Actual source code: sbaijfact.c

petsc-3.7.3 2016-08-01
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  2: #include <../src/mat/impls/baij/seq/baij.h>
  3: #include <../src/mat/impls/sbaij/seq/sbaij.h>
  4: #include <petsc/private/kernels/blockinvert.h>
  5: #include <petscis.h>

  7: /*
  8:   input:
  9:    F -- numeric factor
 10:   output:
 11:    nneg, nzero, npos: matrix inertia
 12: */

 16: PetscErrorCode MatGetInertia_SeqSBAIJ(Mat F,PetscInt *nneig,PetscInt *nzero,PetscInt *npos)
 17: {
 18:   Mat_SeqSBAIJ *fact_ptr = (Mat_SeqSBAIJ*)F->data;
 19:   MatScalar    *dd       = fact_ptr->a;
 20:   PetscInt     mbs       =fact_ptr->mbs,bs=F->rmap->bs,i,nneig_tmp,npos_tmp,*fi = fact_ptr->diag;

 23:   if (bs != 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"No support for bs: %D >1 yet",bs);
 24:   nneig_tmp = 0; npos_tmp = 0;
 25:   for (i=0; i<mbs; i++) {
 26:     if (PetscRealPart(dd[*fi]) > 0.0) npos_tmp++;
 27:     else if (PetscRealPart(dd[*fi]) < 0.0) nneig_tmp++;
 28:     fi++;
 29:   }
 30:   if (nneig) *nneig = nneig_tmp;
 31:   if (npos)  *npos  = npos_tmp;
 32:   if (nzero) *nzero = mbs - nneig_tmp - npos_tmp;
 33:   return(0);
 34: }

 36: /*
 37:   Symbolic U^T*D*U factorization for SBAIJ format. Modified from SSF of YSMP.
 38:   Use Modified Sparse Row (MSR) storage for u and ju. See page 85, "Iterative Methods ..." by Saad.
 39: */
 42: PetscErrorCode MatCholeskyFactorSymbolic_SeqSBAIJ_MSR(Mat F,Mat A,IS perm,const MatFactorInfo *info)
 43: {
 44:   Mat_SeqSBAIJ   *a = (Mat_SeqSBAIJ*)A->data,*b;
 46:   const PetscInt *rip,*ai,*aj;
 47:   PetscInt       i,mbs = a->mbs,*jutmp,bs = A->rmap->bs,bs2=a->bs2;
 48:   PetscInt       m,reallocs = 0,prow;
 49:   PetscInt       *jl,*q,jmin,jmax,juidx,nzk,qm,*iu,*ju,k,j,vj,umax,maxadd;
 50:   PetscReal      f = info->fill;
 51:   PetscBool      perm_identity;

 54:   /* check whether perm is the identity mapping */
 55:   ISIdentity(perm,&perm_identity);
 56:   ISGetIndices(perm,&rip);

 58:   if (perm_identity) { /* without permutation */
 59:     a->permute = PETSC_FALSE;

 61:     ai = a->i; aj = a->j;
 62:   } else {            /* non-trivial permutation */
 63:     a->permute = PETSC_TRUE;

 65:     MatReorderingSeqSBAIJ(A,perm);

 67:     ai = a->inew; aj = a->jnew;
 68:   }

 70:   /* initialization */
 71:   PetscMalloc1(mbs+1,&iu);
 72:   umax  = (PetscInt)(f*ai[mbs] + 1); umax += mbs + 1;
 73:   PetscMalloc1(umax,&ju);
 74:   iu[0] = mbs+1;
 75:   juidx = mbs + 1; /* index for ju */
 76:   /* jl linked list for pivot row -- linked list for col index */
 77:   PetscMalloc2(mbs,&jl,mbs,&q);
 78:   for (i=0; i<mbs; i++) {
 79:     jl[i] = mbs;
 80:     q[i]  = 0;
 81:   }

 83:   /* for each row k */
 84:   for (k=0; k<mbs; k++) {
 85:     for (i=0; i<mbs; i++) q[i] = 0;  /* to be removed! */
 86:     nzk  = 0; /* num. of nz blocks in k-th block row with diagonal block excluded */
 87:     q[k] = mbs;
 88:     /* initialize nonzero structure of k-th row to row rip[k] of A */
 89:     jmin = ai[rip[k]] +1; /* exclude diag[k] */
 90:     jmax = ai[rip[k]+1];
 91:     for (j=jmin; j<jmax; j++) {
 92:       vj = rip[aj[j]]; /* col. value */
 93:       if (vj > k) {
 94:         qm = k;
 95:         do {
 96:           m = qm; qm = q[m];
 97:         } while (qm < vj);
 98:         if (qm == vj) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Duplicate entry in A\n");
 99:         nzk++;
100:         q[m]  = vj;
101:         q[vj] = qm;
102:       } /* if (vj > k) */
103:     } /* for (j=jmin; j<jmax; j++) */

105:     /* modify nonzero structure of k-th row by computing fill-in
106:        for each row i to be merged in */
107:     prow = k;
108:     prow = jl[prow]; /* next pivot row (== mbs for symbolic factorization) */

110:     while (prow < k) {
111:       /* merge row prow into k-th row */
112:       jmin = iu[prow] + 1; jmax = iu[prow+1];
113:       qm   = k;
114:       for (j=jmin; j<jmax; j++) {
115:         vj = ju[j];
116:         do {
117:           m = qm; qm = q[m];
118:         } while (qm < vj);
119:         if (qm != vj) {
120:           nzk++; q[m] = vj; q[vj] = qm; qm = vj;
121:         }
122:       }
123:       prow = jl[prow]; /* next pivot row */
124:     }

126:     /* add k to row list for first nonzero element in k-th row */
127:     if (nzk > 0) {
128:       i     = q[k]; /* col value of first nonzero element in U(k, k+1:mbs-1) */
129:       jl[k] = jl[i]; jl[i] = k;
130:     }
131:     iu[k+1] = iu[k] + nzk;

133:     /* allocate more space to ju if needed */
134:     if (iu[k+1] > umax) {
135:       /* estimate how much additional space we will need */
136:       /* use the strategy suggested by David Hysom <hysom@perch-t.icase.edu> */
137:       /* just double the memory each time */
138:       maxadd = umax;
139:       if (maxadd < nzk) maxadd = (mbs-k)*(nzk+1)/2;
140:       umax += maxadd;

142:       /* allocate a longer ju */
143:       PetscMalloc1(umax,&jutmp);
144:       PetscMemcpy(jutmp,ju,iu[k]*sizeof(PetscInt));
145:       PetscFree(ju);
146:       ju   = jutmp;
147:       reallocs++; /* count how many times we realloc */
148:     }

150:     /* save nonzero structure of k-th row in ju */
151:     i=k;
152:     while (nzk--) {
153:       i           = q[i];
154:       ju[juidx++] = i;
155:     }
156:   }

158: #if defined(PETSC_USE_INFO)
159:   if (ai[mbs] != 0) {
160:     PetscReal af = ((PetscReal)iu[mbs])/((PetscReal)ai[mbs]);
161:     PetscInfo3(A,"Reallocs %D Fill ratio:given %g needed %g\n",reallocs,(double)f,(double)af);
162:     PetscInfo1(A,"Run with -pc_factor_fill %g or use \n",(double)af);
163:     PetscInfo1(A,"PCFactorSetFill(pc,%g);\n",(double)af);
164:     PetscInfo(A,"for best performance.\n");
165:   } else {
166:     PetscInfo(A,"Empty matrix.\n");
167:   }
168: #endif

170:   ISRestoreIndices(perm,&rip);
171:   PetscFree2(jl,q);

173:   /* put together the new matrix */
174:   MatSeqSBAIJSetPreallocation_SeqSBAIJ(F,bs,MAT_SKIP_ALLOCATION,NULL);

176:   /* PetscLogObjectParent((PetscObject)B,(PetscObject)iperm); */
177:   b                = (Mat_SeqSBAIJ*)(F)->data;
178:   b->singlemalloc  = PETSC_FALSE;
179:   b->free_a        = PETSC_TRUE;
180:   b->free_ij       = PETSC_TRUE;

182:   PetscMalloc1((iu[mbs]+1)*bs2,&b->a);
183:   b->j    = ju;
184:   b->i    = iu;
185:   b->diag = 0;
186:   b->ilen = 0;
187:   b->imax = 0;
188:   b->row  = perm;

190:   b->pivotinblocks = PETSC_FALSE; /* need to get from MatFactorInfo */

192:   PetscObjectReference((PetscObject)perm);

194:   b->icol = perm;
195:   PetscObjectReference((PetscObject)perm);
196:   PetscMalloc1(bs*mbs+bs,&b->solve_work);
197:   /* In b structure:  Free imax, ilen, old a, old j.
198:      Allocate idnew, solve_work, new a, new j */
199:   PetscLogObjectMemory((PetscObject)F,(iu[mbs]-mbs)*(sizeof(PetscInt)+sizeof(MatScalar)));
200:   b->maxnz = b->nz = iu[mbs];

