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 PetscDefined(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;

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

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

516:     if (type == IS_GLOBAL && size > 1) {
517:       PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
518:       if (*flg) {
519:         PetscInt n, min = PETSC_INT_MAX, max = PETSC_INT_MIN;
520:         PetscInt maxprev;

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

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

536: static PetscErrorCode ISGetInfo_Unique_Private(IS is, ISInfoType type, PetscBool *flg)
537: {
538:   MPI_Comm    comm;
539:   PetscMPIInt size, rank;
540:   PetscInt    i;

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

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

569:     PetscCall(PetscFree(idx));
570:     if (type == IS_GLOBAL && size > 1) {
571:       PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
572:       if (*flg) {
573:         PetscInt min = PETSC_INT_MAX, max = PETSC_INT_MIN, maxprev;

575:         if (!idx) {
576:           PetscCall(ISGetLocalSize(is, &n));
577:           PetscCall(PetscMalloc1(n, &idx));
578:           PetscCall(ISGetIndicesCopy_Private(is, idx));
579:         }
580:         PetscCall(PetscParallelSortInt(is->map, is->map, idx, idx));
581:         if (n) {
582:           min = idx[0];
583:           max = idx[n - 1];
584:         }
585:         for (i = 1; i < n; i++)
586:           if (idx[i] == idx[i - 1]) break;
587:         if (i < n) *flg = PETSC_FALSE;
588:         maxprev = PETSC_INT_MIN;
589:         PetscCallMPI(MPI_Exscan(&max, &maxprev, 1, MPIU_INT, MPI_MAX, comm));
590:         if (rank && (maxprev == min)) *flg = PETSC_FALSE;
591:         PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
592:       }
593:     }
594:     PetscCall(PetscFree(idx));
595:   }
596:   PetscFunctionReturn(PETSC_SUCCESS);
597: }

599: static PetscErrorCode ISGetInfo_Permutation(IS is, ISInfoType type, PetscBool *flg)
600: {
601:   MPI_Comm    comm;
602:   PetscMPIInt size;

604:   PetscFunctionBegin;
605:   comm = PetscObjectComm((PetscObject)is);
606:   PetscCallMPI(MPI_Comm_size(comm, &size));
607:   if (type == IS_GLOBAL && is->ops->permglobal) {
608:     PetscUseTypeMethod(is, permglobal, flg);
609:   } else if (type == IS_LOCAL && is->ops->permlocal) {
610:     PetscUseTypeMethod(is, permlocal, flg);
611:   } else {
612:     PetscInt  n, i, rStart;
613:     PetscInt *idx;

615:     PetscCall(ISGetLocalSize(is, &n));
616:     PetscCall(PetscMalloc1(n, &idx));
617:     PetscCall(ISGetIndicesCopy_Private(is, idx));
618:     if (type == IS_GLOBAL) {
619:       PetscCall(PetscParallelSortInt(is->map, is->map, idx, idx));
620:       PetscCall(PetscLayoutGetRange(is->map, &rStart, NULL));
621:     } else {
622:       PetscCall(PetscIntSortSemiOrdered(n, idx));
623:       rStart = 0;
624:     }
625:     *flg = PETSC_TRUE;
626:     for (i = 0; i < n; i++) {
627:       if (idx[i] != rStart + i) break;
628:     }
629:     if (i < n) *flg = PETSC_FALSE;
630:     if (type == IS_GLOBAL && size > 1) PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
631:     PetscCall(PetscFree(idx));
632:   }
633:   PetscFunctionReturn(PETSC_SUCCESS);
634: }

636: static PetscErrorCode ISGetInfo_Interval(IS is, ISInfoType type, PetscBool *flg)
637: {
638:   MPI_Comm    comm;
639:   PetscMPIInt size, rank;
640:   PetscInt    i;

642:   PetscFunctionBegin;
643:   comm = PetscObjectComm((PetscObject)is);
644:   PetscCallMPI(MPI_Comm_size(comm, &size));
645:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
646:   if (type == IS_GLOBAL && is->ops->intervalglobal) {
647:     PetscUseTypeMethod(is, intervalglobal, flg);
648:   } else {
649:     /* determine if the array is locally an interval */
650:     if (type == IS_GLOBAL && size > 1) {
651:       /* call ISGetInfo so that a cached value will be used if possible */
652:       PetscCall(ISGetInfo(is, IS_INTERVAL, IS_LOCAL, PETSC_TRUE, flg));
653:     } else if (is->ops->intervallocal) {
654:       PetscUseTypeMethod(is, intervallocal, flg);
655:     } else {
656:       PetscInt        n;
657:       const PetscInt *idx;
658:       /* default: get the local indices and directly check */
659:       *flg = PETSC_TRUE;
660:       PetscCall(ISGetLocalSize(is, &n));
661:       PetscCall(ISGetIndices(is, &idx));
662:       for (i = 1; i < n; i++)
663:         if (idx[i] != idx[i - 1] + 1) break;
664:       if (i < n) *flg = PETSC_FALSE;
665:       PetscCall(ISRestoreIndices(is, &idx));
666:     }

668:     if (type == IS_GLOBAL && size > 1) {
669:       PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
670:       if (*flg) {
671:         PetscInt n, min = PETSC_INT_MAX, max = PETSC_INT_MIN;
672:         PetscInt maxprev;

674:         PetscCall(ISGetLocalSize(is, &n));
675:         if (n) PetscCall(ISGetMinMax(is, &min, &max));
676:         maxprev = PETSC_INT_MIN;
677:         PetscCallMPI(MPI_Exscan(&max, &maxprev, 1, MPIU_INT, MPI_MAX, comm));
678:         if (rank && n && (maxprev != min - 1)) *flg = PETSC_FALSE;
679:         PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
680:       }
681:     }
682:   }
683:   PetscFunctionReturn(PETSC_SUCCESS);
684: }

686: static PetscErrorCode ISGetInfo_Identity(IS is, ISInfoType type, PetscBool *flg)
687: {
688:   MPI_Comm    comm;
689:   PetscMPIInt size;

691:   PetscFunctionBegin;
692:   comm = PetscObjectComm((PetscObject)is);
693:   PetscCallMPI(MPI_Comm_size(comm, &size));
694:   if (type == IS_GLOBAL && is->ops->intervalglobal) {
695:     PetscBool isinterval;

697:     PetscUseTypeMethod(is, intervalglobal, &isinterval);
698:     *flg = PETSC_FALSE;
699:     if (isinterval) {
700:       PetscInt min;

702:       PetscCall(ISGetMinMax(is, &min, NULL));
703:       PetscCallMPI(MPI_Bcast(&min, 1, MPIU_INT, 0, comm));
704:       if (min == 0) *flg = PETSC_TRUE;
705:     }
706:   } else if (type == IS_LOCAL && is->ops->intervallocal) {
707:     PetscBool isinterval;

