xref: /petsc/src/mat/impls/baij/seq/baijfact3.c (revision 6abefa4f446b2ea91915da4e25ea0defa83db48e)
1 #define PETSCMAT_DLL
2 
3 /*
4     Factorization code for BAIJ format.
5 */
6 #include "../src/mat/impls/baij/seq/baij.h"
7 #include "../src/mat/blockinvert.h"
8 
9 #undef __FUNCT__
10 #define __FUNCT__ "MatSeqBAIJSetNumericFactorization"
11 /*
12    This is used to set the numeric factorization for both LU and ILU symbolic factorization
13 */
14 PetscErrorCode MatSeqBAIJSetNumericFactorization(Mat fact,PetscTruth natural)
15 {
16   PetscFunctionBegin;
17   if(natural){
18     switch (fact->rmap->bs){
19     case 2:
20       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_2_NaturalOrdering;
21       break;
22     case 3:
23       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_3_NaturalOrdering;
24       break;
25     case 4:
26       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4_NaturalOrdering;
27       break;
28     case 5:
29        fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_5_NaturalOrdering;
30        break;
31     case 6:
32       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_6_NaturalOrdering;
33       break;
34     case 7:
35       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_7_NaturalOrdering;
36       break;
37     case 15:
38       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_15_NaturalOrdering;
39       break;
40     default:
41       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_N;
42       break;
43     }
44   }
45   else{
46     switch (fact->rmap->bs){
47     case 2:
48       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_2;
49       break;
50     case 3:
51       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_3;
52       break;
53     case 4:
54       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4;
55       break;
56     case 5:
57       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_5;
58       break;
59     case 6:
60       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_6;
61       break;
62     case 7:
63       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_7;
64       break;
65     default:
66       fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_N;
67       break;
68     }
69   }
70   PetscFunctionReturn(0);
71 }
72 
73 PetscErrorCode MatSeqBAIJSetNumericFactorization_inplace(Mat inA,PetscTruth natural)
74 {
75   PetscFunctionBegin;
76   if (natural) {
77     switch (inA->rmap->bs) {
78     case 1:
79       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_1_inplace;
80       break;
81     case 2:
82       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_2_NaturalOrdering_inplace;
83       break;
84     case 3:
85       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_3_NaturalOrdering_inplace;
86       break;
87     case 4:
88 #if defined(PETSC_USE_SCALAR_MAT_SINGLE)
89       {
90         PetscTruth  sse_enabled_local;
91         PetscErrorCode ierr;
92         ierr = PetscSSEIsEnabled(inA->comm,&sse_enabled_local,PETSC_NULL);CHKERRQ(ierr);
93         if (sse_enabled_local) {
94 #  if defined(PETSC_HAVE_SSE)
95           int i,*AJ=a->j,nz=a->nz,n=a->mbs;
96           if (n==(unsigned short)n) {
97             unsigned short *aj=(unsigned short *)AJ;
98             for (i=0;i<nz;i++) {
99               aj[i] = (unsigned short)AJ[i];
100             }
101             inA->ops->setunfactored   = MatSetUnfactored_SeqBAIJ_4_NaturalOrdering_SSE_usj;
102             inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4_NaturalOrdering_SSE_usj;
103             ierr = PetscInfo(inA,"Using special SSE, in-place natural ordering, ushort j index factor BS=4\n");CHKERRQ(ierr);
104           } else {
105         /* Scale the column indices for easier indexing in MatSolve. */
106 /*            for (i=0;i<nz;i++) { */
107 /*              AJ[i] = AJ[i]*4; */
108 /*            } */
109             inA->ops->setunfactored   = MatSetUnfactored_SeqBAIJ_4_NaturalOrdering_SSE;
110             inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4_NaturalOrdering_SSE;
111             ierr = PetscInfo(inA,"Using special SSE, in-place natural ordering, int j index factor BS=4\n");CHKERRQ(ierr);
112           }
113 #  else
114         /* This should never be reached.  If so, problem in PetscSSEIsEnabled. */
115           SETERRQ(PETSC_ERR_SUP,"SSE Hardware unavailable");
116 #  endif
117         } else {
118           inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4_NaturalOrdering_inplace;
119         }
120       }
121 #else
122       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4_NaturalOrdering_inplace;
123 #endif
124       break;
125     case 5:
126       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_5_NaturalOrdering_inplace;
127       break;
128     case 6:
129       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_6_NaturalOrdering_inplace;
130       break;
131     case 7:
132       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_7_NaturalOrdering_inplace;
133       break;
134     default:
135       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_N_inplace;
136       break;
137     }
138   } else {
139     switch (inA->rmap->bs) {
140     case 1:
141       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_1_inplace;
142       break;
143     case 2:
144       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_2_inplace;
145       break;
146     case 3:
147       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_3_inplace;
148       break;
149     case 4:
150       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4_inplace;
151       break;
152     case 5:
153       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_5_inplace;
154       break;
155     case 6:
156       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_6_inplace;
157       break;
158     case 7:
159       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_7_inplace;
160       break;
161     default:
162       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_N_inplace;
163       break;
164     }
165   }
166   PetscFunctionReturn(0);
167 }
168 
169 /*
170     The symbolic factorization code is identical to that for AIJ format,
171   except for very small changes since this is now a SeqBAIJ datastructure.
