Actual source code: index.c

  1: /*
  2:    Defines the abstract operations on index sets, i.e. the public interface.
  3: */
  4: #include <petsc/private/isimpl.h>
  5: #include <petscviewer.h>
  6: #include <petscsf.h>

  8: /* Logging support */
  9: PetscClassId IS_CLASSID;
 10: /* TODO: Much more events are missing! */
 11: PetscLogEvent IS_View;
 12: PetscLogEvent IS_Load;

 14: /*@
 15:   ISRenumber - Renumbers the non-negative entries of an index set in a contiguous way, starting from 0.

 17:   Collective

 19:   Input Parameters:
 20: + subset      - the index set
 21: - subset_mult - the multiplicity of each entry in subset (optional, can be `NULL`)

 23:   Output Parameters:
 24: + N        - one past the largest entry of the new `IS`
 25: - subset_n - the new `IS`

 27:   Level: intermediate

 29:   Note:
 30:   All negative entries are mapped to -1. Indices with non positive multiplicities are skipped.

 32: .seealso: `IS`
 33: @*/
 34: PetscErrorCode ISRenumber(IS subset, IS subset_mult, PetscInt *N, IS *subset_n)
 35: {
 36:   PetscSF         sf;
 37:   PetscLayout     map;
 38:   const PetscInt *idxs, *idxs_mult = NULL;
 39:   PetscInt       *leaf_data, *root_data, *gidxs, *ilocal, *ilocalneg;
 40:   PetscInt        N_n, n, i, bounds[2], Nl, ibs;
 41:   PetscInt        n_n, nlocals, start, first_index, npos, nneg;
 42:   PetscMPIInt     commsize;
 43:   PetscBool       first_found, isblock;

 45:   PetscFunctionBegin;
 48:   if (N) PetscAssertPointer(N, 3);
 49:   else if (!subset_n) PetscFunctionReturn(PETSC_SUCCESS);
 50:   PetscCall(ISGetLocalSize(subset, &n));
 51:   if (subset_mult) {
 52:     PetscCall(ISGetLocalSize(subset_mult, &i));
 53:     PetscCheck(i == n, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Local subset and multiplicity sizes don't match! %" PetscInt_FMT " != %" PetscInt_FMT, n, i);
 54:   }
 55:   /* create workspace layout for computing global indices of subset */
 56:   PetscCall(PetscMalloc1(n, &ilocal));
 57:   PetscCall(PetscMalloc1(n, &ilocalneg));
 58:   PetscCall(ISGetIndices(subset, &idxs));
 59:   PetscCall(ISGetBlockSize(subset, &ibs));
 60:   PetscCall(PetscObjectTypeCompare((PetscObject)subset, ISBLOCK, &isblock));
 61:   if (subset_mult) PetscCall(ISGetIndices(subset_mult, &idxs_mult));
 62:   bounds[0] = PETSC_INT_MAX;
 63:   bounds[1] = PETSC_INT_MIN;
 64:   for (i = 0, npos = 0, nneg = 0; i < n; i++) {
 65:     if (idxs[i] < 0) {
 66:       ilocalneg[nneg++] = i;
 67:       continue;
 68:     }
 69:     if (idxs[i] < bounds[0]) bounds[0] = idxs[i];
 70:     if (idxs[i] > bounds[1]) bounds[1] = idxs[i];
 71:     ilocal[npos++] = i;
 72:   }
 73:   if (npos == n) {
 74:     PetscCall(PetscFree(ilocal));
 75:     PetscCall(PetscFree(ilocalneg));
 76:   }

 78:   /* create sf : leaf_data == multiplicity of indexes, root data == global index in layout */
 79:   PetscCall(PetscMalloc1(n, &leaf_data));
 80:   for (i = 0; i < n; i++) leaf_data[i] = idxs_mult ? PetscMax(idxs_mult[i], 0) : 1;

 82:   /* local size of new subset */
 83:   n_n = 0;
 84:   for (i = 0; i < n; i++) n_n += leaf_data[i];
 85:   if (ilocalneg)
 86:     for (i = 0; i < nneg; i++) leaf_data[ilocalneg[i]] = 0;
 87:   PetscCall(PetscFree(ilocalneg));
 88:   PetscCall(PetscMalloc1(PetscMax(n_n, n), &gidxs)); /* allocating extra space to reuse gidxs */
 89:   /* check for early termination (all negative) */
 90:   PetscCall(PetscGlobalMinMaxInt(PetscObjectComm((PetscObject)subset), bounds, bounds));
 91:   if (bounds[1] < bounds[0]) {
 92:     if (N) *N = 0;
 93:     if (subset_n) { /* all negative */
 94:       for (i = 0; i < n_n; i++) gidxs[i] = -1;
 95:       PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)subset), n_n, gidxs, PETSC_COPY_VALUES, subset_n));
 96:     }
 97:     PetscCall(PetscFree(leaf_data));
 98:     PetscCall(PetscFree(gidxs));
 99:     PetscCall(ISRestoreIndices(subset, &idxs));
100:     if (subset_mult) PetscCall(ISRestoreIndices(subset_mult, &idxs_mult));
101:     PetscCall(PetscFree(ilocal));
102:     PetscCall(PetscFree(ilocalneg));
103:     PetscFunctionReturn(PETSC_SUCCESS);
104:   }

106:   /* split work */
107:   N_n = bounds[1] - bounds[0] + 1;
108:   PetscCall(PetscLayoutCreate(PetscObjectComm((PetscObject)subset), &map));
109:   PetscCall(PetscLayoutSetBlockSize(map, 1));
110:   PetscCall(PetscLayoutSetSize(map, N_n));
111:   PetscCall(PetscLayoutSetUp(map));
112:   PetscCall(PetscLayoutGetLocalSize(map, &Nl));

114:   /* global indexes in layout */
115:   for (i = 0; i < npos; i++) gidxs[i] = (ilocal ? idxs[ilocal[i]] : idxs[i]) - bounds[0];
116:   PetscCall(ISRestoreIndices(subset, &idxs));
117:   PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)subset), &sf));
118:   PetscCall(PetscSFSetGraphLayout(sf, map, npos, ilocal, PETSC_USE_POINTER, gidxs));
119:   PetscCall(PetscLayoutDestroy(&map));

121:   /* reduce from leaves to roots */
122:   PetscCall(PetscCalloc1(Nl, &root_data));
123:   PetscCall(PetscSFReduceBegin(sf, MPIU_INT, leaf_data, root_data, MPI_MAX));
124:   PetscCall(PetscSFReduceEnd(sf, MPIU_INT, leaf_data, root_data, MPI_MAX));

126:   /* count indexes in local part of layout */
127:   nlocals     = 0;
128:   first_index = -1;
129:   first_found = PETSC_FALSE;
130:   for (i = 0; i < Nl; i++) {
131:     if (!first_found && root_data[i]) {
132:       first_found = PETSC_TRUE;
133:       first_index = i;
134:     }
135:     nlocals += root_data[i];
136:   }

138:   /* cumulative of number of indexes and size of subset without holes */
139: #if defined(PETSC_HAVE_MPI_EXSCAN)
140:   start = 0;
141:   PetscCallMPI(MPI_Exscan(&nlocals, &start, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)subset)));
142: #else
143:   PetscCallMPI(MPI_Scan(&nlocals, &start, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)subset)));
144:   start = start - nlocals;
145: #endif

147:   if (N) { /* compute total size of new subset if requested */
148:     *N = start + nlocals;
149:     PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)subset), &commsize));
150:     PetscCallMPI(MPI_Bcast(N, 1, MPIU_INT, commsize - 1, PetscObjectComm((PetscObject)subset)));
151:   }

153:   if (!subset_n) {
154:     PetscCall(PetscFree(gidxs));
155:     PetscCall(PetscSFDestroy(&sf));
156:     PetscCall(PetscFree(leaf_data));
157:     PetscCall(PetscFree(root_data));
158:     PetscCall(PetscFree(ilocal));
159:     if (subset_mult) PetscCall(ISRestoreIndices(subset_mult, &idxs_mult));
160:     PetscFunctionReturn(PETSC_SUCCESS);
161:   }

163:   /* adapt root data with cumulative */
164:   if (first_found) {
165:     PetscInt old_index;

167:     root_data[first_index] += start;
168:     old_index = first_index;
169:     for (i = first_index + 1; i < Nl; i++) {
170:       if (root_data[i]) {
171:         root_data[i] += root_data[old_index];
172:         old_index = i;
173:       }
174:     }
175:   }

177:   /* from roots to leaves */
178:   PetscCall(PetscSFBcastBegin(sf, MPIU_INT, root_data, leaf_data, MPI_REPLACE));
179:   PetscCall(PetscSFBcastEnd(sf, MPIU_INT, root_data, leaf_data, MPI_REPLACE));
180:   PetscCall(PetscSFDestroy(&sf));

182:   /* create new IS with global indexes without holes */
183:   for (i = 0; i < n_n; i++) gidxs[i] = -1;
184:   if (subset_mult) {
185:     PetscInt cum;

187:     isblock = PETSC_FALSE;
188:     for (i = 0, cum = 0; i < n; i++)
189:       for (PetscInt j = 0; j < idxs_mult[i]; j++) gidxs[cum++] = leaf_data[i] - idxs_mult[i] + j;
190:   } else
191:     for (i = 0; i < n; i++) gidxs[i] = leaf_data[i] - 1;

193:   if (isblock) {
194:     if (ibs > 1)
195:       for (i = 0; i < n_n / ibs; i++) gidxs[i] = gidxs[i * ibs] / ibs;
196:     PetscCall(ISCreateBlock(PetscObjectComm((PetscObject)subset), ibs, n_n / ibs, gidxs, PETSC_COPY_VALUES, subset_n));
197:   } else {
198:     PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)subset), n_n, gidxs, PETSC_COPY_VALUES, subset_n));
199:   }
200:   if (subset_mult) PetscCall(ISRestoreIndices(subset_mult, &idxs_mult));
201:   PetscCall(PetscFree(gidxs));
202:   PetscCall(PetscFree(leaf_data));
203:   PetscCall(PetscFree(root_data));
204:   PetscCall(PetscFree(ilocal));
205:   PetscFunctionReturn(PETSC_SUCCESS);
206: }

208: /*@
209:   ISCreateSubIS - Create a sub index set from a global index set selecting some components.

