xref: /petsc/src/mat/impls/baij/seq/baijfact3.c (revision 485e8061b00aa6aa607af9dbdc9c890e58f9f145)
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_newdatastruct"
11 /*
12    This is used to set the numeric factorization for both LU and ILU symbolic factorization
13 */
14 PetscErrorCode MatSeqBAIJSetNumericFactorization_newdatastruct(Mat fact,PetscTruth natural)
15 {
16   PetscFunctionBegin;
17   switch (fact->rmap->bs){
18   case 2:
19     fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_2_newdatastruct;
20     break;
21   case 3:
22     fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_3_newdatastruct;
23     break;
24   case 4:
25     fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4_newdatastruct;
26     break;
27   case 5:
28     fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_5_newdatastruct;
29     break;
30   case 6:
31     fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_6_newdatastruct;
32     break;
33   case 7:
34     fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_7_newdatastruct;
35     break;
36   default:
37     fact->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_N_newdatastruct;
38     break;
39   }
40   PetscFunctionReturn(0);
41 }
42 
43 PetscErrorCode MatSeqBAIJSetNumericFactorization(Mat inA,PetscTruth natural)
44 {
45   PetscFunctionBegin;
46   if (natural) {
47     switch (inA->rmap->bs) {
48     case 1:
49       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_1;
50       break;
51     case 2:
52       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_2_NaturalOrdering;
53       break;
54     case 3:
55       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_3_NaturalOrdering;
56       break;
57     case 4:
58 #if defined(PETSC_USE_SCALAR_MAT_SINGLE)
59       {
60         PetscTruth  sse_enabled_local;
61         PetscErrorCode ierr;
62         ierr = PetscSSEIsEnabled(inA->comm,&sse_enabled_local,PETSC_NULL);CHKERRQ(ierr);
63         if (sse_enabled_local) {
64 #  if defined(PETSC_HAVE_SSE)
65           int i,*AJ=a->j,nz=a->nz,n=a->mbs;
66           if (n==(unsigned short)n) {
67             unsigned short *aj=(unsigned short *)AJ;
68             for (i=0;i<nz;i++) {
69               aj[i] = (unsigned short)AJ[i];
70             }
71             inA->ops->setunfactored   = MatSetUnfactored_SeqBAIJ_4_NaturalOrdering_SSE_usj;
72             inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4_NaturalOrdering_SSE_usj;
73             ierr = PetscInfo(inA,"Using special SSE, in-place natural ordering, ushort j index factor BS=4\n");CHKERRQ(ierr);
74           } else {
75         /* Scale the column indices for easier indexing in MatSolve. */
76 /*            for (i=0;i<nz;i++) { */
77 /*              AJ[i] = AJ[i]*4; */
78 /*            } */
79             inA->ops->setunfactored   = MatSetUnfactored_SeqBAIJ_4_NaturalOrdering_SSE;
80             inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4_NaturalOrdering_SSE;
81             ierr = PetscInfo(inA,"Using special SSE, in-place natural ordering, int j index factor BS=4\n");CHKERRQ(ierr);
82           }
83 #  else
84         /* This should never be reached.  If so, problem in PetscSSEIsEnabled. */
85           SETERRQ(PETSC_ERR_SUP,"SSE Hardware unavailable");
86 #  endif
87         } else {
88           inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4_NaturalOrdering;
89         }
90       }
91 #else
92       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4_NaturalOrdering;
93 #endif
94       break;
95     case 5:
96       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_5_NaturalOrdering;
97       break;
98     case 6:
99       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_6_NaturalOrdering;
100       break;
101     case 7:
102       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_7_NaturalOrdering;
103       break;
104     default:
105       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_N;
106       break;
107     }
108   } else {
109     switch (inA->rmap->bs) {
110     case 1:
111       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_1;
112       break;
113     case 2:
114       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_2;
115       break;
116     case 3:
117       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_3;
118       break;
119     case 4:
120       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4;
121       break;
122     case 5:
123       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_5;
124       break;
125     case 6:
126       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_6;
127       break;
128     case 7:
129       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_7;
130       break;
131     default:
132       inA->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_N;
133       break;
134     }
135   }
136   PetscFunctionReturn(0);
137 }
138 
139 /*
140     The symbolic factorization code is identical to that for AIJ format,
141   except for very small changes since this is now a SeqBAIJ datastructure.
