(VecGetArrayRead(shell->dshift, &d));
193     PetscCall(VecGetArrayRead(X, &x));
194     PetscCall(VecGetArray(Y, &y));
195     if (conjugate)
196       for (i = 0; i < m; i++) y[i] = vscale * y[i] + PetscConj(d[i]) * x[i];
197     else
198       for (i = 0; i < m; i++) y[i] = vscale * y[i] + d[i] * x[i];
199     PetscCall(VecRestoreArrayRead(shell->dshift, &d));
200     PetscCall(VecRestoreArrayRead(X, &x));
201     PetscCall(VecRestoreArray(Y, &y));
202   } else {
203     PetscCall(VecScale(Y, vscale));
204   }
205   if (vshift != 0.0) PetscCall(VecAXPY(Y, vshift, X)); /* if test is for non-square matrices */
206   PetscFunctionReturn(PETSC_SUCCESS);
207 }
208 
209 static PetscErrorCode MatShellGetContext_Shell(Mat mat, void *ctx)
210 {
211   Mat_Shell *shell = (Mat_Shell *)mat->data;
212 
213   PetscFunctionBegin;
214   if (shell->ctxcontainer) PetscCall(PetscContainerGetPointer(shell->ctxcontainer, (void **)ctx));
215   else *(void **)ctx = NULL;
216   PetscFunctionReturn(PETSC_SUCCESS);
217 }
218 
219 /*@
220   MatShellGetContext - Returns the user-provided context associated with a `MATSHELL` shell matrix.
221 
222   Not Collective
223 
224   Input Parameter:
225 . mat - the matrix, should have been created with `MatCreateShell()`
226 
227   Output Parameter:
228 . ctx - the user provided context
229 
230   Level: advanced
231 
232   Fortran Notes:
233   You must write a Fortran interface definition for this
234   function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.
235 
236 .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellSetOperation()`, `MatShellSetContext()`
237 @*/
238 PetscErrorCode MatShellGetContext(Mat mat, void *ctx)
239 {
240   PetscFunctionBegin;
241   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
242   PetscAssertPointer(ctx, 2);
243   PetscUseMethod(mat, "MatShellGetContext_C", (Mat, void *), (mat, ctx));
244   PetscFunctionReturn(PETSC_SUCCESS);
245 }
246 
247 static PetscErrorCode MatZeroRowsColumns_Local_Shell(Mat mat, PetscInt nr, PetscInt rows[], PetscInt nc, PetscInt cols[], PetscScalar diag, PetscBool rc)
248 {
249   Mat_Shell      *shell = (Mat_Shell *)mat->data;
250   Vec             x = NULL, b = NULL;
251   IS              is1, is2;
252   const PetscInt *ridxs;
253   PetscInt       *idxs, *gidxs;
254   PetscInt        cum, rst, cst, i;
255 
256   PetscFunctionBegin;
257   if (!shell->zvals) PetscCall(MatCreateVecs(mat, NULL, &shell->zvals));
258   if (!shell->zvals_w) PetscCall(VecDuplicate(shell->zvals, &shell->zvals_w));
259   PetscCall(MatGetOwnershipRange(mat, &rst, NULL));
260   PetscCall(MatGetOwnershipRangeColumn(mat, &cst, NULL));
261 
262   /* Expand/create index set of zeroed rows */
263   PetscCall(PetscMalloc1(nr, &idxs));
264   for (i = 0; i < nr; i++) idxs[i] = rows[i] + rst;
265   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, nr, idxs, PETSC_OWN_POINTER, &is1));
266   PetscCall(ISSort(is1));
267   PetscCall(VecISSet(shell->zvals, is1, diag));
268   if (shell->zrows) {
269     PetscCall(ISSum(shell->zrows, is1, &is2));
270     PetscCall(ISDestroy(&shell->zrows));
271     PetscCall(ISDestroy(&is1));
272     shell->zrows = is2;
273   } else shell->zrows = is1;
274 
275   /* Create scatters for diagonal values communications */
276   PetscCall(VecScatterDestroy(&shell->zvals_sct_c));
277   PetscCall(VecScatterDestroy(&shell->zvals_sct_r));
278 
279   /* row scatter: from/to left vector */
280   PetscCall(MatCreateVecs(mat, &x, &b));
281   PetscCall(VecScatterCreate(b, shell->zrows, shell->zvals_w, shell->zrows, &shell->zvals_sct_r));
282 
283   /* col scatter: from right vector to left vector */
284   PetscCall(ISGetIndices(shell->zrows, &ridxs));
285   PetscCall(ISGetLocalSize(shell->zrows, &nr));
286   PetscCall(PetscMalloc1(nr, &gidxs));
287   for (i = 0, cum = 0; i < nr; i++) {
288     if (ridxs[i] >= mat->cmap->N) continue;
289     gidxs[cum] = ridxs[i];
290     cum++;
291   }
292   PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)mat), cum, gidxs, PETSC_OWN_POINTER, &is1));
293   PetscCall(VecScatterCreate(x, is1, shell->zvals_w, is1, &shell->zvals_sct_c));
294   PetscCall(ISDestroy(&is1));
295   PetscCall(VecDestroy(&x));
296   PetscCall(VecDestroy(&b));
297 
298   /* Expand/create index set of zeroed columns */
299   if (rc) {
300     PetscCall(PetscMalloc1(nc, &idxs));
301     for (i = 0; i < nc; i++) idxs[i] = cols[i] + cst;
302     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, nc, idxs, PETSC_OWN_POINTER, &is1));
303     PetscCall(ISSort(is1));
304     if (shell->zcols) {
305       PetscCall(ISSum(shell->zcols, is1, &is2));
306       PetscCall(ISDestroy(&shell->zcols));
307       PetscCall(ISDestroy(&is1));
308       shell->zcols = is2;
309     } else shell->zcols = is1;
310   }
311   PetscFunctionReturn(PETSC_SUCCESS);
312 }
313 
314 static PetscErrorCode MatZeroRows_Shell(Mat mat, PetscInt n, const PetscInt rows[], PetscScalar diag, Vec x, Vec b)
315 {
316   Mat_Shell *shell = (Mat_Shell *)mat->data;
317   PetscInt   nr, *lrows;
318 
319   PetscFunctionBegin;
320   if (x && b) {
321     Vec          xt;
322     PetscScalar *vals;
323     PetscInt    *gcols, i, st, nl, nc;
324 
325     PetscCall(PetscMalloc1(n, &gcols));
326     for (i = 0, nc = 0; i < n; i++)
327       if (rows[i] < mat->cmap->N) gcols[nc++] = rows[i];
328 
329     PetscCall(MatCreateVecs(mat, &xt, NULL));
330     PetscCall(VecCopy(x, xt));
331     PetscCall(PetscCalloc1(nc, &vals));
332     PetscCall(VecSetValues(xt, nc, gcols, vals, INSERT_VALUES)); /* xt = [x1, 0] */
333     PetscCall(PetscFree(vals));
334     PetscCall(VecAssemblyBegin(xt));
335     PetscCall(VecAssemblyEnd(xt));
336     PetscCall(VecAYPX(xt, -1.0, x)); /* xt = [0, x2] */
337 
338     PetscCall(VecGetOwnershipRange(xt, &st, NULL));
339     PetscCall(VecGetLocalSize(xt, &nl));
340     PetscCall(VecGetArray(xt, &vals));
341     for (i = 0; i < nl; i++) {
342       PetscInt g = i + st;
343       if (g > mat->rmap->N) continue;
344       if (PetscAbsScalar(vals[i]) == 0.0) continue;
345       PetscCall(VecSetValue(b, g, diag * vals[i], INSERT_VALUES));
346     }
347     PetscCall(VecRestoreArray(xt, &vals));
348     PetscCall(VecAssemblyBegin(b));
349     PetscCall(VecAssemblyEnd(b)); /* b  = [b1, x2 * diag] */
350     PetscCall(VecDestroy(&xt));
351     PetscCall(PetscFree(gcols));
352   }
353   PetscCall(PetscLayoutMapLocal(mat->rmap, n, rows, &nr, &lrows, NULL));
354   PetscCall(MatZeroRowsColumns_Local_Shell(mat, nr, lrows, 0, NULL, diag, PETSC_FALSE));
355   if (shell->axpy) PetscCall(MatZeroRows(shell->axpy, n, rows, 0.0, NULL, NULL));
356   PetscCall(PetscFree(lrows));
357   PetscFunctionReturn(PETSC_SUCCESS);
358 }
359 
360 static PetscErrorCode MatZeroRowsColumns_Shell(Mat mat, PetscInt n, const PetscInt rowscols[], PetscScalar diag, Vec x, Vec b)
361 {
362   Mat_Shell *shell = (Mat_Shell *)mat->data;
363   PetscInt  *lrows, *lcols;
364   PetscInt   nr, nc;
365   PetscBool  congruent;
366 
367   PetscFunctionBegin;
368   if (x && b) {
369     Vec          xt, bt;
370     PetscScalar *vals;
371     PetscInt    *grows, *gcols, i, st, nl;
372 
373     PetscCall(PetscMalloc2(n, &grows, n, &gcols));
374     for (i = 0, nr = 0; i < n; i++)
375       if (rowscols[i] < mat->rmap->N) grows[nr++] = rowscols[i];
376     for (i = 0, nc = 0; i < n; i++)
377       if (rowscols[i] < mat->cmap->N) gcols[nc++] = rowscols[i];
378     PetscCall(PetscCalloc1(n, &vals));
379 
380     PetscCall(MatCreateVecs(mat, &xt, &bt));
381     PetscCall(VecCopy(x, xt));
382     PetscCall(VecSetValues(xt, nc, gcols, vals, INSERT_VALUES)); /* xt = [x1, 0] */
383     PetscCall(VecAssemblyBegin(xt));
384     PetscCall(VecAssemblyEnd(xt));
385     PetscCall(VecAXPY(xt, -1.0, x));                             /* xt = [0, -x2] */
386     PetscCall(MatMult(mat, xt, bt));                             /* bt = [-A12*x2,-A22*x2] */
387     PetscCall(VecSetValues(bt, nr, grows, vals, INSERT_VALUES)); /* bt = [-A12*x2,0] */
388     PetscCall(VecAssemblyBegin(bt));
389     PetscCall(VecAssemblyEnd(bt));
390     PetscCall(VecAXPY(b, 1.0, bt));                              /* b  = [b1 - A12*x2, b2] */
391     PetscCall(VecSetValues(bt, nr, grows, vals, INSERT_VALUES)); /* b  = [b1 - A12*x2, 0] */
392     PetscCall(VecAssemblyBegin(bt));
393     PetscCall(VecAssemblyEnd(bt));
394     PetscCall(PetscFree(vals));
395 
396     PetscCall(VecGetOwnershipRange(xt, &st, NULL));
397     PetscCall(VecGetLocalSize(xt, &nl));
398     PetscCall(VecGetArray(xt, &vals));
399     for (i = 0; i < nl; i++) {
400       PetscInt g = i + st;
401       if (g > mat->rmap->N) continue;
402       if (PetscAbsScalar(vals[i]) == 0.0) continue;
403       PetscCall(VecSetValue(b, g, -diag * vals[i], INSERT_VALUES));
404     }
405     PetscCall(VecRestoreArray(xt, &vals));
406     PetscCall(VecAssemblyBegin(b));
407     PetscCall(VecAssemblyEnd(b)); /* b  = [b1 - A12*x2, x2 * diag] */
408     PetscCall(VecDestroy(&xt));
409     PetscCall(VecDestroy(&bt));
410     PetscCall(PetscFree2(grows, gcols));
411   }
412   PetscCall(PetscLayoutMapLocal(mat->rmap, n, rowscols, &nr, &lrows, NULL));
413   PetscCall(MatHasCongruentLayouts(mat, &congruent));
414   if (congruent) {
415     nc    = nr;
416     lcols = lrows;
417   } else { /* MatZeroRowsColumns implicitly assumes the rowscols indices are for a square matrix, here we handle a more general case */
418     PetscInt i, nt, *t;
419 
420     PetscCall(PetscMalloc1(n, &t));
421     for (i = 0, nt = 0; i < n; i++)
422       if (rowscols[i] < mat->cmap->N) t[nt++] = rowscols[i];
423     PetscCall(PetscLayoutMapLocal(mat->cmap, nt, t, &nc, &lcols, NULL));
424     PetscCall(PetscFree(t));
425   }
426   PetscCall(MatZeroRowsColumns_Local_Shell(mat, nr, lrows, nc, lcols, diag, PETSC_TRUE));
427   if (!congruent) PetscCall(PetscFree(lcols));
428   PetscCall(PetscFree(lrows));
429   if (shell->axpy) PetscCall(MatZeroRowsColumns(shell->axpy, n, rowscols, 0.0, NULL, NULL));
430   PetscFunctionReturn(PETSC_SUCCESS);
431 }
432 
433 static PetscErrorCode MatDestroy_Shell(Mat mat)
434 {
435   Mat_Shell              *shell = (Mat_Shell *)mat->data;
436   MatShellMatFunctionList matmat;
437 
438   PetscFunctionBegin;
439   if (shell->ops->destroy) PetscCall((*shell->ops->destroy)(mat));
440   PetscCall(PetscMemzero(shell->ops, sizeof(struct _MatShellOps)));
441   PetscCall(VecDestroy(&shell->left));
442   PetscCall(VecDestroy(&shell->right));
443   PetscCall(VecDestroy(&shell->dshift));
444   PetscCall(VecDestroy(&shell->left_work));
445   PetscCall(VecDestroy(&shell->right_work));
446   PetscCall(VecDestroy(&shell->left_add_work));
447   PetscCall(VecDestroy(&shell->right_add_work));
448   PetscCall(VecDestroy(&shell->axpy_left));
449   PetscCall(VecDestroy(&shell->axpy_right));
450   PetscCall(MatDestroy(&shell->axpy));
451   PetscCall(VecDestroy(&shell->zvals_w));
452   PetscCall(VecDestroy(&shell->zvals));
453   PetscCall(VecScatterDestroy(&shell->zvals_sct_c));
454   PetscCall(VecScatterDestroy(&shell->zvals_sct_r));
455   PetscCall(ISDestroy(&shell->zrows));
456   PetscCall(ISDestroy(&shell->zcols));
457 
458   matmat = shell->matmat;
459   while (matmat) {
460     MatShellMatFunctionList next = matmat->next;
461 
462     PetscCall(PetscObjectComposeFunction((PetscObject)mat, matmat->composedname, NULL));
463     PetscCall(PetscFree(matmat->composedname));
464     PetscCall(PetscFree(matmat->resultname));
465     PetscCall(PetscFree(matmat));
466     matmat = next;
467   }
468   PetscCall(MatShellSetContext(mat, NULL));
469   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellGetContext_C", NULL));
470   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellSetContext_C", NULL));
471   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellSetContextDestroy_C", NULL));
472   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellSetVecType_C", NULL));
473   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellSetManageScalingShifts_C", NULL));
474   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellGetScalingShifts_C", NULL));