211:   Collective

213:   Input Parameters:
214: + is    - the index set
215: - comps - which components we will extract from `is`

217:   Output Parameters:
218: . subis - the new sub index set

220:   Example usage:
221:   We have an index set `is` living on 3 processes with the following values\:
222:   | 4 9 0 | 2 6 7 | 10 11 1|
223:   and another index set `comps` used to indicate which components of is  we want to take,
224:   | 7 5  | 1 2 | 0 4|
225:   The output index set `subis` should look like\:
226:   | 11 7 | 9 0 | 4 6|

228:   Level: intermediate

230: .seealso: `IS`, `VecGetSubVector()`, `MatCreateSubMatrix()`
231: @*/
232: PetscErrorCode ISCreateSubIS(IS is, IS comps, IS *subis)
233: {
234:   PetscSF         sf;
235:   const PetscInt *is_indices, *comps_indices;
236:   PetscInt       *subis_indices, nroots, nleaves, *mine, i, lidx;
237:   PetscMPIInt     owner;
238:   PetscSFNode    *remote;
239:   MPI_Comm        comm;

241:   PetscFunctionBegin;
244:   PetscAssertPointer(subis, 3);

246:   PetscCall(PetscObjectGetComm((PetscObject)is, &comm));
247:   PetscCall(ISGetLocalSize(comps, &nleaves));
248:   PetscCall(ISGetLocalSize(is, &nroots));
249:   PetscCall(PetscMalloc1(nleaves, &remote));
250:   PetscCall(PetscMalloc1(nleaves, &mine));
251:   PetscCall(ISGetIndices(comps, &comps_indices));
252:   /*
253:    * Construct a PetscSF in which "is" data serves as roots and "subis" is leaves.
254:    * Root data are sent to leaves using PetscSFBcast().
255:    * */
256:   for (i = 0; i < nleaves; i++) {
257:     mine[i] = i;
258:     /* Connect a remote root with the current leaf. The value on the remote root
259:      * will be received by the current local leaf.
260:      * */
261:     owner = -1;
262:     lidx  = -1;
263:     PetscCall(PetscLayoutFindOwnerIndex(is->map, comps_indices[i], &owner, &lidx));
264:     remote[i].rank  = owner;
265:     remote[i].index = lidx;
266:   }
267:   PetscCall(ISRestoreIndices(comps, &comps_indices));
268:   PetscCall(PetscSFCreate(comm, &sf));
269:   PetscCall(PetscSFSetFromOptions(sf));
270:   PetscCall(PetscSFSetGraph(sf, nroots, nleaves, mine, PETSC_OWN_POINTER, remote, PETSC_OWN_POINTER));

272:   PetscCall(PetscMalloc1(nleaves, &subis_indices));
273:   PetscCall(ISGetIndices(is, &is_indices));
274:   PetscCall(PetscSFBcastBegin(sf, MPIU_INT, is_indices, subis_indices, MPI_REPLACE));
275:   PetscCall(PetscSFBcastEnd(sf, MPIU_INT, is_indices, subis_indices, MPI_REPLACE));
276:   PetscCall(ISRestoreIndices(is, &is_indices));
277:   PetscCall(PetscSFDestroy(&sf));
278:   PetscCall(ISCreateGeneral(comm, nleaves, subis_indices, PETSC_OWN_POINTER, subis));
279:   PetscFunctionReturn(PETSC_SUCCESS);
280: }

282: /*@
283:   ISClearInfoCache - clear the cache of computed index set properties

285:   Not Collective

287:   Input Parameters:
288: + is                    - the index set
289: - clear_permanent_local - whether to remove the permanent status of local properties

291:   Level: developer

293:   Note:
294:   Because all processes must agree on the global permanent status of a property,
295:   the permanent status can only be changed with `ISSetInfo()`, because this routine is not collective

297: .seealso: `IS`, `ISInfo`, `ISInfoType`, `ISSetInfo()`
298: @*/
299: PetscErrorCode ISClearInfoCache(IS is, PetscBool clear_permanent_local)
300: {
301:   PetscInt i, j;

303:   PetscFunctionBegin;
306:   for (i = 0; i < IS_INFO_MAX; i++) {
307:     if (clear_permanent_local) is->info_permanent[IS_LOCAL][i] = PETSC_FALSE;
308:     for (j = 0; j < 2; j++) {
309:       if (!is->info_permanent[j][i]) is->info[j][i] = IS_INFO_UNKNOWN;
310:     }
311:   }
312:   PetscFunctionReturn(PETSC_SUCCESS);
313: }

315: static PetscErrorCode ISSetInfo_Internal(IS is, ISInfo info, ISInfoType type, ISInfoBool ipermanent, PetscBool flg)
316: {
317:   ISInfoBool iflg          = flg ? IS_INFO_TRUE : IS_INFO_FALSE;
318:   PetscInt   itype         = (type == IS_LOCAL) ? 0 : 1;
319:   PetscBool  permanent_set = (ipermanent == IS_INFO_UNKNOWN) ? PETSC_FALSE : PETSC_TRUE;
320:   PetscBool  permanent     = (ipermanent == IS_INFO_TRUE) ? PETSC_TRUE : PETSC_FALSE;

322:   PetscFunctionBegin;
323:   /* set this property */
324:   is->info[itype][(int)info] = iflg;
325:   if (permanent_set) is->info_permanent[itype][(int)info] = permanent;
326:   /* set implications */
327:   switch (info) {
328:   case IS_SORTED:
329:     if (PetscDefined(USE_DEBUG) && flg) {
330:       PetscInt        n;
331:       const PetscInt *indices;

333:       PetscCall(ISGetLocalSize(is, &n));
334:       PetscCall(ISGetIndices(is, &indices));
335:       PetscCall(PetscSortedInt(n, indices, &flg));
336:       if (type == IS_GLOBAL) PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &flg, 1, MPI_C_BOOL, MPI_LAND, PetscObjectComm((PetscObject)is)));
337:       PetscCheck(flg, type == IS_GLOBAL ? PetscObjectComm((PetscObject)is) : PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "IS is not sorted");
338:       PetscCall(ISRestoreIndices(is, &indices));
339:     }
340:     if (flg && type == IS_GLOBAL) { /* an array that is globally sorted is also locally sorted */
341:       is->info[IS_LOCAL][(int)info] = IS_INFO_TRUE;
342:       /* global permanence implies local permanence */
343:       if (permanent_set && permanent) is->info_permanent[IS_LOCAL][(int)info] = PETSC_TRUE;
344:     }
345:     if (!flg) { /* if an array is not sorted, it cannot be an interval or the identity */
346:       is->info[itype][IS_INTERVAL] = IS_INFO_FALSE;
347:       is->info[itype][IS_IDENTITY] = IS_INFO_FALSE;
348:       if (permanent_set) {
349:         is->info_permanent[itype][IS_INTERVAL] = permanent;
350:         is->info_permanent[itype][IS_IDENTITY] = permanent;
351:       }
352:     }
353:     break;
354:   case IS_UNIQUE:
355:     if (flg && type == IS_GLOBAL) { /* an array that is globally unique is also locally unique */
356:       is->info[IS_LOCAL][(int)info] = IS_INFO_TRUE;
357:       /* global permanence implies local permanence */
358:       if (permanent_set && permanent) is->info_permanent[IS_LOCAL][(int)info] = PETSC_TRUE;
359:     }
360:     if (!flg) { /* if an array is not unique, it cannot be a permutation, and interval, or the identity */
361:       is->info[itype][IS_PERMUTATION] = IS_INFO_FALSE;
362:       is->info[itype][IS_INTERVAL]    = IS_INFO_FALSE;
363:       is->info[itype][IS_IDENTITY]    = IS_INFO_FALSE;
364:       if (permanent_set) {
365:         is->info_permanent[itype][IS_PERMUTATION] = permanent;
366:         is->info_permanent[itype][IS_INTERVAL]    = permanent;
367:         is->info_permanent[itype][IS_IDENTITY]    = permanent;
368:       }
369:     }
370:     break;
371:   case IS_PERMUTATION:
372:     if (flg) { /* an array that is a permutation is unique and is unique locally */
373:       is->info[itype][IS_UNIQUE]    = IS_INFO_TRUE;
374:       is->info[IS_LOCAL][IS_UNIQUE] = IS_INFO_TRUE;
375:       if (permanent_set && permanent) {
376:         is->info_permanent[itype][IS_UNIQUE]    = PETSC_TRUE;
377:         is->info_permanent[IS_LOCAL][IS_UNIQUE] = PETSC_TRUE;
378:       }
379:     } else { /* an array that is not a permutation cannot be the identity */
380:       is->info[itype][IS_IDENTITY] = IS_INFO_FALSE;
381:       if (permanent_set) is->info_permanent[itype][IS_IDENTITY] = permanent;
382:     }
383:     break;
384:   case IS_INTERVAL:
385:     if (flg) { /* an array that is an interval is sorted and unique */
386:       is->info[itype][IS_SORTED]    = IS_INFO_TRUE;
387:       is->info[IS_LOCAL][IS_SORTED] = IS_INFO_TRUE;
388:       is->info[itype][IS_UNIQUE]    = IS_INFO_TRUE;
389:       is->info[IS_LOCAL][IS_UNIQUE] = IS_INFO_TRUE;
390:       if (permanent_set && permanent) {
391:         is->info_permanent[itype][IS_SORTED]    = PETSC_TRUE;
392:         is->info_permanent[IS_LOCAL][IS_SORTED] = PETSC_TRUE;
393:         is->info_permanent[itype][IS_UNIQUE]    = PETSC_TRUE;
394:         is->info_permanent[IS_LOCAL][IS_UNIQUE] = PETSC_TRUE;
395:       }
396:     } else { /* an array that is not an interval cannot be the identity */
397:       is->info[itype][IS_IDENTITY] = IS_INFO_FALSE;
398:       if (permanent_set) is->info_permanent[itype][IS_IDENTITY] = permanent;
399:     }
400:     break;
401:   case IS_IDENTITY:
402:     if (flg) { /* an array that is the identity is sorted, unique, an interval, and a permutation */
403:       is->info[itype][IS_SORTED]      = IS_INFO_TRUE;
404:       is->info[IS_LOCAL][IS_SORTED]   = IS_INFO_TRUE;
405:       is->info[itype][IS_UNIQUE]      = IS_INFO_TRUE;
406:       is->info[IS_LOCAL][IS_UNIQUE]   = IS_INFO_TRUE;
407:       is->info[itype][IS_PERMUTATION] = IS_INFO_TRUE;
408:       is->info[itype][IS_INTERVAL]    = IS_INFO_TRUE;
409:       is->info[IS_LOCAL][IS_INTERVAL] = IS_INFO_TRUE;
410:       if (permanent_set && permanent) {
411:         is->info_permanent[itype][IS_SORTED]      = PETSC_TRUE;
412:         is->info_permanent[IS_LOCAL][IS_SORTED]   = PETSC_TRUE;
413:         is->info_permanent[itype][IS_UNIQUE]      = PETSC_TRUE;
414:         is->info_permanent[IS_LOCAL][IS_UNIQUE]   = PETSC_TRUE;
415:         is->info_permanent[itype][IS_PERMUTATION] = PETSC_TRUE;
416:         is->info_permanent[itype][IS_INTERVAL]    = PETSC_TRUE;
417:         is->info_permanent[IS_LOCAL][IS_INTERVAL] = PETSC_TRUE;
418:       }
419:     }
420:     break;
421:   default:
422:     PetscCheck(type != IS_LOCAL, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Unknown IS property");
423:     SETERRQ(PetscObjectComm((PetscObject)is), PETSC_ERR_ARG_OUTOFRANGE, "Unknown IS property");
424:   }
425:   PetscFunctionReturn(PETSC_SUCCESS);
426: }

428: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
429: /*@
430:   ISSetInfo - Set known information about an index set.