142   NOT good code reuse.
143 */
144 #include "petscbt.h"
145 #include "../src/mat/utils/freespace.h"
146 
147 #undef __FUNCT__
148 #define __FUNCT__ "MatLUFactorSymbolic_SeqBAIJ_newdatastruct"
149 PetscErrorCode MatLUFactorSymbolic_SeqBAIJ_newdatastruct(Mat B,Mat A,IS isrow,IS iscol,const MatFactorInfo *info)
150 {
151   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b;
152   PetscInt           n=a->mbs,bs = A->rmap->bs,bs2=a->bs2;
153   PetscTruth         row_identity,col_identity,both_identity;
154   IS                 isicol;
155   PetscErrorCode     ierr;
156   const PetscInt     *r,*ic;
157   PetscInt           i,*ai=a->i,*aj=a->j;
158   PetscInt           *bi,*bj,*ajtmp;
159   PetscInt           *bdiag,row,nnz,nzi,reallocs=0,nzbd,*im;
160   PetscReal          f;
161   PetscInt           nlnk,*lnk,k,**bi_ptr;
162   PetscFreeSpaceList free_space=PETSC_NULL,current_space=PETSC_NULL;
163   PetscBT            lnkbt;
164 
165   PetscFunctionBegin;
166   if (A->rmap->N != A->cmap->N) SETERRQ(PETSC_ERR_ARG_WRONG,"matrix must be square");
167   ierr = ISInvertPermutation(iscol,PETSC_DECIDE,&isicol);CHKERRQ(ierr);
168   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
169   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
170 
171   /* get new row and diagonal pointers, must be allocated separately because they will be given to the Mat_SeqAIJ and freed separately */
172   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bi);CHKERRQ(ierr);
173   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bdiag);CHKERRQ(ierr);
174   bi[0] = bdiag[0] = 0;
175 
176   /* linked list for storing column indices of the active row */
177   nlnk = n + 1;
178   ierr = PetscLLCreate(n,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
179 
180   ierr = PetscMalloc2(n+1,PetscInt**,&bi_ptr,n+1,PetscInt,&im);CHKERRQ(ierr);
181 
182   /* initial FreeSpace size is f*(ai[n]+1) */
183   f = info->fill;
184   ierr = PetscFreeSpaceGet((PetscInt)(f*(ai[n]+1)),&free_space);CHKERRQ(ierr);
185   current_space = free_space;
186 
187   for (i=0; i<n; i++) {
188     /* copy previous fill into linked list */
189     nzi = 0;
190     nnz = ai[r[i]+1] - ai[r[i]];
191     if (!nnz) SETERRQ2(PETSC_ERR_MAT_LU_ZRPVT,"Empty row in matrix: row in original ordering %D in permuted ordering %D",r[i],i);
192     ajtmp = aj + ai[r[i]];
193     ierr = PetscLLAddPerm(nnz,ajtmp,ic,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
194     nzi += nlnk;
195 
196     /* add pivot rows into linked list */
197     row = lnk[n];
198     while (row < i) {
199       nzbd    = bdiag[row] + 1; /* num of entries in the row with column index <= row */
200       ajtmp   = bi_ptr[row] + nzbd; /* points to the entry next to the diagonal */
201       ierr = PetscLLAddSortedLU(ajtmp,row,nlnk,lnk,lnkbt,i,nzbd,im);CHKERRQ(ierr);
202       nzi += nlnk;
203       row  = lnk[row];
204     }
205     bi[i+1] = bi[i] + nzi;
206     im[i]   = nzi;
207 
208     /* mark bdiag */
209     nzbd = 0;
210     nnz  = nzi;
211     k    = lnk[n];
212     while (nnz-- && k < i){
213       nzbd++;
214       k = lnk[k];
215     }
216     bdiag[i] = nzbd; /* note : bdaig[i] = nnzL as input for PetscFreeSpaceContiguous_LU_v2() */
217 