475   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellSetOperation_C", NULL));
476   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellGetOperation_C", NULL));
477   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellSetMatProductOperation_C", NULL));
478   PetscCall(PetscFree(mat->data));
479   PetscFunctionReturn(PETSC_SUCCESS);
480 }
481 
482 typedef struct {
483   PetscErrorCode (*numeric)(Mat, Mat, Mat, void *);
484   PetscErrorCode (*destroy)(void *);
485   void *userdata;
486   Mat   B;
487   Mat   Bt;
488   Mat   axpy;
489 } MatMatDataShell;
490 
491 static PetscErrorCode DestroyMatMatDataShell(void *data)
492 {
493   MatMatDataShell *mmdata = (MatMatDataShell *)data;
494 
495   PetscFunctionBegin;
496   if (mmdata->destroy) PetscCall((*mmdata->destroy)(mmdata->userdata));
497   PetscCall(MatDestroy(&mmdata->B));
498   PetscCall(MatDestroy(&mmdata->Bt));
499   PetscCall(MatDestroy(&mmdata->axpy));
500   PetscCall(PetscFree(mmdata));
501   PetscFunctionReturn(PETSC_SUCCESS);
502 }
503 
504 static PetscErrorCode MatProductNumeric_Shell_X(Mat D)
505 {
506   Mat_Product     *product;
507   Mat              A, B;
508   MatMatDataShell *mdata;
509   PetscScalar      zero = 0.0;
510 
511   PetscFunctionBegin;
512   MatCheckProduct(D, 1);
513   product = D->product;
514   PetscCheck(product->data, PetscObjectComm((PetscObject)D), PETSC_ERR_PLIB, "Product data empty");
515   A     = product->A;
516   B     = product->B;
517   mdata = (MatMatDataShell *)product->data;
518   if (mdata->numeric) {
519     Mat_Shell *shell                = (Mat_Shell *)A->data;
520     PetscErrorCode (*stashsym)(Mat) = D->ops->productsymbolic;
521     PetscErrorCode (*stashnum)(Mat) = D->ops->productnumeric;
522     PetscBool useBmdata = PETSC_FALSE, newB = PETSC_TRUE;
523 
524     if (shell->managescalingshifts) {
525       PetscCheck(!shell->zcols && !shell->zrows, PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProduct not supported with zeroed rows/columns");
526       if (shell->right || shell->left) {
527         useBmdata = PETSC_TRUE;
528         if (!mdata->B) {
529           PetscCall(MatDuplicate(B, MAT_SHARE_NONZERO_PATTERN, &mdata->B));
530         } else {
531           newB = PETSC_FALSE;
532         }
533         PetscCall(MatCopy(B, mdata->B, SAME_NONZERO_PATTERN));
534       }
535       switch (product->type) {
536       case MATPRODUCT_AB: /* s L A R B + v L R B + L D R B */
537         if (shell->right) PetscCall(MatDiagonalScale(mdata->B, shell->right, NULL));
538         break;
539       case MATPRODUCT_AtB: /* s R A^t L B + v R L B + R D L B */
540         if (shell->left) PetscCall(MatDiagonalScale(mdata->B, shell->left, NULL));
541         break;
542       case MATPRODUCT_ABt: /* s L A R B^t + v L R B^t + L D R B^t */
543         if (shell->right) PetscCall(MatDiagonalScale(mdata->B, NULL, shell->right));
544         break;
545       case MATPRODUCT_RARt: /* s B L A R B^t + v B L R B^t + B L D R B^t */
546         if (shell->right && shell->left) {
547           PetscBool flg;
548 
549           PetscCall(VecEqual(shell->right, shell->left, &flg));
550           PetscCheck(flg, PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProductSymbolic type %s not supported for %s and %s matrices because left scaling != from right scaling", MatProductTypes[product->type], ((PetscObject)A)->type_name,
551                      ((PetscObject)B)->type_name);
552         }
553         if (shell->right) PetscCall(MatDiagonalScale(mdata->B, NULL, shell->right));
554         break;
555       case MATPRODUCT_PtAP: /* s B^t L A R B + v B^t L R B + B^t L D R B */
556         if (shell->right && shell->left) {
557           PetscBool flg;
558 
559           PetscCall(VecEqual(shell->right, shell->left, &flg));
560           PetscCheck(flg, PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProductSymbolic type %s not supported for %s and %s matrices because left scaling != from right scaling", MatProductTypes[product->type], ((PetscObject)A)->type_name,
561                      ((PetscObject)B)->type_name);
562         }
563         if (shell->right) PetscCall(MatDiagonalScale(mdata->B, shell->right, NULL));
564         break;
565       default:
566         SETERRQ(PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProductSymbolic type %s not supported for %s and %s matrices", MatProductTypes[product->type], ((PetscObject)A)->type_name, ((PetscObject)B)->type_name);
567       }
568     }
569     /* allow the user to call MatMat operations on D */
570     D->product              = NULL;
571     D->ops->productsymbolic = NULL;
572     D->ops->productnumeric  = NULL;
573 
574     PetscCall((*mdata->numeric)(A, useBmdata ? mdata->B : B, D, mdata->userdata));
575 
576     /* clear any leftover user data and restore D pointers */
577     PetscCall(MatProductClear(D));
578     D->ops->productsymbolic = stashsym;
579     D->ops->productnumeric  = stashnum;
580     D->product              = product;
581 
582     if (shell->managescalingshifts) {
583       PetscCall(MatScale(D, shell->vscale));
584       switch (product->type) {
585       case MATPRODUCT_AB:  /* s L A R B + v L R B + L D R B */
586       case MATPRODUCT_ABt: /* s L A R B^t + v L R B^t + L D R B^t */
587         if (shell->left) {
588           PetscCall(MatDiagonalScale(D, shell->left, NULL));
589           if (shell->dshift || shell->vshift != zero) {
590             if (!shell->left_work) PetscCall(MatCreateVecs(A, NULL, &shell->left_work));
591             if (shell->dshift) {
592               PetscCall(VecCopy(shell->dshift, shell->left_work));
593               PetscCall(VecShift(shell->left_work, shell->vshift));
594               PetscCall(VecPointwiseMult(shell->left_work, shell->left_work, shell->left));
595             } else {
596               PetscCall(VecSet(shell->left_work, shell->vshift));
597             }
598             if (product->type == MATPRODUCT_ABt) {
599               MatReuse     reuse = mdata->Bt ? MAT_REUSE_MATRIX : MAT_INITIAL_MATRIX;
600               MatStructure str   = mdata->Bt ? SUBSET_NONZERO_PATTERN : DIFFERENT_NONZERO_PATTERN;
601 
602               PetscCall(MatTranspose(mdata->B, reuse, &mdata->Bt));
603               PetscCall(MatDiagonalScale(mdata->Bt, shell->left_work, NULL));
604               PetscCall(MatAXPY(D, 1.0, mdata->Bt, str));
605             } else {
606               MatStructure str = newB ? DIFFERENT_NONZERO_PATTERN : SUBSET_NONZERO_PATTERN;
607 
608               PetscCall(MatDiagonalScale(mdata->B, shell->left_work, NULL));
609               PetscCall(MatAXPY(D, 1.0, mdata->B, str));
610             }
611           }
612         }
613         break;
614       case MATPRODUCT_AtB: /* s R A^t L B + v R L B + R D L B */
615         if (shell->right) {
616           PetscCall(MatDiagonalScale(D, shell->right, NULL));
617           if (shell->dshift || shell->vshift != zero) {
618             MatStructure str = newB ? DIFFERENT_NONZERO_PATTERN : SUBSET_NONZERO_PATTERN;
619 
620             if (!shell->right_work) PetscCall(MatCreateVecs(A, &shell->right_work, NULL));
621             if (shell->dshift) {
622               PetscCall(VecCopy(shell->dshift, shell->right_work));
623               PetscCall(VecShift(shell->right_work, shell->vshift));
624               PetscCall(VecPointwiseMult(shell->right_work, shell->right_work, shell->right));
625             } else {
626               PetscCall(VecSet(shell->right_work, shell->vshift));
627             }
628             PetscCall(MatDiagonalScale(mdata->B, shell->right_work, NULL));
629             PetscCall(MatAXPY(D, 1.0, mdata->B, str));
630           }
631         }
632         break;
633       case MATPRODUCT_PtAP: /* s B^t L A R B + v B^t L R B + B^t L D R B */
634       case MATPRODUCT_RARt: /* s B L A R B^t + v B L R B^t + B L D R B^t */
635         PetscCheck(!shell->dshift && shell->vshift == zero, PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProductSymbolic type %s not supported for %s and %s matrices with diagonal shift", MatProductTypes[product->type], ((PetscObject)A)->type_name,
636                    ((PetscObject)B)->type_name);
637         break;
638       default:
639         SETERRQ(PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProductSymbolic type %s not supported for %s and %s matrices", MatProductTypes[product->type], ((PetscObject)A)->type_name, ((PetscObject)B)->type_name);
640       }
641       if (shell->axpy && shell->axpy_vscale != zero) {
642         Mat              X;
643         PetscObjectState axpy_state;
644         MatStructure     str = DIFFERENT_NONZERO_PATTERN; /* not sure it is safe to ever use SUBSET_NONZERO_PATTERN */
645 
646         PetscCall(MatShellGetContext(shell->axpy, &X));
647         PetscCall(PetscObjectStateGet((PetscObject)X, &axpy_state));
648         PetscCheck(shell->axpy_state == axpy_state, PetscObjectComm((PetscObject)A), PETSC_ERR_ORDER, "Invalid AXPY state: cannot modify the X matrix passed to MatAXPY(Y,a,X,...)");
649         if (!mdata->axpy) {
650           str = DIFFERENT_NONZERO_PATTERN;
651           PetscCall(MatProductCreate(shell->axpy, B, NULL, &mdata->axpy));
652           PetscCall(MatProductSetType(mdata->axpy, product->type));
653           PetscCall(MatProductSetFromOptions(mdata->axpy));
654           PetscCall(MatProductSymbolic(mdata->axpy));
655         } else { /* May be that shell->axpy has changed */
656           PetscBool flg;
657 
658           PetscCall(MatProductReplaceMats(shell->axpy, B, NULL, mdata->axpy));
659           PetscCall(MatHasOperation(mdata->axpy, MATOP_PRODUCTSYMBOLIC, &flg));
660           if (!flg) {
661             str = DIFFERENT_NONZERO_PATTERN;
662             PetscCall(MatProductSetFromOptions(mdata->axpy));
663             PetscCall(MatProductSymbolic(mdata->axpy));
664           }
665         }
666         PetscCall(MatProductNumeric(mdata->axpy));
667         PetscCall(MatAXPY(D, shell->axpy_vscale, mdata->axpy, str));
668       }
669     }
670   } else SETERRQ(PetscObjectComm((PetscObject)D), PETSC_ERR_PLIB, "Missing numeric operation");
671   PetscFunctionReturn(PETSC_SUCCESS);
672 }
673 
674 static PetscErrorCode MatProductSymbolic_Shell_X(Mat D)
675 {
676   Mat_Product            *product;
677   Mat                     A, B;
678   MatShellMatFunctionList matmat;
679   Mat_Shell              *shell;
680   PetscBool               flg = PETSC_FALSE;
681   char                    composedname[256];
682   MatMatDataShell        *mdata;
683 
684   PetscFunctionBegin;
685   MatCheckProduct(D, 1);
686   product = D->product;
687   PetscCheck(!product->data, PetscObjectComm((PetscObject)D), PETSC_ERR_PLIB, "Product data not empty");
688   A      = product->A;
689   B      = product->B;
690   shell  = (Mat_Shell *)A->data;
691   matmat = shell->matmat;
692   PetscCall(PetscSNPrintf(composedname, sizeof(composedname), "MatProductSetFromOptions_%s_%s_C", ((PetscObject)A)->type_name, ((PetscObject)B)->type_name));
693   while (matmat) {
694     PetscCall(PetscStrcmp(composedname, matmat->composedname, &flg));
695     flg = (PetscBool)(flg && (matmat->ptype == product->type));
696     if (flg) break;
697     matmat = matmat->next;
698   }
699   PetscCheck(flg, PetscObjectComm((PetscObject)A), PETSC_ERR_PLIB, "Composedname \"%s\" for product type %s not found", composedname, MatProductTypes[product->type]);
700   switch (product->type) {
701   case MATPRODUCT_AB:
702     PetscCall(MatSetSizes(D, A->rmap->n, B->cmap->n, A->rmap->N, B->cmap->N));
703     break;
704   case MATPRODUCT_AtB:
705     PetscCall(MatSetSizes(D, A->cmap->n, B->cmap->n, A->cmap->N, B->cmap->N));
706     break;
707   case MATPRODUCT_ABt:
708     PetscCall(MatSetSizes(D, A->rmap->n, B->rmap->n, A->rmap->N, B->rmap->N));
709     break;
710   case MATPRODUCT_RARt:
711     PetscCall(MatSetSizes(D, B->rmap->n, B->rmap->n, B->rmap->N, B->rmap->N));
712     break;
713   case MATPRODUCT_PtAP:
714     PetscCall(MatSetSizes(D, B->cmap->n, B->cmap->n, B->cmap->N, B->cmap->N));
715     break;