432:   Logically Collective if `ISInfoType` is `IS_GLOBAL`

434:   Input Parameters:
435: + is        - the index set
436: . info      - describing a property of the index set, one of those listed below,
437: . type      - `IS_LOCAL` if the information describes the local portion of the index set,
438:           `IS_GLOBAL` if it describes the whole index set
439: . permanent - `PETSC_TRUE` if it is known that the property will persist through changes to the index set, `PETSC_FALSE` otherwise
440:                If the user sets a property as permanently known, it will bypass computation of that property
441: - flg       - set the described property as true (`PETSC_TRUE`) or false (`PETSC_FALSE`)

443:   Values of `info` Describing `IS` Structure:
444: + `IS_SORTED`      - the [local part of the] index set is sorted in ascending order
445: . `IS_UNIQUE`      - each entry in the [local part of the] index set is unique
446: . `IS_PERMUTATION` - the [local part of the] index set is a permutation of the integers {0, 1, ..., N-1}, where N is the size of the [local part of the] index set
447: . `IS_INTERVAL`    - the [local part of the] index set is equal to a contiguous range of integers {f, f + 1, ..., f + N-1}
448: - `IS_IDENTITY`    - the [local part of the] index set is equal to the integers {0, 1, ..., N-1}

450:   Level: advanced

452:   Notes:
453:   If type is `IS_GLOBAL`, all processes that share the index set must pass the same value in flg

455:   It is possible to set a property with `ISSetInfo()` that contradicts what would be previously computed with `ISGetInfo()`

457: .seealso: `ISInfo`, `ISInfoType`, `IS`
458: @*/
459: PetscErrorCode ISSetInfo(IS is, ISInfo info, ISInfoType type, PetscBool permanent, PetscBool flg)
460: {
461:   MPI_Comm    comm, errcomm;
462:   PetscMPIInt size;

464:   PetscFunctionBegin;
467:   comm = PetscObjectComm((PetscObject)is);
468:   if (type == IS_GLOBAL) {
472:     errcomm = comm;
473:   } else {
474:     errcomm = PETSC_COMM_SELF;
475:   }

477:   PetscCheck((int)info > IS_INFO_MIN && (int)info < IS_INFO_MAX, errcomm, PETSC_ERR_ARG_OUTOFRANGE, "Option %d is out of range", (int)info);

479:   PetscCallMPI(MPI_Comm_size(comm, &size));
480:   /* do not use global values if size == 1: it makes it easier to keep the implications straight */
481:   if (size == 1) type = IS_LOCAL;
482:   PetscCall(ISSetInfo_Internal(is, info, type, permanent ? IS_INFO_TRUE : IS_INFO_FALSE, flg));
483:   PetscFunctionReturn(PETSC_SUCCESS);
484: }

486: static PetscErrorCode ISGetInfo_Sorted_Private(IS is, ISInfoType type, PetscBool *flg)
487: {
488:   MPI_Comm    comm;
489:   PetscMPIInt size, rank;

491:   PetscFunctionBegin;
492:   comm = PetscObjectComm((PetscObject)is);
493:   PetscCallMPI(MPI_Comm_size(comm, &size));
494:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
495:   if (type == IS_GLOBAL && is->ops->sortedglobal) {
496:     PetscUseTypeMethod(is, sortedglobal, flg);
497:   } else {
498:     PetscBool sortedLocal = PETSC_FALSE;

500:     /* determine if the array is locally sorted */
501:     if (type == IS_GLOBAL && size > 1) {
502:       /* call ISGetInfo so that a cached value will be used if possible */
503:       PetscCall(ISGetInfo(is, IS_SORTED, IS_LOCAL, PETSC_TRUE, &sortedLocal));
504:     } else if (is->ops->sortedlocal) {
505:       PetscUseTypeMethod(is, sortedlocal, &sortedLocal);
506:     } else {
507:       /* default: get the local indices and directly check */
508:       const PetscInt *idx;
509:       PetscInt        n;

511:       PetscCall(ISGetIndices(is, &idx));
512:       PetscCall(ISGetLocalSize(is, &n));
513:       PetscCall(PetscSortedInt(n, idx, &sortedLocal));
514:       PetscCall(ISRestoreIndices(is, &idx));
515:     }

517:     if (type == IS_LOCAL || size == 1) {
518:       *flg = sortedLocal;
519:     } else {
520:       PetscCallMPI(MPIU_Allreduce(&sortedLocal, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
521:       if (*flg) {
522:         PetscInt n, min = PETSC_INT_MAX, max = PETSC_INT_MIN;
523:         PetscInt maxprev;

525:         PetscCall(ISGetLocalSize(is, &n));
526:         if (n) PetscCall(ISGetMinMax(is, &min, &max));
527:         maxprev = PETSC_INT_MIN;
528:         PetscCallMPI(MPI_Exscan(&max, &maxprev, 1, MPIU_INT, MPI_MAX, comm));
529:         if (rank && (maxprev > min)) sortedLocal = PETSC_FALSE;
530:         PetscCallMPI(MPIU_Allreduce(&sortedLocal, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
531:       }
532:     }
533:   }
534:   PetscFunctionReturn(PETSC_SUCCESS);
535: }

537: static PetscErrorCode ISGetIndicesCopy_Private(IS is, PetscInt idx[]);

539: static PetscErrorCode ISGetInfo_Unique_Private(IS is, ISInfoType type, PetscBool *flg)
540: {
541:   MPI_Comm    comm;
542:   PetscMPIInt size, rank;
543:   PetscInt    i;

545:   PetscFunctionBegin;
546:   comm = PetscObjectComm((PetscObject)is);
547:   PetscCallMPI(MPI_Comm_size(comm, &size));
548:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
549:   if (type == IS_GLOBAL && is->ops->uniqueglobal) PetscUseTypeMethod(is, uniqueglobal, flg);
550:   else {
551:     PetscBool uniqueLocal;
552:     PetscInt  n   = -1;
553:     PetscInt *idx = NULL;

555:     /* determine if the array is locally unique */
556:     if (type == IS_GLOBAL && size > 1) {
557:       /* call ISGetInfo so that a cached value will be used if possible */
558:       PetscCall(ISGetInfo(is, IS_UNIQUE, IS_LOCAL, PETSC_TRUE, &uniqueLocal));
559:     } else if (is->ops->uniquelocal) {
560:       PetscUseTypeMethod(is, uniquelocal, &uniqueLocal);
561:     } else {
562:       /* default: get the local indices and directly check */
563:       uniqueLocal = PETSC_TRUE;
564:       PetscCall(ISGetLocalSize(is, &n));
565:       PetscCall(PetscMalloc1(n, &idx));
566:       PetscCall(ISGetIndicesCopy_Private(is, idx));
567:       PetscCall(PetscIntSortSemiOrdered(n, idx));
568:       for (i = 1; i < n; i++)
569:         if (idx[i] == idx[i - 1]) break;
570:       if (i < n) uniqueLocal = PETSC_FALSE;
571:     }

573:     PetscCall(PetscFree(idx));
574:     if (type == IS_LOCAL || size == 1) {
575:       *flg = uniqueLocal;
576:     } else {
577:       PetscCallMPI(MPIU_Allreduce(&uniqueLocal, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
578:       if (*flg) {
579:         PetscInt min = PETSC_INT_MAX, max = PETSC_INT_MIN, maxprev;

581:         if (!idx) {
582:           PetscCall(ISGetLocalSize(is, &n));
583:           PetscCall(PetscMalloc1(n, &idx));
584:           PetscCall(ISGetIndicesCopy_Private(is, idx));
585:         }
586:         PetscCall(PetscParallelSortInt(is->map, is->map, idx, idx));
587:         if (n) {
588:           min = idx[0];
589:           max = idx[n - 1];
590:         }
591:         for (i = 1; i < n; i++)
592:           if (idx[i] == idx[i - 1]) break;
593:         if (i < n) uniqueLocal = PETSC_FALSE;
594:         maxprev = PETSC_INT_MIN;
595:         PetscCallMPI(MPI_Exscan(&max, &maxprev, 1, MPIU_INT, MPI_MAX, comm));
596:         if (rank && (maxprev == min)) uniqueLocal = PETSC_FALSE;
597:         PetscCallMPI(MPIU_Allreduce(&uniqueLocal, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
598:       }
599:     }
600:     PetscCall(PetscFree(idx));
601:   }
602:   PetscFunctionReturn(PETSC_SUCCESS);
603: }

605: static PetscErrorCode ISGetInfo_Permutation(IS is, ISInfoType type, PetscBool *flg)
606: {
607:   MPI_Comm    comm;
608:   PetscMPIInt size;

610:   PetscFunctionBegin;
611:   comm = PetscObjectComm((PetscObject)is);
612:   PetscCallMPI(MPI_Comm_size(comm, &size));
613:   if (type == IS_GLOBAL && is->ops->permglobal) {
614:     PetscUseTypeMethod(is, permglobal, flg);
615:   } else if (type == IS_LOCAL && is->ops->permlocal) {
616:     PetscUseTypeMethod(is, permlocal, flg);
617:   } else {
618:     PetscBool permLocal;
619:     PetscInt  n, i, rStart;
620:     PetscInt *idx;

622:     PetscCall(ISGetLocalSize(is, &n));
623:     PetscCall(PetscMalloc1(n, &idx));
624:     PetscCall(ISGetIndicesCopy_Private(is, idx));
625:     if (type == IS_GLOBAL) {
626:       PetscCall(PetscParallelSortInt(is->map, is->map, idx, idx));
627:       PetscCall(PetscLayoutGetRange(is->map, &rStart, NULL));
628:     } else {
629:       PetscCall(PetscIntSortSemiOrdered(n, idx));
630:       rStart = 0;
631:     }
632:     permLocal = PETSC_TRUE;
633:     for (i = 0; i < n; i++) {
634:       if (idx[i] != rStart + i) break;
635:     }
636:     if (i < n) permLocal = PETSC_FALSE;
637:     if (type == IS_LOCAL || size == 1) {
638:       *flg = permLocal;
639:     } else {
640:       PetscCallMPI(MPIU_Allreduce(&permLocal, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
641:     }
642:     PetscCall(PetscFree(idx));
643:   }
644:   PetscFunctionReturn(PETSC_SUCCESS);
645: }

647: static PetscErrorCode ISGetInfo_Interval(IS is, ISInfoType type, PetscBool *flg)
648: {
649:   MPI_Comm    comm;
650:   PetscMPIInt size, rank;
651:   PetscInt    i;

