Actual source code: index.c

petsc-master 2017-09-24
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  2: /*
  3:    Defines the abstract operations on index sets, i.e. the public interface.
  4: */
  5:  #include <petsc/private/isimpl.h>
  6:  #include <petscviewer.h>
  7:  #include <petscsf.h>

  9: /* Logging support */
 10: PetscClassId IS_CLASSID;

 12: /*@
 13:    ISRenumber - Renumbers an index set (with multiplicities) in a contiguous way.

 15:    Collective on IS

 17:    Input Parmeters:
 18: .  subset - the index set
 19: .  subset_mult - the multiplcity of each entry in subset (optional, can be NULL)

 21:    Output Parameters:
 22: .  N - the maximum entry of the new IS
 23: .  subset_n - the new IS

 25:    Level: intermediate

 27: .seealso:
 28: @*/
 29: PetscErrorCode ISRenumber(IS subset, IS subset_mult, PetscInt *N, IS *subset_n)
 30: {
 31:   PetscSF        sf;
 32:   PetscLayout    map;
 33:   const PetscInt *idxs;
 34:   PetscInt       *leaf_data,*root_data,*gidxs;
 35:   PetscInt       N_n,n,i,lbounds[2],gbounds[2],Nl;
 36:   PetscInt       n_n,nlocals,start,first_index;
 37:   PetscMPIInt    commsize;
 38:   PetscBool      first_found;

 42:   ISGetLocalSize(subset,&n);
 43:   if (subset_mult) {
 45:     ISGetLocalSize(subset,&i);
 46:     if (i != n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Local subset and multiplicity sizes don't match! %d != %d",n,i);
 47:   }
 48:   /* create workspace layout for computing global indices of subset */
 49:   ISGetIndices(subset,&idxs);
 50:   lbounds[0] = lbounds[1] = 0;
 51:   for (i=0;i<n;i++) {
 52:     if (idxs[i] < lbounds[0]) lbounds[0] = idxs[i];
 53:     else if (idxs[i] > lbounds[1]) lbounds[1] = idxs[i];
 54:   }
 55:   lbounds[0] = -lbounds[0];
 56:   MPIU_Allreduce(lbounds,gbounds,2,MPIU_INT,MPI_MAX,PetscObjectComm((PetscObject)subset));
 57:   gbounds[0] = -gbounds[0];
 58:   N_n= gbounds[1] - gbounds[0] + 1;
 59:   PetscLayoutCreate(PetscObjectComm((PetscObject)subset),&map);
 60:   PetscLayoutSetBlockSize(map,1);
 61:   PetscLayoutSetSize(map,N_n);
 62:   PetscLayoutSetUp(map);
 63:   PetscLayoutGetLocalSize(map,&Nl);

 65:   /* create sf : leaf_data == multiplicity of indexes, root data == global index in layout */
 66:   PetscMalloc2(n,&leaf_data,Nl,&root_data);
 67:   if (subset_mult) {
 68:     const PetscInt* idxs_mult;

 70:     ISGetIndices(subset_mult,&idxs_mult);
 71:     PetscMemcpy(leaf_data,idxs_mult,n*sizeof(PetscInt));
 72:     ISRestoreIndices(subset_mult,&idxs_mult);
 73:   } else {
 74:     for (i=0;i<n;i++) leaf_data[i] = 1;
 75:   }
 76:   /* local size of new subset */
 77:   n_n = 0;
 78:   for (i=0;i<n;i++) n_n += leaf_data[i];

 80:   /* global indexes in layout */
 81:   PetscMalloc1(n_n,&gidxs); /* allocating possibly extra space in gidxs which will be used later */
 82:   for (i=0;i<n;i++) gidxs[i] = idxs[i] - gbounds[0];
 83:   ISRestoreIndices(subset,&idxs);
 84:   PetscSFCreate(PetscObjectComm((PetscObject)subset),&sf);
 85:   PetscSFSetGraphLayout(sf,map,n,NULL,PETSC_COPY_VALUES,gidxs);
 86:   PetscLayoutDestroy(&map);

 88:   /* reduce from leaves to roots */
 89:   PetscMemzero(root_data,Nl*sizeof(PetscInt));
 90:   PetscSFReduceBegin(sf,MPIU_INT,leaf_data,root_data,MPI_MAX);
 91:   PetscSFReduceEnd(sf,MPIU_INT,leaf_data,root_data,MPI_MAX);

 93:   /* count indexes in local part of layout */
 94:   nlocals = 0;
 95:   first_index = -1;
 96:   first_found = PETSC_FALSE;
 97:   for (i=0;i<Nl;i++) {
 98:     if (!first_found && root_data[i]) {
 99:       first_found = PETSC_TRUE;
100:       first_index = i;
101:     }
102:     nlocals += root_data[i];
103:   }

105:   /* cumulative of number of indexes and size of subset without holes */
106: #if defined(PETSC_HAVE_MPI_EXSCAN)
107:   start = 0;
108:   MPI_Exscan(&nlocals,&start,1,MPIU_INT,MPI_SUM,PetscObjectComm((PetscObject)subset));
109: #else
110:   MPI_Scan(&nlocals,&start,1,MPIU_INT,MPI_SUM,PetscObjectComm((PetscObject)subset));
111:   start = start-nlocals;
112: #endif

