Actual source code: iscoloring.c

petsc-dev 2014-02-02
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  2: #include <petsc-private/isimpl.h>    /*I "petscis.h"  I*/
  3: #include <petscviewer.h>

  5: const char *const ISColoringTypes[] = {"global","ghosted","ISColoringType","IS_COLORING_",0};

  9: PetscErrorCode ISColoringReference(ISColoring coloring)
 10: {
 12:   (coloring)->refct++;
 13:   return(0);
 14: }

 18: PetscErrorCode ISColoringSetType(ISColoring coloring,ISColoringType type)
 19: {
 21:   (coloring)->ctype = type;
 22:   return(0);
 23: }

 27: /*@
 28:    ISColoringDestroy - Destroys a coloring context.

 30:    Collective on ISColoring

 32:    Input Parameter:
 33: .  iscoloring - the coloring context

 35:    Level: advanced

 37: .seealso: ISColoringView(), MatColoring
 38: @*/
 39: PetscErrorCode  ISColoringDestroy(ISColoring *iscoloring)
 40: {
 41:   PetscInt       i;

 45:   if (!*iscoloring) return(0);
 47:   if (--(*iscoloring)->refct > 0) {*iscoloring = 0; return(0);}

 49:   if ((*iscoloring)->is) {
 50:     for (i=0; i<(*iscoloring)->n; i++) {
 51:       ISDestroy(&(*iscoloring)->is[i]);
 52:     }
 53:     PetscFree((*iscoloring)->is);
 54:   }
 55:   PetscFree((*iscoloring)->colors);
 56:   PetscCommDestroy(&(*iscoloring)->comm);
 57:   PetscFree((*iscoloring));
 58:   return(0);
 59: }

 63: /*
 64:   ISColoringViewFromOptions - Processes command line options to determine if/how an ISColoring object is to be viewed. 

 66:   Collective on ISColoring

 68:   Input Parameters:
 69: + obj   - the ISColoring object
 70: . prefix - prefix to use for viewing, or NULL to use prefix of 'mat'
 71: - optionname - option to activate viewing

 73:   Level: intermediate

 75:   Developer Note: This cannot use PetscObjectViewFromOptions() because ISColoring is not a PetscObject

 77: */
 78: PetscErrorCode ISColoringViewFromOptions(ISColoring obj,const char prefix[],const char optionname[])
 79: {
 80:   PetscErrorCode    ierr;
 81:   PetscViewer       viewer;
 82:   PetscBool         flg;
 83:   static PetscBool  incall = PETSC_FALSE;
 84:   PetscViewerFormat format;

 87:   if (incall) return(0);
 88:   incall = PETSC_TRUE;
 89:   PetscOptionsGetViewer(obj->comm,prefix,optionname,&viewer,&format,&flg);
 90:   if (flg) {
 91:     PetscViewerPushFormat(viewer,format);
 92:     ISColoringView(obj,viewer);
 93:     PetscViewerPopFormat(viewer);
 94:     PetscViewerDestroy(&viewer);
 95:   }
 96:   incall = PETSC_FALSE;
 97:   return(0);
 98: }

102: /*@C
103:    ISColoringView - Views a coloring context.

105:    Collective on ISColoring

107:    Input Parameters:
108: +  iscoloring - the coloring context
109: -  viewer - the viewer

111:    Level: advanced

113: .seealso: ISColoringDestroy(), ISColoringGetIS(), MatColoring
114: @*/
115: PetscErrorCode  ISColoringView(ISColoring iscoloring,PetscViewer viewer)
116: {
117:   PetscInt       i;
119:   PetscBool      iascii;
120:   IS             *is;

124:   if (!viewer) {
125:     PetscViewerASCIIGetStdout(iscoloring->comm,&viewer);
126:   }

129:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
130:   if (iascii) {
131:     MPI_Comm    comm;
132:     PetscMPIInt rank;
133:     PetscObjectGetComm((PetscObject)viewer,&comm);
134:     MPI_Comm_rank(comm,&rank);
135:     PetscViewerASCIISynchronizedAllow(viewer,PETSC_TRUE);
136:     PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Number of colors %d\n",rank,iscoloring->n);
137:     PetscViewerFlush(viewer);
138:     PetscViewerASCIISynchronizedAllow(viewer,PETSC_FALSE);
139:   } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"Viewer type %s not supported for ISColoring",((PetscObject)viewer)->type_name);