653:   PetscFunctionBegin;
654:   comm = PetscObjectComm((PetscObject)is);
655:   PetscCallMPI(MPI_Comm_size(comm, &size));
656:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
657:   if (type == IS_GLOBAL && is->ops->intervalglobal) {
658:     PetscUseTypeMethod(is, intervalglobal, flg);
659:   } else {
660:     PetscBool intervalLocal;

662:     /* determine if the array is locally an interval */
663:     if (type == IS_GLOBAL && size > 1) {
664:       /* call ISGetInfo so that a cached value will be used if possible */
665:       PetscCall(ISGetInfo(is, IS_INTERVAL, IS_LOCAL, PETSC_TRUE, &intervalLocal));
666:     } else if (is->ops->intervallocal) {
667:       PetscUseTypeMethod(is, intervallocal, &intervalLocal);
668:     } else {
669:       PetscInt        n;
670:       const PetscInt *idx;
671:       /* default: get the local indices and directly check */
672:       intervalLocal = PETSC_TRUE;
673:       PetscCall(ISGetLocalSize(is, &n));
674:       PetscCall(ISGetIndices(is, &idx));
675:       for (i = 1; i < n; i++)
676:         if (idx[i] != idx[i - 1] + 1) break;
677:       if (i < n) intervalLocal = PETSC_FALSE;
678:       PetscCall(ISRestoreIndices(is, &idx));
679:     }

681:     if (type == IS_LOCAL || size == 1) {
682:       *flg = intervalLocal;
683:     } else {
684:       PetscCallMPI(MPIU_Allreduce(&intervalLocal, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
685:       if (*flg) {
686:         PetscInt n, min = PETSC_INT_MAX, max = PETSC_INT_MIN;
687:         PetscInt maxprev;

689:         PetscCall(ISGetLocalSize(is, &n));
690:         if (n) PetscCall(ISGetMinMax(is, &min, &max));
691:         maxprev = PETSC_INT_MIN;
692:         PetscCallMPI(MPI_Exscan(&max, &maxprev, 1, MPIU_INT, MPI_MAX, comm));
693:         if (rank && n && (maxprev != min - 1)) intervalLocal = PETSC_FALSE;
694:         PetscCallMPI(MPIU_Allreduce(&intervalLocal, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
695:       }
696:     }
697:   }
698:   PetscFunctionReturn(PETSC_SUCCESS);
699: }

701: static PetscErrorCode ISGetInfo_Identity(IS is, ISInfoType type, PetscBool *flg)
702: {
703:   MPI_Comm    comm;
704:   PetscMPIInt size;

706:   PetscFunctionBegin;
707:   comm = PetscObjectComm((PetscObject)is);
708:   PetscCallMPI(MPI_Comm_size(comm, &size));
709:   if (type == IS_GLOBAL && is->ops->intervalglobal) {
710:     PetscBool isinterval;

712:     PetscUseTypeMethod(is, intervalglobal, &isinterval);
713:     *flg = PETSC_FALSE;
714:     if (isinterval) {
715:       PetscInt min;

717:       PetscCall(ISGetMinMax(is, &min, NULL));
718:       PetscCallMPI(MPI_Bcast(&min, 1, MPIU_INT, 0, comm));
719:       if (min == 0) *flg = PETSC_TRUE;
720:     }
721:   } else if (type == IS_LOCAL && is->ops->intervallocal) {
722:     PetscBool isinterval;

724:     PetscUseTypeMethod(is, intervallocal, &isinterval);
725:     *flg = PETSC_FALSE;
726:     if (isinterval) {
727:       PetscInt min;

729:       PetscCall(ISGetMinMax(is, &min, NULL));
730:       if (min == 0) *flg = PETSC_TRUE;
731:     }
732:   } else {
733:     PetscBool       identLocal;
734:     PetscInt        n, i, rStart;
735:     const PetscInt *idx;

737:     PetscCall(ISGetLocalSize(is, &n));
738:     PetscCall(ISGetIndices(is, &idx));
739:     PetscCall(PetscLayoutGetRange(is->map, &rStart, NULL));
740:     identLocal = PETSC_TRUE;
741:     for (i = 0; i < n; i++) {
742:       if (idx[i] != rStart + i) break;
743:     }
744:     if (i < n) identLocal = PETSC_FALSE;
745:     if (type == IS_LOCAL || size == 1) {
746:       *flg = identLocal;
747:     } else {
748:       PetscCallMPI(MPIU_Allreduce(&identLocal, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
749:     }
750:     PetscCall(ISRestoreIndices(is, &idx));
751:   }
752:   PetscFunctionReturn(PETSC_SUCCESS);
753: }

755: /*@
756:   ISGetInfo - Determine whether an index set satisfies a given property

758:   Collective or Logically Collective if the type is `IS_GLOBAL` (logically collective if the value of the property has been permanently set with `ISSetInfo()`)

760:   Input Parameters:
761: + is      - the index set
762: . info    - describing a property of the index set, one of those listed in the documentation of `ISSetInfo()`
763: . compute - if `PETSC_FALSE`, the property will not be computed if it is not already known and the property will be assumed to be false
764: - type    - whether the property is local (`IS_LOCAL`) or global (`IS_GLOBAL`)

766:   Output Parameter:
767: . flg - whether the property is true (`PETSC_TRUE`) or false (`PETSC_FALSE`)

769:   Level: advanced

771:   Notes:
772:   `ISGetInfo()` uses cached values when possible, which will be incorrect if `ISSetInfo()` has been called with incorrect information.

774:   To clear cached values, use `ISClearInfoCache()`.

776: .seealso: `IS`, `ISInfo`, `ISInfoType`, `ISSetInfo()`, `ISClearInfoCache()`
777: @*/
778: PetscErrorCode ISGetInfo(IS is, ISInfo info, ISInfoType type, PetscBool compute, PetscBool *flg)
779: {
780:   MPI_Comm    comm, errcomm;
781:   PetscMPIInt rank, size;
782:   PetscInt    itype;
783:   PetscBool   hasprop;
784:   PetscBool   infer;

786:   PetscFunctionBegin;
789:   comm = PetscObjectComm((PetscObject)is);
790:   if (type == IS_GLOBAL) {
792:     errcomm = comm;
793:   } else {
794:     errcomm = PETSC_COMM_SELF;
795:   }

797:   PetscCallMPI(MPI_Comm_size(comm, &size));
798:   PetscCallMPI(MPI_Comm_rank(comm, &rank));

800:   PetscCheck((int)info > IS_INFO_MIN && (int)info < IS_INFO_MAX, errcomm, PETSC_ERR_ARG_OUTOFRANGE, "Option %d is out of range", (int)info);
801:   if (size == 1) type = IS_LOCAL;
802:   itype   = (type == IS_LOCAL) ? 0 : 1;
803:   hasprop = PETSC_FALSE;
804:   infer   = PETSC_FALSE;
805:   if (is->info_permanent[itype][(int)info]) {
806:     hasprop = (is->info[itype][(int)info] == IS_INFO_TRUE) ? PETSC_TRUE : PETSC_FALSE;
807:     infer   = PETSC_TRUE;
808:   } else if ((itype == IS_LOCAL) && (is->info[IS_LOCAL][info] != IS_INFO_UNKNOWN)) {
809:     /* we can cache local properties as long as we clear them when the IS changes */
810:     /* NOTE: we only cache local values because there is no ISAssemblyBegin()/ISAssemblyEnd(),
811:      so we have no way of knowing when a cached value has been invalidated by changes on a different process */
812:     hasprop = (is->info[itype][(int)info] == IS_INFO_TRUE) ? PETSC_TRUE : PETSC_FALSE;
813:     infer   = PETSC_TRUE;
814:   } else if (compute) {
815:     switch (info) {
816:     case IS_SORTED:
817:       PetscCall(ISGetInfo_Sorted_Private(is, type, &hasprop));
818:       break;
819:     case IS_UNIQUE:
820:       PetscCall(ISGetInfo_Unique_Private(is, type, &hasprop));
821:       break;
822:     case IS_PERMUTATION:
823:       PetscCall(ISGetInfo_Permutation(is, type, &hasprop));
824:       break;
825:     case IS_INTERVAL:
826:       PetscCall(ISGetInfo_Interval(is, type, &hasprop));
827:       break;
828:     case IS_IDENTITY:
829:       PetscCall(ISGetInfo_Identity(is, type, &hasprop));
830:       break;
831:     default:
832:       SETERRQ(errcomm, PETSC_ERR_ARG_OUTOFRANGE, "Unknown IS property");
833:     }
834:     infer = PETSC_TRUE;
835:   }
836:   /* call ISSetInfo_Internal to keep all of the implications straight */
837:   if (infer) PetscCall(ISSetInfo_Internal(is, info, type, IS_INFO_UNKNOWN, hasprop));
838:   *flg = hasprop;
839:   PetscFunctionReturn(PETSC_SUCCESS);
840: }

842: static PetscErrorCode ISCopyInfo_Private(IS source, IS dest)
843: {
844:   PetscFunctionBegin;
845:   PetscCall(PetscArraycpy(&dest->info[0], &source->info[0], 2));
846:   PetscCall(PetscArraycpy(&dest->info_permanent[0], &source->info_permanent[0], 2));
847:   PetscFunctionReturn(PETSC_SUCCESS);
848: }

850: /*@
851:   ISIdentity - Determines whether index set is the identity mapping.

853:   Collective

855:   Input Parameter:
856: . is - the index set

858:   Output Parameter:
859: . ident - `PETSC_TRUE` if an identity, else `PETSC_FALSE`

861:   Level: intermediate

863:   Note:
864:   If `ISSetIdentity()` (or `ISSetInfo()` for a permanent property) has been called,
865:   `ISIdentity()` will return its answer without communication between processes, but
866:   otherwise the output ident will be computed from `ISGetInfo()`,
867:   which may require synchronization on the communicator of `is`.  To avoid this computation,
868:   call `ISGetInfo()` directly with the compute flag set to `PETSC_FALSE`, and ident will be assumed false.

870: .seealso: `IS`, `ISSetIdentity()`, `ISGetInfo()`
871: @*/
872: PetscErrorCode ISIdentity(IS is, PetscBool *ident)
873: {
874:   PetscFunctionBegin;
876:   PetscAssertPointer(ident, 2);
877:   PetscCall(ISGetInfo(is, IS_IDENTITY, IS_GLOBAL, PETSC_TRUE, ident));
878:   PetscFunctionReturn(PETSC_SUCCESS);
879: }

881: /*@
882:   ISSetIdentity - Informs the index set that it is an identity.

884:   Logically Collective

886:   Input Parameter:
887: . is - the index set

889:   Level: intermediate

891:   Notes:
892:   `is` will be considered the identity permanently, even if indices have been changes (for example, with
893:   `ISGeneralSetIndices()`).  It's a good idea to only set this property if `is` will not change in the future.

895:   To clear this property, use `ISClearInfoCache()`.