716   default:
717     SETERRQ(PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProductSymbolic type %s not supported for %s and %s matrices", MatProductTypes[product->type], ((PetscObject)A)->type_name, ((PetscObject)B)->type_name);
718   }
719   /* respect users who passed in a matrix for which resultname is the base type */
720   if (matmat->resultname) {
721     PetscCall(PetscObjectBaseTypeCompare((PetscObject)D, matmat->resultname, &flg));
722     if (!flg) PetscCall(MatSetType(D, matmat->resultname));
723   }
724   /* If matrix type was not set or different, we need to reset this pointers */
725   D->ops->productsymbolic = MatProductSymbolic_Shell_X;
726   D->ops->productnumeric  = MatProductNumeric_Shell_X;
727   /* attach product data */
728   PetscCall(PetscNew(&mdata));
729   mdata->numeric = matmat->numeric;
730   mdata->destroy = matmat->destroy;
731   if (matmat->symbolic) {
732     PetscCall((*matmat->symbolic)(A, B, D, &mdata->userdata));
733   } else { /* call general setup if symbolic operation not provided */
734     PetscCall(MatSetUp(D));
735   }
736   PetscCheck(D->product, PetscObjectComm((PetscObject)D), PETSC_ERR_COR, "Product disappeared after user symbolic phase");
737   PetscCheck(!D->product->data, PetscObjectComm((PetscObject)D), PETSC_ERR_COR, "Product data not empty after user symbolic phase");
738   D->product->data    = mdata;
739   D->product->destroy = DestroyMatMatDataShell;
740   /* Be sure to reset these pointers if the user did something unexpected */
741   D->ops->productsymbolic = MatProductSymbolic_Shell_X;
742   D->ops->productnumeric  = MatProductNumeric_Shell_X;
743   PetscFunctionReturn(PETSC_SUCCESS);
744 }
745 
746 static PetscErrorCode MatProductSetFromOptions_Shell_X(Mat D)
747 {
748   Mat_Product            *product;
749   Mat                     A, B;
750   MatShellMatFunctionList matmat;
751   Mat_Shell              *shell;
752   PetscBool               flg;
753   char                    composedname[256];
754 
755   PetscFunctionBegin;
756   MatCheckProduct(D, 1);
757   product = D->product;
758   A       = product->A;
759   B       = product->B;
760   PetscCall(MatIsShell(A, &flg));
761   if (!flg) PetscFunctionReturn(PETSC_SUCCESS);
762   shell  = (Mat_Shell *)A->data;
763   matmat = shell->matmat;
764   PetscCall(PetscSNPrintf(composedname, sizeof(composedname), "MatProductSetFromOptions_%s_%s_C", ((PetscObject)A)->type_name, ((PetscObject)B)->type_name));
765   while (matmat) {
766     PetscCall(PetscStrcmp(composedname, matmat->composedname, &flg));
767     flg = (PetscBool)(flg && (matmat->ptype == product->type));
768     if (flg) break;
769     matmat = matmat->next;
770   }
771   if (flg) {
772     D->ops->productsymbolic = MatProductSymbolic_Shell_X;
773   } else PetscCall(PetscInfo(D, "  symbolic product %s not registered for product type %s\n", composedname, MatProductTypes[product->type]));
774   PetscFunctionReturn(PETSC_SUCCESS);
775 }
776 
777 static PetscErrorCode MatShellSetMatProductOperation_Private(Mat A, MatProductType ptype, PetscErrorCode (*symbolic)(Mat, Mat, Mat, void **), PetscErrorCode (*numeric)(Mat, Mat, Mat, void *), PetscErrorCode (*destroy)(void *), char *composedname, const char *resultname)
778 {
779   PetscBool               flg;
780   Mat_Shell              *shell;
781   MatShellMatFunctionList matmat;
782 
783   PetscFunctionBegin;
784   PetscCheck(numeric, PetscObjectComm((PetscObject)A), PETSC_ERR_PLIB, "Missing numeric routine");
785   PetscCheck(composedname, PetscObjectComm((PetscObject)A), PETSC_ERR_PLIB, "Missing composed name");
786 
787   /* add product callback */
788   shell  = (Mat_Shell *)A->data;
789   matmat = shell->matmat;
790   if (!matmat) {
791     PetscCall(PetscNew(&shell->matmat));
792     matmat = shell->matmat;
793   } else {
794     MatShellMatFunctionList entry = matmat;
795     while (entry) {
796       PetscCall(PetscStrcmp(composedname, entry->composedname, &flg));
797       flg    = (PetscBool)(flg && (entry->ptype == ptype));
798       matmat = entry;
799       if (flg) goto set;
800       entry = entry->next;
801     }
802     PetscCall(PetscNew(&matmat->next));
803     matmat = matmat->next;
804   }
805 
806 set:
807   matmat->symbolic = symbolic;
808   matmat->numeric  = numeric;
809   matmat->destroy  = destroy;
810   matmat->ptype    = ptype;
811   PetscCall(PetscFree(matmat->composedname));
812   PetscCall(PetscFree(matmat->resultname));
813   PetscCall(PetscStrallocpy(composedname, &matmat->composedname));
814   PetscCall(PetscStrallocpy(resultname, &matmat->resultname));
815   PetscCall(PetscInfo(A, "Composing %s for product type %s with result %s\n", matmat->composedname, MatProductTypes[matmat->ptype], matmat->resultname ? matmat->resultname : "not specified"));
816   PetscCall(PetscObjectComposeFunction((PetscObject)A, matmat->composedname, MatProductSetFromOptions_Shell_X));
817   PetscFunctionReturn(PETSC_SUCCESS);
818 }
819 
820 /*@C
821   MatShellSetMatProductOperation - Allows user to set a matrix matrix operation for a `MATSHELL` shell matrix.
822 
823   Logically Collective; No Fortran Support
824 
825   Input Parameters:
826 + A        - the `MATSHELL` shell matrix
827 . ptype    - the product type
828 . symbolic - the function for the symbolic phase (can be `NULL`)
829 . numeric  - the function for the numerical phase
830 . destroy  - the function for the destruction of the needed data generated during the symbolic phase (can be `NULL`)
831 . Btype    - the matrix type for the matrix to be multiplied against
832 - Ctype    - the matrix type for the result (can be `NULL`)
833 
834   Level: advanced
835 
836   Example Usage:
837 .vb
838   extern PetscErrorCode usersymbolic(Mat, Mat, Mat, void**);
839   extern PetscErrorCode usernumeric(Mat, Mat, Mat, void*);
840   extern PetscErrorCode userdestroy(void*);
841 
842   MatCreateShell(comm, m, n, M, N, ctx, &A);
843   MatShellSetMatProductOperation(
844     A, MATPRODUCT_AB, usersymbolic, usernumeric, userdestroy,MATSEQAIJ, MATDENSE
845   );
846   // create B of type SEQAIJ etc..
847   MatProductCreate(A, B, PETSC_NULLPTR, &C);
848   MatProductSetType(C, MATPRODUCT_AB);
849   MatProductSetFromOptions(C);
850   MatProductSymbolic(C); // actually runs the user defined symbolic operation
851   MatProductNumeric(C); // actually runs the user defined numeric operation
852   // use C = A * B
853 .ve
854 
855   Notes:
856   `MATPRODUCT_ABC` is not supported yet.
857 
858   If the symbolic phase is not specified, `MatSetUp()` is called on the result matrix that must have its type set if Ctype is `NULL`.
859 
860   Any additional data needed by the matrix product needs to be returned during the symbolic phase and destroyed with the destroy callback.
861   PETSc will take care of calling the user-defined callbacks.
862   It is allowed to specify the same callbacks for different Btype matrix types.
863   The couple (Btype,ptype) uniquely identifies the operation, the last specified callbacks takes precedence.
864 
865 .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`, `MatShellSetContext()`, `MatSetOperation()`, `MatProductType`, `MatType`, `MatSetUp()`
866 @*/
867 PetscErrorCode MatShellSetMatProductOperation(Mat A, MatProductType ptype, PetscErrorCode (*symbolic)(Mat, Mat, Mat, void **), PetscErrorCode (*numeric)(Mat, Mat, Mat, void *), PetscErrorCode (*destroy)(void *), MatType Btype, MatType Ctype)
868 {
869   PetscFunctionBegin;
870   PetscValidHeaderSpecific(A, MAT_CLASSID, 1);
871   PetscValidLogicalCollectiveEnum(A, ptype, 2);
872   PetscCheck(ptype != MATPRODUCT_ABC, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Not for product type %s", MatProductTypes[ptype]);
873   PetscCheck(numeric, PetscObjectComm((PetscObject)A), PETSC_ERR_USER, "Missing numeric routine, argument 4");
874   PetscAssertPointer(Btype, 6);
875   if (Ctype) PetscAssertPointer(Ctype, 7);
876   PetscTryMethod(A, "MatShellSetMatProductOperation_C", (Mat, MatProductType, PetscErrorCode(*)(Mat, Mat, Mat, void **), PetscErrorCode(*)(Mat, Mat, Mat, void *), PetscErrorCode(*)(void *), MatType, MatType), (A, ptype, symbolic, numeric, destroy, Btype, Ctype));
877   PetscFunctionReturn(PETSC_SUCCESS);
878 }
879 
880 static PetscErrorCode MatShellSetMatProductOperation_Shell(Mat A, MatProductType ptype, PetscErrorCode (*symbolic)(Mat, Mat, Mat, void **), PetscErrorCode (*numeric)(Mat, Mat, Mat, void *), PetscErrorCode (*destroy)(void *), MatType Btype, MatType Ctype)
881 {
882   PetscBool   flg;
883   char        composedname[256];
884   MatRootName Bnames = MatRootNameList, Cnames = MatRootNameList;
885   PetscMPIInt size;
886 
887   PetscFunctionBegin;
888   PetscValidType(A, 1);
889   while (Bnames) { /* user passed in the root name */
890     PetscCall(PetscStrcmp(Btype, Bnames->rname, &flg));
891     if (flg) break;
892     Bnames = Bnames->next;
893   }
894   while (Cnames) { /* user passed in the root name */
895     PetscCall(PetscStrcmp(Ctype, Cnames->rname, &flg));
896     if (flg) break;
897     Cnames = Cnames->next;
898   }
899   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)A), &size));
900   Btype = Bnames ? (size > 1 ? Bnames->mname : Bnames->sname) : Btype;
901   Ctype = Cnames ? (size > 1 ? Cnames->mname : Cnames->sname) : Ctype;
902   PetscCall(PetscSNPrintf(composedname, sizeof(composedname), "MatProductSetFromOptions_%s_%s_C", ((PetscObject)A)->type_name, Btype));
903   PetscCall(MatShellSetMatProductOperation_Private(A, ptype, symbolic, numeric, destroy, composedname, Ctype));
904   PetscFunctionReturn(PETSC_SUCCESS);
905 }
906 
907 static PetscErrorCode MatCopy_Shell(Mat A, Mat B, MatStructure str)
908 {
909   Mat_Shell              *shellA = (Mat_Shell *)A->data, *shellB = (Mat_Shell *)B->data;
910   PetscBool               matflg;
911   MatShellMatFunctionList matmatA;
912 
913   PetscFunctionBegin;
914   PetscCall(MatIsShell(B, &matflg));
915   PetscCheck(matflg, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "Matrix %s not derived from MATSHELL", ((PetscObject)B)->type_name);
916 
917   B->ops[0]      = A->ops[0];
918   shellB->ops[0] = shellA->ops[0];
919 
920   if (shellA->ops->copy) PetscCall((*shellA->ops->copy)(A, B, str));
921   shellB->vscale = shellA->vscale;
922   shellB->vshift = shellA->vshift;
923   if (shellA->dshift) {
924     if (!shellB->dshift) PetscCall(VecDuplicate(shellA->dshift, &shellB->dshift));
925     PetscCall(VecCopy(shellA->dshift, shellB->dshift));
926   } else {
927     PetscCall(VecDestroy(&shellB->dshift));
928   }
929   if (shellA->left) {
930     if (!shellB->left) PetscCall(VecDuplicate(shellA->left, &shellB->left));
931     PetscCall(VecCopy(shellA->left, shellB->left));
932   } else {
933     PetscCall(VecDestroy(&shellB->left));
934   }
935   if (shellA->right) {
936     if (!shellB->right) PetscCall(VecDuplicate(shellA->right, &shellB->right));
937     PetscCall(VecCopy(shellA->right, shellB->right));
938   } else {
939     PetscCall(VecDestroy(&shellB->right));
940   }
941   PetscCall(MatDestroy(&shellB->axpy));
942   shellB->axpy_vscale = 0.0;
943   shellB->axpy_state  = 0;
944   if (shellA->axpy) {
945     PetscCall(PetscObjectReference((PetscObject)shellA->axpy));
946     shellB->axpy        = shellA->axpy;
947     shellB->axpy_vscale = shellA->axpy_vscale;
948     shellB->axpy_state  = shellA->axpy_state;
949   }
950   if (shellA->zrows) {
951     PetscCall(ISDuplicate(shellA->zrows, &shellB->zrows));
952     if (shellA->zcols) PetscCall(ISDuplicate(shellA->zcols, &shellB->zcols));
953     PetscCall(VecDuplicate(shellA->zvals, &shellB->zvals));
954     PetscCall(VecCopy(shellA->zvals, shellB->zvals));
955     PetscCall(VecDuplicate(shellA->zvals_w, &shellB->zvals_w));
956     PetscCall(PetscObjectReference((PetscObject)shellA->zvals_sct_r));
957     PetscCall(PetscObjectReference((PetscObject)shellA->zvals_sct_c));
958     shellB->zvals_sct_r = shellA->zvals_sct_r;
959     shellB->zvals_sct_c = shellA->zvals_sct_c;
960   }
961 
962   matmatA = shellA->matmat;
963   if (matmatA) {
964     while (matmatA->next) {