141:   ISColoringGetIS(iscoloring,PETSC_IGNORE,&is);
142:   for (i=0; i<iscoloring->n; i++) {
143:     ISView(iscoloring->is[i],viewer);
144:   }
145:   ISColoringRestoreIS(iscoloring,&is);
146:   return(0);
147: }

151: /*@C
152:    ISColoringGetIS - Extracts index sets from the coloring context

154:    Collective on ISColoring

156:    Input Parameter:
157: .  iscoloring - the coloring context

159:    Output Parameters:
160: +  nn - number of index sets in the coloring context
161: -  is - array of index sets

163:    Level: advanced

165: .seealso: ISColoringRestoreIS(), ISColoringView()
166: @*/
167: PetscErrorCode  ISColoringGetIS(ISColoring iscoloring,PetscInt *nn,IS *isis[])
168: {


174:   if (nn) *nn = iscoloring->n;
175:   if (isis) {
176:     if (!iscoloring->is) {
177:       PetscInt        *mcolors,**ii,nc = iscoloring->n,i,base, n = iscoloring->N;
178:       ISColoringValue *colors = iscoloring->colors;
179:       IS              *is;

181: #if defined(PETSC_USE_DEBUG)
182:       for (i=0; i<n; i++) {
183:         if (((PetscInt)colors[i]) >= nc) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Coloring is our of range index %d value %d number colors %d",(int)i,(int)colors[i],(int)nc);
184:       }
185: #endif

187:       /* generate the lists of nodes for each color */
188:       PetscCalloc1(nc,&mcolors);
189:       for (i=0; i<n; i++) mcolors[colors[i]]++;

191:       PetscMalloc1(nc,&ii);
192:       PetscMalloc1(n,&ii[0]);
193:       for (i=1; i<nc; i++) ii[i] = ii[i-1] + mcolors[i-1];
194:       PetscMemzero(mcolors,nc*sizeof(PetscInt));

196:       if (iscoloring->ctype == IS_COLORING_GLOBAL) {
197:         MPI_Scan(&iscoloring->N,&base,1,MPIU_INT,MPI_SUM,iscoloring->comm);
198:         base -= iscoloring->N;
199:         for (i=0; i<n; i++) ii[colors[i]][mcolors[colors[i]]++] = i + base; /* global idx */
200:       } else if (iscoloring->ctype == IS_COLORING_GHOSTED) {
201:         for (i=0; i<n; i++) ii[colors[i]][mcolors[colors[i]]++] = i;   /* local idx */
202:       } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Not provided for this ISColoringType type");

204:       PetscMalloc1(nc,&is);
205:       for (i=0; i<nc; i++) {
206:         ISCreateGeneral(iscoloring->comm,mcolors[i],ii[i],PETSC_COPY_VALUES,is+i);
207:       }

209:       iscoloring->is = is;
210:       PetscFree(ii[0]);
211:       PetscFree(ii);
212:       PetscFree(mcolors);
213:     }
214:     *isis = iscoloring->is;
215:   }
216:   return(0);
217: }

221: /*@C
222:    ISColoringRestoreIS - Restores the index sets extracted from the coloring context

224:    Collective on ISColoring

226:    Input Parameter:
227: +  iscoloring - the coloring context
228: -  is - array of index sets

230:    Level: advanced

232: .seealso: ISColoringGetIS(), ISColoringView()
233: @*/
234: PetscErrorCode  ISColoringRestoreIS(ISColoring iscoloring,IS *is[])
235: {

239:   /* currently nothing is done here */
240:   return(0);
241: }


246: /*@C
247:     ISColoringCreate - Generates an ISColoring context from lists (provided
248:     by each processor) of colors for each node.