897:   Developer Notes:
898:   Some of these info routines have statements about values changing in the `IS`, this seems to contradict the fact that `IS` cannot be changed?

900: .seealso: `IS`, `ISIdentity()`, `ISSetInfo()`, `ISClearInfoCache()`
901: @*/
902: PetscErrorCode ISSetIdentity(IS is)
903: {
904:   PetscFunctionBegin;
906:   PetscCall(ISSetInfo(is, IS_IDENTITY, IS_GLOBAL, PETSC_TRUE, PETSC_TRUE));
907:   PetscFunctionReturn(PETSC_SUCCESS);
908: }

910: /*@
911:   ISContiguousLocal - Locates an index set with contiguous range within a global range, if possible

913:   Not Collective

915:   Input Parameters:
916: + is     - the index set
917: . gstart - global start
918: - gend   - global end

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

924:   Level: developer

926: .seealso: `IS`, `ISGetLocalSize()`, `VecGetOwnershipRange()`
927: @*/
928: PetscErrorCode ISContiguousLocal(IS is, PetscInt gstart, PetscInt gend, PetscInt *start, PetscBool *contig)
929: {
930:   PetscFunctionBegin;
932:   PetscAssertPointer(start, 4);
933:   PetscAssertPointer(contig, 5);
934:   PetscCheck(gstart <= gend, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "gstart %" PetscInt_FMT " must be less than or equal to gend %" PetscInt_FMT, gstart, gend);
935:   *start  = -1;
936:   *contig = PETSC_FALSE;
937:   PetscTryTypeMethod(is, contiguous, gstart, gend, start, contig);
938:   PetscFunctionReturn(PETSC_SUCCESS);
939: }

941: /*@
942:   ISPermutation - `PETSC_TRUE` or `PETSC_FALSE` depending on whether the
943:   index set has been declared to be a permutation.

945:   Logically Collective

947:   Input Parameter:
948: . is - the index set

950:   Output Parameter:
951: . perm - `PETSC_TRUE` if a permutation, else `PETSC_FALSE`

953:   Level: intermediate

955:   Note:
956:   If it is not already known that `is` is a permutation (if `ISSetPermutation()`
957:   or `ISSetInfo()` has not been called), this routine will not attempt to compute
958:   whether the index set is a permutation and will assume `perm` is `PETSC_FALSE`.
959:   To compute the value when it is not already known, use `ISGetInfo()` with
960:   the compute flag set to `PETSC_TRUE`.

962:   Developer Notes:
963:   Perhaps some of these routines should use the `PetscBool3` enum to return appropriate values

965: .seealso: `IS`, `ISSetPermutation()`, `ISGetInfo()`
966: @*/
967: PetscErrorCode ISPermutation(IS is, PetscBool *perm)
968: {
969:   PetscFunctionBegin;
971:   PetscAssertPointer(perm, 2);
972:   PetscCall(ISGetInfo(is, IS_PERMUTATION, IS_GLOBAL, PETSC_FALSE, perm));
973:   PetscFunctionReturn(PETSC_SUCCESS);
974: }

976: /*@
977:   ISSetPermutation - Informs the index set that it is a permutation.

979:   Logically Collective

981:   Input Parameter:
982: . is - the index set

984:   Level: intermediate

986:   Notes:
987:   `is` will be considered a permutation permanently, even if indices have been changes (for example, with
988:   `ISGeneralSetIndices()`).  It's a good idea to only set this property if `is` will not change in the future.

990:   To clear this property, use `ISClearInfoCache()`.

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

995: .seealso: `IS`, `ISPermutation()`, `ISSetInfo()`, `ISClearInfoCache().`
996: @*/
997: PetscErrorCode ISSetPermutation(IS is)
998: {
999:   PetscFunctionBegin;
1001:   if (PetscDefined(USE_DEBUG)) {
1002:     PetscMPIInt size;

1004:     PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)is), &size));
1005:     if (size == 1) {
1006:       PetscInt        i, n, *idx;
1007:       const PetscInt *iidx;

1009:       PetscCall(ISGetSize(is, &n));
1010:       PetscCall(PetscMalloc1(n, &idx));
1011:       PetscCall(ISGetIndices(is, &iidx));
1012:       PetscCall(PetscArraycpy(idx, iidx, n));
1013:       PetscCall(PetscIntSortSemiOrdered(n, idx));
1014:       for (i = 0; i < n; i++) PetscCheck(idx[i] == i, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Index set is not a permutation");
1015:       PetscCall(PetscFree(idx));
1016:       PetscCall(ISRestoreIndices(is, &iidx));
1017:     }
1018:   }
1019:   PetscCall(ISSetInfo(is, IS_PERMUTATION, IS_GLOBAL, PETSC_TRUE, PETSC_TRUE));
1020:   PetscFunctionReturn(PETSC_SUCCESS);
1021: }

1023: /*@
1024:   ISDestroy - Destroys an index set.

1026:   Collective

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

1031:   Level: beginner

1033: .seealso: `IS`, `ISCreateGeneral()`, `ISCreateStride()`, `ISCreateBlock()`
1034: @*/
1035: PetscErrorCode ISDestroy(IS *is)
1036: {
1037:   PetscFunctionBegin;
1038:   if (!*is) PetscFunctionReturn(PETSC_SUCCESS);
1040:   if (--((PetscObject)*is)->refct > 0) {
1041:     *is = NULL;
1042:     PetscFunctionReturn(PETSC_SUCCESS);
1043:   }
1044:   if ((*is)->complement) {
1045:     PetscInt refcnt;
1046:     PetscCall(PetscObjectGetReference((PetscObject)((*is)->complement), &refcnt));
1047:     PetscCheck(refcnt <= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Nonlocal IS has not been restored");
1048:     PetscCall(ISDestroy(&(*is)->complement));
1049:   }
1050:   PetscTryTypeMethod(*is, destroy);
1051:   PetscCall(PetscLayoutDestroy(&(*is)->map));
1052:   /* Destroy local representations of offproc data. */
1053:   PetscCall(PetscFree((*is)->total));
1054:   PetscCall(PetscFree((*is)->nonlocal));
1055:   PetscCall(PetscHeaderDestroy(is));
1056:   PetscFunctionReturn(PETSC_SUCCESS);
1057: }

1059: /*@
1060:   ISInvertPermutation - Creates a new permutation that is the inverse of
1061:   a given permutation.

1063:   Collective

1065:   Input Parameters:
1066: + is     - the index set
1067: - nlocal - number of indices on this processor in result (ignored for 1 processor) or
1068:             use `PETSC_DECIDE`

1070:   Output Parameter:
1071: . isout - the inverse permutation

1073:   Level: intermediate

1075:   Note:
1076:   For parallel index sets this does the complete parallel permutation, but the
1077:   code is not efficient for huge index sets (10,000,000 indices).

1079: .seealso: `IS`, `ISGetInfo()`, `ISSetPermutation()`, `ISGetPermutation()`
1080: @*/
1081: PetscErrorCode ISInvertPermutation(IS is, PetscInt nlocal, IS *isout)
1082: {
1083:   PetscBool isperm, isidentity, issame;

1085:   PetscFunctionBegin;
1087:   PetscAssertPointer(isout, 3);
1088:   PetscCall(ISGetInfo(is, IS_PERMUTATION, IS_GLOBAL, PETSC_TRUE, &isperm));
1089:   PetscCheck(isperm, PetscObjectComm((PetscObject)is), PETSC_ERR_ARG_WRONG, "Not a permutation");
1090:   PetscCall(ISGetInfo(is, IS_IDENTITY, IS_GLOBAL, PETSC_TRUE, &isidentity));
1091:   issame = PETSC_FALSE;
1092:   if (isidentity) {
1093:     PetscInt  n;
1094:     PetscBool isallsame;

1096:     PetscCall(ISGetLocalSize(is, &n));
1097:     issame = (PetscBool)(n == nlocal);
1098:     PetscCallMPI(MPIU_Allreduce(&issame, &isallsame, 1, MPI_C_BOOL, MPI_LAND, PetscObjectComm((PetscObject)is)));
1099:     issame = isallsame;
1100:   }
1101:   if (issame) PetscCall(ISDuplicate(is, isout));
1102:   else {
1103:     PetscUseTypeMethod(is, invertpermutation, nlocal, isout);
1104:     PetscCall(ISSetPermutation(*isout));
1105:   }
1106:   PetscFunctionReturn(PETSC_SUCCESS);
1107: }

1109: /*@
1110:   ISGetSize - Returns the global length of an index set.

1112:   Not Collective

1114:   Input Parameter:
1115: . is - the index set

1117:   Output Parameter:
1118: . size - the global size

1120:   Level: beginner

1122: .seealso: `IS`
1123: @*/
1124: PetscErrorCode ISGetSize(IS is, PetscInt *size)
1125: {
1126:   PetscFunctionBegin;
1128:   PetscAssertPointer(size, 2);
1129:   *size = is->map->N;
1130:   PetscFunctionReturn(PETSC_SUCCESS);
1131: }

1133: /*@
1134:   ISGetLocalSize - Returns the local (processor) length of an index set.

1136:   Not Collective

1138:   Input Parameter:
1139: . is - the index set

1141:   Output Parameter:
1142: . size - the local size

1144:   Level: beginner

1146: .seealso: `IS`, `ISGetSize()`
1147: @*/
1148: PetscErrorCode ISGetLocalSize(IS is, PetscInt *size)
1149: {
1150:   PetscFunctionBegin;
1152:   PetscAssertPointer(size, 2);
1153:   *size = is->map->n;
1154:   PetscFunctionReturn(PETSC_SUCCESS);
1155: }

1157: /*@
1158:   ISGetLayout - get `PetscLayout` describing index set layout

1160:   Not Collective

1162:   Input Parameter:
1163: . is - the index set

1165:   Output Parameter:
1166: . map - the layout

1168:   Level: developer

1170: .seealso: `IS`, `PetscLayout`, `ISSetLayout()`, `ISGetSize()`, `ISGetLocalSize()`
1171: @*/
1172: PetscErrorCode ISGetLayout(IS is, PetscLayout *map)
1173: {
1174:   PetscFunctionBegin;
1176:   PetscAssertPointer(map, 2);
1177:   *map = is->map;
1178:   PetscFunctionReturn(PETSC_SUCCESS);
1179: }

1181: /*@
1182:   ISSetLayout - set `PetscLayout` describing index set layout

1184:   Collective

1186:   Input Parameters:
1187: + is  - the index set
1188: - map - the layout

1190:   Level: developer

1192:   Notes:
1193:   Users should typically use higher level functions such as `ISCreateGeneral()`.

1195:   This function can be useful in some special cases of constructing a new `IS`, e.g. after `ISCreate()` and before `ISLoad()`.
1196:   Otherwise, it is only valid to replace the layout with a layout known to be equivalent.