172   NOT good code reuse.
173 */
174 #include "petscbt.h"
175 #include "../src/mat/utils/freespace.h"
176 
177 #undef __FUNCT__
178 #define __FUNCT__ "MatLUFactorSymbolic_SeqBAIJ"
179 PetscErrorCode MatLUFactorSymbolic_SeqBAIJ(Mat B,Mat A,IS isrow,IS iscol,const MatFactorInfo *info)
180 {
181   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b;
182   PetscInt           n=a->mbs,bs = A->rmap->bs,bs2=a->bs2;
183   PetscTruth         row_identity,col_identity,both_identity;
184   IS                 isicol;
185   PetscErrorCode     ierr;
186   const PetscInt     *r,*ic;
187   PetscInt           i,*ai=a->i,*aj=a->j;
188   PetscInt           *bi,*bj,*ajtmp;
189   PetscInt           *bdiag,row,nnz,nzi,reallocs=0,nzbd,*im;
190   PetscReal          f;
191   PetscInt           nlnk,*lnk,k,**bi_ptr;
192   PetscFreeSpaceList free_space=PETSC_NULL,current_space=PETSC_NULL;
193   PetscBT            lnkbt;
194 
195   PetscFunctionBegin;
196   if (A->rmap->N != A->cmap->N) SETERRQ(PETSC_ERR_ARG_WRONG,"matrix must be square");
197   ierr = ISInvertPermutation(iscol,PETSC_DECIDE,&isicol);CHKERRQ(ierr);
198   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
199   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
200 
201   /* get new row and diagonal pointers, must be allocated separately because they will be given to the Mat_SeqAIJ and freed separately */
202   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bi);CHKERRQ(ierr);
203   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bdiag);CHKERRQ(ierr);
204   bi[0] = bdiag[0] = 0;
205 
206   /* linked list for storing column indices of the active row */
207   nlnk = n + 1;
208   ierr = PetscLLCreate(n,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
209 
210   ierr = PetscMalloc2(n+1,PetscInt**,&bi_ptr,n+1,PetscInt,&im);CHKERRQ(ierr);
211 
212   /* initial FreeSpace size is f*(ai[n]+1) */
213   f = info->fill;
214   ierr = PetscFreeSpaceGet((PetscInt)(f*(ai[n]+1)),&free_space);CHKERRQ(ierr);
215   current_space = free_space;
216 
217   for (i=0; i<n; i++) {
218     /* copy previous fill into linked list */
219     nzi = 0;
220     nnz = ai[r[i]+1] - ai[r[i]];
221     if (!nnz) SETERRQ2(PETSC_ERR_MAT_LU_ZRPVT,"Empty row in matrix: row in original ordering %D in permuted ordering %D",r[i],i);
222     ajtmp = aj + ai[r[i]];
223     ierr = PetscLLAddPerm(nnz,ajtmp,ic,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
224     nzi += nlnk;
225 
226     /* add pivot rows into linked list */
227     row = lnk[n];
228     while (row < i) {
229       nzbd    = bdiag[row] + 1; /* num of entries in the row with column index <= row */
230       ajtmp   = bi_ptr[row] + nzbd; /* points to the entry next to the diagonal */
231       ierr = PetscLLAddSortedLU(ajtmp,row,nlnk,lnk,lnkbt,i,nzbd,im);CHKERRQ(ierr);
232       nzi += nlnk;
233       row  = lnk[row];
234     }
235     bi[i+1] = bi[i] + nzi;
236     im[i]   = nzi;
237 
238     /* mark bdiag */
239     nzbd = 0;
240     nnz  = nzi;
241     k    = lnk[n];
242     while (nnz-- && k < i){
243       nzbd++;
244       k = lnk[k];
245     }
246     bdiag[i] = nzbd; /* note : bdaig[i] = nnzL as input for PetscFreeSpaceContiguous_LU() */
247 
248     /* if free space is not available, make more free space */