250:     Collective on MPI_Comm

252:     Input Parameters:
253: +   comm - communicator for the processors creating the coloring
254: .   ncolors - max color value
255: .   n - number of nodes on this processor
256: -   colors - array containing the colors for this processor, color
257:              numbers begin at 0. In C/C++ this array must have been obtained with PetscMalloc()
258:              and should NOT be freed (The ISColoringDestroy() will free it).

260:     Output Parameter:
261: .   iscoloring - the resulting coloring data structure

263:     Options Database Key:
264: .   -is_coloring_view - Activates ISColoringView()

266:    Level: advanced

268:     Notes: By default sets coloring type to  IS_COLORING_GLOBAL

270: .seealso: MatColoringCreate(), ISColoringView(), ISColoringDestroy(), ISColoringSetType()

272: @*/
273: PetscErrorCode  ISColoringCreate(MPI_Comm comm,PetscInt ncolors,PetscInt n,const ISColoringValue colors[],ISColoring *iscoloring)
274: {
276:   PetscMPIInt    size,rank,tag;
277:   PetscInt       base,top,i;
278:   PetscInt       nc,ncwork;
279:   MPI_Status     status;

282:   if (ncolors != PETSC_DECIDE && ncolors > IS_COLORING_MAX) {
283:     if (ncolors > 65535) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Max color value exeeds 65535 limit. This number is unrealistic. Perhaps a bug in code?\nCurrent max: %d user rewuested: %d",IS_COLORING_MAX,ncolors);
284:     else                 SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Max color value exeeds limit. Perhaps reconfigure PETSc with --with-is-color-value-type=short?\n Current max: %d user rewuested: %d",IS_COLORING_MAX,ncolors);
285:   }
286:   PetscNew(iscoloring);
287:   PetscCommDuplicate(comm,&(*iscoloring)->comm,&tag);
288:   comm = (*iscoloring)->comm;

290:   /* compute the number of the first node on my processor */
291:   MPI_Comm_size(comm,&size);

293:   /* should use MPI_Scan() */
294:   MPI_Comm_rank(comm,&rank);
295:   if (!rank) {
296:     base = 0;
297:     top  = n;
298:   } else {
299:     MPI_Recv(&base,1,MPIU_INT,rank-1,tag,comm,&status);
300:     top  = base+n;
301:   }
302:   if (rank < size-1) {
303:     MPI_Send(&top,1,MPIU_INT,rank+1,tag,comm);
304:   }

306:   /* compute the total number of colors */
307:   ncwork = 0;
308:   for (i=0; i<n; i++) {
309:     if (ncwork < colors[i]) ncwork = colors[i];
310:   }
311:   ncwork++;
312:   MPI_Allreduce(&ncwork,&nc,1,MPIU_INT,MPI_MAX,comm);
313:   if (nc > ncolors) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_INCOMP,"Number of colors passed in %D is less then the actual number of colors in array %D",ncolors,nc);
314:   (*iscoloring)->n      = nc;
315:   (*iscoloring)->is     = 0;
316:   (*iscoloring)->colors = (ISColoringValue*)colors;
317:   (*iscoloring)->N      = n;
318:   (*iscoloring)->refct  = 1;
319:   (*iscoloring)->ctype  = IS_COLORING_GLOBAL;
320:   ISColoringViewFromOptions(*iscoloring,NULL,"-is_coloring_view");
321:   PetscInfo1(0,"Number of colors %D\n",nc);
322:   return(0);
323: }

327: /*@
328:     ISPartitioningToNumbering - Takes an ISPartitioning and on each processor
329:     generates an IS that contains a new global node number for each index based
330:     on the partitioing.

332:     Collective on IS

334:     Input Parameters
335: .   partitioning - a partitioning as generated by MatPartitioningApply()

337:     Output Parameter:
338: .   is - on each processor the index set that defines the global numbers
339:          (in the new numbering) for all the nodes currently (before the partitioning)
340:          on that processor

342:    Level: advanced

344: .seealso: MatPartitioningCreate(), AOCreateBasic(), ISPartitioningCount()

346: @*/
347: PetscErrorCode  ISPartitioningToNumbering(IS part,IS *is)
348: {
349:   MPI_Comm       comm;
350:   PetscInt       i,np,npt,n,*starts = NULL,*sums = NULL,*lsizes = NULL,*newi = NULL;
351:   const PetscInt *indices = NULL;