965       PetscCall(MatShellSetMatProductOperation_Private(B, matmatA->ptype, matmatA->symbolic, matmatA->numeric, matmatA->destroy, matmatA->composedname, matmatA->resultname));
966       matmatA = matmatA->next;
967     }
968   }
969   PetscFunctionReturn(PETSC_SUCCESS);
970 }
971 
972 static PetscErrorCode MatDuplicate_Shell(Mat mat, MatDuplicateOption op, Mat *M)
973 {
974   PetscFunctionBegin;
975   PetscCall(MatCreateShell(PetscObjectComm((PetscObject)mat), mat->rmap->n, mat->cmap->n, mat->rmap->N, mat->cmap->N, NULL, M));
976   ((Mat_Shell *)(*M)->data)->ctxcontainer = ((Mat_Shell *)mat->data)->ctxcontainer;
977   PetscCall(PetscObjectCompose((PetscObject)*M, "MatShell ctx", (PetscObject)((Mat_Shell *)(*M)->data)->ctxcontainer));
978   PetscCall(PetscObjectChangeTypeName((PetscObject)*M, ((PetscObject)mat)->type_name));
979   if (op == MAT_COPY_VALUES) PetscCall(MatCopy(mat, *M, SAME_NONZERO_PATTERN));
980   PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)mat, (PetscObject)*M));
981   PetscFunctionReturn(PETSC_SUCCESS);
982 }
983 
984 static PetscErrorCode MatMult_Shell(Mat A, Vec x, Vec y)
985 {
986   Mat_Shell       *shell = (Mat_Shell *)A->data;
987   Vec              xx;
988   PetscObjectState instate, outstate;
989 
990   PetscFunctionBegin;
991   PetscCall(MatShellPreZeroRight(A, x, &xx));
992   PetscCall(MatShellPreScaleRight(A, xx, &xx));
993   PetscCall(PetscObjectStateGet((PetscObject)y, &instate));
994   PetscCall((*shell->ops->mult)(A, xx, y));
995   PetscCall(PetscObjectStateGet((PetscObject)y, &outstate));
996   if (instate == outstate) {
997     /* increase the state of the output vector since the user did not update its state themself as should have been done */
998     PetscCall(PetscObjectStateIncrease((PetscObject)y));
999   }
1000   PetscCall(MatShellShiftAndScale(A, xx, y, PETSC_FALSE));
1001   PetscCall(MatShellPostScaleLeft(A, y));
1002   PetscCall(MatShellPostZeroLeft(A, y));
1003 
1004   if (shell->axpy) {
1005     Mat              X;
1006     PetscObjectState axpy_state;
1007 
1008     PetscCall(MatShellGetContext(shell->axpy, &X));
1009     PetscCall(PetscObjectStateGet((PetscObject)X, &axpy_state));
1010     PetscCheck(shell->axpy_state == axpy_state, PetscObjectComm((PetscObject)A), PETSC_ERR_ORDER, "Invalid AXPY state: cannot modify the X matrix passed to MatAXPY(Y,a,X,...)");
1011 
1012     PetscCall(MatCreateVecs(shell->axpy, shell->axpy_right ? NULL : &shell->axpy_right, shell->axpy_left ? NULL : &shell->axpy_left));
1013     PetscCall(VecCopy(x, shell->axpy_right));
1014     PetscCall(MatMult(shell->axpy, shell->axpy_right, shell->axpy_left));
1015     PetscCall(VecAXPY(y, shell->axpy_vscale, shell->axpy_left));
1016   }
1017   PetscFunctionReturn(PETSC_SUCCESS);
1018 }
1019 
1020 static PetscErrorCode MatMultAdd_Shell(Mat A, Vec x, Vec y, Vec z)
1021 {
1022   Mat_Shell *shell = (Mat_Shell *)A->data;
1023 
1024   PetscFunctionBegin;
1025   if (y == z) {
1026     if (!shell->right_add_work) PetscCall(VecDuplicate(z, &shell->right_add_work));
1027     PetscCall(MatMult(A, x, shell->right_add_work));
1028     PetscCall(VecAXPY(z, 1.0, shell->right_add_work));
1029   } else {
1030     PetscCall(MatMult(A, x, z));
1031     PetscCall(VecAXPY(z, 1.0, y));
1032   }
1033   PetscFunctionReturn(PETSC_SUCCESS);
1034 }
1035 
1036 static PetscErrorCode MatMultTranspose_Shell(Mat A, Vec x, Vec y)
1037 {
1038   Mat_Shell       *shell = (Mat_Shell *)A->data;
1039   Vec              xx;
1040   PetscObjectState instate, outstate;
1041 
1042   PetscFunctionBegin;
1043   PetscCall(MatShellPreZeroLeft(A, x, &xx));
1044   PetscCall(MatShellPreScaleLeft(A, xx, &xx, PETSC_FALSE));
1045   PetscCall(PetscObjectStateGet((PetscObject)y, &instate));
1046   PetscCall((*shell->ops->multtranspose)(A, xx, y));
1047   PetscCall(PetscObjectStateGet((PetscObject)y, &outstate));
1048   if (instate == outstate) {
1049     /* increase the state of the output vector since the user did not update its state themself as should have been done */
1050     PetscCall(PetscObjectStateIncrease((PetscObject)y));
1051   }
1052   PetscCall(MatShellShiftAndScale(A, xx, y, PETSC_FALSE));
1053   PetscCall(MatShellPostScaleRight(A, y, PETSC_FALSE));
1054   PetscCall(MatShellPostZeroRight(A, y));
1055 
1056   if (shell->axpy) {
1057     Mat              X;
1058     PetscObjectState axpy_state;
1059 
1060     PetscCall(MatShellGetContext(shell->axpy, &X));
1061     PetscCall(PetscObjectStateGet((PetscObject)X, &axpy_state));
1062     PetscCheck(shell->axpy_state == axpy_state, PetscObjectComm((PetscObject)A), PETSC_ERR_ORDER, "Invalid AXPY state: cannot modify the X matrix passed to MatAXPY(Y,a,X,...)");
1063     PetscCall(MatCreateVecs(shell->axpy, shell->axpy_right ? NULL : &shell->axpy_right, shell->axpy_left ? NULL : &shell->axpy_left));
1064     PetscCall(VecCopy(x, shell->axpy_left));
1065     PetscCall(MatMultTranspose(shell->axpy, shell->axpy_left, shell->axpy_right));
1066     PetscCall(VecAXPY(y, shell->axpy_vscale, shell->axpy_right));
1067   }
1068   PetscFunctionReturn(PETSC_SUCCESS);
1069 }
1070 
1071 static PetscErrorCode MatMultHermitianTranspose_Shell(Mat A, Vec x, Vec y)
1072 {
1073   Mat_Shell       *shell = (Mat_Shell *)A->data;
1074   Vec              xx;
1075   PetscObjectState instate, outstate;
1076 
1077   PetscFunctionBegin;
1078   PetscCall(MatShellPreZeroLeft(A, x, &xx));
1079   PetscCall(MatShellPreScaleLeft(A, xx, &xx, PETSC_TRUE));
1080   PetscCall(PetscObjectStateGet((PetscObject)y, &instate));
1081   PetscCall((*shell->ops->multhermitiantranspose)(A, xx, y));
1082   PetscCall(PetscObjectStateGet((PetscObject)y, &outstate));
1083   if (instate == outstate) {
1084     /* increase the state of the output vector since the user did not update its state themself as should have been done */
1085     PetscCall(PetscObjectStateIncrease((PetscObject)y));
1086   }
1087   PetscCall(MatShellShiftAndScale(A, xx, y, PETSC_TRUE));
1088   PetscCall(MatShellPostScaleRight(A, y, PETSC_TRUE));
1089   PetscCall(MatShellPostZeroRight(A, y));
1090 
1091   if (shell->axpy) {
1092     Mat              X;
1093     PetscObjectState axpy_state;
1094 
1095     PetscCall(MatShellGetContext(shell->axpy, &X));
1096     PetscCall(PetscObjectStateGet((PetscObject)X, &axpy_state));
1097     PetscCheck(shell->axpy_state == axpy_state, PetscObjectComm((PetscObject)A), PETSC_ERR_ORDER, "Invalid AXPY state: cannot modify the X matrix passed to MatAXPY(Y,a,X,...)");
1098     PetscCall(MatCreateVecs(shell->axpy, shell->axpy_right ? NULL : &shell->axpy_right, shell->axpy_left ? NULL : &shell->axpy_left));
1099     PetscCall(VecCopy(x, shell->axpy_left));
1100     PetscCall(MatMultHermitianTranspose(shell->axpy, shell->axpy_left, shell->axpy_right));
1101     PetscCall(VecAXPY(y, PetscConj(shell->axpy_vscale), shell->axpy_right));
1102   }
1103   PetscFunctionReturn(PETSC_SUCCESS);
1104 }
1105 
1106 static PetscErrorCode MatMultTransposeAdd_Shell(Mat A, Vec x, Vec y, Vec z)
1107 {
1108   Mat_Shell *shell = (Mat_Shell *)A->data;
1109 
1110   PetscFunctionBegin;
1111   if (y == z) {
1112     if (!shell->left_add_work) PetscCall(VecDuplicate(z, &shell->left_add_work));
1113     PetscCall(MatMultTranspose(A, x, shell->left_add_work));
1114     PetscCall(VecAXPY(z, 1.0, shell->left_add_work));
1115   } else {
1116     PetscCall(MatMultTranspose(A, x, z));
1117     PetscCall(VecAXPY(z, 1.0, y));
1118   }
1119   PetscFunctionReturn(PETSC_SUCCESS);
1120 }
1121 
1122 static PetscErrorCode MatMultHermitianTransposeAdd_Shell(Mat A, Vec x, Vec y, Vec z)
1123 {
1124   Mat_Shell *shell = (Mat_Shell *)A->data;
1125 
1126   PetscFunctionBegin;
1127   if (y == z) {
1128     if (!shell->left_add_work) PetscCall(VecDuplicate(z, &shell->left_add_work));
1129     PetscCall(MatMultHermitianTranspose(A, x, shell->left_add_work));
1130     PetscCall(VecAXPY(z, 1.0, shell->left_add_work));
1131   } else {
1132     PetscCall(MatMultHermitianTranspose(A, x, z));
1133     PetscCall(VecAXPY(z, 1.0, y));
1134   }
1135   PetscFunctionReturn(PETSC_SUCCESS);
1136 }
1137 
1138 /*
1139           diag(left)(vscale*A + diag(dshift) + vshift I)diag(right)
1140 */
1141 static PetscErrorCode MatGetDiagonal_Shell(Mat A, Vec v)
1142 {
1143   Mat_Shell *shell = (Mat_Shell *)A->data;
1144 
1145   PetscFunctionBegin;
1146   if (shell->ops->getdiagonal) {
1147     PetscCall((*shell->ops->getdiagonal)(A, v));
1148   } else SETERRQ(PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Must provide shell matrix with routine to return diagonal using\nMatShellSetOperation(S,MATOP_GET_DIAGONAL,...)");
1149   PetscCall(VecScale(v, shell->vscale));
1150   if (shell->dshift) PetscCall(VecAXPY(v, 1.0, shell->dshift));
1151   PetscCall(VecShift(v, shell->vshift));
1152   if (shell->left) PetscCall(VecPointwiseMult(v, v, shell->left));
1153   if (shell->right) PetscCall(VecPointwiseMult(v, v, shell->right));
1154   if (shell->zrows) {
1155     PetscCall(VecScatterBegin(shell->zvals_sct_r, shell->zvals, v, INSERT_VALUES, SCATTER_REVERSE));
1156     PetscCall(VecScatterEnd(shell->zvals_sct_r, shell->zvals, v, INSERT_VALUES, SCATTER_REVERSE));
1157   }
1158   if (shell->axpy) {
1159     Mat              X;
1160     PetscObjectState axpy_state;
1161 
1162     PetscCall(MatShellGetContext(shell->axpy, &X));
1163     PetscCall(PetscObjectStateGet((PetscObject)X, &axpy_state));
1164     PetscCheck(shell->axpy_state == axpy_state, PetscObjectComm((PetscObject)A), PETSC_ERR_ORDER, "Invalid AXPY state: cannot modify the X matrix passed to MatAXPY(Y,a,X,...)");
1165     PetscCall(MatCreateVecs(shell->axpy, NULL, shell->axpy_left ? NULL : &shell->axpy_left));
1166     PetscCall(MatGetDiagonal(shell->axpy, shell->axpy_left));
1167     PetscCall(VecAXPY(v, shell->axpy_vscale, shell->axpy_left));
1168   }
1169   PetscFunctionReturn(PETSC_SUCCESS);
1170 }
1171 
1172 static PetscErrorCode MatShift_Shell(Mat Y, PetscScalar a)
1173 {
1174   Mat_Shell *shell = (Mat_Shell *)Y->data;
1175   PetscBool  flg;
1176 
1177   PetscFunctionBegin;
1178   PetscCall(MatHasCongruentLayouts(Y, &flg));
1179   PetscCheck(flg, PetscObjectComm((PetscObject)Y), PETSC_ERR_SUP, "Cannot shift shell matrix if it is not congruent");
1180   if (shell->left || shell->right) {
1181     if (!shell->dshift) {
1182       PetscCall(VecDuplicate(shell->left ? shell->left : shell->right, &shell->dshift));
1183       PetscCall(VecSet(shell->dshift, a));
1184     } else {
1185       if (shell->left) PetscCall(VecPointwiseMult(shell->dshift, shell->dshift, shell->left));
1186       if (shell->right) PetscCall(VecPointwiseMult(shell->dshift, shell->dshift, shell->right));
1187       PetscCall(VecShift(shell->dshift, a));
1188     }
1189     if (shell->left) PetscCall(VecPointwiseDivide(shell->dshift, shell->dshift, shell->left));
1190     if (shell->right) PetscCall(VecPointwiseDivide(shell->dshift, shell->dshift, shell->right));
1191   } else shell->vshift += a;
1192   if (shell->zrows) PetscCall(VecShift(shell->zvals, a));
1193   PetscFunctionReturn(PETSC_SUCCESS);
1194 }
1195 
1196 static PetscErrorCode MatDiagonalSet_Shell_Private(Mat A, Vec D, PetscScalar s)
1197 {
1198   Mat_Shell *shell = (Mat_Shell *)A->data;
1199 
1200   PetscFunctionBegin;
1201   if (!shell->dshift) PetscCall(VecDuplicate(D, &shell->dshift));
1202   if (shell->left || shell->right) {
1203     if (!shell->right_work) PetscCall(VecDuplicate(shell->left ? shell->left : shell->right, &shell->right_work));
1204     if (shell->left && shell->right) {
1205       PetscCall(VecPointwiseDivide(shell->right_work, D, shell->left));
1206       PetscCall(VecPointwiseDivide(shell->right_work, shell->right_work, shell->right));
1207     } else if (shell->left) {
1208       PetscCall(VecPointwiseDivide(shell->right_work, D, shell->left));
1209     } else {
1210       PetscCall(VecPointwiseDivide(shell->right_work, D, shell->right));
1211     }
1212     PetscCall(VecAXPY(shell->dshift, s, shell->right_work));
1213   } else {
1214     PetscCall(VecAXPY(shell->dshift, s, D));
1215   }
1216   PetscFunctionReturn(PETSC_SUCCESS);
1217 }