202:   (F)->info.factor_mallocs   = reallocs;
203:   (F)->info.fill_ratio_given = f;
204:   if (ai[mbs] != 0) {
205:     (F)->info.fill_ratio_needed = ((PetscReal)iu[mbs])/((PetscReal)ai[mbs]);
206:   } else {
207:     (F)->info.fill_ratio_needed = 0.0;
208:   }
209:   MatSeqSBAIJSetNumericFactorization_inplace(F,perm_identity);
210:   return(0);
211: }
212: /*
213:     Symbolic U^T*D*U factorization for SBAIJ format.
214:     See MatICCFactorSymbolic_SeqAIJ() for description of its data structure.
215: */
216: #include <petscbt.h>
217: #include <../src/mat/utils/freespace.h>
220: PetscErrorCode MatCholeskyFactorSymbolic_SeqSBAIJ(Mat fact,Mat A,IS perm,const MatFactorInfo *info)
221: {
222:   Mat_SeqSBAIJ       *a = (Mat_SeqSBAIJ*)A->data;
223:   Mat_SeqSBAIJ       *b;
224:   PetscErrorCode     ierr;
225:   PetscBool          perm_identity,missing;
226:   PetscReal          fill = info->fill;
227:   const PetscInt     *rip,*ai=a->i,*aj=a->j;
228:   PetscInt           i,mbs=a->mbs,bs=A->rmap->bs,reallocs=0,prow;
229:   PetscInt           *jl,jmin,jmax,nzk,*ui,k,j,*il,nextprow;
230:   PetscInt           nlnk,*lnk,ncols,*cols,*uj,**ui_ptr,*uj_ptr,*udiag;
231:   PetscFreeSpaceList free_space=NULL,current_space=NULL;
232:   PetscBT            lnkbt;

235:   if (A->rmap->n != A->cmap->n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Must be square matrix, rows %D columns %D",A->rmap->n,A->cmap->n);
236:   MatMissingDiagonal(A,&missing,&i);
237:   if (missing) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Matrix is missing diagonal entry %D",i);
238:   if (bs > 1) {
239:     MatCholeskyFactorSymbolic_SeqSBAIJ_inplace(fact,A,perm,info);
240:     return(0);
241:   }

243:   /* check whether perm is the identity mapping */
244:   ISIdentity(perm,&perm_identity);
245:   if (!perm_identity) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Matrix reordering is not supported for sbaij matrix. Use aij format");
246:   a->permute = PETSC_FALSE;
247:   ISGetIndices(perm,&rip);

249:   /* initialization */
250:   PetscMalloc1(mbs+1,&ui);
251:   PetscMalloc1(mbs+1,&udiag);
252:   ui[0] = 0;

254:   /* jl: linked list for storing indices of the pivot rows
255:      il: il[i] points to the 1st nonzero entry of U(i,k:mbs-1) */
256:   PetscMalloc4(mbs,&ui_ptr,mbs,&il,mbs,&jl,mbs,&cols);
257:   for (i=0; i<mbs; i++) {
258:     jl[i] = mbs; il[i] = 0;
259:   }

261:   /* create and initialize a linked list for storing column indices of the active row k */
262:   nlnk = mbs + 1;
263:   PetscLLCreate(mbs,mbs,nlnk,lnk,lnkbt);

265:   /* initial FreeSpace size is fill*(ai[mbs]+1) */
266:   PetscFreeSpaceGet(PetscRealIntMultTruncate(fill,ai[mbs]+1),&free_space);
267:   current_space = free_space;

269:   for (k=0; k<mbs; k++) {  /* for each active row k */
270:     /* initialize lnk by the column indices of row rip[k] of A */
271:     nzk   = 0;
272:     ncols = ai[k+1] - ai[k];
273:     if (!ncols) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_MAT_CH_ZRPVT,"Empty row %D in matrix ",k);
274:     for (j=0; j<ncols; j++) {
275:       i       = *(aj + ai[k] + j);
276:       cols[j] = i;
277:     }
278:     PetscLLAdd(ncols,cols,mbs,nlnk,lnk,lnkbt);
279:     nzk += nlnk;

281:     /* update lnk by computing fill-in for each pivot row to be merged in */
282:     prow = jl[k]; /* 1st pivot row */

284:     while (prow < k) {
285:       nextprow = jl[prow];
286:       /* merge prow into k-th row */
287:       jmin   = il[prow] + 1; /* index of the 2nd nzero entry in U(prow,k:mbs-1) */
288:       jmax   = ui[prow+1];
289:       ncols  = jmax-jmin;
290:       uj_ptr = ui_ptr[prow] + jmin - ui[prow]; /* points to the 2nd nzero entry in U(prow,k:mbs-1) */
291:       PetscLLAddSorted(ncols,uj_ptr,mbs,nlnk,lnk,lnkbt);
292:       nzk   += nlnk;

294:       /* update il and jl for prow */
295:       if (jmin < jmax) {
296:         il[prow] = jmin;
297:         j        = *uj_ptr; jl[prow] = jl[j]; jl[j] = prow;
298:       }
299:       prow = nextprow;
300:     }

302:     /* if free space is not available, make more free space */
303:     if (current_space->local_remaining<nzk) {
304:       i    = mbs - k + 1; /* num of unfactored rows */
305:       i    = PetscIntMultTruncate(i,PetscMin(nzk, i-1)); /* i*nzk, i*(i-1): estimated and max additional space needed */
306:       PetscFreeSpaceGet(i,&current_space);
307:       reallocs++;
308:     }

310:     /* copy data into free space, then initialize lnk */
311:     PetscLLClean(mbs,mbs,nzk,lnk,current_space->array,lnkbt);

313:     /* add the k-th row into il and jl */
314:     if (nzk > 1) {
315:       i     = current_space->array[1]; /* col value of the first nonzero element in U(k, k+1:mbs-1) */
316:       jl[k] = jl[i]; jl[i] = k;
317:       il[k] = ui[k] + 1;
318:     }
319:     ui_ptr[k] = current_space->array;

321:     current_space->array           += nzk;
322:     current_space->local_used      += nzk;
323:     current_space->local_remaining -= nzk;

325:     ui[k+1] = ui[k] + nzk;
326:   }

328:   ISRestoreIndices(perm,&rip);
329:   PetscFree4(ui_ptr,il,jl,cols);

331:   /* destroy list of free space and other temporary array(s) */
332:   PetscMalloc1(ui[mbs]+1,&uj);
333:   PetscFreeSpaceContiguous_Cholesky(&free_space,uj,mbs,ui,udiag); /* store matrix factor */
334:   PetscLLDestroy(lnk,lnkbt);

336:   /* put together the new matrix in MATSEQSBAIJ format */
337:   MatSeqSBAIJSetPreallocation_SeqSBAIJ(fact,bs,MAT_SKIP_ALLOCATION,NULL);

339:   b               = (Mat_SeqSBAIJ*)fact->data;
340:   b->singlemalloc = PETSC_FALSE;
341:   b->free_a       = PETSC_TRUE;
342:   b->free_ij      = PETSC_TRUE;

344:   PetscMalloc1(ui[mbs]+1,&b->a);

346:   b->j         = uj;
347:   b->i         = ui;
348:   b->diag      = udiag;
349:   b->free_diag = PETSC_TRUE;
350:   b->ilen      = 0;
351:   b->imax      = 0;
352:   b->row       = perm;
353:   b->icol      = perm;

355:   PetscObjectReference((PetscObject)perm);
356:   PetscObjectReference((PetscObject)perm);

358:   b->pivotinblocks = PETSC_FALSE; /* need to get from MatFactorInfo */

360:   PetscMalloc1(mbs+1,&b->solve_work);
361:   PetscLogObjectMemory((PetscObject)fact,ui[mbs]*(sizeof(PetscInt)+sizeof(MatScalar)));

363:   b->maxnz = b->nz = ui[mbs];

365:   fact->info.factor_mallocs   = reallocs;
366:   fact->info.fill_ratio_given = fill;
367:   if (ai[mbs] != 0) {
368:     fact->info.fill_ratio_needed = ((PetscReal)ui[mbs])/ai[mbs];
369:   } else {
370:     fact->info.fill_ratio_needed = 0.0;
371:   }
372: #if defined(PETSC_USE_INFO)
373:   if (ai[mbs] != 0) {
374:     PetscReal af = fact->info.fill_ratio_needed;
375:     PetscInfo3(A,"Reallocs %D Fill ratio:given %g needed %g\n",reallocs,(double)fill,(double)af);
376:     PetscInfo1(A,"Run with -pc_factor_fill %g or use \n",(double)af);
377:     PetscInfo1(A,"PCFactorSetFill(pc,%g) for best performance.\n",(double)af);
378:   } else {
379:     PetscInfo(A,"Empty matrix.\n");
380:   }
381: #endif
382:   fact->ops->choleskyfactornumeric = MatCholeskyFactorNumeric_SeqSBAIJ_1_NaturalOrdering;
383:   return(0);
384: }

388: PetscErrorCode MatCholeskyFactorSymbolic_SeqSBAIJ_inplace(Mat fact,Mat A,IS perm,const MatFactorInfo *info)
389: {
390:   Mat_SeqSBAIJ       *a = (Mat_SeqSBAIJ*)A->data;
391:   Mat_SeqSBAIJ       *b;
392:   PetscErrorCode     ierr;
393:   PetscBool          perm_identity,missing;
394:   PetscReal          fill = info->fill;
395:   const PetscInt     *rip,*ai,*aj;
396:   PetscInt           i,mbs=a->mbs,bs=A->rmap->bs,reallocs=0,prow,d;
397:   PetscInt           *jl,jmin,jmax,nzk,*ui,k,j,*il,nextprow;
398:   PetscInt           nlnk,*lnk,ncols,*cols,*uj,**ui_ptr,*uj_ptr;
399:   PetscFreeSpaceList free_space=NULL,current_space=NULL;
400:   PetscBT            lnkbt;

403:   MatMissingDiagonal(A,&missing,&d);
404:   if (missing) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Matrix is missing diagonal entry %D",d);