355:   PetscObjectGetComm((PetscObject)part,&comm);

357:   /* count the number of partitions, i.e., virtual processors */
358:   ISGetLocalSize(part,&n);
359:   ISGetIndices(part,&indices);
360:   np   = 0;
361:   for (i=0; i<n; i++) np = PetscMax(np,indices[i]);
362:   MPI_Allreduce(&np,&npt,1,MPIU_INT,MPI_MAX,comm);
363:   np   = npt+1; /* so that it looks like a MPI_Comm_size output */

365:   /*
366:         lsizes - number of elements of each partition on this particular processor
367:         sums - total number of "previous" nodes for any particular partition
368:         starts - global number of first element in each partition on this processor
369:   */
370:   PetscMalloc3(np,&lsizes,np,&starts,np,&sums);
371:   PetscMemzero(lsizes,np*sizeof(PetscInt));
372:   for (i=0; i<n; i++) lsizes[indices[i]]++;
373:   MPI_Allreduce(lsizes,sums,np,MPIU_INT,MPI_SUM,comm);
374:   MPI_Scan(lsizes,starts,np,MPIU_INT,MPI_SUM,comm);
375:   for (i=0; i<np; i++) starts[i] -= lsizes[i];
376:   for (i=1; i<np; i++) {
377:     sums[i]   += sums[i-1];
378:     starts[i] += sums[i-1];
379:   }

381:   /*
382:       For each local index give it the new global number
383:   */
384:   PetscMalloc1(n,&newi);
385:   for (i=0; i<n; i++) newi[i] = starts[indices[i]]++;
386:   PetscFree3(lsizes,starts,sums);

388:   ISRestoreIndices(part,&indices);
389:   ISCreateGeneral(comm,n,newi,PETSC_OWN_POINTER,is);
390:   ISSetPermutation(*is);
391:   return(0);
392: }

396: /*@
397:     ISPartitioningCount - Takes a ISPartitioning and determines the number of
398:     resulting elements on each (partition) process

400:     Collective on IS

402:     Input Parameters:
403: +   partitioning - a partitioning as generated by MatPartitioningApply()
404: -   len - length of the array count, this is the total number of partitions

406:     Output Parameter:
407: .   count - array of length size, to contain the number of elements assigned
408:         to each partition, where size is the number of partitions generated
409:          (see notes below).

411:    Level: advanced

413:     Notes:
414:         By default the number of partitions generated (and thus the length
415:         of count) is the size of the communicator associated with IS,
416:         but it can be set by MatPartitioningSetNParts. The resulting array
417:         of lengths can for instance serve as input of PCBJacobiSetTotalBlocks.


420: .seealso: MatPartitioningCreate(), AOCreateBasic(), ISPartitioningToNumbering(),
421:         MatPartitioningSetNParts(), MatPartitioningApply()

423: @*/
424: PetscErrorCode  ISPartitioningCount(IS part,PetscInt len,PetscInt count[])
425: {
426:   MPI_Comm       comm;
427:   PetscInt       i,n,*lsizes;
428:   const PetscInt *indices;
430:   PetscMPIInt    npp;

433:   PetscObjectGetComm((PetscObject)part,&comm);
434:   if (len == PETSC_DEFAULT) {
435:     PetscMPIInt size;
436:     MPI_Comm_size(comm,&size);
437:     len  = (PetscInt) size;
438:   }

440:   /* count the number of partitions */
441:   ISGetLocalSize(part,&n);
442:   ISGetIndices(part,&indices);
443: #if defined(PETSC_USE_DEBUG)
444:   {
445:     PetscInt np = 0,npt;
446:     for (i=0; i<n; i++) np = PetscMax(np,indices[i]);
447:     MPI_Allreduce(&np,&npt,1,MPIU_INT,MPI_MAX,comm);
448:     np   = npt+1; /* so that it looks like a MPI_Comm_size output */
449:     if (np > len) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Length of count array %D is less than number of partitions %D",len,np);
450:   }
451: #endif