114:   if (N) { /* compute total size of new subset if requested */
115:     *N = start + nlocals;
116:     MPI_Comm_size(PetscObjectComm((PetscObject)subset),&commsize);
117:     MPI_Bcast(N,1,MPIU_INT,commsize-1,PetscObjectComm((PetscObject)subset));
118:   }

120:   /* adapt root data with cumulative */
121:   if (first_found) {
122:     PetscInt old_index;

124:     root_data[first_index] += start;
125:     old_index = first_index;
126:     for (i=first_index+1;i<Nl;i++) {
127:       if (root_data[i]) {
128:         root_data[i] += root_data[old_index];
129:         old_index = i;
130:       }
131:     }
132:   }

134:   /* from roots to leaves */
135:   PetscSFBcastBegin(sf,MPIU_INT,root_data,leaf_data);
136:   PetscSFBcastEnd(sf,MPIU_INT,root_data,leaf_data);
137:   PetscSFDestroy(&sf);

139:   /* create new IS with global indexes without holes */
140:   if (subset_mult) {
141:     const PetscInt* idxs_mult;
142:     PetscInt        cum;

144:     cum = 0;
145:     ISGetIndices(subset_mult,&idxs_mult);
146:     for (i=0;i<n;i++) {
147:       PetscInt j;
148:       for (j=0;j<idxs_mult[i];j++) gidxs[cum++] = leaf_data[i] - idxs_mult[i] + j;
149:     }
150:     ISRestoreIndices(subset_mult,&idxs_mult);
151:   } else {
152:     for (i=0;i<n;i++) {
153:       gidxs[i] = leaf_data[i]-1;
154:     }
155:   }
156:   ISCreateGeneral(PetscObjectComm((PetscObject)subset),n_n,gidxs,PETSC_OWN_POINTER,subset_n);
157:   PetscFree2(leaf_data,root_data);
158:   return(0);
159: }

161: /*@
162:    ISIdentity - Determines whether index set is the identity mapping.

164:    Collective on IS

166:    Input Parmeters:
167: .  is - the index set

169:    Output Parameters:
170: .  ident - PETSC_TRUE if an identity, else PETSC_FALSE

172:    Level: intermediate

174:    Concepts: identity mapping
175:    Concepts: index sets^is identity

177: .seealso: ISSetIdentity()
178: @*/
179: PetscErrorCode  ISIdentity(IS is,PetscBool  *ident)
180: {

186:   *ident = is->isidentity;
187:   if (*ident) return(0);
188:   if (is->ops->identity) {
189:     (*is->ops->identity)(is,ident);
190:   }
191:   return(0);
192: }

194: /*@
195:    ISSetIdentity - Informs the index set that it is an identity.

197:    Logically Collective on IS

199:    Input Parmeters:
200: .  is - the index set

202:    Level: intermediate

204:    Concepts: identity mapping
205:    Concepts: index sets^is identity

207: .seealso: ISIdentity()
208: @*/
209: PetscErrorCode  ISSetIdentity(IS is)
210: {

215:   is->isidentity = PETSC_TRUE;
216:   ISSetPermutation(is);
217:   return(0);
218: }

220: /*@
221:    ISContiguousLocal - Locates an index set with contiguous range within a global range, if possible

223:    Not Collective

225:    Input Parmeters:
226: +  is - the index set
227: .  gstart - global start
228: .  gend - global end

230:    Output Parameters:
231: +  start - start of contiguous block, as an offset from gstart
232: -  contig - PETSC_TRUE if the index set refers to contiguous entries on this process, else PETSC_FALSE

234:    Level: developer

236:    Concepts: index sets^is contiguous

238: .seealso: ISGetLocalSize(), VecGetOwnershipRange()
239: @*/
240: PetscErrorCode  ISContiguousLocal(IS is,PetscInt gstart,PetscInt gend,PetscInt *start,PetscBool *contig)
241: {

248:   if (is->ops->contiguous) {
249:     (*is->ops->contiguous)(is,gstart,gend,start,contig);
250:   } else {
251:     *start  = -1;
252:     *contig = PETSC_FALSE;
253:   }
254:   return(0);
255: }

257: /*@
258:    ISPermutation - PETSC_TRUE or PETSC_FALSE depending on whether the
259:    index set has been declared to be a permutation.

261:    Logically Collective on IS

263:    Input Parmeters:
264: .  is - the index set

266:    Output Parameters:
267: .  perm - PETSC_TRUE if a permutation, else PETSC_FALSE

269:    Level: intermediate

271:   Concepts: permutation
272:   Concepts: index sets^is permutation

274: .seealso: ISSetPermutation()
275: @*/
276: PetscErrorCode  ISPermutation(IS is,PetscBool  *perm)
277: {
281:   *perm = (PetscBool) is->isperm;
282:   return(0);
283: }

285: /*@
286:    ISSetPermutation - Informs the index set that it is a permutation.

288:    Logically Collective on IS

290:    Input Parmeters:
291: .  is - the index set

293:    Level: intermediate

295:   Concepts: permutation
296:   Concepts: index sets^permutation

298:    The debug version of the libraries (./configure --with-debugging=1) checks if the
299:   index set is actually a permutation. The optimized version just believes you.