1218 
1219 static PetscErrorCode MatDiagonalSet_Shell(Mat A, Vec D, InsertMode ins)
1220 {
1221   Mat_Shell *shell = (Mat_Shell *)A->data;
1222   Vec        d;
1223   PetscBool  flg;
1224 
1225   PetscFunctionBegin;
1226   PetscCall(MatHasCongruentLayouts(A, &flg));
1227   PetscCheck(flg, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Cannot diagonal set or shift shell matrix if it is not congruent");
1228   if (ins == INSERT_VALUES) {
1229     PetscCall(VecDuplicate(D, &d));
1230     PetscCall(MatGetDiagonal(A, d));
1231     PetscCall(MatDiagonalSet_Shell_Private(A, d, -1.));
1232     PetscCall(MatDiagonalSet_Shell_Private(A, D, 1.));
1233     PetscCall(VecDestroy(&d));
1234     if (shell->zrows) PetscCall(VecCopy(D, shell->zvals));
1235   } else {
1236     PetscCall(MatDiagonalSet_Shell_Private(A, D, 1.));
1237     if (shell->zrows) PetscCall(VecAXPY(shell->zvals, 1.0, D));
1238   }
1239   PetscFunctionReturn(PETSC_SUCCESS);
1240 }
1241 
1242 static PetscErrorCode MatScale_Shell(Mat Y, PetscScalar a)
1243 {
1244   Mat_Shell *shell = (Mat_Shell *)Y->data;
1245 
1246   PetscFunctionBegin;
1247   shell->vscale *= a;
1248   shell->vshift *= a;
1249   if (shell->dshift) PetscCall(VecScale(shell->dshift, a));
1250   shell->axpy_vscale *= a;
1251   if (shell->zrows) PetscCall(VecScale(shell->zvals, a));
1252   PetscFunctionReturn(PETSC_SUCCESS);
1253 }
1254 
1255 static PetscErrorCode MatDiagonalScale_Shell(Mat Y, Vec left, Vec right)
1256 {
1257   Mat_Shell *shell = (Mat_Shell *)Y->data;
1258 
1259   PetscFunctionBegin;
1260   if (left) {
1261     if (!shell->left) {
1262       PetscCall(VecDuplicate(left, &shell->left));
1263       PetscCall(VecCopy(left, shell->left));
1264     } else {
1265       PetscCall(VecPointwiseMult(shell->left, shell->left, left));
1266     }
1267     if (shell->zrows) PetscCall(VecPointwiseMult(shell->zvals, shell->zvals, left));
1268   }
1269   if (right) {
1270     if (!shell->right) {
1271       PetscCall(VecDuplicate(right, &shell->right));
1272       PetscCall(VecCopy(right, shell->right));
1273     } else {
1274       PetscCall(VecPointwiseMult(shell->right, shell->right, right));
1275     }
1276     if (shell->zrows) {
1277       if (!shell->left_work) PetscCall(MatCreateVecs(Y, NULL, &shell->left_work));
1278       PetscCall(VecSet(shell->zvals_w, 1.0));
1279       PetscCall(VecScatterBegin(shell->zvals_sct_c, right, shell->zvals_w, INSERT_VALUES, SCATTER_FORWARD));
1280       PetscCall(VecScatterEnd(shell->zvals_sct_c, right, shell->zvals_w, INSERT_VALUES, SCATTER_FORWARD));
1281       PetscCall(VecPointwiseMult(shell->zvals, shell->zvals, shell->zvals_w));
1282     }
1283   }
1284   if (shell->axpy) PetscCall(MatDiagonalScale(shell->axpy, left, right));
1285   PetscFunctionReturn(PETSC_SUCCESS);
1286 }
1287 
1288 PETSC_INTERN PetscErrorCode MatAssemblyEnd_Shell(Mat Y, MatAssemblyType t)
1289 {
1290   Mat_Shell *shell = (Mat_Shell *)Y->data;
1291 
1292   PetscFunctionBegin;
1293   if (t == MAT_FINAL_ASSEMBLY) {
1294     shell->vshift      = 0.0;
1295     shell->vscale      = 1.0;
1296     shell->axpy_vscale = 0.0;
1297     shell->axpy_state  = 0;
1298     PetscCall(VecDestroy(&shell->dshift));
1299     PetscCall(VecDestroy(&shell->left));
1300     PetscCall(VecDestroy(&shell->right));
1301     PetscCall(MatDestroy(&shell->axpy));
1302     PetscCall(VecDestroy(&shell->axpy_left));
1303     PetscCall(VecDestroy(&shell->axpy_right));
1304     PetscCall(VecScatterDestroy(&shell->zvals_sct_c));
1305     PetscCall(VecScatterDestroy(&shell->zvals_sct_r));
1306     PetscCall(ISDestroy(&shell->zrows));
1307     PetscCall(ISDestroy(&shell->zcols));
1308   }
1309   PetscFunctionReturn(PETSC_SUCCESS);
1310 }
1311 
1312 static PetscErrorCode MatMissingDiagonal_Shell(Mat A, PetscBool *missing, PetscInt *d)
1313 {
1314   PetscFunctionBegin;
1315   *missing = PETSC_FALSE;
1316   PetscFunctionReturn(PETSC_SUCCESS);
1317 }
1318 
1319 static PetscErrorCode MatAXPY_Shell(Mat Y, PetscScalar a, Mat X, MatStructure str)
1320 {
1321   Mat_Shell *shell = (Mat_Shell *)Y->data;
1322 
1323   PetscFunctionBegin;
1324   if (X == Y) {
1325     PetscCall(MatScale(Y, 1.0 + a));
1326     PetscFunctionReturn(PETSC_SUCCESS);
1327   }
1328   if (!shell->axpy) {
1329     PetscCall(MatConvertFrom_Shell(X, MATSHELL, MAT_INITIAL_MATRIX, &shell->axpy));
1330     shell->axpy_vscale = a;
1331     PetscCall(PetscObjectStateGet((PetscObject)X, &shell->axpy_state));
1332   } else {
1333     PetscCall(MatAXPY(shell->axpy, a / shell->axpy_vscale, X, str));
1334   }
1335   PetscFunctionReturn(PETSC_SUCCESS);
1336 }
1337 
1338 static struct _MatOps MatOps_Values = {NULL,
1339                                        NULL,
1340                                        NULL,
1341                                        NULL,
1342                                        /* 4*/ MatMultAdd_Shell,
1343                                        NULL,
1344                                        MatMultTransposeAdd_Shell,
1345                                        NULL,
1346                                        NULL,
1347                                        NULL,
1348                                        /*10*/ NULL,
1349                                        NULL,
1350                                        NULL,
1351                                        NULL,
1352                                        NULL,
1353                                        /*15*/ NULL,
1354                                        NULL,
1355                                        NULL,
1356                                        MatDiagonalScale_Shell,
1357                                        NULL,
1358                                        /*20*/ NULL,
1359                                        MatAssemblyEnd_Shell,
1360                                        NULL,
1361                                        NULL,
1362                                        /*24*/ MatZeroRows_Shell,
1363                                        NULL,
1364                                        NULL,
1365                                        NULL,
1366                                        NULL,
1367                                        /*29*/ NULL,
1368                                        NULL,
1369                                        NULL,
1370                                        NULL,
1371                                        NULL,
1372                                        /*34*/ MatDuplicate_Shell,
1373                                        NULL,
1374                                        NULL,
1375                                        NULL,
1376                                        NULL,
1377                                        /*39*/ MatAXPY_Shell,
1378                                        NULL,
1379                                        NULL,
1380                                        NULL,
1381                                        MatCopy_Shell,
1382                                        /*44*/ NULL,
1383                                        MatScale_Shell,
1384                                        MatShift_Shell,
1385                                        MatDiagonalSet_Shell,
1386                                        MatZeroRowsColumns_Shell,
1387                                        /*49*/ NULL,
1388                                        NULL,
1389                                        NULL,
1390                                        NULL,
1391                                        NULL,
1392                                        /*54*/ NULL,
1393                                        NULL,
1394                                        NULL,
1395                                        NULL,
1396                                        NULL,
1397                                        /*59*/ NULL,
1398                                        MatDestroy_Shell,
1399                                        NULL,
1400                                        MatConvertFrom_Shell,
1401                                        NULL,
1402                                        /*64*/ NULL,
1403                                        NULL,
1404                                        NULL,
1405                                        NULL,
1406                                        NULL,
1407                                        /*69*/ NULL,
1408                                        NULL,
1409                                        MatConvert_Shell,
1410                                        NULL,
1411                                        NULL,
1412                                        /*74*/ NULL,
1413                                        NULL,
1414                                        NULL,
1415                                        NULL,
1416                                        NULL,
1417                                        /*79*/ NULL,
1418                                        NULL,
1419                                        NULL,
1420                                        NULL,
1421                                        NULL,
1422                                        /*84*/ NULL,
1423                                        NULL,
1424                                        NULL,
1425                                        NULL,
1426                                        NULL,
1427                                        /*89*/ NULL,
1428                                        NULL,
1429                                        NULL,
1430                                        NULL,
1431                                        NULL,
1432                                        /*94*/ NULL,
1433                                        NULL,
1434                                        NULL,
1435                                        NULL,
1436                                        NULL,
1437                                        /*99*/ NULL,
1438                                        NULL,
1439                                        NULL,
1440                                        NULL,
1441                                        NULL,
1442                                        /*104*/ NULL,
1443                                        NULL,
1444                                        NULL,
1445                                        NULL,
1446                                        NULL,
1447                                        /*109*/ NULL,
1448                                        NULL,
1449                                        NULL,
1450                                        NULL,
1451                                        MatMissingDiagonal_Shell,
1452                                        /*114*/ NULL,
1453                                        NULL,
1454                                        NULL,
1455                                        NULL,
1456                                        NULL,
1457                                        /*119*/ NULL,
1458                                        NULL,
1459                                        NULL,
1460                                        MatMultHermitianTransposeAdd_Shell,
1461                                        NULL,
1462                                        /*124*/ NULL,
1463                                        NULL,
1464                                        NULL,
1465                                        NULL,
1466                                        NULL,
1467                                        /*129*/ NULL,
1468                                        NULL,
1469                                        NULL,
1470                                        NULL,
1471                                        NULL,
1472                                        /*134*/ NULL,
1473                                        NULL,
1474                                        NULL,
1475                                        NULL,
1476                                        NULL,
1477                                        /*139*/ NULL,
1478                                        NULL,