453:   /*
454:         lsizes - number of elements of each partition on this particular processor
455:         sums - total number of "previous" nodes for any particular partition
456:         starts - global number of first element in each partition on this processor
457:   */
458:   PetscCalloc1(len,&lsizes);
459:   for (i=0; i<n; i++) lsizes[indices[i]]++;
460:   ISRestoreIndices(part,&indices);
461:   PetscMPIIntCast(len,&npp);
462:   MPI_Allreduce(lsizes,count,npp,MPIU_INT,MPI_SUM,comm);
463:   PetscFree(lsizes);
464:   return(0);
465: }

469: /*@
470:     ISAllGather - Given an index set (IS) on each processor, generates a large
471:     index set (same on each processor) by concatenating together each
472:     processors index set.

474:     Collective on IS

476:     Input Parameter:
477: .   is - the distributed index set

479:     Output Parameter:
480: .   isout - the concatenated index set (same on all processors)

482:     Notes:
483:     ISAllGather() is clearly not scalable for large index sets.

485:     The IS created on each processor must be created with a common
486:     communicator (e.g., PETSC_COMM_WORLD). If the index sets were created
487:     with PETSC_COMM_SELF, this routine will not work as expected, since
488:     each process will generate its own new IS that consists only of
489:     itself.

491:     The communicator for this new IS is PETSC_COMM_SELF

493:     Level: intermediate

495:     Concepts: gather^index sets
496:     Concepts: index sets^gathering to all processors
497:     Concepts: IS^gathering to all processors

499: .seealso: ISCreateGeneral(), ISCreateStride(), ISCreateBlock()
500: @*/
501: PetscErrorCode  ISAllGather(IS is,IS *isout)
502: {
504:   PetscInt       *indices,n,i,N,step,first;
505:   const PetscInt *lindices;
506:   MPI_Comm       comm;
507:   PetscMPIInt    size,*sizes = NULL,*offsets = NULL,nn;
508:   PetscBool      stride;


514:   PetscObjectGetComm((PetscObject)is,&comm);
515:   MPI_Comm_size(comm,&size);
516:   ISGetLocalSize(is,&n);
517:   PetscObjectTypeCompare((PetscObject)is,ISSTRIDE,&stride);
518:   if (size == 1 && stride) { /* should handle parallel ISStride also */
519:     ISStrideGetInfo(is,&first,&step);
520:     ISCreateStride(PETSC_COMM_SELF,n,first,step,isout);
521:   } else {
522:     PetscMalloc2(size,&sizes,size,&offsets);

524:     PetscMPIIntCast(n,&nn);
525:     MPI_Allgather(&nn,1,MPI_INT,sizes,1,MPI_INT,comm);
526:     offsets[0] = 0;
527:     for (i=1; i<size; i++) offsets[i] = offsets[i-1] + sizes[i-1];
528:     N = offsets[size-1] + sizes[size-1];

530:     PetscMalloc1(N,&indices);
531:     ISGetIndices(is,&lindices);
532:     MPI_Allgatherv((void*)lindices,nn,MPIU_INT,indices,sizes,offsets,MPIU_INT,comm);
533:     ISRestoreIndices(is,&lindices);
534:     PetscFree2(sizes,offsets);

536:     ISCreateGeneral(PETSC_COMM_SELF,N,indices,PETSC_OWN_POINTER,isout);
537:   }
538:   return(0);
539: }

543: /*@C
544:     ISAllGatherColors - Given a a set of colors on each processor, generates a large
545:     set (same on each processor) by concatenating together each processors colors

547:     Collective on MPI_Comm

549:     Input Parameter:
550: +   comm - communicator to share the indices
551: .   n - local size of set
552: -   lindices - local colors

554:     Output Parameter:
555: +   outN - total number of indices
556: -   outindices - all of the colors

558:     Notes:
559:     ISAllGatherColors() is clearly not scalable for large index sets.