1198: .seealso: `IS`, `PetscLayout`, `ISCreate()`, `ISGetLayout()`, `ISGetSize()`, `ISGetLocalSize()`
1199: @*/
1200: PetscErrorCode ISSetLayout(IS is, PetscLayout map)
1201: {
1202:   PetscFunctionBegin;
1204:   PetscAssertPointer(map, 2);
1205:   PetscCall(PetscLayoutReference(map, &is->map));
1206:   PetscFunctionReturn(PETSC_SUCCESS);
1207: }

1209: /*@C
1210:   ISGetIndices - Returns a pointer to the indices.  The user should call
1211:   `ISRestoreIndices()` after having looked at the indices.  The user should
1212:   NOT change the indices.

1214:   Not Collective

1216:   Input Parameter:
1217: . is - the index set

1219:   Output Parameter:
1220: . ptr - the location to put the pointer to the indices

1222:   Level: intermediate

1224:   Fortran Note:
1225: .vb
1226:   PetscInt, pointer :: ptr(:)
1227: .ve

1229: .seealso: `IS`, `ISRestoreIndices()`
1230: @*/
1231: PetscErrorCode ISGetIndices(IS is, const PetscInt *ptr[])
1232: {
1233:   PetscFunctionBegin;
1235:   PetscAssertPointer(ptr, 2);
1236:   PetscUseTypeMethod(is, getindices, ptr);
1237:   PetscFunctionReturn(PETSC_SUCCESS);
1238: }

1240: /*@
1241:   ISGetMinMax - Gets the minimum and maximum values in an `IS`

1243:   Not Collective

1245:   Input Parameter:
1246: . is - the index set

1248:   Output Parameters:
1249: + min - the minimum value, you may pass `NULL`
1250: - max - the maximum value, you may pass `NULL`

1252:   Level: intermediate

1254:   Notes:
1255:   Empty index sets return min=`PETSC_INT_MAX` and max=`PETSC_INT_MIN`.

1257:   In parallel, it returns the `min` and `max` of the local portion of `is`

1259: .seealso: `IS`, `ISGetIndices()`, `ISRestoreIndices()`
1260: @*/
1261: PetscErrorCode ISGetMinMax(IS is, PetscInt *min, PetscInt *max)
1262: {
1263:   PetscFunctionBegin;
1265:   if (min) *min = is->min;
1266:   if (max) *max = is->max;
1267:   PetscFunctionReturn(PETSC_SUCCESS);
1268: }

1270: /*@
1271:   ISLocate - determine the location of an index within the local component of an index set

1273:   Not Collective

1275:   Input Parameters:
1276: + is  - the index set
1277: - key - the search key

1279:   Output Parameter:
1280: . location - if >= 0, a location within the index set that is equal to the key, otherwise the key is not in the index set

1282:   Level: intermediate

1284: .seealso: `IS`
1285:  @*/
1286: PetscErrorCode ISLocate(IS is, PetscInt key, PetscInt *location)
1287: {
1288:   PetscFunctionBegin;
1289:   if (is->ops->locate) PetscUseTypeMethod(is, locate, key, location);
1290:   else {
1291:     PetscInt        numIdx;
1292:     PetscBool       sorted;
1293:     const PetscInt *idx;

1295:     PetscCall(ISGetLocalSize(is, &numIdx));
1296:     PetscCall(ISGetIndices(is, &idx));
1297:     PetscCall(ISSorted(is, &sorted));
1298:     if (sorted) {
1299:       PetscCall(PetscFindInt(key, numIdx, idx, location));
1300:     } else {
1301:       PetscInt i;

1303:       *location = -1;
1304:       for (i = 0; i < numIdx; i++) {
1305:         if (idx[i] == key) {
1306:           *location = i;
1307:           break;
1308:         }
1309:       }
1310:     }
1311:     PetscCall(ISRestoreIndices(is, &idx));
1312:   }
1313:   PetscFunctionReturn(PETSC_SUCCESS);
1314: }

1316: /*@C
1317:   ISRestoreIndices - Restores an index set to a usable state after a call to `ISGetIndices()`.

1319:   Not Collective

1321:   Input Parameters:
1322: + is  - the index set
1323: - ptr - the pointer obtained by `ISGetIndices()`

1325:   Level: intermediate

1327:   Fortran Note:
1328: .vb
1329:   PetscInt, pointer :: ptr(:)
1330: .ve

1332: .seealso: `IS`, `ISGetIndices()`
1333: @*/
1334: PetscErrorCode ISRestoreIndices(IS is, const PetscInt *ptr[])
1335: {
1336:   PetscFunctionBegin;
1338:   PetscAssertPointer(ptr, 2);
1339:   PetscTryTypeMethod(is, restoreindices, ptr);
1340:   PetscFunctionReturn(PETSC_SUCCESS);
1341: }

1343: static PetscErrorCode ISGatherTotal_Private(IS is)
1344: {
1345:   PetscInt        i, n, N;
1346:   const PetscInt *lindices;
1347:   MPI_Comm        comm;
1348:   PetscMPIInt     rank, size, *sizes = NULL, *offsets = NULL, nn;

1350:   PetscFunctionBegin;

1353:   PetscCall(PetscObjectGetComm((PetscObject)is, &comm));
1354:   PetscCallMPI(MPI_Comm_size(comm, &size));
1355:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
1356:   PetscCall(ISGetLocalSize(is, &n));
1357:   PetscCall(PetscMalloc2(size, &sizes, size, &offsets));

1359:   PetscCall(PetscMPIIntCast(n, &nn));
1360:   PetscCallMPI(MPI_Allgather(&nn, 1, MPI_INT, sizes, 1, MPI_INT, comm));
1361:   offsets[0] = 0;
1362:   for (i = 1; i < size; ++i) offsets[i] = offsets[i - 1] + sizes[i - 1];
1363:   N = offsets[size - 1] + sizes[size - 1];

1365:   PetscCall(PetscMalloc1(N, &is->total));
1366:   PetscCall(ISGetIndices(is, &lindices));
1367:   PetscCallMPI(MPI_Allgatherv((void *)lindices, nn, MPIU_INT, is->total, sizes, offsets, MPIU_INT, comm));
1368:   PetscCall(ISRestoreIndices(is, &lindices));
1369:   is->local_offset = offsets[rank];
1370:   PetscCall(PetscFree2(sizes, offsets));
1371:   PetscFunctionReturn(PETSC_SUCCESS);
1372: }

1374: /*@C
1375:   ISGetTotalIndices - Retrieve an array containing all indices across the communicator.

1377:   Collective

1379:   Input Parameter:
1380: . is - the index set

1382:   Output Parameter:
1383: . indices - total indices with rank 0 indices first, and so on; total array size is
1384:              the same as returned with `ISGetSize()`.

1386:   Level: intermediate

1388:   Notes:
1389:   this is potentially nonscalable, but depends on the size of the total index set
1390:   and the size of the communicator. This may be feasible for index sets defined on
1391:   subcommunicators, such that the set size does not grow with `PETSC_WORLD_COMM`.
1392:   Note also that there is no way to tell where the local part of the indices starts
1393:   (use `ISGetIndices()` and `ISGetNonlocalIndices()` to retrieve just the local and just
1394:   the nonlocal part (complement), respectively).

1396: .seealso: `IS`, `ISRestoreTotalIndices()`, `ISGetNonlocalIndices()`, `ISGetSize()`
1397: @*/
1398: PetscErrorCode ISGetTotalIndices(IS is, const PetscInt *indices[])
1399: {
1400:   PetscMPIInt size;

1402:   PetscFunctionBegin;
1404:   PetscAssertPointer(indices, 2);
1405:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)is), &size));
1406:   if (size == 1) PetscUseTypeMethod(is, getindices, indices);
1407:   else {
1408:     if (!is->total) PetscCall(ISGatherTotal_Private(is));
1409:     *indices = is->total;
1410:   }
1411:   PetscFunctionReturn(PETSC_SUCCESS);
1412: }

1414: /*@C
1415:   ISRestoreTotalIndices - Restore the index array obtained with `ISGetTotalIndices()`.

1417:   Not Collective.

1419:   Input Parameters:
1420: + is      - the index set
1421: - indices - index array; must be the array obtained with `ISGetTotalIndices()`

1423:   Level: intermediate

1425: .seealso: `IS`, `ISGetNonlocalIndices()`
1426: @*/
1427: PetscErrorCode ISRestoreTotalIndices(IS is, const PetscInt *indices[])
1428: {
1429:   PetscMPIInt size;

1431:   PetscFunctionBegin;
1433:   PetscAssertPointer(indices, 2);
1434:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)is), &size));
1435:   if (size == 1) {
1436:     PetscUseTypeMethod(is, restoreindices, indices);
1437:   } else {
1438:     PetscCheck(is->total == *indices, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Index array pointer being restored does not point to the array obtained from the IS.");
1439:   }
1440:   PetscFunctionReturn(PETSC_SUCCESS);
1441: }

1443: /*@C
1444:   ISGetNonlocalIndices - Retrieve an array of indices from remote processors
1445:   in this communicator.

1447:   Collective

1449:   Input Parameter:
1450: . is - the index set

1452:   Output Parameter:
1453: . indices - indices with rank 0 indices first, and so on,  omitting
1454:              the current rank.  Total number of indices is the difference
1455:              total and local, obtained with `ISGetSize()` and `ISGetLocalSize()`,
1456:              respectively.

1458:   Level: intermediate

1460:   Notes:
1461:   Restore the indices using `ISRestoreNonlocalIndices()`.

1463:   The same scalability considerations as those for `ISGetTotalIndices()` apply here.

1465: .seealso: `IS`, `ISGetTotalIndices()`, `ISRestoreNonlocalIndices()`, `ISGetSize()`, `ISGetLocalSize().`
1466: @*/
1467: PetscErrorCode ISGetNonlocalIndices(IS is, const PetscInt *indices[])
1468: {
1469:   PetscMPIInt size;
1470:   PetscInt    n, N;

1472:   PetscFunctionBegin;
1474:   PetscAssertPointer(indices, 2);
1475:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)is), &size));
1476:   if (size == 1) *indices = NULL;
1477:   else {
1478:     if (!is->total) PetscCall(ISGatherTotal_Private(is));
1479:     PetscCall(ISGetLocalSize(is, &n));
1480:     PetscCall(ISGetSize(is, &N));
1481:     PetscCall(PetscMalloc1(N - n, &is->nonlocal));
1482:     PetscCall(PetscArraycpy(is->nonlocal, is->total, is->local_offset));
1483:     PetscCall(PetscArraycpy(is->nonlocal + is->local_offset, is->total + is->local_offset + n, N - is->local_offset - n));
1484:     *indices = is->nonlocal;
1485:   }
1486:   PetscFunctionReturn(PETSC_SUCCESS);
1487: }

1489: /*@C
1490:   ISRestoreNonlocalIndices - Restore the index array obtained with `ISGetNonlocalIndices()`.

1492:   Not Collective.