709:     PetscUseTypeMethod(is, intervallocal, &isinterval);
710:     *flg = PETSC_FALSE;
711:     if (isinterval) {
712:       PetscInt min;

714:       PetscCall(ISGetMinMax(is, &min, NULL));
715:       if (min == 0) *flg = PETSC_TRUE;
716:     }
717:   } else {
718:     PetscInt        n, i, rStart;
719:     const PetscInt *idx;

721:     PetscCall(ISGetLocalSize(is, &n));
722:     PetscCall(ISGetIndices(is, &idx));
723:     PetscCall(PetscLayoutGetRange(is->map, &rStart, NULL));
724:     *flg = PETSC_TRUE;
725:     for (i = 0; i < n; i++) {
726:       if (idx[i] != rStart + i) break;
727:     }
728:     if (i < n) *flg = PETSC_FALSE;
729:     if (type == IS_GLOBAL && size > 1) PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
730:     PetscCall(ISRestoreIndices(is, &idx));
731:   }
732:   PetscFunctionReturn(PETSC_SUCCESS);
733: }

735: /*@
736:   ISGetInfo - Determine whether an index set satisfies a given property

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

740:   Input Parameters:
741: + is      - the index set
742: . info    - describing a property of the index set, one of those listed in the documentation of `ISSetInfo()`
743: . 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
744: - type    - whether the property is local (`IS_LOCAL`) or global (`IS_GLOBAL`)

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

749:   Level: advanced

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

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

756: .seealso: `IS`, `ISInfo`, `ISInfoType`, `ISSetInfo()`, `ISClearInfoCache()`
757: @*/
758: PetscErrorCode ISGetInfo(IS is, ISInfo info, ISInfoType type, PetscBool compute, PetscBool *flg)
759: {
760:   MPI_Comm    comm, errcomm;
761:   PetscMPIInt rank, size;
762:   PetscInt    itype;
763:   PetscBool   hasprop;
764:   PetscBool   infer;

766:   PetscFunctionBegin;
769:   comm = PetscObjectComm((PetscObject)is);
770:   if (type == IS_GLOBAL) {
772:     errcomm = comm;
773:   } else {
774:     errcomm = PETSC_COMM_SELF;
775:   }

777:   PetscCallMPI(MPI_Comm_size(comm, &size));
778:   PetscCallMPI(MPI_Comm_rank(comm, &rank));

780:   PetscCheck((int)info > IS_INFO_MIN && (int)info < IS_INFO_MAX, errcomm, PETSC_ERR_ARG_OUTOFRANGE, "Option %d is out of range", (int)info);
781:   if (size == 1) type = IS_LOCAL;
782:   itype   = (type == IS_LOCAL) ? 0 : 1;
783:   hasprop = PETSC_FALSE;
784:   infer   = PETSC_FALSE;
785:   if (is->info_permanent[itype][(int)info]) {
786:     hasprop = (is->info[itype][(int)info] == IS_INFO_TRUE) ? PETSC_TRUE : PETSC_FALSE;
787:     infer   = PETSC_TRUE;
788:   } else if ((itype == IS_LOCAL) && (is->info[IS_LOCAL][info] != IS_INFO_UNKNOWN)) {
789:     /* we can cache local properties as long as we clear them when the IS changes */
790:     /* NOTE: we only cache local values because there is no ISAssemblyBegin()/ISAssemblyEnd(),
791:      so we have no way of knowing when a cached value has been invalidated by changes on a different process */
792:     hasprop = (is->info[itype][(int)info] == IS_INFO_TRUE) ? PETSC_TRUE : PETSC_FALSE;
793:     infer   = PETSC_TRUE;
794:   } else if (compute) {
795:     switch (info) {
796:     case IS_SORTED:
797:       PetscCall(ISGetInfo_Sorted_Private(is, type, &hasprop));
798:       break;
799:     case IS_UNIQUE:
800:       PetscCall(ISGetInfo_Unique_Private(is, type, &hasprop));
801:       break;
802:     case IS_PERMUTATION:
803:       PetscCall(ISGetInfo_Permutation(is, type, &hasprop));
804:       break;
805:     case IS_INTERVAL:
806:       PetscCall(ISGetInfo_Interval(is, type, &hasprop));
807:       break;
808:     case IS_IDENTITY:
809:       PetscCall(ISGetInfo_Identity(is, type, &hasprop));
810:       break;
811:     default:
812:       SETERRQ(errcomm, PETSC_ERR_ARG_OUTOFRANGE, "Unknown IS property");
813:     }
814:     infer = PETSC_TRUE;
815:   }
816:   /* call ISSetInfo_Internal to keep all of the implications straight */
817:   if (infer) PetscCall(ISSetInfo_Internal(is, info, type, IS_INFO_UNKNOWN, hasprop));
818:   *flg = hasprop;
819:   PetscFunctionReturn(PETSC_SUCCESS);
820: }

822: static PetscErrorCode ISCopyInfo_Private(IS source, IS dest)
823: {
824:   PetscFunctionBegin;
825:   PetscCall(PetscArraycpy(&dest->info[0], &source->info[0], 2));
826:   PetscCall(PetscArraycpy(&dest->info_permanent[0], &source->info_permanent[0], 2));
827:   PetscFunctionReturn(PETSC_SUCCESS);
828: }

830: /*@
831:   ISIdentity - Determines whether index set is the identity mapping.

833:   Collective

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

838:   Output Parameter:
839: . ident - `PETSC_TRUE` if an identity, else `PETSC_FALSE`

841:   Level: intermediate

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

850: .seealso: `IS`, `ISSetIdentity()`, `ISGetInfo()`
851: @*/
852: PetscErrorCode ISIdentity(IS is, PetscBool *ident)
853: {
854:   PetscFunctionBegin;
856:   PetscAssertPointer(ident, 2);
857:   PetscCall(ISGetInfo(is, IS_IDENTITY, IS_GLOBAL, PETSC_TRUE, ident));
858:   PetscFunctionReturn(PETSC_SUCCESS);
859: }

861: /*@
862:   ISSetIdentity - Informs the index set that it is an identity.