406:   /*
407:    This code originally uses Modified Sparse Row (MSR) storage
408:    (see page 85, "Iterative Methods ..." by Saad) for the output matrix B - bad choise!
409:    Then it is rewritten so the factor B takes seqsbaij format. However the associated
410:    MatCholeskyFactorNumeric_() have not been modified for the cases of bs>1 or !perm_identity,
411:    thus the original code in MSR format is still used for these cases.
412:    The code below should replace MatCholeskyFactorSymbolic_SeqSBAIJ_MSR() whenever
413:    MatCholeskyFactorNumeric_() is modified for using sbaij symbolic factor.
414:   */
415:   if (bs > 1) {
416:     MatCholeskyFactorSymbolic_SeqSBAIJ_MSR(fact,A,perm,info);
417:     return(0);
418:   }

420:   /* check whether perm is the identity mapping */
421:   ISIdentity(perm,&perm_identity);

423:   if (perm_identity) {
424:     a->permute = PETSC_FALSE;

426:     ai = a->i; aj = a->j;
427:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Matrix reordering is not supported for sbaij matrix. Use aij format");
428:   ISGetIndices(perm,&rip);

430:   /* initialization */
431:   PetscMalloc1(mbs+1,&ui);
432:   ui[0] = 0;

434:   /* jl: linked list for storing indices of the pivot rows
435:      il: il[i] points to the 1st nonzero entry of U(i,k:mbs-1) */
436:   PetscMalloc4(mbs,&ui_ptr,mbs,&il,mbs,&jl,mbs,&cols);
437:   for (i=0; i<mbs; i++) {
438:     jl[i] = mbs; il[i] = 0;
439:   }

441:   /* create and initialize a linked list for storing column indices of the active row k */
442:   nlnk = mbs + 1;
443:   PetscLLCreate(mbs,mbs,nlnk,lnk,lnkbt);

445:   /* initial FreeSpace size is fill*(ai[mbs]+1) */
446:   PetscFreeSpaceGet(PetscRealIntMultTruncate(fill,ai[mbs]+1),&free_space);
447:   current_space = free_space;

449:   for (k=0; k<mbs; k++) {  /* for each active row k */
450:     /* initialize lnk by the column indices of row rip[k] of A */
451:     nzk   = 0;
452:     ncols = ai[rip[k]+1] - ai[rip[k]];
453:     for (j=0; j<ncols; j++) {
454:       i       = *(aj + ai[rip[k]] + j);
455:       cols[j] = rip[i];
456:     }
457:     PetscLLAdd(ncols,cols,mbs,nlnk,lnk,lnkbt);
458:     nzk += nlnk;

460:     /* update lnk by computing fill-in for each pivot row to be merged in */
461:     prow = jl[k]; /* 1st pivot row */

463:     while (prow < k) {
464:       nextprow = jl[prow];
465:       /* merge prow into k-th row */
466:       jmin   = il[prow] + 1; /* index of the 2nd nzero entry in U(prow,k:mbs-1) */
467:       jmax   = ui[prow+1];
468:       ncols  = jmax-jmin;
469:       uj_ptr = ui_ptr[prow] + jmin - ui[prow]; /* points to the 2nd nzero entry in U(prow,k:mbs-1) */
470:       PetscLLAddSorted(ncols,uj_ptr,mbs,nlnk,lnk,lnkbt);
471:       nzk   += nlnk;

473:       /* update il and jl for prow */
474:       if (jmin < jmax) {
475:         il[prow] = jmin;

477:         j = *uj_ptr; jl[prow] = jl[j]; jl[j] = prow;
478:       }
479:       prow = nextprow;
480:     }

482:     /* if free space is not available, make more free space */
483:     if (current_space->local_remaining<nzk) {
484:       i    = mbs - k + 1; /* num of unfactored rows */
485:       i    = PetscMin(PetscIntMultTruncate(i,nzk), PetscIntMultTruncate(i,i-1)); /* i*nzk, i*(i-1): estimated and max additional space needed */
486:       PetscFreeSpaceGet(i,&current_space);
487:       reallocs++;
488:     }

490:     /* copy data into free space, then initialize lnk */
491:     PetscLLClean(mbs,mbs,nzk,lnk,current_space->array,lnkbt);

493:     /* add the k-th row into il and jl */
494:     if (nzk-1 > 0) {
495:       i     = current_space->array[1]; /* col value of the first nonzero element in U(k, k+1:mbs-1) */
496:       jl[k] = jl[i]; jl[i] = k;
497:       il[k] = ui[k] + 1;
498:     }
499:     ui_ptr[k] = current_space->array;

501:     current_space->array           += nzk;
502:     current_space->local_used      += nzk;
503:     current_space->local_remaining -= nzk;

505:     ui[k+1] = ui[k] + nzk;
506:   }

508:   ISRestoreIndices(perm,&rip);
509:   PetscFree4(ui_ptr,il,jl,cols);

511:   /* destroy list of free space and other temporary array(s) */
512:   PetscMalloc1(ui[mbs]+1,&uj);
513:   PetscFreeSpaceContiguous(&free_space,uj);
514:   PetscLLDestroy(lnk,lnkbt);

516:   /* put together the new matrix in MATSEQSBAIJ format */
517:   MatSeqSBAIJSetPreallocation_SeqSBAIJ(fact,bs,MAT_SKIP_ALLOCATION,NULL);

519:   b               = (Mat_SeqSBAIJ*)fact->data;
520:   b->singlemalloc = PETSC_FALSE;
521:   b->free_a       = PETSC_TRUE;
522:   b->free_ij      = PETSC_TRUE;

524:   PetscMalloc1(ui[mbs]+1,&b->a);

526:   b->j    = uj;
527:   b->i    = ui;
528:   b->diag = 0;
529:   b->ilen = 0;
530:   b->imax = 0;
531:   b->row  = perm;

533:   b->pivotinblocks = PETSC_FALSE; /* need to get from MatFactorInfo */

535:   PetscObjectReference((PetscObject)perm);
536:   b->icol  = perm;
537:   PetscObjectReference((PetscObject)perm);
538:   PetscMalloc1(mbs+1,&b->solve_work);
539:   PetscLogObjectMemory((PetscObject)fact,(ui[mbs]-mbs)*(sizeof(PetscInt)+sizeof(MatScalar)));
540:   b->maxnz = b->nz = ui[mbs];

542:   fact->info.factor_mallocs   = reallocs;
543:   fact->info.fill_ratio_given = fill;
544:   if (ai[mbs] != 0) {
545:     fact->info.fill_ratio_needed = ((PetscReal)ui[mbs])/ai[mbs];
546:   } else {
547:     fact->info.fill_ratio_needed = 0.0;
548:   }
549: #if defined(PETSC_USE_INFO)
550:   if (ai[mbs] != 0) {
551:     PetscReal af = fact->info.fill_ratio_needed;
552:     PetscInfo3(A,"Reallocs %D Fill ratio:given %g needed %g\n",reallocs,(double)fill,(double)af);
553:     PetscInfo1(A,"Run with -pc_factor_fill %g or use \n",(double)af);
554:     PetscInfo1(A,"PCFactorSetFill(pc,%g) for best performance.\n",(double)af);
555:   } else {
556:     PetscInfo(A,"Empty matrix.\n");
557:   }
558: #endif
559:   MatSeqSBAIJSetNumericFactorization_inplace(fact,perm_identity);
560:   return(0);
561: }

565: PetscErrorCode MatCholeskyFactorNumeric_SeqSBAIJ_N(Mat C,Mat A,const MatFactorInfo *info)
566: {
567:   Mat_SeqSBAIJ   *a   = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ*)C->data;
568:   IS             perm = b->row;
570:   const PetscInt *ai,*aj,*perm_ptr,mbs=a->mbs,*bi=b->i,*bj=b->j;
571:   PetscInt       i,j;
572:   PetscInt       *a2anew,k,k1,jmin,jmax,*jl,*il,vj,nexti,ili;
573:   PetscInt       bs  =A->rmap->bs,bs2 = a->bs2;
574:   MatScalar      *ba = b->a,*aa,*ap,*dk,*uik;
575:   MatScalar      *u,*diag,*rtmp,*rtmp_ptr;
576:   MatScalar      *work;
577:   PetscInt       *pivots;
578:   PetscBool      allowzeropivot,zeropivotdetected;

581:   /* initialization */
582:   PetscCalloc1(bs2*mbs,&rtmp);
583:   PetscMalloc2(mbs,&il,mbs,&jl);
584:   allowzeropivot = PetscNot(A->erroriffailure);

586:   il[0] = 0;
587:   for (i=0; i<mbs; i++) jl[i] = mbs;
588: 
589:   PetscMalloc3(bs2,&dk,bs2,&uik,bs,&work);
590:   PetscMalloc1(bs,&pivots);

592:   ISGetIndices(perm,&perm_ptr);

594:   /* check permutation */
595:   if (!a->permute) {
596:     ai = a->i; aj = a->j; aa = a->a;
597:   } else {
598:     ai   = a->inew; aj = a->jnew;
599:     PetscMalloc1(bs2*ai[mbs],&aa);
600:     PetscMemcpy(aa,a->a,bs2*ai[mbs]*sizeof(MatScalar));
601:     PetscMalloc1(ai[mbs],&a2anew);
602:     PetscMemcpy(a2anew,a->a2anew,(ai[mbs])*sizeof(PetscInt));