249     if (current_space->local_remaining<nzi) {
250       nnz = 2*(n - i)*nzi; /* estimated and max additional space needed */
251       ierr = PetscFreeSpaceGet(nnz,&current_space);CHKERRQ(ierr);
252       reallocs++;
253     }
254 
255     /* copy data into free space, then initialize lnk */
256     ierr = PetscLLClean(n,n,nzi,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
257     bi_ptr[i] = current_space->array;
258     current_space->array           += nzi;
259     current_space->local_used      += nzi;
260     current_space->local_remaining -= nzi;
261   }
262 #if defined(PETSC_USE_INFO)
263   if (ai[n] != 0) {
264     PetscReal af = ((PetscReal)bi[n])/((PetscReal)ai[n]);
265     ierr = PetscInfo3(A,"Reallocs %D Fill ratio:given %G needed %G\n",reallocs,f,af);CHKERRQ(ierr);
266     ierr = PetscInfo1(A,"Run with -pc_factor_fill %G or use \n",af);CHKERRQ(ierr);
267     ierr = PetscInfo1(A,"PCFactorSetFill(pc,%G);\n",af);CHKERRQ(ierr);
268     ierr = PetscInfo(A,"for best performance.\n");CHKERRQ(ierr);
269   } else {
270     ierr = PetscInfo(A,"Empty matrix\n");CHKERRQ(ierr);
271   }
272 #endif
273 
274   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
275   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
276 
277   /* destroy list of free space and other temporary array(s) */
278   ierr = PetscMalloc((bi[n]+1)*sizeof(PetscInt),&bj);CHKERRQ(ierr);
279   ierr = PetscFreeSpaceContiguous_LU(&free_space,bj,n,bi,bdiag);CHKERRQ(ierr);
280   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
281   ierr = PetscFree2(bi_ptr,im);CHKERRQ(ierr);
282 
283   /* put together the new matrix */
284   ierr = MatSeqBAIJSetPreallocation_SeqBAIJ(B,bs,MAT_SKIP_ALLOCATION,PETSC_NULL);CHKERRQ(ierr);
285   ierr = PetscLogObjectParent(B,isicol);CHKERRQ(ierr);
286   b    = (Mat_SeqBAIJ*)(B)->data;
287   b->free_a       = PETSC_TRUE;
288   b->free_ij      = PETSC_TRUE;
289   b->singlemalloc = PETSC_FALSE;
290   ierr          = PetscMalloc((bdiag[0]+1)*sizeof(MatScalar)*bs2,&b->a);CHKERRQ(ierr);
291   b->j          = bj;
292   b->i          = bi;
293   b->diag       = bdiag;
294   b->free_diag  = PETSC_TRUE;
295   b->ilen       = 0;
296   b->imax       = 0;
297   b->row        = isrow;
298   b->col        = iscol;
299   b->pivotinblocks = (info->pivotinblocks) ? PETSC_TRUE : PETSC_FALSE;
300   ierr          = PetscObjectReference((PetscObject)isrow);CHKERRQ(ierr);
301   ierr          = PetscObjectReference((PetscObject)iscol);CHKERRQ(ierr);
302   b->icol       = isicol;
303   ierr = PetscMalloc((bs*n+bs)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
304   ierr = PetscLogObjectMemory(B,(bdiag[0]+1)*(sizeof(PetscInt)+sizeof(PetscScalar)*bs2));CHKERRQ(ierr);
305 
306   b->maxnz = b->nz = bdiag[0]+1;
307   B->factor                =  MAT_FACTOR_LU;
308   B->info.factor_mallocs   = reallocs;
309   B->info.fill_ratio_given = f;
310 
311   if (ai[n] != 0) {
312     B->info.fill_ratio_needed = ((PetscReal)(bdiag[0]+1))/((PetscReal)ai[n]);
313   } else {
314     B->info.fill_ratio_needed = 0.0;
315   }
316 
317   ierr = ISIdentity(isrow,&row_identity);CHKERRQ(ierr);
318   ierr = ISIdentity(iscol,&col_identity);CHKERRQ(ierr);
319   both_identity = (PetscTruth) (row_identity && col_identity);
320   ierr = MatSeqBAIJSetNumericFactorization(B,both_identity);CHKERRQ(ierr);