1479                                        NULL,
1480                                        NULL,
1481                                        NULL,
1482                                        /*144*/ NULL,
1483                                        NULL,
1484                                        NULL,
1485                                        NULL,
1486                                        NULL,
1487                                        NULL,
1488                                        /*150*/ NULL,
1489                                        NULL,
1490                                        NULL};
1491 
1492 static PetscErrorCode MatShellSetContext_Shell(Mat mat, void *ctx)
1493 {
1494   Mat_Shell *shell = (Mat_Shell *)mat->data;
1495 
1496   PetscFunctionBegin;
1497   if (ctx) {
1498     PetscContainer ctxcontainer;
1499     PetscCall(PetscContainerCreate(PetscObjectComm((PetscObject)mat), &ctxcontainer));
1500     PetscCall(PetscContainerSetPointer(ctxcontainer, ctx));
1501     PetscCall(PetscObjectCompose((PetscObject)mat, "MatShell ctx", (PetscObject)ctxcontainer));
1502     shell->ctxcontainer = ctxcontainer;
1503     PetscCall(PetscContainerDestroy(&ctxcontainer));
1504   } else {
1505     PetscCall(PetscObjectCompose((PetscObject)mat, "MatShell ctx", NULL));
1506     shell->ctxcontainer = NULL;
1507   }
1508   PetscFunctionReturn(PETSC_SUCCESS);
1509 }
1510 
1511 static PetscErrorCode MatShellSetContextDestroy_Shell(Mat mat, PetscErrorCode (*f)(void *))
1512 {
1513   Mat_Shell *shell = (Mat_Shell *)mat->data;
1514 
1515   PetscFunctionBegin;
1516   if (shell->ctxcontainer) PetscCall(PetscContainerSetUserDestroy(shell->ctxcontainer, f));
1517   PetscFunctionReturn(PETSC_SUCCESS);
1518 }
1519 
1520 PetscErrorCode MatShellSetContext_Immutable(Mat mat, void *ctx)
1521 {
1522   PetscFunctionBegin;
1523   SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot call MatShellSetContext() for a %s, it is used internally by the structure", ((PetscObject)mat)->type_name);
1524   PetscFunctionReturn(PETSC_SUCCESS);
1525 }
1526 
1527 PetscErrorCode MatShellSetContextDestroy_Immutable(Mat mat, PetscErrorCode (*f)(void *))
1528 {
1529   PetscFunctionBegin;
1530   SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot call MatShellSetContextDestroy() for a %s, it is used internally by the structure", ((PetscObject)mat)->type_name);
1531   PetscFunctionReturn(PETSC_SUCCESS);
1532 }
1533 
1534 PetscErrorCode MatShellSetManageScalingShifts_Immutable(Mat mat)
1535 {
1536   PetscFunctionBegin;
1537   SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot call MatShellSetManageScalingShifts() for a %s, it is used internally by the structure", ((PetscObject)mat)->type_name);
1538   PetscFunctionReturn(PETSC_SUCCESS);
1539 }
1540 
1541 static PetscErrorCode MatShellSetVecType_Shell(Mat mat, VecType vtype)
1542 {
1543   PetscFunctionBegin;
1544   PetscCall(PetscFree(mat->defaultvectype));
1545   PetscCall(PetscStrallocpy(vtype, (char **)&mat->defaultvectype));
1546   PetscFunctionReturn(PETSC_SUCCESS);
1547 }
1548 
1549 static PetscErrorCode MatShellSetManageScalingShifts_Shell(Mat A)
1550 {
1551   Mat_Shell *shell = (Mat_Shell *)A->data;
1552 
1553   PetscFunctionBegin;
1554   shell->managescalingshifts = PETSC_FALSE;
1555   A->ops->diagonalset        = NULL;
1556   A->ops->diagonalscale      = NULL;
1557   A->ops->scale              = NULL;
1558   A->ops->shift              = NULL;
1559   A->ops->axpy               = NULL;
1560   PetscFunctionReturn(PETSC_SUCCESS);
1561 }
1562 
1563 static PetscErrorCode MatShellGetScalingShifts_Shell(Mat A, PetscScalar *vshift, PetscScalar *vscale, Vec *dshift, Vec *left, Vec *right, Mat *axpy, IS *zrows, IS *zcols)
1564 {
1565   Mat_Shell *shell = (Mat_Shell *)A->data;
1566 
1567   PetscFunctionBegin;
1568   PetscCheck(shell->managescalingshifts, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Cannot get scaling and shifts if MatShellSetManageScalingShifts() has been called");
1569   if (vshift == MAT_SHELL_NOT_ALLOWED) PetscCheck(shell->vshift == 0.0, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: vshift != 0.0, set via MatShift()");
1570   else if (vshift) *vshift = shell->vshift;
1571   if (vscale == MAT_SHELL_NOT_ALLOWED) PetscCheck(shell->vscale == 1.0, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: vscale != 1.0, set via MatScale()");
1572   else if (vscale) *vscale = shell->vscale;
1573   if (dshift == MAT_SHELL_NOT_ALLOWED) PetscCheck(!shell->dshift, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: dshift, set via MatDiagonalSet()");
1574   else if (dshift) *dshift = shell->dshift;
1575   if (left == MAT_SHELL_NOT_ALLOWED) PetscCheck(!shell->left, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: left, set via MatDiagonalScale()");
1576   else if (left) *left = shell->left;
1577   if (right == MAT_SHELL_NOT_ALLOWED) PetscCheck(!shell->right, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: right, set via MatDiagonalScale()");
1578   else if (right) *right = shell->right;
1579   if (axpy == MAT_SHELL_NOT_ALLOWED) PetscCheck(!shell->axpy, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: axpy, set via MatAXPY()");
1580   else if (axpy) *axpy = shell->axpy;
1581   if (zrows == MAT_SHELL_NOT_ALLOWED) PetscCheck(!shell->zrows, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: zrows, set via MatZeroRows()");
1582   else if (zrows) *zrows = shell->zrows;
1583   if (zcols == MAT_SHELL_NOT_ALLOWED) PetscCheck(!shell->zcols, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: zcols, set via MatZeroRowsColumns()");
1584   else if (zcols) *zcols = shell->zcols;
1585   PetscFunctionReturn(PETSC_SUCCESS);
1586 }
1587 
1588 static PetscErrorCode MatShellSetOperation_Shell(Mat mat, MatOperation op, void (*f)(void))
1589 {
1590   Mat_Shell *shell = (Mat_Shell *)mat->data;
1591 
1592   PetscFunctionBegin;
1593   switch (op) {
1594   case MATOP_DESTROY:
1595     shell->ops->destroy = (PetscErrorCode(*)(Mat))f;
1596     break;
1597   case MATOP_VIEW:
1598     if (!mat->ops->viewnative) mat->ops->viewnative = mat->ops->view;
1599     mat->ops->view = (PetscErrorCode(*)(Mat, PetscViewer))f;
1600     break;
1601   case MATOP_COPY:
1602     shell->ops->copy = (PetscErrorCode(*)(Mat, Mat, MatStructure))f;
1603     break;
1604   case MATOP_DIAGONAL_SET:
1605   case MATOP_DIAGONAL_SCALE:
1606   case MATOP_SHIFT:
1607   case MATOP_SCALE:
1608   case MATOP_AXPY:
1609   case MATOP_ZERO_ROWS:
1610   case MATOP_ZERO_ROWS_COLUMNS:
1611     PetscCheck(!shell->managescalingshifts, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "MATSHELL is managing scalings and shifts, see MatShellSetManageScalingShifts()");
1612     (((void (**)(void))mat->ops)[op]) = f;
1613     break;
1614   case MATOP_GET_DIAGONAL:
1615     if (shell->managescalingshifts) {
1616       shell->ops->getdiagonal = (PetscErrorCode(*)(Mat, Vec))f;
1617       mat->ops->getdiagonal   = MatGetDiagonal_Shell;
1618     } else {
1619       shell->ops->getdiagonal = NULL;
1620       mat->ops->getdiagonal   = (PetscErrorCode(*)(Mat, Vec))f;
1621     }
1622     break;
1623   case MATOP_MULT:
1624     if (shell->managescalingshifts) {
1625       shell->ops->mult = (PetscErrorCode(*)(Mat, Vec, Vec))f;
1626       mat->ops->mult   = MatMult_Shell;
1627     } else {
1628       shell->ops->mult = NULL;
1629       mat->ops->mult   = (PetscErrorCode(*)(Mat, Vec, Vec))f;
1630     }
1631     break;
1632   case MATOP_MULT_TRANSPOSE:
1633     if (shell->managescalingshifts) {
1634       shell->ops->multtranspose = (PetscErrorCode(*)(Mat, Vec, Vec))f;
1635       mat->ops->multtranspose   = MatMultTranspose_Shell;
1636     } else {
1637       shell->ops->multtranspose = NULL;
1638       mat->ops->multtranspose   = (PetscErrorCode(*)(Mat, Vec, Vec))f;
1639     }
1640     break;
1641   case MATOP_MULT_HERMITIAN_TRANSPOSE:
1642     if (shell->managescalingshifts) {
1643       shell->ops->multhermitiantranspose = (PetscErrorCode(*)(Mat, Vec, Vec))f;
1644       mat->ops->multhermitiantranspose   = MatMultHermitianTranspose_Shell;
1645     } else {
1646       shell->ops->multhermitiantranspose = NULL;
1647       mat->ops->multhermitiantranspose   = (PetscErrorCode(*)(Mat, Vec, Vec))f;
1648     }
1649     break;
1650   default:
1651     (((void (**)(void))mat->ops)[op]) = f;
1652     break;
1653   }
1654   PetscFunctionReturn(PETSC_SUCCESS);
1655 }
1656 
1657 static PetscErrorCode MatShellGetOperation_Shell(Mat mat, MatOperation op, void (**f)(void))
1658 {
1659   Mat_Shell *shell = (Mat_Shell *)mat->data;
1660 
1661   PetscFunctionBegin;
1662   switch (op) {
1663   case MATOP_DESTROY:
1664     *f = (void (*)(void))shell->ops->destroy;
1665     break;
1666   case MATOP_VIEW:
1667     *f = (void (*)(void))mat->ops->view;
1668     break;
1669   case MATOP_COPY:
1670     *f = (void (*)(void))shell->ops->copy;
1671     break;
1672   case MATOP_DIAGONAL_SET:
1673   case MATOP_DIAGONAL_SCALE:
1674   case MATOP_SHIFT:
1675   case MATOP_SCALE:
1676   case MATOP_AXPY:
1677   case MATOP_ZERO_ROWS:
1678   case MATOP_ZERO_ROWS_COLUMNS:
1679     *f = (((void (**)(void))mat->ops)[op]);
1680     break;
1681   case MATOP_GET_DIAGONAL:
1682     if (shell->ops->getdiagonal) *f = (void (*)(void))shell->ops->getdiagonal;
1683     else *f = (((void (**)(void))mat->ops)[op]);
1684     break;
1685   case MATOP_MULT:
1686     if (shell->ops->mult) *f = (void (*)(void))shell->ops->mult;
1687     else *f = (((void (**)(void))mat->ops)[op]);
1688     break;
1689   case MATOP_MULT_TRANSPOSE:
1690     if (shell->ops->multtranspose) *f = (void (*)(void))shell->ops->multtranspose;
1691     else *f = (((void (**)(void))mat->ops)[op]);
1692     break;
1693   case MATOP_MULT_HERMITIAN_TRANSPOSE:
1694     if (shell->ops->multhermitiantranspose) *f = (void (*)(void))shell->ops->multhermitiantranspose;
1695     else *f = (((void (**)(void))mat->ops)[op]);
1696     break;
1697   default:
1698     *f = (((void (**)(void))mat->ops)[op]);
1699   }
1700   PetscFunctionReturn(PETSC_SUCCESS);
1701 }
1702 
1703 /*MC
1704    MATSHELL - MATSHELL = "shell" - A matrix type to be used to define your own matrix type -- perhaps matrix-free.
1705 
1706   Level: advanced
1707 
1708 .seealso: [](ch_matrices), `Mat`, `MatCreateShell()`
1709 M*/
1710 
1711 PETSC_EXTERN PetscErrorCode MatCreate_Shell(Mat A)
1712 {
1713   Mat_Shell *b;
1714 
1715   PetscFunctionBegin;
1716   PetscCall(PetscNew(&b));
1717   A->data   = (void *)b;
1718   A->ops[0] = MatOps_Values;
1719 
1720   b->ctxcontainer        = NULL;
1721   b->vshift              = 0.0;
1722   b->vscale              = 1.0;
1723   b->managescalingshifts = PETSC_TRUE;
1724   A->assembled           = PETSC_TRUE;
1725   A->preallocated        = PETSC_FALSE;
1726 
1727   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellGetContext_C", MatShellGetContext_Shell));
1728   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellSetContext_C", MatShellSetContext_Shell));
1729   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellSetContextDestroy_C", MatShellSetContextDestroy_Shell));
1730   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellSetVecType_C", MatShellSetVecType_Shell));
1731   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellSetManageScalingShifts_C", MatShellSetManageScalingShifts_Shell));
1732   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellGetScalingShifts_C", MatShellGetScalingShifts_Shell));
1733   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellSetOperation_C", MatShellSetOperation_Shell));
1734   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellGetOperation_C", MatShellGetOperation_Shell));
1735   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellSetMatProductOperation_C", MatShellSetMatProductOperation_Shell));
1736   PetscCall(PetscObjectChangeTypeName((PetscObject)A, MATSHELL));
1737   PetscFunctionReturn(PETSC_SUCCESS);
1738 }
1739 
1740 /*@C
1741   MatCreateShell - Creates a new matrix of `MatType` `MATSHELL` for use with a user-defined
1742   private data storage format.