604:     for (i=0; i<mbs; i++) {
605:       jmin = ai[i]; jmax = ai[i+1];
606:       for (j=jmin; j<jmax; j++) {
607:         while (a2anew[j] != j) {
608:           k = a2anew[j]; a2anew[j] = a2anew[k]; a2anew[k] = k;
609:           for (k1=0; k1<bs2; k1++) {
610:             dk[k1]       = aa[k*bs2+k1];
611:             aa[k*bs2+k1] = aa[j*bs2+k1];
612:             aa[j*bs2+k1] = dk[k1];
613:           }
614:         }
615:         /* transform columnoriented blocks that lie in the lower triangle to roworiented blocks */
616:         if (i > aj[j]) {
617:           /* printf("change orientation, row: %d, col: %d\n",i,aj[j]); */
618:           ap = aa + j*bs2;                     /* ptr to the beginning of j-th block of aa */
619:           for (k=0; k<bs2; k++) dk[k] = ap[k]; /* dk <- j-th block of aa */
620:           for (k=0; k<bs; k++) {               /* j-th block of aa <- dk^T */
621:             for (k1=0; k1<bs; k1++) *ap++ = dk[k + bs*k1];
622:           }
623:         }
624:       }
625:     }
626:     PetscFree(a2anew);
627:   }

629:   /* for each row k */
630:   for (k = 0; k<mbs; k++) {

632:     /*initialize k-th row with elements nonzero in row perm(k) of A */
633:     jmin = ai[perm_ptr[k]]; jmax = ai[perm_ptr[k]+1];

635:     ap = aa + jmin*bs2;
636:     for (j = jmin; j < jmax; j++) {
637:       vj       = perm_ptr[aj[j]];   /* block col. index */
638:       rtmp_ptr = rtmp + vj*bs2;
639:       for (i=0; i<bs2; i++) *rtmp_ptr++ = *ap++;
640:     }

642:     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
643:     PetscMemcpy(dk,rtmp+k*bs2,bs2*sizeof(MatScalar));
644:     i    = jl[k]; /* first row to be added to k_th row  */

646:     while (i < k) {
647:       nexti = jl[i]; /* next row to be added to k_th row */

649:       /* compute multiplier */
650:       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */

652:       /* uik = -inv(Di)*U_bar(i,k) */
653:       diag = ba + i*bs2;
654:       u    = ba + ili*bs2;
655:       PetscMemzero(uik,bs2*sizeof(MatScalar));
656:       PetscKernel_A_gets_A_minus_B_times_C(bs,uik,diag,u);

658:       /* update D(k) += -U(i,k)^T * U_bar(i,k) */
659:       PetscKernel_A_gets_A_plus_Btranspose_times_C(bs,dk,uik,u);
660:       PetscLogFlops(4.0*bs*bs2);

662:       /* update -U(i,k) */
663:       PetscMemcpy(ba+ili*bs2,uik,bs2*sizeof(MatScalar));

665:       /* add multiple of row i to k-th row ... */
666:       jmin = ili + 1; jmax = bi[i+1];
667:       if (jmin < jmax) {
668:         for (j=jmin; j<jmax; j++) {
669:           /* rtmp += -U(i,k)^T * U_bar(i,j) */
670:           rtmp_ptr = rtmp + bj[j]*bs2;
671:           u        = ba + j*bs2;
672:           PetscKernel_A_gets_A_plus_Btranspose_times_C(bs,rtmp_ptr,uik,u);
673:         }
674:         PetscLogFlops(2.0*bs*bs2*(jmax-jmin));

676:         /* ... add i to row list for next nonzero entry */
677:         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
678:         j     = bj[jmin];
679:         jl[i] = jl[j]; jl[j] = i; /* update jl */
680:       }
681:       i = nexti;
682:     }

684:     /* save nonzero entries in k-th row of U ... */

686:     /* invert diagonal block */
687:     diag = ba+k*bs2;
688:     PetscMemcpy(diag,dk,bs2*sizeof(MatScalar));

690:     PetscKernel_A_gets_inverse_A(bs,diag,pivots,work,allowzeropivot,&zeropivotdetected);
691:     if (zeropivotdetected) C->errortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;

693:     jmin = bi[k]; jmax = bi[k+1];
694:     if (jmin < jmax) {
695:       for (j=jmin; j<jmax; j++) {
696:         vj       = bj[j];      /* block col. index of U */
697:         u        = ba + j*bs2;
698:         rtmp_ptr = rtmp + vj*bs2;
699:         for (k1=0; k1<bs2; k1++) {
700:           *u++        = *rtmp_ptr;
701:           *rtmp_ptr++ = 0.0;
702:         }
703:       }

705:       /* ... add k to row list for first nonzero entry in k-th row */
706:       il[k] = jmin;
707:       i     = bj[jmin];
708:       jl[k] = jl[i]; jl[i] = k;
709:     }
710:   }

712:   PetscFree(rtmp);
713:   PetscFree2(il,jl);
714:   PetscFree3(dk,uik,work);
715:   PetscFree(pivots);
716:   if (a->permute) {
717:     PetscFree(aa);
718:   }

720:   ISRestoreIndices(perm,&perm_ptr);

722:   C->ops->solve          = MatSolve_SeqSBAIJ_N_inplace;
723:   C->ops->solvetranspose = MatSolve_SeqSBAIJ_N_inplace;
724:   C->ops->forwardsolve   = MatForwardSolve_SeqSBAIJ_N_inplace;
725:   C->ops->backwardsolve  = MatBackwardSolve_SeqSBAIJ_N_inplace;

727:   C->assembled    = PETSC_TRUE;
728:   C->preallocated = PETSC_TRUE;

730:   PetscLogFlops(1.3333*bs*bs2*b->mbs); /* from inverting diagonal blocks */
731:   return(0);
732: }

736: PetscErrorCode MatCholeskyFactorNumeric_SeqSBAIJ_N_NaturalOrdering(Mat C,Mat A,const MatFactorInfo *info)
737: {
738:   Mat_SeqSBAIJ   *a = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ*)C->data;
740:   PetscInt       i,j,mbs=a->mbs,*bi=b->i,*bj=b->j;
741:   PetscInt       *ai,*aj,k,k1,jmin,jmax,*jl,*il,vj,nexti,ili;
742:   PetscInt       bs  =A->rmap->bs,bs2 = a->bs2;
743:   MatScalar      *ba = b->a,*aa,*ap,*dk,*uik;
744:   MatScalar      *u,*diag,*rtmp,*rtmp_ptr;
745:   MatScalar      *work;
746:   PetscInt       *pivots;
747:   PetscBool      allowzeropivot,zeropivotdetected;

750:   PetscCalloc1(bs2*mbs,&rtmp);
751:   PetscMalloc2(mbs,&il,mbs,&jl);
752:   il[0] = 0;
753:   for (i=0; i<mbs; i++) jl[i] = mbs;
754: 
755:   PetscMalloc3(bs2,&dk,bs2,&uik,bs,&work);
756:   PetscMalloc1(bs,&pivots);
757:   allowzeropivot = PetscNot(A->erroriffailure);

759:   ai = a->i; aj = a->j; aa = a->a;

761:   /* for each row k */
762:   for (k = 0; k<mbs; k++) {

764:     /*initialize k-th row with elements nonzero in row k of A */
765:     jmin = ai[k]; jmax = ai[k+1];
766:     ap   = aa + jmin*bs2;
767:     for (j = jmin; j < jmax; j++) {
768:       vj       = aj[j];   /* block col. index */
769:       rtmp_ptr = rtmp + vj*bs2;
770:       for (i=0; i<bs2; i++) *rtmp_ptr++ = *ap++;
771:     }

773:     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
774:     PetscMemcpy(dk,rtmp+k*bs2,bs2*sizeof(MatScalar));
775:     i    = jl[k]; /* first row to be added to k_th row  */

777:     while (i < k) {
778:       nexti = jl[i]; /* next row to be added to k_th row */

780:       /* compute multiplier */
781:       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */

783:       /* uik = -inv(Di)*U_bar(i,k) */
784:       diag = ba + i*bs2;
785:       u    = ba + ili*bs2;
786:       PetscMemzero(uik,bs2*sizeof(MatScalar));
787:       PetscKernel_A_gets_A_minus_B_times_C(bs,uik,diag,u);

789:       /* update D(k) += -U(i,k)^T * U_bar(i,k) */
790:       PetscKernel_A_gets_A_plus_Btranspose_times_C(bs,dk,uik,u);
791:       PetscLogFlops(2.0*bs*bs2);

793:       /* update -U(i,k) */
794:       PetscMemcpy(ba+ili*bs2,uik,bs2*sizeof(MatScalar));

796:       /* add multiple of row i to k-th row ... */
797:       jmin = ili + 1; jmax = bi[i+1];
798:       if (jmin < jmax) {
799:         for (j=jmin; j<jmax; j++) {
800:           /* rtmp += -U(i,k)^T * U_bar(i,j) */
801:           rtmp_ptr = rtmp + bj[j]*bs2;
802:           u        = ba + j*bs2;
803:           PetscKernel_A_gets_A_plus_Btranspose_times_C(bs,rtmp_ptr,uik,u);
804:         }
805:         PetscLogFlops(2.0*bs*bs2*(jmax-jmin));

807:         /* ... add i to row list for next nonzero entry */
808:         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
809:         j     = bj[jmin];
810:         jl[i] = jl[j]; jl[j] = i; /* update jl */
811:       }
812:       i = nexti;
813:     }

815:     /* save nonzero entries in k-th row of U ... */

817:     /* invert diagonal block */
818:     diag = ba+k*bs2;
819:     PetscMemcpy(diag,dk,bs2*sizeof(MatScalar));

821:     PetscKernel_A_gets_inverse_A(bs,diag,pivots,work,allowzeropivot,&zeropivotdetected);
822:     if (zeropivotdetected) C->errortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;

824:     jmin = bi[k]; jmax = bi[k+1];
825:     if (jmin < jmax) {
826:       for (j=jmin; j<jmax; j++) {
827:         vj       = bj[j];      /* block col. index of U */
828:         u        = ba + j*bs2;
829:         rtmp_ptr = rtmp + vj*bs2;
830:         for (k1=0; k1<bs2; k1++) {
831:           *u++        = *rtmp_ptr;
832:           *rtmp_ptr++ = 0.0;
833:         }
834:       }