321   PetscFunctionReturn(0);
322  }
323 
324 #undef __FUNCT__
325 #define __FUNCT__ "MatLUFactorSymbolic_SeqBAIJ_inplace"
326 PetscErrorCode MatLUFactorSymbolic_SeqBAIJ_inplace(Mat B,Mat A,IS isrow,IS iscol,const MatFactorInfo *info)
327 {
328   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b;
329   PetscInt           n=a->mbs,bs = A->rmap->bs,bs2=a->bs2;
330   PetscTruth         row_identity,col_identity,both_identity;
331   IS                 isicol;
332   PetscErrorCode     ierr;
333   const PetscInt     *r,*ic;
334   PetscInt           i,*ai=a->i,*aj=a->j;
335   PetscInt           *bi,*bj,*ajtmp;
336   PetscInt           *bdiag,row,nnz,nzi,reallocs=0,nzbd,*im;
337   PetscReal          f;
338   PetscInt           nlnk,*lnk,k,**bi_ptr;
339   PetscFreeSpaceList free_space=PETSC_NULL,current_space=PETSC_NULL;
340   PetscBT            lnkbt;
341 
342   PetscFunctionBegin;
343   if (A->rmap->N != A->cmap->N) SETERRQ(PETSC_ERR_ARG_WRONG,"matrix must be square");
344   ierr = ISInvertPermutation(iscol,PETSC_DECIDE,&isicol);CHKERRQ(ierr);
345   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
346   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
347 
348   /* get new row and diagonal pointers, must be allocated separately because they will be given to the Mat_SeqAIJ and freed separately */
349   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bi);CHKERRQ(ierr);
350   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bdiag);CHKERRQ(ierr);
351 
352   bi[0] = bdiag[0] = 0;
353 
354   /* linked list for storing column indices of the active row */
355   nlnk = n + 1;
356   ierr = PetscLLCreate(n,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
357 
358   ierr = PetscMalloc2(n+1,PetscInt**,&bi_ptr,n+1,PetscInt,&im);CHKERRQ(ierr);
359 
360   /* initial FreeSpace size is f*(ai[n]+1) */
361   f = info->fill;
362   ierr = PetscFreeSpaceGet((PetscInt)(f*(ai[n]+1)),&free_space);CHKERRQ(ierr);
363   current_space = free_space;
364 
365   for (i=0; i<n; i++) {
366     /* copy previous fill into linked list */
367     nzi = 0;
368     nnz = ai[r[i]+1] - ai[r[i]];
369     if (!nnz) SETERRQ2(PETSC_ERR_MAT_LU_ZRPVT,"Empty row in matrix: row in original ordering %D in permuted ordering %D",r[i],i);
370     ajtmp = aj + ai[r[i]];
371     ierr = PetscLLAddPerm(nnz,ajtmp,ic,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
372     nzi += nlnk;
373 
374     /* add pivot rows into linked list */
375     row = lnk[n];
376     while (row < i) {
377       nzbd    = bdiag[row] - bi[row] + 1; /* num of entries in the row with column index <= row */
378       ajtmp   = bi_ptr[row] + nzbd; /* points to the entry next to the diagonal */
379       ierr = PetscLLAddSortedLU(ajtmp,row,nlnk,lnk,lnkbt,i,nzbd,im);CHKERRQ(ierr);
380       nzi += nlnk;
381       row  = lnk[row];
382     }
383     bi[i+1] = bi[i] + nzi;
384     im[i]   = nzi;
385 
386     /* mark bdiag */
387     nzbd = 0;
388     nnz  = nzi;
389     k    = lnk[n];
390     while (nnz-- && k < i){
391       nzbd++;
392       k = lnk[k];
393     }
394     bdiag[i] = bi[i] + nzbd;
395 
396     /* if free space is not available, make more free space */
397     if (current_space->local_remaining<nzi) {