864:   Logically Collective

866:   Input Parameter:
867: . is - the index set

869:   Level: intermediate

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

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

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

880: .seealso: `IS`, `ISIdentity()`, `ISSetInfo()`, `ISClearInfoCache()`
881: @*/
882: PetscErrorCode ISSetIdentity(IS is)
883: {
884:   PetscFunctionBegin;
886:   PetscCall(ISSetInfo(is, IS_IDENTITY, IS_GLOBAL, PETSC_TRUE, PETSC_TRUE));
887:   PetscFunctionReturn(PETSC_SUCCESS);
888: }

890: /*@
891:   ISContiguousLocal - Locates an index set with contiguous range within a global range, if possible

893:   Not Collective

895:   Input Parameters:
896: + is     - the index set
897: . gstart - global start
898: - gend   - global end

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

904:   Level: developer

906: .seealso: `IS`, `ISGetLocalSize()`, `VecGetOwnershipRange()`
907: @*/
908: PetscErrorCode ISContiguousLocal(IS is, PetscInt gstart, PetscInt gend, PetscInt *start, PetscBool *contig)
909: {
910:   PetscFunctionBegin;
912:   PetscAssertPointer(start, 4);
913:   PetscAssertPointer(contig, 5);
914:   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);
915:   *start  = -1;
916:   *contig = PETSC_FALSE;
917:   PetscTryTypeMethod(is, contiguous, gstart, gend, start, contig);
918:   PetscFunctionReturn(PETSC_SUCCESS);
919: }

921: /*@
922:   ISPermutation - `PETSC_TRUE` or `PETSC_FALSE` depending on whether the
923:   index set has been declared to be a permutation.

925:   Logically Collective

927:   Input Parameter:
928: . is - the index set

930:   Output Parameter:
931: . perm - `PETSC_TRUE` if a permutation, else `PETSC_FALSE`

933:   Level: intermediate

935:   Note:
936:   If it is not already known that `is` is a permutation (if `ISSetPermutation()`
937:   or `ISSetInfo()` has not been called), this routine will not attempt to compute
938:   whether the index set is a permutation and will assume `perm` is `PETSC_FALSE`.
939:   To compute the value when it is not already known, use `ISGetInfo()` with
940:   the compute flag set to `PETSC_TRUE`.

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

945: .seealso: `IS`, `ISSetPermutation()`, `ISGetInfo()`
946: @*/
947: PetscErrorCode ISPermutation(IS is, PetscBool *perm)
948: {
949:   PetscFunctionBegin;
951:   PetscAssertPointer(perm, 2);
952:   PetscCall(ISGetInfo(is, IS_PERMUTATION, IS_GLOBAL, PETSC_FALSE, perm));
953:   PetscFunctionReturn(PETSC_SUCCESS);
954: }

956: /*@
957:   ISSetPermutation - Informs the index set that it is a permutation.

959:   Logically Collective

961:   Input Parameter:
962: . is - the index set

964:   Level: intermediate

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

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

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

975: .seealso: `IS`, `ISPermutation()`, `ISSetInfo()`, `ISClearInfoCache().`
976: @*/
977: PetscErrorCode ISSetPermutation(IS is)
978: {
979:   PetscFunctionBegin;
981:   if (PetscDefined(USE_DEBUG)) {
982:     PetscMPIInt size;

984:     PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)is), &size));
985:     if (size == 1) {
986:       PetscInt        i, n, *idx;
987:       const PetscInt *iidx;

989:       PetscCall(ISGetSize(is, &n));
990:       PetscCall(PetscMalloc1(n, &idx));
991:       PetscCall(ISGetIndices(is, &iidx));
992:       PetscCall(PetscArraycpy(idx, iidx, n));
993:       PetscCall(PetscIntSortSemiOrdered(n, idx));
994:       for (i = 0; i < n; i++) PetscCheck(idx[i] == i, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Index set is not a permutation");
995:       PetscCall(PetscFree(idx));
996:       PetscCall(ISRestoreIndices(is, &iidx));
997:     }
998:   }
999:   PetscCall(ISSetInfo(is, IS_PERMUTATION, IS_GLOBAL, PETSC_TRUE, PETSC_TRUE));
1000:   PetscFunctionReturn(PETSC_SUCCESS);
1001: }

1003: /*@
1004:   ISDestroy - Destroys an index set.

1006:   Collective

1008:   Input Parameter:
1009: . is - the index set

1011:   Level: beginner

1013: .seealso: `IS`, `ISCreateGeneral()`, `ISCreateStride()`, `ISCreateBlock()`
1014: @*/
1015: PetscErrorCode ISDestroy(IS *is)
1016: {
1017:   PetscFunctionBegin;
1018:   if (!*is) PetscFunctionReturn(PETSC_SUCCESS);
1020:   if (--((PetscObject)*is)->refct > 0) {
1021:     *is = NULL;
1022:     PetscFunctionReturn(PETSC_SUCCESS);
1023:   }
1024:   if ((*is)->complement) {
1025:     PetscInt refcnt;
1026:     PetscCall(PetscObjectGetReference((PetscObject)((*is)->complement), &refcnt));
1027:     PetscCheck(refcnt <= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Nonlocal IS has not been restored");
1028:     PetscCall(ISDestroy(&(*is)->complement));
1029:   }
1030:   PetscTryTypeMethod(*is, destroy);
1031:   PetscCall(PetscLayoutDestroy(&(*is)->map));
1032:   /* Destroy local representations of offproc data. */
1033:   PetscCall(PetscFree((*is)->total));
1034:   PetscCall(PetscFree((*is)->nonlocal));
1035:   PetscCall(PetscHeaderDestroy(is));
1036:   PetscFunctionReturn(PETSC_SUCCESS);
1037: }

1039: /*@
1040:   ISInvertPermutation - Creates a new permutation that is the inverse of
1041:   a given permutation.

1043:   Collective

1045:   Input Parameters:
1046: + is     - the index set
1047: - nlocal - number of indices on this processor in result (ignored for 1 processor) or
1048:             use `PETSC_DECIDE`

1050:   Output Parameter:
1051: . isout - the inverse permutation

1053:   Level: intermediate

1055:   Note:
1056:   For parallel index sets this does the complete parallel permutation, but the
1057:   code is not efficient for huge index sets (10,000,000 indices).

1059: .seealso: `IS`, `ISGetInfo()`, `ISSetPermutation()`, `ISGetPermutation()`
1060: @*/
1061: PetscErrorCode ISInvertPermutation(IS is, PetscInt nlocal, IS *isout)
1062: {
1063:   PetscBool isperm, isidentity, issame;

1065:   PetscFunctionBegin;
1067:   PetscAssertPointer(isout, 3);
1068:   PetscCall(ISGetInfo(is, IS_PERMUTATION, IS_GLOBAL, PETSC_TRUE, &isperm));
1069:   PetscCheck(isperm, PetscObjectComm((PetscObject)is), PETSC_ERR_ARG_WRONG, "Not a permutation");
1070:   PetscCall(ISGetInfo(is, IS_IDENTITY, IS_GLOBAL, PETSC_TRUE, &isidentity));
1071:   issame = PETSC_FALSE;
1072:   if (isidentity) {
1073:     PetscInt n;

1075:     PetscCall(ISGetLocalSize(is, &n));
1076:     issame = (PetscBool)(n == nlocal);
1077:     PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &issame, 1, MPI_C_BOOL, MPI_LAND, PetscObjectComm((PetscObject)is)));
1078:   }
1079:   if (issame) PetscCall(ISDuplicate(is, isout));
1080:   else {
1081:     PetscUseTypeMethod(is, invertpermutation, nlocal, isout);
1082:     PetscCall(ISSetPermutation(*isout));
1083:   }
1084:   PetscFunctionReturn(PETSC_SUCCESS);
1085: }

1087: /*@
1088:   ISGetSize - Returns the global length of an index set.