301: .seealso: ISPermutation()
302: @*/
303: PetscErrorCode  ISSetPermutation(IS is)
304: {
307: #if defined(PETSC_USE_DEBUG)
308:   {
309:     PetscMPIInt    size;

312:     MPI_Comm_size(PetscObjectComm((PetscObject)is),&size);
313:     if (size == 1) {
314:       PetscInt       i,n,*idx;
315:       const PetscInt *iidx;

317:       ISGetSize(is,&n);
318:       PetscMalloc1(n,&idx);
319:       ISGetIndices(is,&iidx);
320:       PetscMemcpy(idx,iidx,n*sizeof(PetscInt));
321:       PetscSortInt(n,idx);
322:       for (i=0; i<n; i++) {
323:         if (idx[i] != i) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Index set is not a permutation");
324:       }
325:       PetscFree(idx);
326:       ISRestoreIndices(is,&iidx);
327:     }
328:   }
329: #endif
330:   is->isperm = PETSC_TRUE;
331:   return(0);
332: }

334: /*@
335:    ISDestroy - Destroys an index set.

337:    Collective on IS

339:    Input Parameters:
340: .  is - the index set

342:    Level: beginner

344: .seealso: ISCreateGeneral(), ISCreateStride(), ISCreateBlocked()
345: @*/
346: PetscErrorCode  ISDestroy(IS *is)
347: {

351:   if (!*is) return(0);
353:   if (--((PetscObject)(*is))->refct > 0) {*is = 0; return(0);}
354:   if ((*is)->complement) {
355:     PetscInt refcnt;
356:     PetscObjectGetReference((PetscObject)((*is)->complement), &refcnt);
357:     if (refcnt > 1) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Nonlocal IS has not been restored");
358:     ISDestroy(&(*is)->complement);
359:   }
360:   if ((*is)->ops->destroy) {
361:     (*(*is)->ops->destroy)(*is);
362:   }
363:   PetscLayoutDestroy(&(*is)->map);
364:   /* Destroy local representations of offproc data. */
365:   PetscFree((*is)->total);
366:   PetscFree((*is)->nonlocal);
367:   PetscHeaderDestroy(is);
368:   return(0);
369: }

371: /*@
372:    ISInvertPermutation - Creates a new permutation that is the inverse of
373:                          a given permutation.

375:    Collective on IS

377:    Input Parameter:
378: +  is - the index set
379: -  nlocal - number of indices on this processor in result (ignored for 1 proccessor) or
380:             use PETSC_DECIDE

382:    Output Parameter:
383: .  isout - the inverse permutation

385:    Level: intermediate

387:    Notes: For parallel index sets this does the complete parallel permutation, but the
388:     code is not efficient for huge index sets (10,000,000 indices).

390:    Concepts: inverse permutation
391:    Concepts: permutation^inverse
392:    Concepts: index sets^inverting
393: @*/
394: PetscErrorCode  ISInvertPermutation(IS is,PetscInt nlocal,IS *isout)
395: {

401:   if (!is->isperm) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Not a permutation, must call ISSetPermutation() on the IS first");
402:   if (is->isidentity) {
403:     ISDuplicate(is,isout);
404:   } else {
405:     (*is->ops->invertpermutation)(is,nlocal,isout);
406:     ISSetPermutation(*isout);
407:   }
408:   return(0);
409: }

411: /*@
412:    ISGetSize - Returns the global length of an index set.

414:    Not Collective

416:    Input Parameter:
417: .  is - the index set

419:    Output Parameter:
420: .  size - the global size

422:    Level: beginner

424:    Concepts: size^of index set
425:    Concepts: index sets^size

427: @*/
428: PetscErrorCode  ISGetSize(IS is,PetscInt *size)
429: {

435:   (*is->ops->getsize)(is,size);
436:   return(0);
437: }

439: /*@
440:    ISGetLocalSize - Returns the local (processor) length of an index set.

442:    Not Collective

444:    Input Parameter:
445: .  is - the index set

447:    Output Parameter:
448: .  size - the local size

450:    Level: beginner

452:    Concepts: size^of index set
453:    Concepts: local size^of index set
454:    Concepts: index sets^local size

456: @*/
457: PetscErrorCode  ISGetLocalSize(IS is,PetscInt *size)
458: {

464:   (*is->ops->getlocalsize)(is,size);
465:   return(0);
466: }

468: /*@C
469:    ISGetIndices - Returns a pointer to the indices.  The user should call
470:    ISRestoreIndices() after having looked at the indices.  The user should
471:    NOT change the indices.

473:    Not Collective

475:    Input Parameter:
476: .  is - the index set

478:    Output Parameter:
479: .  ptr - the location to put the pointer to the indices

481:    Fortran Note:
482:    This routine has two different interfaces from Fortran; the first is not recommend, it does not require Fortran 90
483: $    IS          is
484: $    integer     is_array(1)
485: $    PetscOffset i_is
486: $    int         ierr
487: $       call ISGetIndices(is,is_array,i_is,ierr)
488: $
489: $   Access first local entry in list
490: $      value = is_array(i_is + 1)
491: $
492: $      ...... other code
493: $       call ISRestoreIndices(is,is_array,i_is,ierr)
494:    The second Fortran interface is recommended.
495: $          use petscisdef
496: $          PetscInt, pointer :: array(:)
497: $          PetscErrorCode  ierr
498: $          IS       i
499: $          call ISGetIndicesF90(i,array,ierr)



503:    See the Fortran chapter of the users manual and
504:    petsc/src/is/examples/[tutorials,tests] for details.