218     /* if free space is not available, make more free space */
219     if (current_space->local_remaining<nzi) {
220       nnz = 2*(n - i)*nzi; /* estimated and max additional space needed */
221       ierr = PetscFreeSpaceGet(nnz,&current_space);CHKERRQ(ierr);
222       reallocs++;
223     }
224 
225     /* copy data into free space, then initialize lnk */
226     ierr = PetscLLClean(n,n,nzi,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
227     bi_ptr[i] = current_space->array;
228     current_space->array           += nzi;
229     current_space->local_used      += nzi;
230     current_space->local_remaining -= nzi;
231   }
232 #if defined(PETSC_USE_INFO)
233   if (ai[n] != 0) {
234     PetscReal af = ((PetscReal)bi[n])/((PetscReal)ai[n]);
235     ierr = PetscInfo3(A,"Reallocs %D Fill ratio:given %G needed %G\n",reallocs,f,af);CHKERRQ(ierr);
236     ierr = PetscInfo1(A,"Run with -pc_factor_fill %G or use \n",af);CHKERRQ(ierr);
237     ierr = PetscInfo1(A,"PCFactorSetFill(pc,%G);\n",af);CHKERRQ(ierr);
238     ierr = PetscInfo(A,"for best performance.\n");CHKERRQ(ierr);
239   } else {
240     ierr = PetscInfo(A,"Empty matrix\n");CHKERRQ(ierr);
241   }
242 #endif
243 
244   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
245   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
246 
247   /* destroy list of free space and other temporary array(s) */
248   ierr = PetscMalloc((bi[n]+1)*sizeof(PetscInt),&bj);CHKERRQ(ierr);
249   ierr = PetscFreeSpaceContiguous_LU_v2(&free_space,bj,n,bi,bdiag);CHKERRQ(ierr);
250   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
251   ierr = PetscFree2(bi_ptr,im);CHKERRQ(ierr);
252 
253   /* put together the new matrix */
254   ierr = MatSeqBAIJSetPreallocation_SeqBAIJ(B,bs,MAT_SKIP_ALLOCATION,PETSC_NULL);CHKERRQ(ierr);
255   ierr = PetscLogObjectParent(B,isicol);CHKERRQ(ierr);
256   b    = (Mat_SeqBAIJ*)(B)->data;
257   b->free_a       = PETSC_TRUE;
258   b->free_ij      = PETSC_TRUE;
259   b->singlemalloc = PETSC_FALSE;
260   ierr          = PetscMalloc((bdiag[0]+1)*sizeof(MatScalar)*bs2,&b->a);CHKERRQ(ierr);
261   b->j          = bj;
262   b->i          = bi;
263   b->diag       = bdiag;
264   b->free_diag  = PETSC_TRUE;
265   b->ilen       = 0;
266   b->imax       = 0;
267   b->row        = isrow;
268   b->col        = iscol;
269   b->pivotinblocks = (info->pivotinblocks) ? PETSC_TRUE : PETSC_FALSE;
270   ierr          = PetscObjectReference((PetscObject)isrow);CHKERRQ(ierr);
271   ierr          = PetscObjectReference((PetscObject)iscol);CHKERRQ(ierr);
272   b->icol       = isicol;
273   ierr = PetscMalloc((bs*n+bs)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
274   ierr = PetscLogObjectMemory(B,(bdiag[0]+1)*(sizeof(PetscInt)+sizeof(PetscScalar)*bs2));CHKERRQ(ierr);
275 
276   b->maxnz = b->nz = bdiag[0]+1;
277   B->factor                =  MAT_FACTOR_LU;
278   B->info.factor_mallocs   = reallocs;
279   B->info.fill_ratio_given = f;
280 
281   if (ai[n] != 0) {
282     B->info.fill_ratio_needed = ((PetscReal)(bdiag[0]+1))/((PetscReal)ai[n]);
283   } else {
284     B->info.fill_ratio_needed = 0.0;
285   }
286 
287   ierr = ISIdentity(isrow,&row_identity);CHKERRQ(ierr);
288   ierr = ISIdentity(iscol,&col_identity);CHKERRQ(ierr);
289   both_identity = (PetscTruth) (row_identity && col_identity);