1090:   Not Collective

1092:   Input Parameter:
1093: . is - the index set

1095:   Output Parameter:
1096: . size - the global size

1098:   Level: beginner

1100: .seealso: `IS`
1101: @*/
1102: PetscErrorCode ISGetSize(IS is, PetscInt *size)
1103: {
1104:   PetscFunctionBegin;
1106:   PetscAssertPointer(size, 2);
1107:   *size = is->map->N;
1108:   PetscFunctionReturn(PETSC_SUCCESS);
1109: }

1111: /*@
1112:   ISGetLocalSize - Returns the local (processor) length of an index set.

1114:   Not Collective

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

1119:   Output Parameter:
1120: . size - the local size

1122:   Level: beginner

1124: .seealso: `IS`, `ISGetSize()`
1125: @*/
1126: PetscErrorCode ISGetLocalSize(IS is, PetscInt *size)
1127: {
1128:   PetscFunctionBegin;
1130:   PetscAssertPointer(size, 2);
1131:   *size = is->map->n;
1132:   PetscFunctionReturn(PETSC_SUCCESS);
1133: }

1135: /*@
1136:   ISGetLayout - get `PetscLayout` describing index set layout

1138:   Not Collective

1140:   Input Parameter:
1141: . is - the index set

1143:   Output Parameter:
1144: . map - the layout

1146:   Level: developer

1148: .seealso: `IS`, `PetscLayout`, `ISSetLayout()`, `ISGetSize()`, `ISGetLocalSize()`
1149: @*/
1150: PetscErrorCode ISGetLayout(IS is, PetscLayout *map)
1151: {
1152:   PetscFunctionBegin;
1154:   PetscAssertPointer(map, 2);
1155:   *map = is->map;
1156:   PetscFunctionReturn(PETSC_SUCCESS);
1157: }

1159: /*@
1160:   ISSetLayout - set `PetscLayout` describing index set layout

1162:   Collective

1164:   Input Parameters:
1165: + is  - the index set
1166: - map - the layout

1168:   Level: developer

1170:   Notes:
1171:   Users should typically use higher level functions such as `ISCreateGeneral()`.

1173:   This function can be useful in some special cases of constructing a new `IS`, e.g. after `ISCreate()` and before `ISLoad()`.
1174:   Otherwise, it is only valid to replace the layout with a layout known to be equivalent.

1176: .seealso: `IS`, `PetscLayout`, `ISCreate()`, `ISGetLayout()`, `ISGetSize()`, `ISGetLocalSize()`
1177: @*/
1178: PetscErrorCode ISSetLayout(IS is, PetscLayout map)
1179: {
1180:   PetscFunctionBegin;
1182:   PetscAssertPointer(map, 2);
1183:   PetscCall(PetscLayoutReference(map, &is->map));
1184:   PetscFunctionReturn(PETSC_SUCCESS);
1185: }

1187: /*@
1188:   ISGetIndices - Returns a pointer to the indices.  The user should call
1189:   `ISRestoreIndices()` after having looked at the indices.  The user should
1190:   NOT change the indices.

1192:   Not Collective

1194:   Input Parameter:
1195: . is - the index set

1197:   Output Parameter:
1198: . ptr - the location to put the pointer to the indices

1200:   Level: intermediate

1202:   Fortran Note:
1203: .vb
1204:   PetscInt, pointer :: ptr(:)
1205: .ve

1207: .seealso: `IS`, `ISRestoreIndices()`
1208: @*/
1209: PetscErrorCode ISGetIndices(IS is, const PetscInt *ptr[])
1210: {
1211:   PetscFunctionBegin;
1213:   PetscAssertPointer(ptr, 2);
1214:   PetscUseTypeMethod(is, getindices, ptr);
1215:   PetscFunctionReturn(PETSC_SUCCESS);
1216: }

1218: /*@
1219:   ISGetMinMax - Gets the minimum and maximum values in an `IS`

1221:   Not Collective

1223:   Input Parameter:
1224: . is - the index set

1226:   Output Parameters:
1227: + min - the minimum value, you may pass `NULL`
1228: - max - the maximum value, you may pass `NULL`

1230:   Level: intermediate

1232:   Notes:
1233:   Empty index sets return min=`PETSC_INT_MAX` and max=`PETSC_INT_MIN`.

1235:   In parallel, it returns the `min` and `max` of the local portion of `is`

1237: .seealso: `IS`, `ISGetIndices()`, `ISRestoreIndices()`
1238: @*/
1239: PetscErrorCode ISGetMinMax(IS is, PetscInt *min, PetscInt *max)
1240: {
1241:   PetscFunctionBegin;
1243:   if (min) *min = is->min;
1244:   if (max) *max = is->max;
1245:   PetscFunctionReturn(PETSC_SUCCESS);
1246: }

1248: /*@
1249:   ISLocate - determine the location of an index within the local component of an index set

1251:   Not Collective

1253:   Input Parameters:
1254: + is  - the index set
1255: - key - the search key

1257:   Output Parameter:
1258: . location - if >= 0, a location within the index set that is equal to the key, otherwise the key is not in the index set

1260:   Level: intermediate

1262: .seealso: `IS`
1263:  @*/
1264: PetscErrorCode ISLocate(IS is, PetscInt key, PetscInt *location)
1265: {
1266:   PetscFunctionBegin;
1267:   if (is->ops->locate) PetscUseTypeMethod(is, locate, key, location);
1268:   else {
1269:     PetscInt        numIdx;
1270:     PetscBool       sorted;
1271:     const PetscInt *idx;

1273:     PetscCall(ISGetLocalSize(is, &numIdx));
1274:     PetscCall(ISGetIndices(is, &idx));
1275:     PetscCall(ISSorted(is, &sorted));
1276:     if (sorted) {
1277:       PetscCall(PetscFindInt(key, numIdx, idx, location));
1278:     } else {
1279:       *location = -1;
1280:       for (PetscInt i = 0; i < numIdx; i++) {
1281:         if (idx[i] == key) {
1282:           *location = i;
1283:           break;
1284:         }
1285:       }
1286:     }
1287:     PetscCall(ISRestoreIndices(is, &idx));
1288:   }
1289:   PetscFunctionReturn(PETSC_SUCCESS);
1290: }

1292: /*@
1293:   ISRestoreIndices - Restores an index set to a usable state after a call to `ISGetIndices()`.