398       nnz = (n - i)*nzi; /* estimated and max additional space needed */
399       ierr = PetscFreeSpaceGet(nnz,&current_space);CHKERRQ(ierr);
400       reallocs++;
401     }
402 
403     /* copy data into free space, then initialize lnk */
404     ierr = PetscLLClean(n,n,nzi,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
405     bi_ptr[i] = current_space->array;
406     current_space->array           += nzi;
407     current_space->local_used      += nzi;
408     current_space->local_remaining -= nzi;
409   }
410 #if defined(PETSC_USE_INFO)
411   if (ai[n] != 0) {
412     PetscReal af = ((PetscReal)bi[n])/((PetscReal)ai[n]);
413     ierr = PetscInfo3(A,"Reallocs %D Fill ratio:given %G needed %G\n",reallocs,f,af);CHKERRQ(ierr);
414     ierr = PetscInfo1(A,"Run with -pc_factor_fill %G or use \n",af);CHKERRQ(ierr);
415     ierr = PetscInfo1(A,"PCFactorSetFill(pc,%G);\n",af);CHKERRQ(ierr);
416     ierr = PetscInfo(A,"for best performance.\n");CHKERRQ(ierr);
417   } else {
418     ierr = PetscInfo(A,"Empty matrix\n");CHKERRQ(ierr);
419   }
420 #endif
421 
422   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
423   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
424 
425   /* destroy list of free space and other temporary array(s) */
426   ierr = PetscMalloc((bi[n]+1)*sizeof(PetscInt),&bj);CHKERRQ(ierr);
427   ierr = PetscFreeSpaceContiguous(&free_space,bj);CHKERRQ(ierr);
428   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
429   ierr = PetscFree2(bi_ptr,im);CHKERRQ(ierr);
430 
431   /* put together the new matrix */
432   ierr = MatSeqBAIJSetPreallocation_SeqBAIJ(B,bs,MAT_SKIP_ALLOCATION,PETSC_NULL);CHKERRQ(ierr);
433   ierr = PetscLogObjectParent(B,isicol);CHKERRQ(ierr);
434   b    = (Mat_SeqBAIJ*)(B)->data;
435   b->free_a       = PETSC_TRUE;
436   b->free_ij      = PETSC_TRUE;
437   b->singlemalloc = PETSC_FALSE;
438   ierr          = PetscMalloc((bi[n]+1)*sizeof(MatScalar)*bs2,&b->a);CHKERRQ(ierr);
439   b->j          = bj;
440   b->i          = bi;
441   b->diag       = bdiag;
442   b->free_diag  = PETSC_TRUE;
443   b->ilen       = 0;
444   b->imax       = 0;
445   b->row        = isrow;
446   b->col        = iscol;
447   b->pivotinblocks = (info->pivotinblocks) ? PETSC_TRUE : PETSC_FALSE;
448   ierr          = PetscObjectReference((PetscObject)isrow);CHKERRQ(ierr);
449   ierr          = PetscObjectReference((PetscObject)iscol);CHKERRQ(ierr);
450   b->icol       = isicol;
451   ierr = PetscMalloc((bs*n+bs)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
452   ierr = PetscLogObjectMemory(B,(bi[n]-n)*(sizeof(PetscInt)+sizeof(PetscScalar)*bs2));CHKERRQ(ierr);
453 
454   b->maxnz = b->nz = bi[n] ;
455   (B)->factor                =  MAT_FACTOR_LU;
456   (B)->info.factor_mallocs   = reallocs;
457   (B)->info.fill_ratio_given = f;
458 
459   if (ai[n] != 0) {
460     (B)->info.fill_ratio_needed = ((PetscReal)bi[n])/((PetscReal)ai[n]);
461   } else {
462     (B)->info.fill_ratio_needed = 0.0;
463   }
464 
465   ierr = ISIdentity(isrow,&row_identity);CHKERRQ(ierr);
466   ierr = ISIdentity(iscol,&col_identity);CHKERRQ(ierr);
467   both_identity = (PetscTruth) (row_identity && col_identity);
468   ierr = MatSeqBAIJSetNumericFactorization_inplace(B,both_identity);CHKERRQ(ierr);
469   PetscFunctionReturn(0);
470  }
471 
472