290   if(both_identity){
291      switch(bs){
292      case 2:
293         B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_2_NaturalOrdering_newdatastruct;
294         B->ops->solve           = MatSolve_SeqBAIJ_2_NaturalOrdering_newdatastruct_v2;
295         break;
296      case 3:
297 	B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_3_NaturalOrdering_newdatastruct;
298         B->ops->solve = MatSolve_SeqBAIJ_3_NaturalOrdering_newdatastruct_v2;
299         break;
300      case 4:
301         B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4_NaturalOrdering_newdatastruct;
302         B->ops->solve = MatSolve_SeqBAIJ_4_NaturalOrdering_newdatastruct_v2;
303         break;
304      case 5:
305         B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_5_NaturalOrdering_newdatastruct;
306         B->ops->solve = MatSolve_SeqBAIJ_5_NaturalOrdering_newdatastruct_v2;
307         break;
308      case 6:
309         B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_6_NaturalOrdering_newdatastruct;
310         B->ops->solve = MatSolve_SeqBAIJ_6_NaturalOrdering_newdatastruct_v2;
311         break;
312      case 7:
313         B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_7_NaturalOrdering_newdatastruct;
314         B->ops->solve = MatSolve_SeqBAIJ_7_NaturalOrdering_newdatastruct_v2;
315         break;
316      default:
317         B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_N_newdatastruct;
318         B->ops->solve = MatSolve_SeqBAIJ_N_NaturalOrdering_newdatastruct_v2;
319       }
320    }
321    else {
322      switch(bs){
323      case 2:
324         B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_2_newdatastruct;
325         B->ops->solve           = MatSolve_SeqBAIJ_2_newdatastruct_v2;
326         break;
327      case 3:
328 	B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_3_newdatastruct;
329         B->ops->solve = MatSolve_SeqBAIJ_3_newdatastruct_v2;
330         break;
331      case 4:
332         B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_4_newdatastruct;
333         B->ops->solve = MatSolve_SeqBAIJ_4_newdatastruct_v2;
334         break;
335      case 5:
336         B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_5_newdatastruct;
337         B->ops->solve = MatSolve_SeqBAIJ_5_newdatastruct_v2;
338         break;
339      case 6:
340         B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_6_newdatastruct;
341         B->ops->solve = MatSolve_SeqBAIJ_6_newdatastruct_v2;
342         break;
343      case 7:
344         B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_7_newdatastruct;
345         B->ops->solve = MatSolve_SeqBAIJ_7_newdatastruct_v2;
346         break;
347      default:
348         B->ops->lufactornumeric = MatLUFactorNumeric_SeqBAIJ_N_newdatastruct;
349         B->ops->solve = MatSolve_SeqBAIJ_N_newdatastruct_v2;
350       }
351    }
352   /*  ierr = MatSeqBAIJSetNumericFactorization(B,both_identity);CHKERRQ(ierr); */
353   PetscFunctionReturn(0);
354  }
355 
356 #undef __FUNCT__
357 #define __FUNCT__ "MatLUFactorSymbolic_SeqBAIJ"
358 PetscErrorCode MatLUFactorSymbolic_SeqBAIJ(Mat B,Mat A,IS isrow,IS iscol,const MatFactorInfo *info)
359 {
360   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b;