1295:   Not Collective

1297:   Input Parameters:
1298: + is  - the index set
1299: - ptr - the pointer obtained by `ISGetIndices()`

1301:   Level: intermediate

1303:   Fortran Note:
1304: .vb
1305:   PetscInt, pointer :: ptr(:)
1306: .ve

1308: .seealso: `IS`, `ISGetIndices()`
1309: @*/
1310: PetscErrorCode ISRestoreIndices(IS is, const PetscInt *ptr[])
1311: {
1312:   PetscFunctionBegin;
1314:   PetscAssertPointer(ptr, 2);
1315:   PetscTryTypeMethod(is, restoreindices, ptr);
1316:   PetscFunctionReturn(PETSC_SUCCESS);
1317: }

1319: static PetscErrorCode ISGatherTotal_Private(IS is)
1320: {
1321:   PetscInt        i, n, N;
1322:   const PetscInt *lindices;
1323:   MPI_Comm        comm;
1324:   PetscMPIInt     rank, size, *sizes = NULL, *offsets = NULL, nn;

1326:   PetscFunctionBegin;

1329:   PetscCall(PetscObjectGetComm((PetscObject)is, &comm));
1330:   PetscCallMPI(MPI_Comm_size(comm, &size));
1331:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
1332:   PetscCall(ISGetLocalSize(is, &n));
1333:   PetscCall(PetscMalloc2(size, &sizes, size, &offsets));

1335:   PetscCall(PetscMPIIntCast(n, &nn));
1336:   PetscCallMPI(MPI_Allgather(&nn, 1, MPI_INT, sizes, 1, MPI_INT, comm));
1337:   offsets[0] = 0;
1338:   for (i = 1; i < size; ++i) offsets[i] = offsets[i - 1] + sizes[i - 1];
1339:   N = offsets[size - 1] + sizes[size - 1];

1341:   PetscCall(PetscMalloc1(N, &is->total));
1342:   PetscCall(ISGetIndices(is, &lindices));
1343:   PetscCallMPI(MPI_Allgatherv((void *)lindices, nn, MPIU_INT, is->total, sizes, offsets, MPIU_INT, comm));
1344:   PetscCall(ISRestoreIndices(is, &lindices));
1345:   is->local_offset = offsets[rank];
1346:   PetscCall(PetscFree2(sizes, offsets));
1347:   PetscFunctionReturn(PETSC_SUCCESS);
1348: }

1350: /*@
1351:   ISGetTotalIndices - Retrieve an array containing all indices across the communicator.

1353:   Collective

1355:   Input Parameter:
1356: . is - the index set

1358:   Output Parameter:
1359: . indices - total indices with rank 0 indices first, and so on; total array size is
1360:              the same as returned with `ISGetSize()`.

1362:   Level: intermediate

1364:   Notes:
1365:   this is potentially nonscalable, but depends on the size of the total index set
1366:   and the size of the communicator. This may be feasible for index sets defined on
1367:   subcommunicators, such that the set size does not grow with `PETSC_WORLD_COMM`.
1368:   Note also that there is no way to tell where the local part of the indices starts
1369:   (use `ISGetIndices()` and `ISGetNonlocalIndices()` to retrieve just the local and just
1370:   the nonlocal part (complement), respectively).

1372: .seealso: `IS`, `ISRestoreTotalIndices()`, `ISGetNonlocalIndices()`, `ISGetSize()`
1373: @*/
1374: PetscErrorCode ISGetTotalIndices(IS is, const PetscInt *indices[])
1375: {
1376:   PetscMPIInt size;

1378:   PetscFunctionBegin;
1380:   PetscAssertPointer(indices, 2);
1381:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)is), &size));
1382:   if (size == 1) PetscUseTypeMethod(is, getindices, indices);
1383:   else {
1384:     if (!is->total) PetscCall(ISGatherTotal_Private(is));
1385:     *indices = is->total;
1386:   }
1387:   PetscFunctionReturn(PETSC_SUCCESS);
1388: }

1390: /*@
1391:   ISRestoreTotalIndices - Restore the index array obtained with `ISGetTotalIndices()`.

1393:   Not Collective.

1395:   Input Parameters:
1396: + is      - the index set
1397: - indices - index array; must be the array obtained with `ISGetTotalIndices()`

1399:   Level: intermediate

1401: .seealso: `IS`, `ISGetNonlocalIndices()`
1402: @*/
1403: PetscErrorCode ISRestoreTotalIndices(IS is, const PetscInt *indices[])
1404: {
1405:   PetscMPIInt size;

1407:   PetscFunctionBegin;
1409:   PetscAssertPointer(indices, 2);
1410:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)is), &size));
1411:   if (size == 1) {
1412:     PetscUseTypeMethod(is, restoreindices, indices);
1413:   } else {
1414:     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.");
1415:   }
1416:   PetscFunctionReturn(PETSC_SUCCESS);
1417: }

1419: /*@
1420:   ISGetNonlocalIndices - Retrieve an array of indices from remote processors
1421:   in this communicator.

1423:   Collective

1425:   Input Parameter:
1426: . is - the index set

1428:   Output Parameter:
1429: . indices - indices with rank 0 indices first, and so on,  omitting
1430:              the current rank.  Total number of indices is the difference
1431:              total and local, obtained with `ISGetSize()` and `ISGetLocalSize()`,
1432:              respectively.

1434:   Level: intermediate

1436:   Notes:
1437:   Restore the indices using `ISRestoreNonlocalIndices()`.

1439:   The same scalability considerations as those for `ISGetTotalIndices()` apply here.

1441: .seealso: `IS`, `ISGetTotalIndices()`, `ISRestoreNonlocalIndices()`, `ISGetSize()`, `ISGetLocalSize().`
1442: @*/
1443: PetscErrorCode ISGetNonlocalIndices(IS is, const PetscInt *indices[])
1444: {
1445:   PetscMPIInt size;
1446:   PetscInt    n, N;

1448:   PetscFunctionBegin;
1450:   PetscAssertPointer(indices, 2);
1451:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)is), &size));
1452:   if (size == 1) *indices = NULL;
1453:   else {
1454:     if (!is->total) PetscCall(ISGatherTotal_Private(is));
1455:     PetscCall(ISGetLocalSize(is, &n));
1456:     PetscCall(ISGetSize(is, &N));
1457:     PetscCall(PetscMalloc1(N - n, &is->nonlocal));
1458:     PetscCall(PetscArraycpy(is->nonlocal, is->total, is->local_offset));
1459:     PetscCall(PetscArraycpy(is->nonlocal + is->local_offset, is->total + is->local_offset + n, N - is->local_offset - n));
1460:     *indices = is->nonlocal;
1461:   }
1462:   PetscFunctionReturn(PETSC_SUCCESS);
1463: }

1465: /*@
1466:   ISRestoreNonlocalIndices - Restore the index array obtained with `ISGetNonlocalIndices()`.

1468:   Not Collective.