506:    Level: intermediate

508:    Concepts: index sets^getting indices
509:    Concepts: indices of index set

511: .seealso: ISRestoreIndices(), ISGetIndicesF90()
512: @*/
513: PetscErrorCode  ISGetIndices(IS is,const PetscInt *ptr[])
514: {

520:   (*is->ops->getindices)(is,ptr);
521:   return(0);
522: }

524: /*@C
525:    ISGetMinMax - Gets the minimum and maximum values in an IS

527:    Not Collective

529:    Input Parameter:
530: .  is - the index set

532:    Output Parameter:
533: +   min - the minimum value
534: -   max - the maximum value

536:    Level: intermediate

538:    Notes: Empty index sets return min=PETSC_MAX_INT and max=PETSC_MIN_INT.

540:    Concepts: index sets^getting indices
541:    Concepts: indices of index set

543: .seealso: ISGetIndices(), ISRestoreIndices(), ISGetIndicesF90()
544: @*/
545: PetscErrorCode  ISGetMinMax(IS is,PetscInt *min,PetscInt *max)
546: {
549:   if (min) *min = is->min;
550:   if (max) *max = is->max;
551:   return(0);
552: }

554: /*@
555:   ISLocate - determine the location of an index within the local component of an index set

557:   Not Collective

559:   Input Parameter:
560: + is - the index set
561: - key - the search key

563:   Output Parameter:
564: . location - if >= 0, a location within the index set that is equal to the key, otherwise the key is not in the index set

566:   Level: intermediate
567: @*/
568: PetscErrorCode ISLocate(IS is, PetscInt key, PetscInt *location)
569: {

573:   if (is->ops->locate) {
574:     (*is->ops->locate)(is,key,location);
575:   } else {
576:     PetscInt       numIdx;
577:     PetscBool      sorted;
578:     const PetscInt *idx;

580:     ISGetLocalSize(is,&numIdx);
581:     ISGetIndices(is,&idx);
582:     ISSorted(is,&sorted);
583:     if (sorted) {
584:       PetscFindInt(key,numIdx,idx,location);
585:     } else {
586:       PetscInt i;

588:       *location = -1;
589:       for (i = 0; i < numIdx; i++) {
590:         if (idx[i] == key) {
591:           *location = i;
592:           break;
593:         }
594:       }
595:     }
596:     ISRestoreIndices(is,&idx);
597:   }
598:   return(0);
599: }

601: /*@C
602:    ISRestoreIndices - Restores an index set to a usable state after a call
603:                       to ISGetIndices().

605:    Not Collective

607:    Input Parameters:
608: +  is - the index set
609: -  ptr - the pointer obtained by ISGetIndices()

611:    Fortran Note:
612:    This routine is used differently from Fortran
613: $    IS          is
614: $    integer     is_array(1)
615: $    PetscOffset i_is
616: $    int         ierr
617: $       call ISGetIndices(is,is_array,i_is,ierr)
618: $
619: $   Access first local entry in list
620: $      value = is_array(i_is + 1)
621: $
622: $      ...... other code
623: $       call ISRestoreIndices(is,is_array,i_is,ierr)

625:    See the Fortran chapter of the users manual and
626:    petsc/src/is/examples/[tutorials,tests] for details.

628:    Level: intermediate

630:    Note:
631:    This routine zeros out ptr. This is to prevent accidental us of the array after it has been restored.

633: .seealso: ISGetIndices(), ISRestoreIndicesF90()
634: @*/
635: PetscErrorCode  ISRestoreIndices(IS is,const PetscInt *ptr[])
636: {

642:   if (is->ops->restoreindices) {
643:     (*is->ops->restoreindices)(is,ptr);
644:   }
645:   return(0);
646: }

648: static PetscErrorCode ISGatherTotal_Private(IS is)
649: {
651:   PetscInt       i,n,N;
652:   const PetscInt *lindices;
653:   MPI_Comm       comm;
654:   PetscMPIInt    rank,size,*sizes = NULL,*offsets = NULL,nn;


659:   PetscObjectGetComm((PetscObject)is,&comm);
660:   MPI_Comm_size(comm,&size);
661:   MPI_Comm_rank(comm,&rank);
662:   ISGetLocalSize(is,&n);
663:   PetscMalloc2(size,&sizes,size,&offsets);

665:   PetscMPIIntCast(n,&nn);
666:   MPI_Allgather(&nn,1,MPI_INT,sizes,1,MPI_INT,comm);
667:   offsets[0] = 0;
668:   for (i=1; i<size; ++i) offsets[i] = offsets[i-1] + sizes[i-1];
669:   N = offsets[size-1] + sizes[size-1];

671:   PetscMalloc1(N,&(is->total));
672:   ISGetIndices(is,&lindices);
673:   MPI_Allgatherv((void*)lindices,nn,MPIU_INT,is->total,sizes,offsets,MPIU_INT,comm);
674:   ISRestoreIndices(is,&lindices);
675:   is->local_offset = offsets[rank];
676:   PetscFree2(sizes,offsets);
677:   return(0);
678: }

680: /*@C
681:    ISGetTotalIndices - Retrieve an array containing all indices across the communicator.

683:    Collective on IS

685:    Input Parameter:
686: .  is - the index set

688:    Output Parameter:
689: .  indices - total indices with rank 0 indices first, and so on; total array size is
690:              the same as returned with ISGetSize().