836:       /* ... add k to row list for first nonzero entry in k-th row */
837:       il[k] = jmin;
838:       i     = bj[jmin];
839:       jl[k] = jl[i]; jl[i] = k;
840:     }
841:   }

843:   PetscFree(rtmp);
844:   PetscFree2(il,jl);
845:   PetscFree3(dk,uik,work);
846:   PetscFree(pivots);

848:   C->ops->solve          = MatSolve_SeqSBAIJ_N_NaturalOrdering_inplace;
849:   C->ops->solvetranspose = MatSolve_SeqSBAIJ_N_NaturalOrdering_inplace;
850:   C->ops->forwardsolve   = MatForwardSolve_SeqSBAIJ_N_NaturalOrdering_inplace;
851:   C->ops->backwardsolve  = MatBackwardSolve_SeqSBAIJ_N_NaturalOrdering_inplace;
852:   C->assembled           = PETSC_TRUE;
853:   C->preallocated        = PETSC_TRUE;

855:   PetscLogFlops(1.3333*bs*bs2*b->mbs); /* from inverting diagonal blocks */
856:   return(0);
857: }

859: /*
860:     Numeric U^T*D*U factorization for SBAIJ format. Modified from SNF of YSMP.
861:     Version for blocks 2 by 2.
862: */
865: PetscErrorCode MatCholeskyFactorNumeric_SeqSBAIJ_2(Mat C,Mat A,const MatFactorInfo *info)
866: {
867:   Mat_SeqSBAIJ   *a   = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ*)C->data;
868:   IS             perm = b->row;
870:   const PetscInt *ai,*aj,*perm_ptr;
871:   PetscInt       i,j,mbs=a->mbs,*bi=b->i,*bj=b->j;
872:   PetscInt       *a2anew,k,k1,jmin,jmax,*jl,*il,vj,nexti,ili;
873:   MatScalar      *ba = b->a,*aa,*ap;
874:   MatScalar      *u,*diag,*rtmp,*rtmp_ptr,dk[4],uik[4];
875:   PetscReal      shift = info->shiftamount;
876:   PetscBool      allowzeropivot,zeropivotdetected;

879:   allowzeropivot = PetscNot(A->erroriffailure);

881:   /* initialization */
882:   /* il and jl record the first nonzero element in each row of the accessing
883:      window U(0:k, k:mbs-1).
884:      jl:    list of rows to be added to uneliminated rows
885:             i>= k: jl(i) is the first row to be added to row i
886:             i<  k: jl(i) is the row following row i in some list of rows
887:             jl(i) = mbs indicates the end of a list
888:      il(i): points to the first nonzero element in columns k,...,mbs-1 of
889:             row i of U */
890:   PetscCalloc1(4*mbs,&rtmp);
891:   PetscMalloc2(mbs,&il,mbs,&jl);
892:   il[0] = 0;
893:   for (i=0; i<mbs; i++) jl[i] = mbs;
894: 
895:   ISGetIndices(perm,&perm_ptr);

897:   /* check permutation */
898:   if (!a->permute) {
899:     ai = a->i; aj = a->j; aa = a->a;
900:   } else {
901:     ai   = a->inew; aj = a->jnew;
902:     PetscMalloc1(4*ai[mbs],&aa);
903:     PetscMemcpy(aa,a->a,4*ai[mbs]*sizeof(MatScalar));
904:     PetscMalloc1(ai[mbs],&a2anew);
905:     PetscMemcpy(a2anew,a->a2anew,(ai[mbs])*sizeof(PetscInt));

907:     for (i=0; i<mbs; i++) {
908:       jmin = ai[i]; jmax = ai[i+1];
909:       for (j=jmin; j<jmax; j++) {
910:         while (a2anew[j] != j) {
911:           k = a2anew[j]; a2anew[j] = a2anew[k]; a2anew[k] = k;
912:           for (k1=0; k1<4; k1++) {
913:             dk[k1]     = aa[k*4+k1];
914:             aa[k*4+k1] = aa[j*4+k1];
915:             aa[j*4+k1] = dk[k1];
916:           }
917:         }
918:         /* transform columnoriented blocks that lie in the lower triangle to roworiented blocks */
919:         if (i > aj[j]) {
920:           /* printf("change orientation, row: %d, col: %d\n",i,aj[j]); */
921:           ap    = aa + j*4;  /* ptr to the beginning of the block */
922:           dk[1] = ap[1];     /* swap ap[1] and ap[2] */
923:           ap[1] = ap[2];
924:           ap[2] = dk[1];
925:         }
926:       }
927:     }
928:     PetscFree(a2anew);
929:   }

931:   /* for each row k */
932:   for (k = 0; k<mbs; k++) {

934:     /*initialize k-th row with elements nonzero in row perm(k) of A */
935:     jmin = ai[perm_ptr[k]]; jmax = ai[perm_ptr[k]+1];
936:     ap   = aa + jmin*4;
937:     for (j = jmin; j < jmax; j++) {
938:       vj       = perm_ptr[aj[j]];   /* block col. index */
939:       rtmp_ptr = rtmp + vj*4;
940:       for (i=0; i<4; i++) *rtmp_ptr++ = *ap++;
941:     }

943:     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
944:     PetscMemcpy(dk,rtmp+k*4,4*sizeof(MatScalar));
945:     i    = jl[k]; /* first row to be added to k_th row  */

947:     while (i < k) {
948:       nexti = jl[i]; /* next row to be added to k_th row */

950:       /* compute multiplier */
951:       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */

953:       /* uik = -inv(Di)*U_bar(i,k): - ba[ili]*ba[i] */
954:       diag   = ba + i*4;
955:       u      = ba + ili*4;
956:       uik[0] = -(diag[0]*u[0] + diag[2]*u[1]);
957:       uik[1] = -(diag[1]*u[0] + diag[3]*u[1]);
958:       uik[2] = -(diag[0]*u[2] + diag[2]*u[3]);
959:       uik[3] = -(diag[1]*u[2] + diag[3]*u[3]);

961:       /* update D(k) += -U(i,k)^T * U_bar(i,k): dk += uik*ba[ili] */
962:       dk[0] += uik[0]*u[0] + uik[1]*u[1];
963:       dk[1] += uik[2]*u[0] + uik[3]*u[1];
964:       dk[2] += uik[0]*u[2] + uik[1]*u[3];
965:       dk[3] += uik[2]*u[2] + uik[3]*u[3];

967:       PetscLogFlops(16.0*2.0);

969:       /* update -U(i,k): ba[ili] = uik */
970:       PetscMemcpy(ba+ili*4,uik,4*sizeof(MatScalar));

972:       /* add multiple of row i to k-th row ... */
973:       jmin = ili + 1; jmax = bi[i+1];
974:       if (jmin < jmax) {
975:         for (j=jmin; j<jmax; j++) {
976:           /* rtmp += -U(i,k)^T * U_bar(i,j): rtmp[bj[j]] += uik*ba[j]; */
977:           rtmp_ptr     = rtmp + bj[j]*4;
978:           u            = ba + j*4;
979:           rtmp_ptr[0] += uik[0]*u[0] + uik[1]*u[1];
980:           rtmp_ptr[1] += uik[2]*u[0] + uik[3]*u[1];
981:           rtmp_ptr[2] += uik[0]*u[2] + uik[1]*u[3];
982:           rtmp_ptr[3] += uik[2]*u[2] + uik[3]*u[3];
983:         }
984:         PetscLogFlops(16.0*(jmax-jmin));

986:         /* ... add i to row list for next nonzero entry */
987:         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
988:         j     = bj[jmin];
989:         jl[i] = jl[j]; jl[j] = i; /* update jl */
990:       }
991:       i = nexti;
992:     }

994:     /* save nonzero entries in k-th row of U ... */

996:     /* invert diagonal block */
997:     diag = ba+k*4;
998:     PetscMemcpy(diag,dk,4*sizeof(MatScalar));
999:     PetscKernel_A_gets_inverse_A_2(diag,shift,allowzeropivot,&zeropivotdetected);
1000:     if (zeropivotdetected) C->errortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;

1002:     jmin = bi[k]; jmax = bi[k+1];
1003:     if (jmin < jmax) {
1004:       for (j=jmin; j<jmax; j++) {
1005:         vj       = bj[j];      /* block col. index of U */
1006:         u        = ba + j*4;
1007:         rtmp_ptr = rtmp + vj*4;
1008:         for (k1=0; k1<4; k1++) {
1009:           *u++        = *rtmp_ptr;
1010:           *rtmp_ptr++ = 0.0;
1011:         }
1012:       }

1014:       /* ... add k to row list for first nonzero entry in k-th row */
1015:       il[k] = jmin;
1016:       i     = bj[jmin];
1017:       jl[k] = jl[i]; jl[i] = k;
1018:     }
1019:   }

1021:   PetscFree(rtmp);
1022:   PetscFree2(il,jl);
1023:   if (a->permute) {
1024:     PetscFree(aa);
1025:   }
1026:   ISRestoreIndices(perm,&perm_ptr);

1028:   C->ops->solve          = MatSolve_SeqSBAIJ_2_inplace;
1029:   C->ops->solvetranspose = MatSolve_SeqSBAIJ_2_inplace;
1030:   C->assembled           = PETSC_TRUE;
1031:   C->preallocated        = PETSC_TRUE;

1033:   PetscLogFlops(1.3333*8*b->mbs); /* from inverting diagonal blocks */
1034:   return(0);
1035: }