1470:   Input Parameters:
1471: + is      - the index set
1472: - indices - index array; must be the array obtained with `ISGetNonlocalIndices()`

1474:   Level: intermediate

1476: .seealso: `IS`, `ISGetTotalIndices()`, `ISGetNonlocalIndices()`, `ISRestoreTotalIndices()`
1477: @*/
1478: PetscErrorCode ISRestoreNonlocalIndices(IS is, const PetscInt *indices[])
1479: {
1480:   PetscFunctionBegin;
1482:   PetscAssertPointer(indices, 2);
1483:   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.");
1484:   PetscFunctionReturn(PETSC_SUCCESS);
1485: }

1487: /*@
1488:   ISGetNonlocalIS - Gather all nonlocal indices for this `IS` and present
1489:   them as another sequential index set.

1491:   Collective

1493:   Input Parameter:
1494: . is - the index set

1496:   Output Parameter:
1497: . complement - sequential `IS` with indices identical to the result of
1498:                 `ISGetNonlocalIndices()`

1500:   Level: intermediate

1502:   Notes:
1503:   Complement represents the result of `ISGetNonlocalIndices()` as an `IS`.
1504:   Therefore scalability issues similar to `ISGetNonlocalIndices()` apply.

1506:   The resulting `IS` must be restored using `ISRestoreNonlocalIS()`.

1508: .seealso: `IS`, `ISGetNonlocalIndices()`, `ISRestoreNonlocalIndices()`, `ISAllGather()`, `ISGetSize()`
1509: @*/
1510: PetscErrorCode ISGetNonlocalIS(IS is, IS *complement)
1511: {
1512:   PetscFunctionBegin;
1514:   PetscAssertPointer(complement, 2);
1515:   /* Check if the complement exists already. */
1516:   if (is->complement) {
1517:     *complement = is->complement;
1518:     PetscCall(PetscObjectReference((PetscObject)is->complement));
1519:   } else {
1520:     PetscInt        N, n;
1521:     const PetscInt *idx;
1522:     PetscCall(ISGetSize(is, &N));
1523:     PetscCall(ISGetLocalSize(is, &n));
1524:     PetscCall(ISGetNonlocalIndices(is, &idx));
1525:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, N - n, idx, PETSC_USE_POINTER, &is->complement));
1526:     PetscCall(PetscObjectReference((PetscObject)is->complement));
1527:     *complement = is->complement;
1528:   }
1529:   PetscFunctionReturn(PETSC_SUCCESS);
1530: }

1532: /*@
1533:   ISRestoreNonlocalIS - Restore the `IS` obtained with `ISGetNonlocalIS()`.

1535:   Not collective.

1537:   Input Parameters:
1538: + is         - the index set
1539: - complement - index set of `is`'s nonlocal indices

1541:   Level: intermediate

1543: .seealso: `IS`, `ISGetNonlocalIS()`, `ISGetNonlocalIndices()`, `ISRestoreNonlocalIndices()`
1544: @*/
1545: PetscErrorCode ISRestoreNonlocalIS(IS is, IS *complement)
1546: {
1547:   PetscInt refcnt;

1549:   PetscFunctionBegin;
1551:   PetscAssertPointer(complement, 2);
1552:   PetscCheck(*complement == is->complement, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Complement IS being restored was not obtained with ISGetNonlocalIS()");
1553:   PetscCall(PetscObjectGetReference((PetscObject)is->complement, &refcnt));
1554:   PetscCheck(refcnt > 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Duplicate call to ISRestoreNonlocalIS() detected");
1555:   PetscCall(PetscObjectDereference((PetscObject)is->complement));
1556:   PetscFunctionReturn(PETSC_SUCCESS);
1557: }

1559: /*@
1560:   ISViewFromOptions - View an `IS` based on options in the options database

1562:   Collective

1564:   Input Parameters:
1565: + A    - the index set
1566: . obj  - Optional object that provides the prefix for the options database
1567: - name - command line option

1569:   Options Database Key:
1570: . -name [viewertype][:...] - option name and values. See `PetscObjectViewFromOptions()` for the possible arguments

1572:   Level: intermediate

1574: .seealso: `IS`, `ISView()`, `PetscObjectViewFromOptions()`, `ISCreate()`
1575: @*/
1576: PetscErrorCode ISViewFromOptions(IS A, PetscObject obj, const char name[])
1577: {
1578:   PetscFunctionBegin;
1580:   PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
1581:   PetscFunctionReturn(PETSC_SUCCESS);
1582: }

1584: /*@
1585:   ISView - Displays an index set.

1587:   Collective

1589:   Input Parameters:
1590: + is     - the index set
1591: - viewer - viewer used to display the set, for example `PETSC_VIEWER_STDOUT_SELF`.

1593:   Level: intermediate

1595: .seealso: `IS`, `PetscViewer`, `PetscViewerASCIIOpen()`, `ISViewFromOptions()`
1596: @*/
1597: PetscErrorCode ISView(IS is, PetscViewer viewer)
1598: {
1599:   PetscFunctionBegin;
1601:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)is), &viewer));
1603:   PetscCheckSameComm(is, 1, viewer, 2);

1605:   PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)is, viewer));
1606:   PetscCall(PetscLogEventBegin(IS_View, is, viewer, 0, 0));
1607:   PetscUseTypeMethod(is, view, viewer);
1608:   PetscCall(PetscLogEventEnd(IS_View, is, viewer, 0, 0));
1609:   PetscFunctionReturn(PETSC_SUCCESS);
1610: }

1612: /*@
1613:   ISLoad - Loads an index set that has been stored in binary or HDF5 format with `ISView()`.

1615:   Collective

1617:   Input Parameters:
1618: + is     - the newly loaded index set, this needs to have been created with `ISCreate()` or some related function before a call to `ISLoad()`.
1619: - viewer - binary file viewer, obtained from `PetscViewerBinaryOpen()` or HDF5 file viewer, obtained from `PetscViewerHDF5Open()`

1621:   Level: intermediate

1623:   Notes:
1624:   IF using HDF5, you must assign the IS the same name as was used in `is`
1625:   that was stored in the file using `PetscObjectSetName()`. Otherwise you will
1626:   get the error message: "Cannot H5DOpen2() with Vec name NAMEOFOBJECT"

1628: .seealso: `IS`, `PetscViewerBinaryOpen()`, `ISView()`, `MatLoad()`, `VecLoad()`
1629: @*/
1630: PetscErrorCode ISLoad(IS is, PetscViewer viewer)
1631: {
1632:   PetscBool isbinary, ishdf5;

1634:   PetscFunctionBegin;
1637:   PetscCheckSameComm(is, 1, viewer, 2);
1638:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
1639:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERHDF5, &ishdf5));
1640:   PetscCheck(isbinary || ishdf5, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid viewer; open viewer with PetscViewerBinaryOpen()");
1641:   if (!((PetscObject)is)->type_name) PetscCall(ISSetType(is, ISGENERAL));
1642:   PetscCall(PetscLogEventBegin(IS_Load, is, viewer, 0, 0));
1643:   PetscUseTypeMethod(is, load, viewer);
1644:   PetscCall(PetscLogEventEnd(IS_Load, is, viewer, 0, 0));
1645:   PetscFunctionReturn(PETSC_SUCCESS);
1646: }

1648: /*@
1649:   ISSort - Sorts the indices of an index set.