1743 
1744   Collective
1745 
1746   Input Parameters:
1747 + comm - MPI communicator
1748 . m    - number of local rows (or `PETSC_DECIDE` to have calculated if `M` is given)
1749 . n    - number of local columns (or `PETSC_DECIDE` to have calculated if `N` is given)
1750 . M    - number of global rows (may be `PETSC_DETERMINE` to have calculated if `m` is given)
1751 . N    - number of global columns (may be `PETSC_DETERMINE` to have calculated if `n` is given)
1752 - ctx  - pointer to data needed by the shell matrix routines
1753 
1754   Output Parameter:
1755 . A - the matrix
1756 
1757   Level: advanced
1758 
1759   Example Usage:
1760 .vb
1761   extern PetscErrorCode mult(Mat, Vec, Vec);
1762 
1763   MatCreateShell(comm, m, n, M, N, ctx, &mat);
1764   MatShellSetOperation(mat, MATOP_MULT, (void(*)(void))mult);
1765   // Use matrix for operations that have been set
1766   MatDestroy(mat);
1767 .ve
1768 
1769   Notes:
1770   The shell matrix type is intended to provide a simple class to use
1771   with `KSP` (such as, for use with matrix-free methods). You should not
1772   use the shell type if you plan to define a complete matrix class.
1773 
1774   PETSc requires that matrices and vectors being used for certain
1775   operations are partitioned accordingly.  For example, when
1776   creating a shell matrix, `A`, that supports parallel matrix-vector
1777   products using `MatMult`(A,x,y) the user should set the number
1778   of local matrix rows to be the number of local elements of the
1779   corresponding result vector, y. Note that this is information is
1780   required for use of the matrix interface routines, even though
1781   the shell matrix may not actually be physically partitioned.
1782   For example,
1783 
1784 .vb
1785      Vec x, y
1786      extern PetscErrorCode mult(Mat,Vec,Vec);
1787      Mat A
1788 
1789      VecCreateMPI(comm,PETSC_DECIDE,M,&y);
1790      VecCreateMPI(comm,PETSC_DECIDE,N,&x);
1791      VecGetLocalSize(y,&m);
1792      VecGetLocalSize(x,&n);
1793      MatCreateShell(comm,m,n,M,N,ctx,&A);
1794      MatShellSetOperation(mat,MATOP_MULT,(void(*)(void))mult);
1795      MatMult(A,x,y);
1796      MatDestroy(&A);
1797      VecDestroy(&y);
1798      VecDestroy(&x);
1799 .ve
1800 
1801   `MATSHELL` handles `MatShift()`, `MatDiagonalSet()`, `MatDiagonalScale()`, `MatAXPY()`, `MatScale()`, `MatZeroRows()` and `MatZeroRowsColumns()`
1802   internally, so these  operations cannot be overwritten unless `MatShellSetManageScalingShifts()` is called.
1803 
1804   Developer Notes:
1805   For rectangular matrices do all the scalings and shifts make sense?
1806 
1807   Regarding shifting and scaling. The general form is
1808 
1809   diag(left)(vscale*A + diag(dshift) + vshift I)diag(right)
1810 
1811   The order you apply the operations is important. For example if you have a dshift then
1812   apply a MatScale(s) you get s*vscale*A + s*diag(shift). But if you first scale and then shift
1813   you get s*vscale*A + diag(shift)
1814 
1815   A is the user provided function.
1816 
1817   `KSP`/`PC` uses changes in the `Mat`'s "state" to decide if preconditioners need to be rebuilt `PCSetUp()` only calls the setup() for
1818   for the `PC` implementation if the `Mat` state has increased from the previous call. Thus to get changes in a `MATSHELL` to trigger
1819   an update in the preconditioner you must call `MatAssemblyBegin()` and `MatAssemblyEnd()` or `PetscObjectStateIncrease`((`PetscObject`)mat);
1820   each time the `MATSHELL` matrix has changed.
1821 
1822   Matrix product operations (i.e. `MatMat()`, `MatTransposeMat()` etc) can be specified using `MatShellSetMatProductOperation()`
1823 
1824   Calling `MatAssemblyBegin()`/`MatAssemblyEnd()` on a `MATSHELL` removes any previously supplied shift and scales that were provided
1825   with `MatDiagonalSet()`, `MatShift()`, `MatScale()`, or `MatDiagonalScale()`.
1826 
1827   Fortran Notes:
1828   To use this from Fortran with a `ctx` you must write an interface definition for this
1829   function and for `MatShellGetContext()` that tells Fortran the Fortran derived data type you are passing
1830   in as the `ctx` argument.
1831 
1832 .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatShellSetOperation()`, `MatHasOperation()`, `MatShellGetContext()`, `MatShellSetContext()`, `MatShellSetManageScalingShifts()`, `MatShellSetMatProductOperation()`
1833 @*/
1834 PetscErrorCode MatCreateShell(MPI_Comm comm, PetscInt m, PetscInt n, PetscInt M, PetscInt N, void *ctx, Mat *A)
1835 {
1836   PetscFunctionBegin;
1837   PetscCall(MatCreate(comm, A));
1838   PetscCall(MatSetSizes(*A, m, n, M, N));
1839   PetscCall(MatSetType(*A, MATSHELL));
1840   PetscCall(MatShellSetContext(*A, ctx));
1841   PetscCall(MatSetUp(*A));
1842   PetscFunctionReturn(PETSC_SUCCESS);
1843 }
1844 
1845 /*@
1846   MatShellSetContext - sets the context for a `MATSHELL` shell matrix
1847 
1848   Logically Collective
1849 
1850   Input Parameters:
1851 + mat - the `MATSHELL` shell matrix
1852 - ctx - the context
1853 
1854   Level: advanced
1855 
1856   Fortran Notes:
1857   You must write a Fortran interface definition for this
1858   function that tells Fortran the Fortran derived data type that you are passing in as the `ctx` argument.
1859 
1860 .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`
1861 @*/
1862 PetscErrorCode MatShellSetContext(Mat mat, void *ctx)
1863 {
1864   PetscFunctionBegin;
1865   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
1866   PetscTryMethod(mat, "MatShellSetContext_C", (Mat, void *), (mat, ctx));
1867   PetscFunctionReturn(PETSC_SUCCESS);
1868 }
1869 
1870 /*@C
1871   MatShellSetContextDestroy - sets the destroy function for a `MATSHELL` shell matrix context
1872 
1873   Logically Collective
1874 
1875   Input Parameters:
1876 + mat - the shell matrix
1877 - f   - the context destroy function
1878 
1879   Level: advanced
1880 
1881   Note:
1882   If the `MatShell` is never duplicated, the behavior of this function is equivalent
1883   to `MatShellSetOperation`(`Mat`,`MATOP_DESTROY`,f). However, `MatShellSetContextDestroy()`
1884   ensures proper reference counting for the user provided context data in the case that
1885   the `MATSHELL` is duplicated.
1886 
1887 .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellSetContext()`
1888 @*/
1889 PetscErrorCode MatShellSetContextDestroy(Mat mat, PetscErrorCode (*f)(void *))
1890 {
1891   PetscFunctionBegin;
1892   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
1893   PetscTryMethod(mat, "MatShellSetContextDestroy_C", (Mat, PetscErrorCode(*)(void *)), (mat, f));
1894   PetscFunctionReturn(PETSC_SUCCESS);
1895 }
1896 
1897 /*@C
1898   MatShellSetVecType - Sets the `VecType` of `Vec` returned by `MatCreateVecs()`
1899 
1900   Logically Collective
1901 
1902   Input Parameters:
1903 + mat   - the `MATSHELL` shell matrix
1904 - vtype - type to use for creating vectors
1905 
1906   Level: advanced
1907 
1908 .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateVecs()`
1909 @*/
1910 PetscErrorCode MatShellSetVecType(Mat mat, VecType vtype)
1911 {
1912   PetscFunctionBegin;
1913   PetscTryMethod(mat, "MatShellSetVecType_C", (Mat, VecType), (mat, vtype));
1914   PetscFunctionReturn(PETSC_SUCCESS);
1915 }
1916 
1917 /*@
1918   MatShellSetManageScalingShifts - Allows the user to control the scaling and shift operations of the `MATSHELL`. Must be called immediately
1919   after `MatCreateShell()`
1920 
1921   Logically Collective
1922 
1923   Input Parameter:
1924 . A - the `MATSHELL` shell matrix
1925 
1926   Level: advanced
1927 
1928 .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`, `MatShellSetContext()`, `MatShellSetOperation()`
1929 @*/
1930 PetscErrorCode MatShellSetManageScalingShifts(Mat A)
1931 {
1932   PetscFunctionBegin;
1933   PetscValidHeaderSpecific(A, MAT_CLASSID, 1);
1934   PetscTryMethod(A, "MatShellSetManageScalingShifts_C", (Mat), (A));
1935   PetscFunctionReturn(PETSC_SUCCESS);
1936 }
1937 
1938 // PetscClangLinter pragma disable: -fdoc-internal-linkage
1939 /*@C
1940   MatShellGetScalingShifts - Gets members of a `MATSHELL` used internally for scaling and
1941   shifting the `Mat` or calling `MatAXPY()`, `MatZeroRows()`, or `MatZeroRowsColumns()` with it
1942 
1943   Logically Collective
1944 
1945   Input Parameter:
1946 . A - the `MATSHELL` shell matrix
1947 
1948   Output Parameters:
1949 + vshift - `PetscScalar` pointer (can be `NULL`), see `MatShift()`, or `MAT_SHELL_NOT_ALLOWED` if the internal shift should be 0
1950 . vscale - `PetscScalar` pointer (can be `NULL`), see `MatScale()`, or `MAT_SHELL_NOT_ALLOWED` if the internal scaling should be 1
1951 . dshift - `Vec` pointer (can be `NULL`), see `MatDiagonalSet()`, or `MAT_SHELL_NOT_ALLOWED` if the internal shift should be `NULL`
1952 . left   - `Vec` pointer (can be `NULL`), see `MatDiagonalScale()`, or `MAT_SHELL_NOT_ALLOWED` if the internal scaling should be `NULL`
1953 . right  - `Vec` pointer (can be `NULL`), see `MatDiagonalScale()`, or `MAT_SHELL_NOT_ALLOWED` if the internal scaling should be `NULL`
1954 . axpy   - `Mat` pointer (can be `NULL`), or `MAT_SHELL_NOT_ALLOWED` if `MatAXPY()` should have not been called on `A`
1955 . zrows  - `Vec` pointer (can be `NULL`), or `MAT_SHELL_NOT_ALLOWED` if `MatZeroRows()` should have not been called on `A`
1956 - zcols  - `Vec` pointer (can be `NULL`), or `MAT_SHELL_NOT_ALLOWED` if `MatZeroRowsColumns()` should have not been called on `A`
1957 
1958   Level: advanced
1959 
1960   Developer Notes:
1961   This is mostly useful to check for corner-cases in `MatType` deriving from
1962   `MATSHELL`, e.g, `MATCOMPOSITE` or `MATVIRTUALTRANSPOSE`, since scaling and
1963   shifts often require extra work which is not always implemented.
1964 
1965 .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShift()`, `MatScale()`, `MatDiagonalSet()`, `MatDiagonalScale()`, `MatAXPY()`, `MatZeroRows()`, `MatZeroRowsColumns()`, `MatShellSetManageScalingShifts()`
1966 @*/
1967 PetscErrorCode MatShellGetScalingShifts(Mat A, PetscScalar *vshift, PetscScalar *vscale, Vec *dshift, Vec *left, Vec *right, Mat *axpy, IS *zrows, IS *zcols)
1968 {
1969   PetscFunctionBegin;
1970   PetscValidHeaderSpecific(A, MAT_CLASSID, 1);
1971   PetscTryMethod(A, "MatShellGetScalingShifts_C", (Mat, PetscScalar *, PetscScalar *, Vec *, Vec *, Vec *, Mat *, IS *, IS *), (A, vshift, vscale, dshift, left, right, axpy, zrows, zcols));
1972   PetscFunctionReturn(PETSC_SUCCESS);
1973 }
1974 
1975 /*@C
1976   MatShellTestMult - Compares the multiply routine provided to the `MATSHELL` with differencing on a given function.