1037: /*
1038:       Version for when blocks are 2 by 2 Using natural ordering
1039: */
1042: PetscErrorCode MatCholeskyFactorNumeric_SeqSBAIJ_2_NaturalOrdering(Mat C,Mat A,const MatFactorInfo *info)
1043: {
1044:   Mat_SeqSBAIJ   *a = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ*)C->data;
1046:   PetscInt       i,j,mbs=a->mbs,*bi=b->i,*bj=b->j;
1047:   PetscInt       *ai,*aj,k,k1,jmin,jmax,*jl,*il,vj,nexti,ili;
1048:   MatScalar      *ba = b->a,*aa,*ap,dk[8],uik[8];
1049:   MatScalar      *u,*diag,*rtmp,*rtmp_ptr;
1050:   PetscReal      shift = info->shiftamount;
1051:   PetscBool      allowzeropivot,zeropivotdetected;

1054:   allowzeropivot = PetscNot(A->erroriffailure);

1056:   /* initialization */
1057:   /* il and jl record the first nonzero element in each row of the accessing
1058:      window U(0:k, k:mbs-1).
1059:      jl:    list of rows to be added to uneliminated rows
1060:             i>= k: jl(i) is the first row to be added to row i
1061:             i<  k: jl(i) is the row following row i in some list of rows
1062:             jl(i) = mbs indicates the end of a list
1063:      il(i): points to the first nonzero element in columns k,...,mbs-1 of
1064:             row i of U */
1065:   PetscCalloc1(4*mbs,&rtmp);
1066:   PetscMalloc2(mbs,&il,mbs,&jl);
1067:   il[0] = 0;
1068:   for (i=0; i<mbs; i++) jl[i] = mbs;
1069: 
1070:   ai = a->i; aj = a->j; aa = a->a;

1072:   /* for each row k */
1073:   for (k = 0; k<mbs; k++) {

1075:     /*initialize k-th row with elements nonzero in row k of A */
1076:     jmin = ai[k]; jmax = ai[k+1];
1077:     ap   = aa + jmin*4;
1078:     for (j = jmin; j < jmax; j++) {
1079:       vj       = aj[j];   /* block col. index */
1080:       rtmp_ptr = rtmp + vj*4;
1081:       for (i=0; i<4; i++) *rtmp_ptr++ = *ap++;
1082:     }

1084:     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
1085:     PetscMemcpy(dk,rtmp+k*4,4*sizeof(MatScalar));
1086:     i    = jl[k]; /* first row to be added to k_th row  */

1088:     while (i < k) {
1089:       nexti = jl[i]; /* next row to be added to k_th row */

1091:       /* compute multiplier */
1092:       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */

1094:       /* uik = -inv(Di)*U_bar(i,k): - ba[ili]*ba[i] */
1095:       diag   = ba + i*4;
1096:       u      = ba + ili*4;
1097:       uik[0] = -(diag[0]*u[0] + diag[2]*u[1]);
1098:       uik[1] = -(diag[1]*u[0] + diag[3]*u[1]);
1099:       uik[2] = -(diag[0]*u[2] + diag[2]*u[3]);
1100:       uik[3] = -(diag[1]*u[2] + diag[3]*u[3]);

1102:       /* update D(k) += -U(i,k)^T * U_bar(i,k): dk += uik*ba[ili] */
1103:       dk[0] += uik[0]*u[0] + uik[1]*u[1];
1104:       dk[1] += uik[2]*u[0] + uik[3]*u[1];
1105:       dk[2] += uik[0]*u[2] + uik[1]*u[3];
1106:       dk[3] += uik[2]*u[2] + uik[3]*u[3];

1108:       PetscLogFlops(16.0*2.0);

1110:       /* update -U(i,k): ba[ili] = uik */
1111:       PetscMemcpy(ba+ili*4,uik,4*sizeof(MatScalar));

1113:       /* add multiple of row i to k-th row ... */
1114:       jmin = ili + 1; jmax = bi[i+1];
1115:       if (jmin < jmax) {
1116:         for (j=jmin; j<jmax; j++) {
1117:           /* rtmp += -U(i,k)^T * U_bar(i,j): rtmp[bj[j]] += uik*ba[j]; */
1118:           rtmp_ptr     = rtmp + bj[j]*4;
1119:           u            = ba + j*4;
1120:           rtmp_ptr[0] += uik[0]*u[0] + uik[1]*u[1];
1121:           rtmp_ptr[1] += uik[2]*u[0] + uik[3]*u[1];
1122:           rtmp_ptr[2] += uik[0]*u[2] + uik[1]*u[3];
1123:           rtmp_ptr[3] += uik[2]*u[2] + uik[3]*u[3];
1124:         }
1125:         PetscLogFlops(16.0*(jmax-jmin));

1127:         /* ... add i to row list for next nonzero entry */
1128:         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
1129:         j     = bj[jmin];
1130:         jl[i] = jl[j]; jl[j] = i; /* update jl */
1131:       }
1132:       i = nexti;
1133:     }

1135:     /* save nonzero entries in k-th row of U ... */

1137:     /* invert diagonal block */
1138:     diag = ba+k*4;
1139:     PetscMemcpy(diag,dk,4*sizeof(MatScalar));
1140:     PetscKernel_A_gets_inverse_A_2(diag,shift,allowzeropivot,&zeropivotdetected);
1141:     if (zeropivotdetected) C->errortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;

1143:     jmin = bi[k]; jmax = bi[k+1];
1144:     if (jmin < jmax) {
1145:       for (j=jmin; j<jmax; j++) {
1146:         vj       = bj[j];      /* block col. index of U */
1147:         u        = ba + j*4;
1148:         rtmp_ptr = rtmp + vj*4;
1149:         for (k1=0; k1<4; k1++) {
1150:           *u++        = *rtmp_ptr;
1151:           *rtmp_ptr++ = 0.0;
1152:         }
1153:       }

1155:       /* ... add k to row list for first nonzero entry in k-th row */
1156:       il[k] = jmin;
1157:       i     = bj[jmin];
1158:       jl[k] = jl[i]; jl[i] = k;
1159:     }
1160:   }

1162:   PetscFree(rtmp);
1163:   PetscFree2(il,jl);

1165:   C->ops->solve          = MatSolve_SeqSBAIJ_2_NaturalOrdering_inplace;
1166:   C->ops->solvetranspose = MatSolve_SeqSBAIJ_2_NaturalOrdering_inplace;
1167:   C->ops->forwardsolve   = MatForwardSolve_SeqSBAIJ_2_NaturalOrdering_inplace;
1168:   C->ops->backwardsolve  = MatBackwardSolve_SeqSBAIJ_2_NaturalOrdering_inplace;
1169:   C->assembled           = PETSC_TRUE;
1170:   C->preallocated        = PETSC_TRUE;

1172:   PetscLogFlops(1.3333*8*b->mbs); /* from inverting diagonal blocks */
1173:   return(0);
1174: }

1176: /*
1177:     Numeric U^T*D*U factorization for SBAIJ format.
1178:     Version for blocks are 1 by 1.
1179: */
1182: PetscErrorCode MatCholeskyFactorNumeric_SeqSBAIJ_1_inplace(Mat C,Mat A,const MatFactorInfo *info)
1183: {
1184:   Mat_SeqSBAIJ   *a=(Mat_SeqSBAIJ*)A->data,*b=(Mat_SeqSBAIJ*)C->data;
1185:   IS             ip=b->row;
1187:   const PetscInt *ai,*aj,*rip;
1188:   PetscInt       *a2anew,i,j,mbs=a->mbs,*bi=b->i,*bj=b->j,*bcol;
1189:   PetscInt       k,jmin,jmax,*jl,*il,col,nexti,ili,nz;
1190:   MatScalar      *rtmp,*ba=b->a,*bval,*aa,dk,uikdi;
1191:   PetscReal      rs;
1192:   FactorShiftCtx sctx;

1195:   /* MatPivotSetUp(): initialize shift context sctx */
1196:   PetscMemzero(&sctx,sizeof(FactorShiftCtx));

1198:   ISGetIndices(ip,&rip);
1199:   if (!a->permute) {
1200:     ai = a->i; aj = a->j; aa = a->a;
1201:   } else {
1202:     ai     = a->inew; aj = a->jnew;
1203:     nz     = ai[mbs];
1204:     PetscMalloc1(nz,&aa);
1205:     a2anew = a->a2anew;
1206:     bval   = a->a;
1207:     for (j=0; j<nz; j++) {
1208:       aa[a2anew[j]] = *(bval++);
1209:     }
1210:   }

1212:   /* initialization */
1213:   /* il and jl record the first nonzero element in each row of the accessing
1214:      window U(0:k, k:mbs-1).
1215:      jl:    list of rows to be added to uneliminated rows
1216:             i>= k: jl(i) is the first row to be added to row i
1217:             i<  k: jl(i) is the row following row i in some list of rows
1218:             jl(i) = mbs indicates the end of a list
1219:      il(i): points to the first nonzero element in columns k,...,mbs-1 of
1220:             row i of U */
1221:   PetscMalloc3(mbs,&rtmp,mbs,&il,mbs,&jl);

1223:   do {
1224:     sctx.newshift = PETSC_FALSE;
1225:     il[0] = 0;
1226:     for (i=0; i<mbs; i++) {
1227:       rtmp[i] = 0.0; jl[i] = mbs;
1228:     }

1230:     for (k = 0; k<mbs; k++) {
1231:       /*initialize k-th row by the perm[k]-th row of A */
1232:       jmin = ai[rip[k]]; jmax = ai[rip[k]+1];
1233:       bval = ba + bi[k];
1234:       for (j = jmin; j < jmax; j++) {
1235:         col       = rip[aj[j]];
1236:         rtmp[col] = aa[j];
1237:         *bval++   = 0.0; /* for in-place factorization */
1238:       }