361   PetscInt           n=a->mbs,bs = A->rmap->bs,bs2=a->bs2;
362   PetscTruth         row_identity,col_identity,both_identity;
363   IS                 isicol;
364   PetscErrorCode     ierr;
365   const PetscInt     *r,*ic;
366   PetscInt           i,*ai=a->i,*aj=a->j;
367   PetscInt           *bi,*bj,*ajtmp;
368   PetscInt           *bdiag,row,nnz,nzi,reallocs=0,nzbd,*im;
369   PetscReal          f;
370   PetscInt           nlnk,*lnk,k,**bi_ptr;
371   PetscFreeSpaceList free_space=PETSC_NULL,current_space=PETSC_NULL;
372   PetscBT            lnkbt;
373   PetscTruth         newdatastruct=PETSC_FALSE;
374 
375   PetscFunctionBegin;
376   ierr = PetscOptionsGetTruth(PETSC_NULL,"-lu_new",&newdatastruct,PETSC_NULL);CHKERRQ(ierr);
377   if(newdatastruct){
378     ierr = MatLUFactorSymbolic_SeqBAIJ_newdatastruct(B,A,isrow,iscol,info);CHKERRQ(ierr);
379     PetscFunctionReturn(0);
380   }
381 
382   if (A->rmap->N != A->cmap->N) SETERRQ(PETSC_ERR_ARG_WRONG,"matrix must be square");
383   ierr = ISInvertPermutation(iscol,PETSC_DECIDE,&isicol);CHKERRQ(ierr);
384   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
385   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
386 
387   /* get new row and diagonal pointers, must be allocated separately because they will be given to the Mat_SeqAIJ and freed separately */
388   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bi);CHKERRQ(ierr);
389   ierr = PetscMalloc((n+1)*sizeof(PetscInt),&bdiag);CHKERRQ(ierr);
390 
391   bi[0] = bdiag[0] = 0;
392 
393   /* linked list for storing column indices of the active row */
394   nlnk = n + 1;
395   ierr = PetscLLCreate(n,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
396 
397   ierr = PetscMalloc2(n+1,PetscInt**,&bi_ptr,n+1,PetscInt,&im);CHKERRQ(ierr);
398 
399   /* initial FreeSpace size is f*(ai[n]+1) */
400   f = info->fill;
401   ierr = PetscFreeSpaceGet((PetscInt)(f*(ai[n]+1)),&free_space);CHKERRQ(ierr);
402   current_space = free_space;
403 
404   for (i=0; i<n; i++) {
405     /* copy previous fill into linked list */
406     nzi = 0;
407     nnz = ai[r[i]+1] - ai[r[i]];
408     if (!nnz) SETERRQ2(PETSC_ERR_MAT_LU_ZRPVT,"Empty row in matrix: row in original ordering %D in permuted ordering %D",r[i],i);
409     ajtmp = aj + ai[r[i]];
410     ierr = PetscLLAddPerm(nnz,ajtmp,ic,n,nlnk,lnk,lnkbt);CHKERRQ(ierr);
411     nzi += nlnk;
412 
413     /* add pivot rows into linked list */
414     row = lnk[n];
415     while (row < i) {
416       nzbd    = bdiag[row] - bi[row] + 1; /* num of entries in the row with column index <= row */
417       ajtmp   = bi_ptr[row] + nzbd; /* points to the entry next to the diagonal */
418       ierr = PetscLLAddSortedLU(ajtmp,row,nlnk,lnk,lnkbt,i,nzbd,im);CHKERRQ(ierr);
419       nzi += nlnk;
420       row  = lnk[row];
421     }
422     bi[i+1] = bi[i] + nzi;
423     im[i]   = nzi;
424 
425     /* mark bdiag */
426     nzbd = 0;
427     nnz  = nzi;
428     k    = lnk[n];
429     while (nnz-- && k < i){
430       nzbd++;
431       k = lnk[k];
432     }
433     bdiag[i] = bi[i] + nzbd;
434 
435     /* if free space is not available, make more free space */
436     if (current_space->local_remaining<nzi) {