692:    Level: intermediate

694:    Notes: this is potentially nonscalable, but depends on the size of the total index set
695:      and the size of the communicator. This may be feasible for index sets defined on
696:      subcommunicators, such that the set size does not grow with PETSC_WORLD_COMM.
697:      Note also that there is no way to tell where the local part of the indices starts
698:      (use ISGetIndices() and ISGetNonlocalIndices() to retrieve just the local and just
699:       the nonlocal part (complement), respectively).

701:    Concepts: index sets^getting nonlocal indices
702: .seealso: ISRestoreTotalIndices(), ISGetNonlocalIndices(), ISGetSize()
703: @*/
704: PetscErrorCode ISGetTotalIndices(IS is, const PetscInt *indices[])
705: {
707:   PetscMPIInt    size;

712:   MPI_Comm_size(PetscObjectComm((PetscObject)is), &size);
713:   if (size == 1) {
714:     (*is->ops->getindices)(is,indices);
715:   } else {
716:     if (!is->total) {
717:       ISGatherTotal_Private(is);
718:     }
719:     *indices = is->total;
720:   }
721:   return(0);
722: }

724: /*@C
725:    ISRestoreTotalIndices - Restore the index array obtained with ISGetTotalIndices().

727:    Not Collective.

729:    Input Parameter:
730: +  is - the index set
731: -  indices - index array; must be the array obtained with ISGetTotalIndices()

733:    Level: intermediate

735:    Concepts: index sets^getting nonlocal indices
736:    Concepts: index sets^restoring nonlocal indices
737: .seealso: ISRestoreTotalIndices(), ISGetNonlocalIndices()
738: @*/
739: PetscErrorCode  ISRestoreTotalIndices(IS is, const PetscInt *indices[])
740: {
742:   PetscMPIInt    size;

747:   MPI_Comm_size(PetscObjectComm((PetscObject)is), &size);
748:   if (size == 1) {
749:     (*is->ops->restoreindices)(is,indices);
750:   } else {
751:     if (is->total != *indices) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Index array pointer being restored does not point to the array obtained from the IS.");
752:   }
753:   return(0);
754: }
755: /*@C
756:    ISGetNonlocalIndices - Retrieve an array of indices from remote processors
757:                        in this communicator.

759:    Collective on IS

761:    Input Parameter:
762: .  is - the index set

764:    Output Parameter:
765: .  indices - indices with rank 0 indices first, and so on,  omitting
766:              the current rank.  Total number of indices is the difference
767:              total and local, obtained with ISGetSize() and ISGetLocalSize(),
768:              respectively.

770:    Level: intermediate

772:    Notes: restore the indices using ISRestoreNonlocalIndices().
773:           The same scalability considerations as those for ISGetTotalIndices
774:           apply here.

776:    Concepts: index sets^getting nonlocal indices
777: .seealso: ISGetTotalIndices(), ISRestoreNonlocalIndices(), ISGetSize(), ISGetLocalSize().
778: @*/
779: PetscErrorCode  ISGetNonlocalIndices(IS is, const PetscInt *indices[])
780: {
782:   PetscMPIInt    size;
783:   PetscInt       n, N;

788:   MPI_Comm_size(PetscObjectComm((PetscObject)is), &size);
789:   if (size == 1) *indices = NULL;
790:   else {
791:     if (!is->total) {
792:       ISGatherTotal_Private(is);
793:     }
794:     ISGetLocalSize(is,&n);
795:     ISGetSize(is,&N);
796:     PetscMalloc1(N-n, &(is->nonlocal));
797:     PetscMemcpy(is->nonlocal, is->total, sizeof(PetscInt)*is->local_offset);
798:     PetscMemcpy(is->nonlocal+is->local_offset, is->total+is->local_offset+n, sizeof(PetscInt)*(N - is->local_offset - n));
799:     *indices = is->nonlocal;
800:   }
801:   return(0);
802: }

804: /*@C
805:    ISRestoreTotalIndices - Restore the index array obtained with ISGetNonlocalIndices().

807:    Not Collective.

809:    Input Parameter:
810: +  is - the index set
811: -  indices - index array; must be the array obtained with ISGetNonlocalIndices()

813:    Level: intermediate

815:    Concepts: index sets^getting nonlocal indices
816:    Concepts: index sets^restoring nonlocal indices
817: .seealso: ISGetTotalIndices(), ISGetNonlocalIndices(), ISRestoreTotalIndices()
818: @*/
819: PetscErrorCode  ISRestoreNonlocalIndices(IS is, const PetscInt *indices[])
820: {
824:   if (is->nonlocal != *indices) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Index array pointer being restored does not point to the array obtained from the IS.");
825:   return(0);
826: }

828: /*@
829:    ISGetNonlocalIS - Gather all nonlocal indices for this IS and present
830:                      them as another sequential index set.


833:    Collective on IS

835:    Input Parameter:
836: .  is - the index set

838:    Output Parameter:
839: .  complement - sequential IS with indices identical to the result of
840:                 ISGetNonlocalIndices()

842:    Level: intermediate

844:    Notes: complement represents the result of ISGetNonlocalIndices as an IS.
845:           Therefore scalability issues similar to ISGetNonlocalIndices apply.
846:           The resulting IS must be restored using ISRestoreNonlocalIS().