562:     Level: intermediate

564:     Concepts: gather^index sets
565:     Concepts: index sets^gathering to all processors
566:     Concepts: IS^gathering to all processors

568: .seealso: ISCreateGeneral(), ISCreateStride(), ISCreateBlock(), ISAllGather()
569: @*/
570: PetscErrorCode  ISAllGatherColors(MPI_Comm comm,PetscInt n,ISColoringValue *lindices,PetscInt *outN,ISColoringValue *outindices[])
571: {
572:   ISColoringValue *indices;
573:   PetscErrorCode  ierr;
574:   PetscInt        i,N;
575:   PetscMPIInt     size,*offsets = NULL,*sizes = NULL, nn = n;

578:   MPI_Comm_size(comm,&size);
579:   PetscMalloc2(size,&sizes,size,&offsets);

581:   MPI_Allgather(&nn,1,MPI_INT,sizes,1,MPI_INT,comm);
582:   offsets[0] = 0;
583:   for (i=1; i<size; i++) offsets[i] = offsets[i-1] + sizes[i-1];
584:   N    = offsets[size-1] + sizes[size-1];
585:   PetscFree2(sizes,offsets);

587:   PetscMalloc1((N+1),&indices);
588:   MPI_Allgatherv(lindices,(PetscMPIInt)n,MPIU_COLORING_VALUE,indices,sizes,offsets,MPIU_COLORING_VALUE,comm);

590:   *outindices = indices;
591:   if (outN) *outN = N;
592:   return(0);
593: }

597: /*@
598:     ISComplement - Given an index set (IS) generates the complement index set. That is all
599:        all indices that are NOT in the given set.

601:     Collective on IS

603:     Input Parameter:
604: +   is - the index set
605: .   nmin - the first index desired in the local part of the complement
606: -   nmax - the largest index desired in the local part of the complement (note that all indices in is must be greater or equal to nmin and less than nmax)

608:     Output Parameter:
609: .   isout - the complement

611:     Notes:  The communicator for this new IS is the same as for the input IS

613:       For a parallel IS, this will generate the local part of the complement on each process

615:       To generate the entire complement (on each process) of a parallel IS, first call ISAllGather() and then
616:     call this routine.

618:     Level: intermediate

620:     Concepts: gather^index sets
621:     Concepts: index sets^gathering to all processors
622:     Concepts: IS^gathering to all processors

624: .seealso: ISCreateGeneral(), ISCreateStride(), ISCreateBlock(), ISAllGather()
625: @*/
626: PetscErrorCode  ISComplement(IS is,PetscInt nmin,PetscInt nmax,IS *isout)
627: {
629:   const PetscInt *indices;
630:   PetscInt       n,i,j,unique,cnt,*nindices;
631:   PetscBool      sorted;

636:   if (nmin < 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"nmin %D cannot be negative",nmin);
637:   if (nmin > nmax) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"nmin %D cannot be greater than nmax %D",nmin,nmax);
638:   ISSorted(is,&sorted);
639:   if (!sorted) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Index set must be sorted");

641:   ISGetLocalSize(is,&n);
642:   ISGetIndices(is,&indices);
643: #if defined(PETSC_USE_DEBUG)
644:   for (i=0; i<n; i++) {
645:     if (indices[i] <  nmin) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Index %D's value %D is smaller than minimum given %D",i,indices[i],nmin);
646:     if (indices[i] >= nmax) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Index %D's value %D is larger than maximum given %D",i,indices[i],nmax);
647:   }
648: #endif
649:   /* Count number of unique entries */
650:   unique = (n>0);
651:   for (i=0; i<n-1; i++) {
652:     if (indices[i+1] != indices[i]) unique++;
653:   }
654:   PetscMalloc1((nmax-nmin-unique),&nindices);
655:   cnt  = 0;
656:   for (i=nmin,j=0; i<nmax; i++) {
657:     if (j<n && i==indices[j]) do { j++; } while (j<n && i==indices[j]);
658:     else nindices[cnt++] = i;
659:   }
660:   if (cnt != nmax-nmin-unique) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Number of entries found in complement %D does not match expected %D",cnt,nmax-nmin-unique);
661:   ISCreateGeneral(PetscObjectComm((PetscObject)is),cnt,nindices,PETSC_OWN_POINTER,isout);
662:   ISRestoreIndices(is,&indices);
663:   return(0);
664: }