437       nnz = (n - i)*nzi; /* estimated and max additional space needed */
438       ierr = PetscFreeSpaceGet(nnz,&current_space);CHKERRQ(ierr);
439       reallocs++;
440     }
441 
442     /* copy data into free space, then initialize lnk */
443     ierr = PetscLLClean(n,n,nzi,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
444     bi_ptr[i] = current_space->array;
445     current_space->array           += nzi;
446     current_space->local_used      += nzi;
447     current_space->local_remaining -= nzi;
448   }
449 #if defined(PETSC_USE_INFO)
450   if (ai[n] != 0) {
451     PetscReal af = ((PetscReal)bi[n])/((PetscReal)ai[n]);
452     ierr = PetscInfo3(A,"Reallocs %D Fill ratio:given %G needed %G\n",reallocs,f,af);CHKERRQ(ierr);
453     ierr = PetscInfo1(A,"Run with -pc_factor_fill %G or use \n",af);CHKERRQ(ierr);
454     ierr = PetscInfo1(A,"PCFactorSetFill(pc,%G);\n",af);CHKERRQ(ierr);
455     ierr = PetscInfo(A,"for best performance.\n");CHKERRQ(ierr);
456   } else {
457     ierr = PetscInfo(A,"Empty matrix\n");CHKERRQ(ierr);
458   }
459 #endif
460 
461   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
462   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
463 
464   /* destroy list of free space and other temporary array(s) */
465   ierr = PetscMalloc((bi[n]+1)*sizeof(PetscInt),&bj);CHKERRQ(ierr);
466   ierr = PetscFreeSpaceContiguous(&free_space,bj);CHKERRQ(ierr);
467   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
468   ierr = PetscFree2(bi_ptr,im);CHKERRQ(ierr);
469 
470   /* put together the new matrix */
471   ierr = MatSeqBAIJSetPreallocation_SeqBAIJ(B,bs,MAT_SKIP_ALLOCATION,PETSC_NULL);CHKERRQ(ierr);
472   ierr = PetscLogObjectParent(B,isicol);CHKERRQ(ierr);
473   b    = (Mat_SeqBAIJ*)(B)->data;
474   b->free_a       = PETSC_TRUE;
475   b->free_ij      = PETSC_TRUE;
476   b->singlemalloc = PETSC_FALSE;
477   ierr          = PetscMalloc((bi[n]+1)*sizeof(MatScalar)*bs2,&b->a);CHKERRQ(ierr);
478   b->j          = bj;
479   b->i          = bi;
480   b->diag       = bdiag;
481   b->free_diag  = PETSC_TRUE;
482   b->ilen       = 0;
483   b->imax       = 0;
484   b->row        = isrow;
485   b->col        = iscol;
486   b->pivotinblocks = (info->pivotinblocks) ? PETSC_TRUE : PETSC_FALSE;
487   ierr          = PetscObjectReference((PetscObject)isrow);CHKERRQ(ierr);
488   ierr          = PetscObjectReference((PetscObject)iscol);CHKERRQ(ierr);
489   b->icol       = isicol;
490   ierr = PetscMalloc((bs*n+bs)*sizeof(PetscScalar),&b->solve_work);CHKERRQ(ierr);
491   ierr = PetscLogObjectMemory(B,(bi[n]-n)*(sizeof(PetscInt)+sizeof(PetscScalar)*bs2));CHKERRQ(ierr);
492 
493   b->maxnz = b->nz = bi[n] ;
494   (B)->factor                =  MAT_FACTOR_LU;
495   (B)->info.factor_mallocs   = reallocs;
496   (B)->info.fill_ratio_given = f;
497 
498   if (ai[n] != 0) {
499     (B)->info.fill_ratio_needed = ((PetscReal)bi[n])/((PetscReal)ai[n]);
500   } else {
501     (B)->info.fill_ratio_needed = 0.0;
502   }
503 
504   ierr = ISIdentity(isrow,&row_identity);CHKERRQ(ierr);
505   ierr = ISIdentity(iscol,&col_identity);CHKERRQ(ierr);
506   both_identity = (PetscTruth) (row_identity && col_identity);
507   ierr = MatSeqBAIJSetNumericFactorization(B,both_identity);CHKERRQ(ierr);
508   PetscFunctionReturn(0);
509  }
510 
511