848:    Concepts: index sets^getting nonlocal indices
849: .seealso: ISGetNonlocalIndices(), ISRestoreNonlocalIndices(),  ISAllGather(), ISGetSize()
850: @*/
851: PetscErrorCode  ISGetNonlocalIS(IS is, IS *complement)
852: {

858:   /* Check if the complement exists already. */
859:   if (is->complement) {
860:     *complement = is->complement;
861:     PetscObjectReference((PetscObject)(is->complement));
862:   } else {
863:     PetscInt       N, n;
864:     const PetscInt *idx;
865:     ISGetSize(is, &N);
866:     ISGetLocalSize(is,&n);
867:     ISGetNonlocalIndices(is, &idx);
868:     ISCreateGeneral(PETSC_COMM_SELF, N-n,idx, PETSC_USE_POINTER, &(is->complement));
869:     PetscObjectReference((PetscObject)is->complement);
870:     *complement = is->complement;
871:   }
872:   return(0);
873: }


876: /*@
877:    ISRestoreNonlocalIS - Restore the IS obtained with ISGetNonlocalIS().

879:    Not collective.

881:    Input Parameter:
882: +  is         - the index set
883: -  complement - index set of is's nonlocal indices

885:    Level: intermediate


888:    Concepts: index sets^getting nonlocal indices
889:    Concepts: index sets^restoring nonlocal indices
890: .seealso: ISGetNonlocalIS(), ISGetNonlocalIndices(), ISRestoreNonlocalIndices()
891: @*/
892: PetscErrorCode  ISRestoreNonlocalIS(IS is, IS *complement)
893: {
895:   PetscInt       refcnt;

900:   if (*complement != is->complement) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Complement IS being restored was not obtained with ISGetNonlocalIS()");
901:   PetscObjectGetReference((PetscObject)(is->complement), &refcnt);
902:   if (refcnt <= 1) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Duplicate call to ISRestoreNonlocalIS() detected");
903:   PetscObjectDereference((PetscObject)(is->complement));
904:   return(0);
905: }

907: /*@C
908:    ISView - Displays an index set.

910:    Collective on IS

912:    Input Parameters:
913: +  is - the index set
914: -  viewer - viewer used to display the set, for example PETSC_VIEWER_STDOUT_SELF.

916:    Level: intermediate

918: .seealso: PetscViewerASCIIOpen()
919: @*/
920: PetscErrorCode  ISView(IS is,PetscViewer viewer)
921: {

926:   if (!viewer) {
927:     PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)is),&viewer);
928:   }

932:   PetscObjectPrintClassNamePrefixType((PetscObject)is,viewer);
933:   (*is->ops->view)(is,viewer);
934:   return(0);
935: }

937: /*@
938:   ISLoad - Loads a vector that has been stored in binary or HDF5 format with ISView().

940:   Collective on PetscViewer

942:   Input Parameters:
943: + is - the newly loaded vector, this needs to have been created with ISCreate() or some related function before a call to ISLoad().
944: - viewer - binary file viewer, obtained from PetscViewerBinaryOpen() or HDF5 file viewer, obtained from PetscViewerHDF5Open()

946:   Level: intermediate

948:   Notes:
949:   IF using HDF5, you must assign the IS the same name as was used in the IS
950:   that was stored in the file using PetscObjectSetName(). Otherwise you will
951:   get the error message: "Cannot H5DOpen2() with Vec name NAMEOFOBJECT"

953:   Concepts: index set^loading from file

955: .seealso: PetscViewerBinaryOpen(), ISView(), MatLoad(), VecLoad()
956: @*/
957: PetscErrorCode ISLoad(IS is, PetscViewer viewer)
958: {
959:   PetscBool      isbinary, ishdf5;

965:   PetscObjectTypeCompare((PetscObject) viewer, PETSCVIEWERBINARY, &isbinary);
966:   PetscObjectTypeCompare((PetscObject) viewer, PETSCVIEWERHDF5, &ishdf5);
967:   if (!isbinary && !ishdf5) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Invalid viewer; open viewer with PetscViewerBinaryOpen()");
968:   if (!((PetscObject)is)->type_name) {ISSetType(is, ISGENERAL);}
969:   (*is->ops->load)(is, viewer);
970:   return(0);
971: }

973: /*@
974:    ISSort - Sorts the indices of an index set.

976:    Collective on IS

978:    Input Parameters:
979: .  is - the index set

981:    Level: intermediate

983:    Concepts: index sets^sorting
984:    Concepts: sorting^index set

986: .seealso: ISSortRemoveDups(), ISSorted()
987: @*/
988: PetscErrorCode  ISSort(IS is)
989: {

994:   (*is->ops->sort)(is);
995:   return(0);
996: }

998: /*@
999:   ISSortRemoveDups - Sorts the indices of an index set, removing duplicates.

1001:   Collective on IS

1003:   Input Parameters:
1004: . is - the index set

1006:   Level: intermediate

1008:   Concepts: index sets^sorting
1009:   Concepts: sorting^index set

1011: .seealso: ISSort(), ISSorted()
1012: @*/
1013: PetscErrorCode ISSortRemoveDups(IS is)
1014: {

1019:   (*is->ops->sortremovedups)(is);
1020:   return(0);
1021: }

1023: /*@
1024:    ISToGeneral - Converts an IS object of any type to ISGENERAL type

1026:    Collective on IS

1028:    Input Parameters:
1029: .  is - the index set

1031:    Level: intermediate

1033:    Concepts: index sets^sorting
1034:    Concepts: sorting^index set

1036: .seealso: ISSorted()
1037: @*/
1038: PetscErrorCode  ISToGeneral(IS is)
1039: {

1044:   if (is->ops->togeneral) {
1045:     (*is->ops->togeneral)(is);
1046:   } else SETERRQ1(PetscObjectComm((PetscObject)is),PETSC_ERR_SUP,"Not written for this type %s",((PetscObject)is)->type_name);
1047:   return(0);
1048: }

1050: /*@
1051:    ISSorted - Checks the indices to determine whether they have been sorted.