1494:   Input Parameters:
1495: + is      - the index set
1496: - indices - index array; must be the array obtained with `ISGetNonlocalIndices()`

1498:   Level: intermediate

1500: .seealso: `IS`, `ISGetTotalIndices()`, `ISGetNonlocalIndices()`, `ISRestoreTotalIndices()`
1501: @*/
1502: PetscErrorCode ISRestoreNonlocalIndices(IS is, const PetscInt *indices[])
1503: {
1504:   PetscFunctionBegin;
1506:   PetscAssertPointer(indices, 2);
1507:   PetscCheck(is->nonlocal == *indices, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Index array pointer being restored does not point to the array obtained from the IS.");
1508:   PetscFunctionReturn(PETSC_SUCCESS);
1509: }

1511: /*@
1512:   ISGetNonlocalIS - Gather all nonlocal indices for this `IS` and present
1513:   them as another sequential index set.

1515:   Collective

1517:   Input Parameter:
1518: . is - the index set

1520:   Output Parameter:
1521: . complement - sequential `IS` with indices identical to the result of
1522:                 `ISGetNonlocalIndices()`

1524:   Level: intermediate

1526:   Notes:
1527:   Complement represents the result of `ISGetNonlocalIndices()` as an `IS`.
1528:   Therefore scalability issues similar to `ISGetNonlocalIndices()` apply.

1530:   The resulting `IS` must be restored using `ISRestoreNonlocalIS()`.

1532: .seealso: `IS`, `ISGetNonlocalIndices()`, `ISRestoreNonlocalIndices()`, `ISAllGather()`, `ISGetSize()`
1533: @*/
1534: PetscErrorCode ISGetNonlocalIS(IS is, IS *complement)
1535: {
1536:   PetscFunctionBegin;
1538:   PetscAssertPointer(complement, 2);
1539:   /* Check if the complement exists already. */
1540:   if (is->complement) {
1541:     *complement = is->complement;
1542:     PetscCall(PetscObjectReference((PetscObject)is->complement));
1543:   } else {
1544:     PetscInt        N, n;
1545:     const PetscInt *idx;
1546:     PetscCall(ISGetSize(is, &N));
1547:     PetscCall(ISGetLocalSize(is, &n));
1548:     PetscCall(ISGetNonlocalIndices(is, &idx));
1549:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, N - n, idx, PETSC_USE_POINTER, &is->complement));
1550:     PetscCall(PetscObjectReference((PetscObject)is->complement));
1551:     *complement = is->complement;
1552:   }
1553:   PetscFunctionReturn(PETSC_SUCCESS);
1554: }

1556: /*@
1557:   ISRestoreNonlocalIS - Restore the `IS` obtained with `ISGetNonlocalIS()`.

1559:   Not collective.

1561:   Input Parameters:
1562: + is         - the index set
1563: - complement - index set of `is`'s nonlocal indices

1565:   Level: intermediate

1567: .seealso: `IS`, `ISGetNonlocalIS()`, `ISGetNonlocalIndices()`, `ISRestoreNonlocalIndices()`
1568: @*/
1569: PetscErrorCode ISRestoreNonlocalIS(IS is, IS *complement)
1570: {
1571:   PetscInt refcnt;

1573:   PetscFunctionBegin;
1575:   PetscAssertPointer(complement, 2);
1576:   PetscCheck(*complement == is->complement, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Complement IS being restored was not obtained with ISGetNonlocalIS()");
1577:   PetscCall(PetscObjectGetReference((PetscObject)is->complement, &refcnt));
1578:   PetscCheck(refcnt > 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Duplicate call to ISRestoreNonlocalIS() detected");
1579:   PetscCall(PetscObjectDereference((PetscObject)is->complement));
1580:   PetscFunctionReturn(PETSC_SUCCESS);
1581: }

1583: /*@
1584:   ISViewFromOptions - View an `IS` based on options in the options database

1586:   Collective

1588:   Input Parameters:
1589: + A    - the index set
1590: . obj  - Optional object that provides the prefix for the options database
1591: - name - command line option

1593:   Level: intermediate

1595:   Note:
1596:   See `PetscObjectViewFromOptions()` for possible `PetscViewer` and `PetscViewerFormat` values

1598: .seealso: `IS`, `ISView()`, `PetscObjectViewFromOptions()`, `ISCreate()`
1599: @*/
1600: PetscErrorCode ISViewFromOptions(IS A, PetscObject obj, const char name[])
1601: {
1602:   PetscFunctionBegin;
1604:   PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
1605:   PetscFunctionReturn(PETSC_SUCCESS);
1606: }

1608: /*@
1609:   ISView - Displays an index set.

1611:   Collective

1613:   Input Parameters:
1614: + is     - the index set
1615: - viewer - viewer used to display the set, for example `PETSC_VIEWER_STDOUT_SELF`.

1617:   Level: intermediate

1619: .seealso: `IS`, `PetscViewer`, `PetscViewerASCIIOpen()`, `ISViewFromOptions()`
1620: @*/
1621: PetscErrorCode ISView(IS is, PetscViewer viewer)
1622: {
1623:   PetscFunctionBegin;
1625:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)is), &viewer));
1627:   PetscCheckSameComm(is, 1, viewer, 2);

1629:   PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)is, viewer));
1630:   PetscCall(PetscLogEventBegin(IS_View, is, viewer, 0, 0));
1631:   PetscUseTypeMethod(is, view, viewer);
1632:   PetscCall(PetscLogEventEnd(IS_View, is, viewer, 0, 0));
1633:   PetscFunctionReturn(PETSC_SUCCESS);
1634: }

1636: /*@
1637:   ISLoad - Loads an index set that has been stored in binary or HDF5 format with `ISView()`.

1639:   Collective

1641:   Input Parameters:
1642: + is     - the newly loaded index set, this needs to have been created with `ISCreate()` or some related function before a call to `ISLoad()`.
1643: - viewer - binary file viewer, obtained from `PetscViewerBinaryOpen()` or HDF5 file viewer, obtained from `PetscViewerHDF5Open()`

1645:   Level: intermediate

1647:   Notes:
1648:   IF using HDF5, you must assign the IS the same name as was used in `is`
1649:   that was stored in the file using `PetscObjectSetName()`. Otherwise you will
1650:   get the error message: "Cannot H5DOpen2() with Vec name NAMEOFOBJECT"

1652: .seealso: `IS`, `PetscViewerBinaryOpen()`, `ISView()`, `MatLoad()`, `VecLoad()`
1653: @*/
1654: PetscErrorCode ISLoad(IS is, PetscViewer viewer)
1655: {
1656:   PetscBool isbinary, ishdf5;

1658:   PetscFunctionBegin;
1661:   PetscCheckSameComm(is, 1, viewer, 2);
1662:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
1663:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERHDF5, &ishdf5));
1664:   PetscCheck(isbinary || ishdf5, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid viewer; open viewer with PetscViewerBinaryOpen()");
1665:   if (!((PetscObject)is)->type_name) PetscCall(ISSetType(is, ISGENERAL));
1666:   PetscCall(PetscLogEventBegin(IS_Load, is, viewer, 0, 0));
1667:   PetscUseTypeMethod(is, load, viewer);
1668:   PetscCall(PetscLogEventEnd(IS_Load, is, viewer, 0, 0));
1669:   PetscFunctionReturn(PETSC_SUCCESS);
1670: }

1672: /*@
1673:   ISSort - Sorts the indices of an index set.

1675:   Collective

1677:   Input Parameter:
1678: . is - the index set

1680:   Level: intermediate

1682: .seealso: `IS`, `ISSortRemoveDups()`, `ISSorted()`
1683: @*/
1684: PetscErrorCode ISSort(IS is)
1685: {
1686:   PetscBool flg;

1688:   PetscFunctionBegin;
1690:   PetscCall(ISGetInfo(is, IS_SORTED, IS_LOCAL, PETSC_FALSE, &flg));
1691:   if (!flg) {
1692:     PetscUseTypeMethod(is, sort);
1693:     PetscCall(ISSetInfo(is, IS_SORTED, IS_LOCAL, is->info_permanent[IS_LOCAL][IS_SORTED], PETSC_TRUE));
1694:   }
1695:   PetscFunctionReturn(PETSC_SUCCESS);
1696: }

1698: /*@
1699:   ISSortRemoveDups - Sorts the indices of an index set, removing duplicates.

1701:   Collective

1703:   Input Parameter:
1704: . is - the index set

1706:   Level: intermediate

1708: .seealso: `IS`, `ISSort()`, `ISSorted()`
1709: @*/
1710: PetscErrorCode ISSortRemoveDups(IS is)
1711: {
1712:   PetscFunctionBegin;
1714:   PetscCall(ISClearInfoCache(is, PETSC_FALSE));
1715:   PetscUseTypeMethod(is, sortremovedups);
1716:   PetscCall(ISSetInfo(is, IS_SORTED, IS_LOCAL, is->info_permanent[IS_LOCAL][IS_SORTED], PETSC_TRUE));
1717:   PetscCall(ISSetInfo(is, IS_UNIQUE, IS_LOCAL, is->info_permanent[IS_LOCAL][IS_UNIQUE], PETSC_TRUE));
1718:   PetscFunctionReturn(PETSC_SUCCESS);
1719: }

1721: /*@
1722:   ISToGeneral - Converts an IS object of any type to `ISGENERAL` type

1724:   Collective

1726:   Input Parameter:
1727: . is - the index set

1729:   Level: intermediate

1731: .seealso: `IS`, `ISSorted()`
1732: @*/
1733: PetscErrorCode ISToGeneral(IS is)
1734: {
1735:   PetscFunctionBegin;
1737:   PetscUseTypeMethod(is, togeneral);
1738:   PetscFunctionReturn(PETSC_SUCCESS);
1739: }

1741: /*@
1742:   ISSorted - Checks the indices to determine whether they have been sorted.

1744:   Not Collective

1746:   Input Parameter:
1747: . is - the index set

1749:   Output Parameter:
1750: . flg - output flag, either `PETSC_TRUE` if the index set is sorted,
1751:          or `PETSC_FALSE` otherwise.

1753:   Level: intermediate

1755:   Note:
1756:   For parallel IS objects this only indicates if the local part of `is`
1757:   is sorted. So some processors may return `PETSC_TRUE` while others may
1758:   return `PETSC_FALSE`.

1760: .seealso: `ISSort()`, `ISSortRemoveDups()`
1761: @*/
1762: PetscErrorCode ISSorted(IS is, PetscBool *flg)
1763: {
1764:   PetscFunctionBegin;
1766:   PetscAssertPointer(flg, 2);
1767:   PetscCall(ISGetInfo(is, IS_SORTED, IS_LOCAL, PETSC_TRUE, flg));
1768:   PetscFunctionReturn(PETSC_SUCCESS);
1769: }

1771: /*@
1772:   ISDuplicate - Creates a duplicate copy of an index set.