1651:   Collective

1653:   Input Parameter:
1654: . is - the index set

1656:   Level: intermediate

1658: .seealso: `IS`, `ISSortRemoveDups()`, `ISSorted()`
1659: @*/
1660: PetscErrorCode ISSort(IS is)
1661: {
1662:   PetscBool flg;

1664:   PetscFunctionBegin;
1666:   PetscCall(ISGetInfo(is, IS_SORTED, IS_LOCAL, PETSC_FALSE, &flg));
1667:   if (!flg) {
1668:     PetscUseTypeMethod(is, sort);
1669:     PetscCall(ISSetInfo(is, IS_SORTED, IS_LOCAL, is->info_permanent[IS_LOCAL][IS_SORTED], PETSC_TRUE));
1670:   }
1671:   PetscFunctionReturn(PETSC_SUCCESS);
1672: }

1674: /*@
1675:   ISSortRemoveDups - Sorts the indices of an index set, removing duplicates.

1677:   Collective

1679:   Input Parameter:
1680: . is - the index set

1682:   Level: intermediate

1684: .seealso: `IS`, `ISSort()`, `ISSorted()`
1685: @*/
1686: PetscErrorCode ISSortRemoveDups(IS is)
1687: {
1688:   PetscFunctionBegin;
1690:   PetscCall(ISClearInfoCache(is, PETSC_FALSE));
1691:   PetscUseTypeMethod(is, sortremovedups);
1692:   PetscCall(ISSetInfo(is, IS_SORTED, IS_LOCAL, is->info_permanent[IS_LOCAL][IS_SORTED], PETSC_TRUE));
1693:   PetscCall(ISSetInfo(is, IS_UNIQUE, IS_LOCAL, is->info_permanent[IS_LOCAL][IS_UNIQUE], PETSC_TRUE));
1694:   PetscFunctionReturn(PETSC_SUCCESS);
1695: }

1697: /*@
1698:   ISToGeneral - Converts an IS object of any type to `ISGENERAL` type

1700:   Collective

1702:   Input Parameter:
1703: . is - the index set

1705:   Level: intermediate

1707: .seealso: `IS`, `ISSorted()`
1708: @*/
1709: PetscErrorCode ISToGeneral(IS is)
1710: {
1711:   PetscFunctionBegin;
1713:   PetscUseTypeMethod(is, togeneral);
1714:   PetscFunctionReturn(PETSC_SUCCESS);
1715: }

1717: /*@
1718:   ISSorted - Checks the indices to determine whether they have been sorted.

1720:   Not Collective

1722:   Input Parameter:
1723: . is - the index set

1725:   Output Parameter:
1726: . flg - output flag, either `PETSC_TRUE` if the index set is sorted,
1727:          or `PETSC_FALSE` otherwise.

1729:   Level: intermediate

1731:   Note:
1732:   For parallel IS objects this only indicates if the local part of `is`
1733:   is sorted. So some processors may return `PETSC_TRUE` while others may
1734:   return `PETSC_FALSE`.

1736: .seealso: `ISSort()`, `ISSortRemoveDups()`
1737: @*/
1738: PetscErrorCode ISSorted(IS is, PetscBool *flg)
1739: {
1740:   PetscFunctionBegin;
1742:   PetscAssertPointer(flg, 2);
1743:   PetscCall(ISGetInfo(is, IS_SORTED, IS_LOCAL, PETSC_TRUE, flg));
1744:   PetscFunctionReturn(PETSC_SUCCESS);
1745: }

1747: /*@
1748:   ISDuplicate - Creates a duplicate copy of an index set.

1750:   Collective

1752:   Input Parameter:
1753: . is - the index set

1755:   Output Parameter:
1756: . newIS - the copy of the index set

1758:   Level: beginner

1760: .seealso: `IS`, `ISCreateGeneral()`, `ISCopy()`
1761: @*/
1762: PetscErrorCode ISDuplicate(IS is, IS *newIS)
1763: {
1764:   PetscFunctionBegin;
1766:   PetscAssertPointer(newIS, 2);
1767:   PetscUseTypeMethod(is, duplicate, newIS);
1768:   PetscCall(ISCopyInfo_Private(is, *newIS));
1769:   PetscFunctionReturn(PETSC_SUCCESS);
1770: }

1772: /*@
1773:   ISCopy - Copies an index set.

1775:   Collective

1777:   Input Parameter:
1778: . is - the index set

1780:   Output Parameter:
1781: . isy - the copy of the index set

1783:   Level: beginner

1785: .seealso: `IS`, `ISDuplicate()`, `ISShift()`
1786: @*/
1787: PetscErrorCode ISCopy(IS is, IS isy)
1788: {
1789:   PetscInt bs, bsy;

1791:   PetscFunctionBegin;
1794:   PetscCheckSameComm(is, 1, isy, 2);
1795:   if (is == isy) PetscFunctionReturn(PETSC_SUCCESS);
1796:   PetscCall(PetscLayoutGetBlockSize(is->map, &bs));
1797:   PetscCall(PetscLayoutGetBlockSize(isy->map, &bsy));
1798:   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);
1799:   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);
1800:   PetscCheck(bs == bsy, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Index sets have different block size %" PetscInt_FMT " != %" PetscInt_FMT, bs, bsy);
1801:   PetscCall(ISCopyInfo_Private(is, isy));
1802:   isy->max = is->max;
1803:   isy->min = is->min;
1804:   PetscUseTypeMethod(is, copy, isy);
1805:   PetscFunctionReturn(PETSC_SUCCESS);
1806: }

1808: /*@
1809:   ISShift - Shift all indices by given offset

1811:   Collective

1813:   Input Parameters:
1814: + is     - the index set
1815: - offset - the offset

1817:   Output Parameter:
1818: . isy - the shifted copy of the input index set

1820:   Level: beginner

1822:   Notes:
1823:   The `offset` can be different across processes.

1825:   `is` and `isy` can be the same.