1053:    Collective on IS

1055:    Input Parameter:
1056: .  is - the index set

1058:    Output Parameter:
1059: .  flg - output flag, either PETSC_TRUE if the index set is sorted,
1060:          or PETSC_FALSE otherwise.

1062:    Notes: For parallel IS objects this only indicates if the local part of the IS
1063:           is sorted. So some processors may return PETSC_TRUE while others may
1064:           return PETSC_FALSE.

1066:    Level: intermediate

1068: .seealso: ISSort(), ISSortRemoveDups()
1069: @*/
1070: PetscErrorCode  ISSorted(IS is,PetscBool  *flg)
1071: {

1077:   (*is->ops->sorted)(is,flg);
1078:   return(0);
1079: }

1081: /*@
1082:    ISDuplicate - Creates a duplicate copy of an index set.

1084:    Collective on IS

1086:    Input Parmeters:
1087: .  is - the index set

1089:    Output Parameters:
1090: .  isnew - the copy of the index set

1092:    Level: beginner

1094:    Concepts: index sets^duplicating

1096: .seealso: ISCreateGeneral(), ISCopy()
1097: @*/
1098: PetscErrorCode  ISDuplicate(IS is,IS *newIS)
1099: {

1105:   (*is->ops->duplicate)(is,newIS);
1106:   (*newIS)->isidentity = is->isidentity;
1107:   (*newIS)->isperm     = is->isperm;
1108:   return(0);
1109: }

1111: /*@
1112:    ISCopy - Copies an index set.

1114:    Collective on IS

1116:    Input Parmeters:
1117: .  is - the index set

1119:    Output Parameters:
1120: .  isy - the copy of the index set

1122:    Level: beginner

1124:    Concepts: index sets^copying

1126: .seealso: ISDuplicate()
1127: @*/
1128: PetscErrorCode  ISCopy(IS is,IS isy)
1129: {

1136:   if (is == isy) return(0);
1137:   (*is->ops->copy)(is,isy);
1138:   isy->isperm     = is->isperm;
1139:   isy->max        = is->max;
1140:   isy->min        = is->min;
1141:   isy->isidentity = is->isidentity;
1142:   return(0);
1143: }

1145: /*@
1146:    ISOnComm - Split a parallel IS on subcomms (usually self) or concatenate index sets on subcomms into a parallel index set

1148:    Collective on IS and comm

1150:    Input Arguments:
1151: + is - index set
1152: . comm - communicator for new index set
1153: - mode - copy semantics, PETSC_USE_POINTER for no-copy if possible, otherwise PETSC_COPY_VALUES

1155:    Output Arguments:
1156: . newis - new IS on comm

1158:    Level: advanced

1160:    Notes:
1161:    It is usually desirable to create a parallel IS and look at the local part when necessary.

1163:    This function is useful if serial ISs must be created independently, or to view many
1164:    logically independent serial ISs.

1166:    The input IS must have the same type on every process.

1168: .seealso: ISSplit()
1169: @*/
1170: PetscErrorCode  ISOnComm(IS is,MPI_Comm comm,PetscCopyMode mode,IS *newis)
1171: {
1173:   PetscMPIInt    match;

1178:   MPI_Comm_compare(PetscObjectComm((PetscObject)is),comm,&match);
1179:   if (mode != PETSC_COPY_VALUES && (match == MPI_IDENT || match == MPI_CONGRUENT)) {
1180:     PetscObjectReference((PetscObject)is);
1181:     *newis = is;
1182:   } else {
1183:     (*is->ops->oncomm)(is,comm,mode,newis);
1184:   }
1185:   return(0);
1186: }

1188: /*@
1189:    ISSetBlockSize - informs an index set that it has a given block size

1191:    Logicall Collective on IS

1193:    Input Arguments:
1194: + is - index set
1195: - bs - block size

1197:    Level: intermediate

1199: .seealso: ISGetBlockSize(), ISCreateBlock()
1200: @*/
1201: PetscErrorCode  ISSetBlockSize(IS is,PetscInt bs)
1202: {

1208:   if (bs < 1) SETERRQ1(PetscObjectComm((PetscObject)is),PETSC_ERR_ARG_OUTOFRANGE,"Block size %D, must be positive",bs);
1209:   (*is->ops->setblocksize)(is,bs);
1210:   return(0);
1211: }

1213: /*@
1214:    ISGetBlockSize - Returns the number of elements in a block.