1774:   Collective

1776:   Input Parameter:
1777: . is - the index set

1779:   Output Parameter:
1780: . newIS - the copy of the index set

1782:   Level: beginner

1784: .seealso: `IS`, `ISCreateGeneral()`, `ISCopy()`
1785: @*/
1786: PetscErrorCode ISDuplicate(IS is, IS *newIS)
1787: {
1788:   PetscFunctionBegin;
1790:   PetscAssertPointer(newIS, 2);
1791:   PetscUseTypeMethod(is, duplicate, newIS);
1792:   PetscCall(ISCopyInfo_Private(is, *newIS));
1793:   PetscFunctionReturn(PETSC_SUCCESS);
1794: }

1796: /*@
1797:   ISCopy - Copies an index set.

1799:   Collective

1801:   Input Parameter:
1802: . is - the index set

1804:   Output Parameter:
1805: . isy - the copy of the index set

1807:   Level: beginner

1809: .seealso: `IS`, `ISDuplicate()`, `ISShift()`
1810: @*/
1811: PetscErrorCode ISCopy(IS is, IS isy)
1812: {
1813:   PetscInt bs, bsy;

1815:   PetscFunctionBegin;
1818:   PetscCheckSameComm(is, 1, isy, 2);
1819:   if (is == isy) PetscFunctionReturn(PETSC_SUCCESS);
1820:   PetscCall(PetscLayoutGetBlockSize(is->map, &bs));
1821:   PetscCall(PetscLayoutGetBlockSize(isy->map, &bsy));
1822:   PetscCheck(is->map->N == isy->map->N, PetscObjectComm((PetscObject)is), PETSC_ERR_ARG_INCOMP, "Index sets have different global size %" PetscInt_FMT " != %" PetscInt_FMT, is->map->N, isy->map->N);
1823:   PetscCheck(is->map->n == isy->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Index sets have different local size %" PetscInt_FMT " != %" PetscInt_FMT, is->map->n, isy->map->n);
1824:   PetscCheck(bs == bsy, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Index sets have different block size %" PetscInt_FMT " != %" PetscInt_FMT, bs, bsy);
1825:   PetscCall(ISCopyInfo_Private(is, isy));
1826:   isy->max = is->max;
1827:   isy->min = is->min;
1828:   PetscUseTypeMethod(is, copy, isy);
1829:   PetscFunctionReturn(PETSC_SUCCESS);
1830: }

1832: /*@
1833:   ISShift - Shift all indices by given offset

1835:   Collective

1837:   Input Parameters:
1838: + is     - the index set
1839: - offset - the offset

1841:   Output Parameter:
1842: . isy - the shifted copy of the input index set

1844:   Level: beginner

1846:   Notes:
1847:   The `offset` can be different across processes.

1849:   `is` and `isy` can be the same.

1851: .seealso: `ISDuplicate()`, `ISCopy()`
1852: @*/
1853: PetscErrorCode ISShift(IS is, PetscInt offset, IS isy)
1854: {
1855:   PetscFunctionBegin;
1858:   PetscCheckSameComm(is, 1, isy, 3);
1859:   if (!offset) {
1860:     PetscCall(ISCopy(is, isy));
1861:     PetscFunctionReturn(PETSC_SUCCESS);
1862:   }
1863:   PetscCheck(is->map->N == isy->map->N, PetscObjectComm((PetscObject)is), PETSC_ERR_ARG_INCOMP, "Index sets have different global size %" PetscInt_FMT " != %" PetscInt_FMT, is->map->N, isy->map->N);
1864:   PetscCheck(is->map->n == isy->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Index sets have different local size %" PetscInt_FMT " != %" PetscInt_FMT, is->map->n, isy->map->n);
1865:   PetscCheck(is->map->bs == isy->map->bs, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Index sets have different block size %" PetscInt_FMT " != %" PetscInt_FMT, is->map->bs, isy->map->bs);
1866:   PetscCall(ISCopyInfo_Private(is, isy));
1867:   if (offset > 0) {
1868:     isy->max = is->max < PETSC_INT_MAX - offset ? is->max + offset : PETSC_INT_MAX;
1869:     isy->min = is->min < PETSC_INT_MAX - offset ? is->min + offset : PETSC_INT_MAX;
1870:   } else {
1871:     isy->max = is->max > PETSC_INT_MIN - offset ? is->max + offset : PETSC_INT_MIN;
1872:     isy->min = is->min > PETSC_INT_MIN - offset ? is->min + offset : PETSC_INT_MIN;
1873:   }
1874:   PetscUseMethod(is, "ISShift_C", (IS, PetscInt, IS), (is, offset, isy));
1875:   PetscFunctionReturn(PETSC_SUCCESS);
1876: }

1878: /*@
1879:   ISOnComm - Split a parallel `IS` on subcomms (usually self) or concatenate index sets on subcomms into a parallel index set

1881:   Collective

1883:   Input Parameters:
1884: + is   - index set
1885: . comm - communicator for new index set
1886: - mode - copy semantics, `PETSC_USE_POINTER` for no-copy if possible, otherwise `PETSC_COPY_VALUES`

1888:   Output Parameter:
1889: . newis - new `IS` on `comm`

1891:   Level: advanced

1893:   Notes:
1894:   It is usually desirable to create a parallel `IS` and look at the local part when necessary.

1896:   This function is useful if serial `IS`s must be created independently, or to view many
1897:   logically independent serial `IS`s.

1899:   The input `IS` must have the same type on every MPI process.

1901: .seealso: `IS`
1902: @*/
1903: PetscErrorCode ISOnComm(IS is, MPI_Comm comm, PetscCopyMode mode, IS *newis)
1904: {
1905:   PetscMPIInt match;

1907:   PetscFunctionBegin;
1909:   PetscAssertPointer(newis, 4);
1910:   PetscCallMPI(MPI_Comm_compare(PetscObjectComm((PetscObject)is), comm, &match));
1911:   if (mode != PETSC_COPY_VALUES && (match == MPI_IDENT || match == MPI_CONGRUENT)) {
1912:     PetscCall(PetscObjectReference((PetscObject)is));
1913:     *newis = is;
1914:   } else PetscUseTypeMethod(is, oncomm, comm, mode, newis);
1915:   PetscFunctionReturn(PETSC_SUCCESS);
1916: }

1918: /*@
1919:   ISSetBlockSize - informs an index set that it has a given block size

1921:   Logicall Collective

1923:   Input Parameters:
1924: + is - index set
1925: - bs - block size

1927:   Level: intermediate

1929:   Notes:
1930:   This is much like the block size for `Vec`s. It indicates that one can think of the indices as
1931:   being in a collection of equal size blocks. For `ISBLOCK` these collections of blocks are all contiguous
1932:   within a block but this is not the case for other `IS`. For example, an `IS` with entries {0, 2, 3, 4, 6, 7} could
1933:   have a block size of three set.

1935:   `ISBlockGetIndices()` only works for `ISBLOCK`, not others.

1937: .seealso: `IS`, `ISGetBlockSize()`, `ISCreateBlock()`, `ISBlockGetIndices()`
1938: @*/
1939: PetscErrorCode ISSetBlockSize(IS is, PetscInt bs)
1940: {
1941:   PetscFunctionBegin;
1944:   PetscCheck(bs >= 1, PetscObjectComm((PetscObject)is), PETSC_ERR_ARG_OUTOFRANGE, "Block size %" PetscInt_FMT ", must be positive", bs);
1945:   if (PetscDefined(USE_DEBUG)) {
1946:     const PetscInt *indices;
1947:     PetscInt        length, i, j;
1948:     PetscCall(ISGetIndices(is, &indices));
1949:     if (indices) {
1950:       PetscCall(ISGetLocalSize(is, &length));
1951:       PetscCheck(length % bs == 0, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Local size %" PetscInt_FMT " not compatible with proposed block size %" PetscInt_FMT, length, bs);
1952:       for (i = 1; i < length / bs; i += bs) {
1953:         for (j = 1; j < bs - 1; j++) {
1954:           PetscCheck(indices[i * bs + j] == indices[(i - 1) * bs + j] + indices[i * bs] - indices[(i - 1) * bs], PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Proposed block size %" PetscInt_FMT " is incompatible with the indices", bs);
1955:         }
1956:       }
1957:     }
1958:     PetscCall(ISRestoreIndices(is, &indices));
1959:   }
1960:   PetscUseTypeMethod(is, setblocksize, bs);
1961:   PetscFunctionReturn(PETSC_SUCCESS);
1962: }

1964: /*@
1965:   ISGetBlockSize - Returns the number of elements in a block.

1967:   Not Collective

1969:   Input Parameter:
1970: . is - the index set

1972:   Output Parameter:
1973: . size - the number of elements in a block

1975:   Level: intermediate

1977:   Note:
1978:   See `ISSetBlockSize()`

1980: .seealso: `IS`, `ISBlockGetSize()`, `ISGetSize()`, `ISCreateBlock()`, `ISSetBlockSize()`
1981: @*/
1982: PetscErrorCode ISGetBlockSize(IS is, PetscInt *size)
1983: {
1984:   PetscFunctionBegin;
1985:   PetscCall(PetscLayoutGetBlockSize(is->map, size));
1986:   PetscFunctionReturn(PETSC_SUCCESS);
1987: }

1989: /*@
1990:   ISSetCompressOutput - set the flag for output compression

1992:   Logicall Collective

1994:   Input Parameters:
1995: + is       - index set
1996: - compress - flag for output compression

1998:   Level: intermediate

2000: .seealso: `IS`, `ISGetCompressOutput()`, `ISView()`
2001: @*/
2002: PetscErrorCode ISSetCompressOutput(IS is, PetscBool compress)
2003: {
2004:   PetscFunctionBegin;
2007:   is->compressOutput = compress;
2008:   PetscFunctionReturn(PETSC_SUCCESS);
2009: }

2011: /*@
2012:   ISGetCompressOutput - Returns the flag for output compression

2014:   Not Collective

2016:   Input Parameter:
2017: . is - the index set

2019:   Output Parameter:
2020: . compress - the flag to compress output

2022:   Level: intermediate

2024: .seealso: `IS`, `ISSetCompressOutput()`, `ISView()`
2025: @*/
2026: PetscErrorCode ISGetCompressOutput(IS is, PetscBool *compress)
2027: {
2028:   PetscFunctionBegin;
2030:   PetscAssertPointer(compress, 2);
2031:   *compress = is->compressOutput;
2032:   PetscFunctionReturn(PETSC_SUCCESS);
2033: }

2035: static PetscErrorCode ISGetIndicesCopy_Private(IS is, PetscInt idx[])
2036: {
2037:   PetscInt        len, i;
2038:   const PetscInt *ptr;

2040:   PetscFunctionBegin;
2041:   PetscCall(ISGetLocalSize(is, &len));
2042:   PetscCall(ISGetIndices(is, &ptr));
2043:   for (i = 0; i < len; i++) idx[i] = ptr[i];
2044:   PetscCall(ISRestoreIndices(is, &ptr));
2045:   PetscFunctionReturn(PETSC_SUCCESS);
2046: }