1827: .seealso: `ISDuplicate()`, `ISCopy()`
1828: @*/
1829: PetscErrorCode ISShift(IS is, PetscInt offset, IS isy)
1830: {
1831:   PetscFunctionBegin;
1834:   PetscCheckSameComm(is, 1, isy, 3);
1835:   if (!offset) {
1836:     PetscCall(ISCopy(is, isy));
1837:     PetscFunctionReturn(PETSC_SUCCESS);
1838:   }
1839:   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);
1840:   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);
1841:   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);
1842:   PetscCall(ISCopyInfo_Private(is, isy));
1843:   if (offset > 0) {
1844:     isy->max = is->max < PETSC_INT_MAX - offset ? is->max + offset : PETSC_INT_MAX;
1845:     isy->min = is->min < PETSC_INT_MAX - offset ? is->min + offset : PETSC_INT_MAX;
1846:   } else {
1847:     isy->max = is->max > PETSC_INT_MIN - offset ? is->max + offset : PETSC_INT_MIN;
1848:     isy->min = is->min > PETSC_INT_MIN - offset ? is->min + offset : PETSC_INT_MIN;
1849:   }
1850:   PetscUseMethod(is, "ISShift_C", (IS, PetscInt, IS), (is, offset, isy));
1851:   PetscFunctionReturn(PETSC_SUCCESS);
1852: }

1854: /*@
1855:   ISOnComm - Split a parallel `IS` on subcomms (usually self) or concatenate index sets on subcomms into a parallel index set

1857:   Collective

1859:   Input Parameters:
1860: + is   - index set
1861: . comm - communicator for new index set
1862: - mode - copy semantics, `PETSC_USE_POINTER` for no-copy if possible, otherwise `PETSC_COPY_VALUES`

1864:   Output Parameter:
1865: . newis - new `IS` on `comm`

1867:   Level: advanced

1869:   Notes:
1870:   It is usually desirable to create a parallel `IS` and look at the local part when necessary.

1872:   This function is useful if serial `IS`s must be created independently, or to view many
1873:   logically independent serial `IS`s.

1875:   The input `IS` must have the same type on every MPI process.

1877: .seealso: `IS`
1878: @*/
1879: PetscErrorCode ISOnComm(IS is, MPI_Comm comm, PetscCopyMode mode, IS *newis)
1880: {
1881:   PetscMPIInt match;

1883:   PetscFunctionBegin;
1885:   PetscAssertPointer(newis, 4);
1886:   PetscCallMPI(MPI_Comm_compare(PetscObjectComm((PetscObject)is), comm, &match));
1887:   if (mode != PETSC_COPY_VALUES && (match == MPI_IDENT || match == MPI_CONGRUENT)) {
1888:     PetscCall(PetscObjectReference((PetscObject)is));
1889:     *newis = is;
1890:   } else PetscUseTypeMethod(is, oncomm, comm, mode, newis);
1891:   PetscFunctionReturn(PETSC_SUCCESS);
1892: }

1894: /*@
1895:   ISSetBlockSize - informs an index set that it has a given block size

1897:   Logicall Collective

1899:   Input Parameters:
1900: + is - index set
1901: - bs - block size

1903:   Level: intermediate

1905:   Notes:
1906:   This is much like the block size for `Vec`s. It indicates that one can think of the indices as
1907:   being in a collection of equal size blocks. For `ISBLOCK` these collections of blocks are all contiguous
1908:   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
1909:   have a block size of three set.

1911:   `ISBlockGetIndices()` only works for `ISBLOCK`, not others.

1913: .seealso: `IS`, `ISGetBlockSize()`, `ISCreateBlock()`, `ISBlockGetIndices()`
1914: @*/
1915: PetscErrorCode ISSetBlockSize(IS is, PetscInt bs)
1916: {
1917:   PetscFunctionBegin;
1920:   PetscCheck(bs >= 1, PetscObjectComm((PetscObject)is), PETSC_ERR_ARG_OUTOFRANGE, "Block size %" PetscInt_FMT ", must be positive", bs);
1921:   if (PetscDefined(USE_DEBUG)) {
1922:     const PetscInt *indices;
1923:     PetscInt        length, i, j;
1924:     PetscCall(ISGetIndices(is, &indices));
1925:     if (indices) {
1926:       PetscCall(ISGetLocalSize(is, &length));
1927:       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);
1928:       for (i = 1; i < length / bs; i += bs) {
1929:         for (j = 1; j < bs - 1; j++) {
1930:           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);
1931:         }
1932:       }
1933:     }
1934:     PetscCall(ISRestoreIndices(is, &indices));
1935:   }
1936:   PetscUseTypeMethod(is, setblocksize, bs);
1937:   PetscFunctionReturn(PETSC_SUCCESS);
1938: }

1940: /*@
1941:   ISGetBlockSize - Returns the number of elements in a block.

1943:   Not Collective

1945:   Input Parameter:
1946: . is - the index set

1948:   Output Parameter:
1949: . size - the number of elements in a block

1951:   Level: intermediate

1953:   Note:
1954:   See `ISSetBlockSize()`

1956: .seealso: `IS`, `ISBlockGetSize()`, `ISGetSize()`, `ISCreateBlock()`, `ISSetBlockSize()`
1957: @*/
1958: PetscErrorCode ISGetBlockSize(IS is, PetscInt *size)
1959: {
1960:   PetscFunctionBegin;
1961:   PetscCall(PetscLayoutGetBlockSize(is->map, size));
1962:   PetscFunctionReturn(PETSC_SUCCESS);
1963: }

1965: /*@
1966:   ISSetCompressOutput - set the flag for output compression

1968:   Logicall Collective

1970:   Input Parameters:
1971: + is       - index set
1972: - compress - flag for output compression

1974:   Level: intermediate

1976: .seealso: `IS`, `ISGetCompressOutput()`, `ISView()`
1977: @*/
1978: PetscErrorCode ISSetCompressOutput(IS is, PetscBool compress)
1979: {
1980:   PetscFunctionBegin;
1983:   is->compressOutput = compress;
1984:   PetscFunctionReturn(PETSC_SUCCESS);
1985: }

1987: /*@
1988:   ISGetCompressOutput - Returns the flag for output compression

1990:   Not Collective

1992:   Input Parameter:
1993: . is - the index set

1995:   Output Parameter:
1996: . compress - the flag to compress output

1998:   Level: intermediate

2000: .seealso: `IS`, `ISSetCompressOutput()`, `ISView()`
2001: @*/
2002: PetscErrorCode ISGetCompressOutput(IS is, PetscBool *compress)
2003: {
2004:   PetscFunctionBegin;
2006:   PetscAssertPointer(compress, 2);
2007:   *compress = is->compressOutput;
2008:   PetscFunctionReturn(PETSC_SUCCESS);
2009: }

2011: static PetscErrorCode ISGetIndicesCopy_Private(IS is, PetscInt idx[])
2012: {
2013:   PetscInt        len;
2014:   const PetscInt *ptr;

2016:   PetscFunctionBegin;
2017:   PetscCall(ISGetLocalSize(is, &len));
2018:   PetscCall(ISGetIndices(is, &ptr));
2019:   for (PetscInt i = 0; i < len; i++) idx[i] = ptr[i];
2020:   PetscCall(ISRestoreIndices(is, &ptr));
2021:   PetscFunctionReturn(PETSC_SUCCESS);
2022: }