1216:    Not Collective

1218:    Input Parameter:
1219: .  is - the index set

1221:    Output Parameter:
1222: .  size - the number of elements in a block

1224:    Level: intermediate

1226:    Concepts: IS^block size
1227:    Concepts: index sets^block size

1229: .seealso: ISBlockGetSize(), ISGetSize(), ISCreateBlock(), ISSetBlockSize()
1230: @*/
1231: PetscErrorCode  ISGetBlockSize(IS is,PetscInt *size)
1232: {

1236:   PetscLayoutGetBlockSize(is->map, size);
1237:   return(0);
1238: }

1240: PetscErrorCode ISGetIndicesCopy(IS is, PetscInt idx[])
1241: {
1243:   PetscInt       len,i;
1244:   const PetscInt *ptr;

1247:   ISGetSize(is,&len);
1248:   ISGetIndices(is,&ptr);
1249:   for (i=0; i<len; i++) idx[i] = ptr[i];
1250:   ISRestoreIndices(is,&ptr);
1251:   return(0);
1252: }

1254: /*MC
1255:     ISGetIndicesF90 - Accesses the elements of an index set from Fortran90.
1256:     The users should call ISRestoreIndicesF90() after having looked at the
1257:     indices.  The user should NOT change the indices.

1259:     Synopsis:
1260:     ISGetIndicesF90(IS x,{integer, pointer :: xx_v(:)},integer ierr)

1262:     Not collective

1264:     Input Parameter:
1265: .   x - index set

1267:     Output Parameters:
1268: +   xx_v - the Fortran90 pointer to the array
1269: -   ierr - error code

1271:     Example of Usage:
1272: .vb
1273:     PetscScalar, pointer xx_v(:)
1274:     ....
1275:     call ISGetIndicesF90(x,xx_v,ierr)
1276:     a = xx_v(3)
1277:     call ISRestoreIndicesF90(x,xx_v,ierr)
1278: .ve

1280:     Notes:
1281:     Not yet supported for all F90 compilers.

1283:     Level: intermediate

1285: .seealso:  ISRestoreIndicesF90(), ISGetIndices(), ISRestoreIndices()

1287:   Concepts: index sets^getting indices in f90
1288:   Concepts: indices of index set in f90

1290: M*/

1292: /*MC
1293:     ISRestoreIndicesF90 - Restores an index set to a usable state after
1294:     a call to ISGetIndicesF90().

1296:     Synopsis:
1297:     ISRestoreIndicesF90(IS x,{integer, pointer :: xx_v(:)},integer ierr)

1299:     Not collective

1301:     Input Parameters:
1302: .   x - index set
1303: .   xx_v - the Fortran90 pointer to the array

1305:     Output Parameter:
1306: .   ierr - error code


1309:     Example of Usage:
1310: .vb
1311:     PetscScalar, pointer xx_v(:)
1312:     ....
1313:     call ISGetIndicesF90(x,xx_v,ierr)
1314:     a = xx_v(3)
1315:     call ISRestoreIndicesF90(x,xx_v,ierr)
1316: .ve

1318:     Notes:
1319:     Not yet supported for all F90 compilers.

1321:     Level: intermediate

1323: .seealso:  ISGetIndicesF90(), ISGetIndices(), ISRestoreIndices()

1325: M*/

1327: /*MC
1328:     ISBlockGetIndicesF90 - Accesses the elements of an index set from Fortran90.
1329:     The users should call ISBlockRestoreIndicesF90() after having looked at the
1330:     indices.  The user should NOT change the indices.

1332:     Synopsis:
1333:     ISBlockGetIndicesF90(IS x,{integer, pointer :: xx_v(:)},integer ierr)

1335:     Not collective

1337:     Input Parameter:
1338: .   x - index set

1340:     Output Parameters:
1341: +   xx_v - the Fortran90 pointer to the array
1342: -   ierr - error code
1343:     Example of Usage:
1344: .vb
1345:     PetscScalar, pointer xx_v(:)
1346:     ....
1347:     call ISBlockGetIndicesF90(x,xx_v,ierr)
1348:     a = xx_v(3)
1349:     call ISBlockRestoreIndicesF90(x,xx_v,ierr)
1350: .ve

1352:     Notes:
1353:     Not yet supported for all F90 compilers

1355:     Level: intermediate

1357: .seealso:  ISBlockRestoreIndicesF90(), ISGetIndices(), ISRestoreIndices(),
1358:            ISRestoreIndices()

1360:   Concepts: index sets^getting block indices in f90
1361:   Concepts: indices of index set in f90
1362:   Concepts: block^ indices of index set in f90

1364: M*/

1366: /*MC
1367:     ISBlockRestoreIndicesF90 - Restores an index set to a usable state after
1368:     a call to ISBlockGetIndicesF90().

1370:     Synopsis:
1371:     ISBlockRestoreIndicesF90(IS x,{integer, pointer :: xx_v(:)},integer ierr)

1373:     Not Collective

1375:     Input Parameters:
1376: +   x - index set
1377: -   xx_v - the Fortran90 pointer to the array

1379:     Output Parameter:
1380: .   ierr - error code

1382:     Example of Usage:
1383: .vb
1384:     PetscScalar, pointer xx_v(:)
1385:     ....
1386:     call ISBlockGetIndicesF90(x,xx_v,ierr)
1387:     a = xx_v(3)
1388:     call ISBlockRestoreIndicesF90(x,xx_v,ierr)
1389: .ve

1391:     Notes:
1392:     Not yet supported for all F90 compilers

1394:     Level: intermediate

1396: .seealso:  ISBlockGetIndicesF90(), ISGetIndices(), ISRestoreIndices(), ISRestoreIndicesF90()

1398: M*/