1240:       /* shift the diagonal of the matrix */
1241:       if (sctx.nshift) rtmp[k] += sctx.shift_amount;

1243:       /* modify k-th row by adding in those rows i with U(i,k)!=0 */
1244:       dk = rtmp[k];
1245:       i  = jl[k]; /* first row to be added to k_th row  */

1247:       while (i < k) {
1248:         nexti = jl[i]; /* next row to be added to k_th row */

1250:         /* compute multiplier, update diag(k) and U(i,k) */
1251:         ili     = il[i]; /* index of first nonzero element in U(i,k:bms-1) */
1252:         uikdi   = -ba[ili]*ba[bi[i]]; /* diagonal(k) */
1253:         dk     += uikdi*ba[ili];
1254:         ba[ili] = uikdi; /* -U(i,k) */

1256:         /* add multiple of row i to k-th row */
1257:         jmin = ili + 1; jmax = bi[i+1];
1258:         if (jmin < jmax) {
1259:           for (j=jmin; j<jmax; j++) rtmp[bj[j]] += uikdi*ba[j];
1260:           PetscLogFlops(2.0*(jmax-jmin));

1262:           /* update il and jl for row i */
1263:           il[i] = jmin;
1264:           j     = bj[jmin]; jl[i] = jl[j]; jl[j] = i;
1265:         }
1266:         i = nexti;
1267:       }

1269:       /* shift the diagonals when zero pivot is detected */
1270:       /* compute rs=sum of abs(off-diagonal) */
1271:       rs   = 0.0;
1272:       jmin = bi[k]+1;
1273:       nz   = bi[k+1] - jmin;
1274:       if (nz) {
1275:         bcol = bj + jmin;
1276:         while (nz--) {
1277:           rs += PetscAbsScalar(rtmp[*bcol]);
1278:           bcol++;
1279:         }
1280:       }

1282:       sctx.rs = rs;
1283:       sctx.pv = dk;
1284:       MatPivotCheck(C,A,info,&sctx,k);
1285:       if (sctx.newshift) break;    /* sctx.shift_amount is updated */
1286:       dk = sctx.pv;

1288:       /* copy data into U(k,:) */
1289:       ba[bi[k]] = 1.0/dk; /* U(k,k) */
1290:       jmin      = bi[k]+1; jmax = bi[k+1];
1291:       if (jmin < jmax) {
1292:         for (j=jmin; j<jmax; j++) {
1293:           col = bj[j]; ba[j] = rtmp[col]; rtmp[col] = 0.0;
1294:         }
1295:         /* add the k-th row into il and jl */
1296:         il[k] = jmin;
1297:         i     = bj[jmin]; jl[k] = jl[i]; jl[i] = k;
1298:       }
1299:     }
1300:   } while (sctx.newshift);
1301:   PetscFree3(rtmp,il,jl);
1302:   if (a->permute) {PetscFree(aa);}

1304:   ISRestoreIndices(ip,&rip);

1306:   C->ops->solve          = MatSolve_SeqSBAIJ_1_inplace;
1307:   C->ops->solves         = MatSolves_SeqSBAIJ_1_inplace;
1308:   C->ops->solvetranspose = MatSolve_SeqSBAIJ_1_inplace;
1309:   C->ops->forwardsolve   = MatForwardSolve_SeqSBAIJ_1_inplace;
1310:   C->ops->backwardsolve  = MatBackwardSolve_SeqSBAIJ_1_inplace;
1311:   C->assembled           = PETSC_TRUE;
1312:   C->preallocated        = PETSC_TRUE;

1314:   PetscLogFlops(C->rmap->N);
1315:   if (sctx.nshift) {
1316:     if (info->shifttype == (PetscReal)MAT_SHIFT_NONZERO) {
1317:       PetscInfo2(A,"number of shiftnz tries %D, shift_amount %g\n",sctx.nshift,(double)sctx.shift_amount);
1318:     } else if (info->shifttype == (PetscReal)MAT_SHIFT_POSITIVE_DEFINITE) {
1319:       PetscInfo2(A,"number of shiftpd tries %D, shift_amount %g\n",sctx.nshift,(double)sctx.shift_amount);
1320:     }
1321:   }
1322:   return(0);
1323: }

1325: /*
1326:   Version for when blocks are 1 by 1 Using natural ordering under new datastructure
1327:   Modified from MatCholeskyFactorNumeric_SeqAIJ()
1328: */
1331: PetscErrorCode MatCholeskyFactorNumeric_SeqSBAIJ_1_NaturalOrdering(Mat B,Mat A,const MatFactorInfo *info)
1332: {
1333:   Mat_SeqSBAIJ   *a=(Mat_SeqSBAIJ*)A->data;
1334:   Mat_SeqSBAIJ   *b=(Mat_SeqSBAIJ*)B->data;
1336:   PetscInt       i,j,mbs=A->rmap->n,*bi=b->i,*bj=b->j,*bdiag=b->diag,*bjtmp;
1337:   PetscInt       *ai=a->i,*aj=a->j,*ajtmp;
1338:   PetscInt       k,jmin,jmax,*c2r,*il,col,nexti,ili,nz;
1339:   MatScalar      *rtmp,*ba=b->a,*bval,*aa=a->a,dk,uikdi;
1340:   FactorShiftCtx sctx;
1341:   PetscReal      rs;
1342:   MatScalar      d,*v;

1345:   PetscMalloc3(mbs,&rtmp,mbs,&il,mbs,&c2r);

1347:   /* MatPivotSetUp(): initialize shift context sctx */
1348:   PetscMemzero(&sctx,sizeof(FactorShiftCtx));

1350:   if (info->shifttype == (PetscReal)MAT_SHIFT_POSITIVE_DEFINITE) { /* set sctx.shift_top=max{rs} */
1351:     sctx.shift_top = info->zeropivot;

1353:     PetscMemzero(rtmp,mbs*sizeof(MatScalar));

1355:     for (i=0; i<mbs; i++) {
1356:       /* calculate sum(|aij|)-RealPart(aii), amt of shift needed for this row */
1357:       d        = (aa)[a->diag[i]];
1358:       rtmp[i] += -PetscRealPart(d);  /* diagonal entry */
1359:       ajtmp    = aj + ai[i] + 1;     /* exclude diagonal */
1360:       v        = aa + ai[i] + 1;
1361:       nz       = ai[i+1] - ai[i] - 1;
1362:       for (j=0; j<nz; j++) {
1363:         rtmp[i]        += PetscAbsScalar(v[j]);
1364:         rtmp[ajtmp[j]] += PetscAbsScalar(v[j]);
1365:       }
1366:       if (PetscRealPart(rtmp[i]) > sctx.shift_top) sctx.shift_top = PetscRealPart(rtmp[i]);
1367:     }
1368:     sctx.shift_top *= 1.1;
1369:     sctx.nshift_max = 5;
1370:     sctx.shift_lo   = 0.;
1371:     sctx.shift_hi   = 1.;
1372:   }

1374:   /* allocate working arrays
1375:      c2r: linked list, keep track of pivot rows for a given column. c2r[col]: head of the list for a given col
1376:      il:  for active k row, il[i] gives the index of the 1st nonzero entry in U[i,k:n-1] in bj and ba arrays
1377:   */
1378:   do {
1379:     sctx.newshift = PETSC_FALSE;

1381:     for (i=0; i<mbs; i++) c2r[i] = mbs;
1382:     if (mbs) il[0] = 0;

1384:     for (k = 0; k<mbs; k++) {
1385:       /* zero rtmp */
1386:       nz    = bi[k+1] - bi[k];
1387:       bjtmp = bj + bi[k];
1388:       for (j=0; j<nz; j++) rtmp[bjtmp[j]] = 0.0;

1390:       /* load in initial unfactored row */
1391:       bval = ba + bi[k];
1392:       jmin = ai[k]; jmax = ai[k+1];
1393:       for (j = jmin; j < jmax; j++) {
1394:         col       = aj[j];
1395:         rtmp[col] = aa[j];
1396:         *bval++   = 0.0; /* for in-place factorization */
1397:       }
1398:       /* shift the diagonal of the matrix: ZeropivotApply() */
1399:       rtmp[k] += sctx.shift_amount;  /* shift the diagonal of the matrix */

1401:       /* modify k-th row by adding in those rows i with U(i,k)!=0 */
1402:       dk = rtmp[k];
1403:       i  = c2r[k]; /* first row to be added to k_th row  */

1405:       while (i < k) {
1406:         nexti = c2r[i]; /* next row to be added to k_th row */

1408:         /* compute multiplier, update diag(k) and U(i,k) */
1409:         ili     = il[i]; /* index of first nonzero element in U(i,k:bms-1) */
1410:         uikdi   = -ba[ili]*ba[bdiag[i]]; /* diagonal(k) */
1411:         dk     += uikdi*ba[ili]; /* update diag[k] */
1412:         ba[ili] = uikdi; /* -U(i,k) */

1414:         /* add multiple of row i to k-th row */
1415:         jmin = ili + 1; jmax = bi[i+1];
1416:         if (jmin < jmax) {
1417:           for (j=jmin; j<jmax; j++) rtmp[bj[j]] += uikdi*ba[j];
1418:           /* update il and c2r for row i */
1419:           il[i] = jmin;
1420:           j     = bj[jmin]; c2r[i] = c2r[j]; c2r[j] = i;
1421:         }
1422:         i = nexti;
1423:       }