1977 
1978   Logically Collective; No Fortran Support
1979 
1980   Input Parameters:
1981 + mat  - the `MATSHELL` shell matrix
1982 . f    - the function
1983 . base - differences are computed around this vector, see `MatMFFDSetBase()`, for Jacobians this is the point at which the Jacobian is being evaluated
1984 - ctx  - an optional context for the function
1985 
1986   Output Parameter:
1987 . flg - `PETSC_TRUE` if the multiply is likely correct
1988 
1989   Options Database Key:
1990 . -mat_shell_test_mult_view - print if any differences are detected between the products and print the difference
1991 
1992   Level: advanced
1993 
1994 .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`, `MatShellTestMultTranspose()`
1995 @*/
1996 PetscErrorCode MatShellTestMult(Mat mat, PetscErrorCode (*f)(void *, Vec, Vec), Vec base, void *ctx, PetscBool *flg)
1997 {
1998   PetscInt  m, n;
1999   Mat       mf, Dmf, Dmat, Ddiff;
2000   PetscReal Diffnorm, Dmfnorm;
2001   PetscBool v = PETSC_FALSE, flag = PETSC_TRUE;
2002 
2003   PetscFunctionBegin;
2004   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
2005   PetscCall(PetscOptionsHasName(NULL, ((PetscObject)mat)->prefix, "-mat_shell_test_mult_view", &v));
2006   PetscCall(MatGetLocalSize(mat, &m, &n));
2007   PetscCall(MatCreateMFFD(PetscObjectComm((PetscObject)mat), m, n, PETSC_DECIDE, PETSC_DECIDE, &mf));
2008   PetscCall(MatMFFDSetFunction(mf, f, ctx));
2009   PetscCall(MatMFFDSetBase(mf, base, NULL));
2010 
2011   PetscCall(MatComputeOperator(mf, MATAIJ, &Dmf));
2012   PetscCall(MatComputeOperator(mat, MATAIJ, &Dmat));
2013 
2014   PetscCall(MatDuplicate(Dmat, MAT_COPY_VALUES, &Ddiff));
2015   PetscCall(MatAXPY(Ddiff, -1.0, Dmf, DIFFERENT_NONZERO_PATTERN));
2016   PetscCall(MatNorm(Ddiff, NORM_FROBENIUS, &Diffnorm));
2017   PetscCall(MatNorm(Dmf, NORM_FROBENIUS, &Dmfnorm));
2018   if (Diffnorm / Dmfnorm > 10 * PETSC_SQRT_MACHINE_EPSILON) {
2019     flag = PETSC_FALSE;
2020     if (v) {
2021       PetscCall(PetscPrintf(PetscObjectComm((PetscObject)mat), "MATSHELL and matrix-free multiple appear to produce different results.\n Norm Ratio %g Difference results followed by finite difference one\n", (double)(Diffnorm / Dmfnorm)));
2022       PetscCall(MatViewFromOptions(Ddiff, (PetscObject)mat, "-mat_shell_test_mult_view"));
2023       PetscCall(MatViewFromOptions(Dmf, (PetscObject)mat, "-mat_shell_test_mult_view"));
2024       PetscCall(MatViewFromOptions(Dmat, (PetscObject)mat, "-mat_shell_test_mult_view"));
2025     }
2026   } else if (v) {
2027     PetscCall(PetscPrintf(PetscObjectComm((PetscObject)mat), "MATSHELL and matrix-free multiple appear to produce the same results\n"));
2028   }
2029   if (flg) *flg = flag;
2030   PetscCall(MatDestroy(&Ddiff));
2031   PetscCall(MatDestroy(&mf));
2032   PetscCall(MatDestroy(&Dmf));
2033   PetscCall(MatDestroy(&Dmat));
2034   PetscFunctionReturn(PETSC_SUCCESS);
2035 }
2036 
2037 /*@C
2038   MatShellTestMultTranspose - Compares the multiply transpose routine provided to the `MATSHELL` with differencing on a given function.
2039 
2040   Logically Collective; No Fortran Support
2041 
2042   Input Parameters:
2043 + mat  - the `MATSHELL` shell matrix
2044 . f    - the function
2045 . base - differences are computed around this vector, see `MatMFFDSetBase()`, for Jacobians this is the point at which the Jacobian is being evaluated
2046 - ctx  - an optional context for the function
2047 
2048   Output Parameter:
2049 . flg - `PETSC_TRUE` if the multiply is likely correct
2050 
2051   Options Database Key:
2052 . -mat_shell_test_mult_view - print if any differences are detected between the products and print the difference
2053 
2054   Level: advanced
2055 
2056 .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`, `MatShellTestMult()`
2057 @*/
2058 PetscErrorCode MatShellTestMultTranspose(Mat mat, PetscErrorCode (*f)(void *, Vec, Vec), Vec base, void *ctx, PetscBool *flg)
2059 {
2060   Vec       x, y, z;
2061   PetscInt  m, n, M, N;
2062   Mat       mf, Dmf, Dmat, Ddiff;
2063   PetscReal Diffnorm, Dmfnorm;
2064   PetscBool v = PETSC_FALSE, flag = PETSC_TRUE;
2065 
2066   PetscFunctionBegin;
2067   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
2068   PetscCall(PetscOptionsHasName(NULL, ((PetscObject)mat)->prefix, "-mat_shell_test_mult_transpose_view", &v));
2069   PetscCall(MatCreateVecs(mat, &x, &y));
2070   PetscCall(VecDuplicate(y, &z));
2071   PetscCall(MatGetLocalSize(mat, &m, &n));
2072   PetscCall(MatGetSize(mat, &M, &N));
2073   PetscCall(MatCreateMFFD(PetscObjectComm((PetscObject)mat), m, n, M, N, &mf));
2074   PetscCall(MatMFFDSetFunction(mf, f, ctx));
2075   PetscCall(MatMFFDSetBase(mf, base, NULL));
2076   PetscCall(MatComputeOperator(mf, MATAIJ, &Dmf));
2077   PetscCall(MatTranspose(Dmf, MAT_INPLACE_MATRIX, &Dmf));
2078   PetscCall(MatComputeOperatorTranspose(mat, MATAIJ, &Dmat));
2079 
2080   PetscCall(MatDuplicate(Dmat, MAT_COPY_VALUES, &Ddiff));
2081   PetscCall(MatAXPY(Ddiff, -1.0, Dmf, DIFFERENT_NONZERO_PATTERN));
2082   PetscCall(MatNorm(Ddiff, NORM_FROBENIUS, &Diffnorm));
2083   PetscCall(MatNorm(Dmf, NORM_FROBENIUS, &Dmfnorm));
2084   if (Diffnorm / Dmfnorm > 10 * PETSC_SQRT_MACHINE_EPSILON) {
2085     flag = PETSC_FALSE;
2086     if (v) {
2087       PetscCall(PetscPrintf(PetscObjectComm((PetscObject)mat), "MATSHELL and matrix-free multiple appear to produce different results.\n Norm Ratio %g Difference results followed by finite difference one\n", (double)(Diffnorm / Dmfnorm)));
2088       PetscCall(MatViewFromOptions(Ddiff, (PetscObject)mat, "-mat_shell_test_mult_transpose_view"));
2089       PetscCall(MatViewFromOptions(Dmf, (PetscObject)mat, "-mat_shell_test_mult_transpose_view"));
2090       PetscCall(MatViewFromOptions(Dmat, (PetscObject)mat, "-mat_shell_test_mult_transpose_view"));
2091     }
2092   } else if (v) {
2093     PetscCall(PetscPrintf(PetscObjectComm((PetscObject)mat), "MATSHELL transpose and matrix-free multiple appear to produce the same results\n"));
2094   }
2095   if (flg) *flg = flag;
2096   PetscCall(MatDestroy(&mf));
2097   PetscCall(MatDestroy(&Dmat));
2098   PetscCall(MatDestroy(&Ddiff));
2099   PetscCall(MatDestroy(&Dmf));
2100   PetscCall(VecDestroy(&x));
2101   PetscCall(VecDestroy(&y));
2102   PetscCall(VecDestroy(&z));
2103   PetscFunctionReturn(PETSC_SUCCESS);
2104 }
2105 
2106 /*@C
2107   MatShellSetOperation - Allows user to set a matrix operation for a `MATSHELL` shell matrix.
2108 
2109   Logically Collective
2110 
2111   Input Parameters:
2112 + mat - the `MATSHELL` shell matrix
2113 . op  - the name of the operation
2114 - g   - the function that provides the operation.
2115 
2116   Level: advanced
2117 
2118   Example Usage:
2119 .vb
2120   extern PetscErrorCode usermult(Mat, Vec, Vec);
2121 
2122   MatCreateShell(comm, m, n, M, N, ctx, &A);
2123   MatShellSetOperation(A, MATOP_MULT, (void(*)(void))usermult);
2124 .ve
2125 
2126   Notes:
2127   See the file include/petscmat.h for a complete list of matrix
2128   operations, which all have the form MATOP_<OPERATION>, where
2129   <OPERATION> is the name (in all capital letters) of the
2130   user interface routine (e.g., `MatMult()` -> `MATOP_MULT`).
2131 
2132   All user-provided functions (except for `MATOP_DESTROY`) should have the same calling
2133   sequence as the usual matrix interface routines, since they
2134   are intended to be accessed via the usual matrix interface
2135   routines, e.g.,
2136 $       MatMult(Mat, Vec, Vec) -> usermult(Mat, Vec, Vec)
2137 
2138   In particular each function MUST return an error code of 0 on success and
2139   nonzero on failure.
2140 
2141   Within each user-defined routine, the user should call
2142   `MatShellGetContext()` to obtain the user-defined context that was
2143   set by `MatCreateShell()`.
2144 
2145   Use `MatSetOperation()` to set an operation for any matrix type. For matrix product operations (i.e. `MatMatXXX()`, `MatTransposeMatXXX()` etc)
2146   use `MatShellSetMatProductOperation()`
2147 
2148   Fortran Notes:
2149   For `MatCreateVecs()` the user code should check if the input left or right matrix is -1 and in that case not
2150   generate a matrix. See src/mat/tests/ex120f.F
2151 
2152 .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`, `MatShellSetContext()`, `MatSetOperation()`, `MatShellSetManageScalingShifts()`, `MatShellSetMatProductOperation()`
2153 @*/
2154 PetscErrorCode MatShellSetOperation(Mat mat, MatOperation op, void (*g)(void))
2155 {
2156   PetscFunctionBegin;
2157   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
2158   PetscTryMethod(mat, "MatShellSetOperation_C", (Mat, MatOperation, void (*)(void)), (mat, op, g));
2159   PetscFunctionReturn(PETSC_SUCCESS);
2160 }
2161 
2162 /*@C
2163   MatShellGetOperation - Gets a matrix function for a `MATSHELL` shell matrix.
2164 
2165   Not Collective
2166 
2167   Input Parameters:
2168 + mat - the `MATSHELL` shell matrix
2169 - op  - the name of the operation
2170 
2171   Output Parameter:
2172 . g - the function that provides the operation.
2173 
2174   Level: advanced
2175 
2176   Notes:
2177   See the file include/petscmat.h for a complete list of matrix
2178   operations, which all have the form MATOP_<OPERATION>, where
2179   <OPERATION> is the name (in all capital letters) of the
2180   user interface routine (e.g., `MatMult()` -> `MATOP_MULT`).
2181 
2182   All user-provided functions have the same calling
2183   sequence as the usual matrix interface routines, since they
2184   are intended to be accessed via the usual matrix interface
2185   routines, e.g.,
2186 $       MatMult(Mat, Vec, Vec) -> usermult(Mat, Vec, Vec)
2187 
2188   Within each user-defined routine, the user should call
2189   `MatShellGetContext()` to obtain the user-defined context that was
2190   set by `MatCreateShell()`.
2191 
2192 .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellSetOperation()`, `MatShellSetContext()`
2193 @*/
2194 PetscErrorCode MatShellGetOperation(Mat mat, MatOperation op, void (**g)(void))
2195 {
2196   PetscFunctionBegin;
2197   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
2198   PetscUseMethod(mat, "MatShellGetOperation_C", (Mat, MatOperation, void (**)(void)), (mat, op, g));
2199   PetscFunctionReturn(PETSC_SUCCESS);
2200 }
2201 
2202 /*@
2203   MatIsShell - Inquires if a matrix is derived from `MATSHELL`
2204 
2205   Input Parameter:
2206 . mat - the matrix
2207 
2208   Output Parameter:
2209 . flg - the Boolean value
2210 
2211   Level: developer
2212 
2213 .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MATMFFD`, `MatCreateShell()`, `MATTRANSPOSEVIRTUAL`, `MATSCHURCOMPLEMENT`
2214 @*/
2215 PetscErrorCode MatIsShell(Mat mat, PetscBool *flg)
2216 {
2217   PetscFunctionBegin;
2218   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
2219   PetscAssertPointer(flg, 2);
2220   *flg = (PetscBool)(mat->ops->destroy == MatDestroy_Shell);
2221   PetscFunctionReturn(PETSC_SUCCESS);
2222 }
2223