1425:       /* copy data into U(k,:) */
1426:       rs   = 0.0;
1427:       jmin = bi[k]; jmax = bi[k+1]-1;
1428:       if (jmin < jmax) {
1429:         for (j=jmin; j<jmax; j++) {
1430:           col = bj[j]; ba[j] = rtmp[col]; rs += PetscAbsScalar(ba[j]);
1431:         }
1432:         /* add the k-th row into il and c2r */
1433:         il[k] = jmin;
1434:         i     = bj[jmin]; c2r[k] = c2r[i]; c2r[i] = k;
1435:       }

1437:       sctx.rs = rs;
1438:       sctx.pv = dk;
1439:       MatPivotCheck(B,A,info,&sctx,k);
1440:       if (sctx.newshift) break;
1441:       dk = sctx.pv;

1443:       ba[bdiag[k]] = 1.0/dk; /* U(k,k) */
1444:     }
1445:   } while (sctx.newshift);

1447:   PetscFree3(rtmp,il,c2r);

1449:   B->ops->solve          = MatSolve_SeqSBAIJ_1_NaturalOrdering;
1450:   B->ops->solves         = MatSolves_SeqSBAIJ_1;
1451:   B->ops->solvetranspose = MatSolve_SeqSBAIJ_1_NaturalOrdering;
1452:   B->ops->forwardsolve   = MatForwardSolve_SeqSBAIJ_1_NaturalOrdering;
1453:   B->ops->backwardsolve  = MatBackwardSolve_SeqSBAIJ_1_NaturalOrdering;

1455:   B->assembled    = PETSC_TRUE;
1456:   B->preallocated = PETSC_TRUE;

1458:   PetscLogFlops(B->rmap->n);

1460:   /* MatPivotView() */
1461:   if (sctx.nshift) {
1462:     if (info->shifttype == (PetscReal)MAT_SHIFT_POSITIVE_DEFINITE) {
1463:       PetscInfo4(A,"number of shift_pd tries %D, shift_amount %g, diagonal shifted up by %e fraction top_value %e\n",sctx.nshift,(double)sctx.shift_amount,(double)sctx.shift_fraction,(double)sctx.shift_top);
1464:     } else if (info->shifttype == (PetscReal)MAT_SHIFT_NONZERO) {
1465:       PetscInfo2(A,"number of shift_nz tries %D, shift_amount %g\n",sctx.nshift,(double)sctx.shift_amount);
1466:     } else if (info->shifttype == (PetscReal)MAT_SHIFT_INBLOCKS) {
1467:       PetscInfo2(A,"number of shift_inblocks applied %D, each shift_amount %g\n",sctx.nshift,(double)info->shiftamount);
1468:     }
1469:   }
1470:   return(0);
1471: }

1475: PetscErrorCode MatCholeskyFactorNumeric_SeqSBAIJ_1_NaturalOrdering_inplace(Mat C,Mat A,const MatFactorInfo *info)
1476: {
1477:   Mat_SeqSBAIJ   *a=(Mat_SeqSBAIJ*)A->data,*b=(Mat_SeqSBAIJ*)C->data;
1479:   PetscInt       i,j,mbs = a->mbs;
1480:   PetscInt       *ai=a->i,*aj=a->j,*bi=b->i,*bj=b->j;
1481:   PetscInt       k,jmin,*jl,*il,nexti,ili,*acol,*bcol,nz;
1482:   MatScalar      *rtmp,*ba=b->a,*aa=a->a,dk,uikdi,*aval,*bval;
1483:   PetscReal      rs;
1484:   FactorShiftCtx sctx;

1487:   /* MatPivotSetUp(): initialize shift context sctx */
1488:   PetscMemzero(&sctx,sizeof(FactorShiftCtx));

1490:   /* initialization */
1491:   /* il and jl record the first nonzero element in each row of the accessing
1492:      window U(0:k, k:mbs-1).
1493:      jl:    list of rows to be added to uneliminated rows
1494:             i>= k: jl(i) is the first row to be added to row i
1495:             i<  k: jl(i) is the row following row i in some list of rows
1496:             jl(i) = mbs indicates the end of a list
1497:      il(i): points to the first nonzero element in U(i,k:mbs-1)
1498:   */
1499:   PetscMalloc1(mbs,&rtmp);
1500:   PetscMalloc2(mbs,&il,mbs,&jl);

1502:   do {
1503:     sctx.newshift = PETSC_FALSE;
1504:     il[0] = 0;
1505:     for (i=0; i<mbs; i++) {
1506:       rtmp[i] = 0.0; jl[i] = mbs;
1507:     }

1509:     for (k = 0; k<mbs; k++) {
1510:       /*initialize k-th row with elements nonzero in row perm(k) of A */
1511:       nz   = ai[k+1] - ai[k];
1512:       acol = aj + ai[k];
1513:       aval = aa + ai[k];
1514:       bval = ba + bi[k];
1515:       while (nz--) {
1516:         rtmp[*acol++] = *aval++;
1517:         *bval++       = 0.0; /* for in-place factorization */
1518:       }

1520:       /* shift the diagonal of the matrix */
1521:       if (sctx.nshift) rtmp[k] += sctx.shift_amount;

1523:       /* modify k-th row by adding in those rows i with U(i,k)!=0 */
1524:       dk = rtmp[k];
1525:       i  = jl[k]; /* first row to be added to k_th row  */

1527:       while (i < k) {
1528:         nexti = jl[i]; /* next row to be added to k_th row */
1529:         /* compute multiplier, update D(k) and U(i,k) */
1530:         ili     = il[i]; /* index of first nonzero element in U(i,k:bms-1) */
1531:         uikdi   = -ba[ili]*ba[bi[i]];
1532:         dk     += uikdi*ba[ili];
1533:         ba[ili] = uikdi; /* -U(i,k) */

1535:         /* add multiple of row i to k-th row ... */
1536:         jmin = ili + 1;
1537:         nz   = bi[i+1] - jmin;
1538:         if (nz > 0) {
1539:           bcol = bj + jmin;
1540:           bval = ba + jmin;
1541:           PetscLogFlops(2.0*nz);
1542:           while (nz--) rtmp[*bcol++] += uikdi*(*bval++);

1544:           /* update il and jl for i-th row */
1545:           il[i] = jmin;
1546:           j     = bj[jmin]; jl[i] = jl[j]; jl[j] = i;
1547:         }
1548:         i = nexti;
1549:       }

1551:       /* shift the diagonals when zero pivot is detected */
1552:       /* compute rs=sum of abs(off-diagonal) */
1553:       rs   = 0.0;
1554:       jmin = bi[k]+1;
1555:       nz   = bi[k+1] - jmin;
1556:       if (nz) {
1557:         bcol = bj + jmin;
1558:         while (nz--) {
1559:           rs += PetscAbsScalar(rtmp[*bcol]);
1560:           bcol++;
1561:         }
1562:       }

1564:       sctx.rs = rs;
1565:       sctx.pv = dk;
1566:       MatPivotCheck(C,A,info,&sctx,k);
1567:       if (sctx.newshift) break;    /* sctx.shift_amount is updated */
1568:       dk = sctx.pv;

1570:       /* copy data into U(k,:) */
1571:       ba[bi[k]] = 1.0/dk;
1572:       jmin      = bi[k]+1;
1573:       nz        = bi[k+1] - jmin;
1574:       if (nz) {
1575:         bcol = bj + jmin;
1576:         bval = ba + jmin;
1577:         while (nz--) {
1578:           *bval++       = rtmp[*bcol];
1579:           rtmp[*bcol++] = 0.0;
1580:         }
1581:         /* add k-th row into il and jl */
1582:         il[k] = jmin;
1583:         i     = bj[jmin]; jl[k] = jl[i]; jl[i] = k;
1584:       }
1585:     } /* end of for (k = 0; k<mbs; k++) */
1586:   } while (sctx.newshift);
1587:   PetscFree(rtmp);
1588:   PetscFree2(il,jl);

1590:   C->ops->solve          = MatSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
1591:   C->ops->solves         = MatSolves_SeqSBAIJ_1_inplace;
1592:   C->ops->solvetranspose = MatSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
1593:   C->ops->forwardsolve   = MatForwardSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
1594:   C->ops->backwardsolve  = MatBackwardSolve_SeqSBAIJ_1_NaturalOrdering_inplace;

1596:   C->assembled    = PETSC_TRUE;
1597:   C->preallocated = PETSC_TRUE;

1599:   PetscLogFlops(C->rmap->N);
1600:   if (sctx.nshift) {
1601:     if (info->shifttype == (PetscReal)MAT_SHIFT_NONZERO) {
1602:       PetscInfo2(A,"number of shiftnz tries %D, shift_amount %g\n",sctx.nshift,(double)sctx.shift_amount);
1603:     } else if (info->shifttype == (PetscReal)MAT_SHIFT_POSITIVE_DEFINITE) {
1604:       PetscInfo2(A,"number of shiftpd tries %D, shift_amount %g\n",sctx.nshift,(double)sctx.shift_amount);
1605:     }
1606:   }
1607:   return(0);
1608: }

1612: PetscErrorCode MatCholeskyFactor_SeqSBAIJ(Mat A,IS perm,const MatFactorInfo *info)
1613: {
1615:   Mat            C;

1618:   MatGetFactor(A,"petsc",MAT_FACTOR_CHOLESKY,&C);
1619:   MatCholeskyFactorSymbolic(C,A,perm,info);
1620:   MatCholeskyFactorNumeric(C,A,info);

1622:   A->ops->solve          = C->ops->solve;
1623:   A->ops->solvetranspose = C->ops->solvetranspose;

1625:   MatHeaderMerge(A,&C);
1626:   return(0);
1627: }