Actual source code: pbvec.c
2: /*
3: This file contains routines for Parallel vector operations.
4: */
5: #include <petscsys.h>
6: #include <../src/vec/vec/impls/mpi/pvecimpl.h>
8: extern PetscErrorCode VecView_MPI_Draw(Vec, PetscViewer);
10: PetscErrorCode VecPlaceArray_MPI(Vec vin, const PetscScalar *a)
11: {
12: Vec_MPI *v = (Vec_MPI *)vin->data;
14: PetscFunctionBegin;
15: PetscCheck(!v->unplacedarray, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "VecPlaceArray() was already called on this vector, without a call to VecResetArray()");
16: v->unplacedarray = v->array; /* save previous array so reset can bring it back */
17: v->array = (PetscScalar *)a;
18: if (v->localrep) PetscCall(VecPlaceArray(v->localrep, a));
19: PetscFunctionReturn(PETSC_SUCCESS);
20: }
22: PetscErrorCode VecDuplicate_MPI(Vec win, Vec *v)
23: {
24: Vec_MPI *vw, *w = (Vec_MPI *)win->data;
25: PetscScalar *array;
27: PetscFunctionBegin;
28: PetscCall(VecCreate(PetscObjectComm((PetscObject)win), v));
29: PetscCall(PetscLayoutReference(win->map, &(*v)->map));
31: PetscCall(VecCreate_MPI_Private(*v, PETSC_TRUE, w->nghost, NULL));
32: vw = (Vec_MPI *)(*v)->data;
33: PetscCall(PetscMemcpy((*v)->ops, win->ops, sizeof(*win->ops)));
35: /* save local representation of the parallel vector (and scatter) if it exists */
36: if (w->localrep) {
37: PetscCall(VecGetArray(*v, &array));
38: PetscCall(VecCreateSeqWithArray(PETSC_COMM_SELF, PetscAbs(win->map->bs), win->map->n + w->nghost, array, &vw->localrep));
39: PetscCall(PetscMemcpy(vw->localrep->ops, w->localrep->ops, sizeof(*w->localrep->ops)));
40: PetscCall(VecRestoreArray(*v, &array));
42: vw->localupdate = w->localupdate;
43: if (vw->localupdate) PetscCall(PetscObjectReference((PetscObject)vw->localupdate));
44: }
46: /* New vector should inherit stashing property of parent */
47: (*v)->stash.donotstash = win->stash.donotstash;
48: (*v)->stash.ignorenegidx = win->stash.ignorenegidx;
50: PetscCall(PetscObjectListDuplicate(((PetscObject)win)->olist, &((PetscObject)(*v))->olist));
51: PetscCall(PetscFunctionListDuplicate(((PetscObject)win)->qlist, &((PetscObject)(*v))->qlist));
53: (*v)->map->bs = PetscAbs(win->map->bs);
54: (*v)->bstash.bs = win->bstash.bs;
55: PetscFunctionReturn(PETSC_SUCCESS);
56: }
58: static PetscErrorCode VecSetOption_MPI(Vec V, VecOption op, PetscBool flag)
59: {
60: Vec_MPI *v = (Vec_MPI *)V->data;
62: PetscFunctionBegin;
63: switch (op) {
64: case VEC_IGNORE_OFF_PROC_ENTRIES:
65: V->stash.donotstash = flag;
66: break;
67: case VEC_IGNORE_NEGATIVE_INDICES:
68: V->stash.ignorenegidx = flag;
69: break;
70: case VEC_SUBSET_OFF_PROC_ENTRIES:
71: v->assembly_subset = flag; /* See the same logic in MatAssembly wrt MAT_SUBSET_OFF_PROC_ENTRIES */
72: if (!v->assembly_subset) { /* User indicates "do not reuse the communication pattern" */
73: PetscCall(VecAssemblyReset_MPI(V)); /* Reset existing pattern to free memory */
74: v->first_assembly_done = PETSC_FALSE; /* Mark the first assembly is not done */
75: }
76: break;
77: }
79: PetscFunctionReturn(PETSC_SUCCESS);
80: }
82: PetscErrorCode VecResetArray_MPI(Vec vin)
83: {
84: Vec_MPI *v = (Vec_MPI *)vin->data;
86: PetscFunctionBegin;
87: v->array = v->unplacedarray;
88: v->unplacedarray = NULL;
89: if (v->localrep) PetscCall(VecResetArray(v->localrep));
90: PetscFunctionReturn(PETSC_SUCCESS);
91: }
93: static PetscErrorCode VecAssemblySend_MPI_Private(MPI_Comm comm, const PetscMPIInt tag[], PetscMPIInt rankid, PetscMPIInt rank, void *sdata, MPI_Request req[], void *ctx)
94: {
95: Vec X = (Vec)ctx;
96: Vec_MPI *x = (Vec_MPI *)X->data;
97: VecAssemblyHeader *hdr = (VecAssemblyHeader *)sdata;
98: PetscInt bs = X->map->bs;
100: PetscFunctionBegin;
101: /* x->first_assembly_done indicates we are reusing a communication network. In that case, some
102: messages can be empty, but we have to send them this time if we sent them before because the
103: receiver is expecting them.
104: */
105: if (hdr->count || (x->first_assembly_done && x->sendptrs[rankid].ints)) {
106: PetscCallMPI(MPI_Isend(x->sendptrs[rankid].ints, hdr->count, MPIU_INT, rank, tag[0], comm, &req[0]));
107: PetscCallMPI(MPI_Isend(x->sendptrs[rankid].scalars, hdr->count, MPIU_SCALAR, rank, tag[1], comm, &req[1]));
108: }
109: if (hdr->bcount || (x->first_assembly_done && x->sendptrs[rankid].intb)) {
110: PetscCallMPI(MPI_Isend(x->sendptrs[rankid].intb, hdr->bcount, MPIU_INT, rank, tag[2], comm, &req[2]));
111: PetscCallMPI(MPI_Isend(x->sendptrs[rankid].scalarb, hdr->bcount * bs, MPIU_SCALAR, rank, tag[3], comm, &req[3]));
112: }
113: PetscFunctionReturn(PETSC_SUCCESS);
114: }
116: static PetscErrorCode VecAssemblyRecv_MPI_Private(MPI_Comm comm, const PetscMPIInt tag[], PetscMPIInt rank, void *rdata, MPI_Request req[], void *ctx)
117: {
118: Vec X = (Vec)ctx;
119: Vec_MPI *x = (Vec_MPI *)X->data;
120: VecAssemblyHeader *hdr = (VecAssemblyHeader *)rdata;
121: PetscInt bs = X->map->bs;
122: VecAssemblyFrame *frame;
124: PetscFunctionBegin;
125: PetscCall(PetscSegBufferGet(x->segrecvframe, 1, &frame));
127: if (hdr->count) {
128: PetscCall(PetscSegBufferGet(x->segrecvint, hdr->count, &frame->ints));
129: PetscCallMPI(MPI_Irecv(frame->ints, hdr->count, MPIU_INT, rank, tag[0], comm, &req[0]));
130: PetscCall(PetscSegBufferGet(x->segrecvscalar, hdr->count, &frame->scalars));
131: PetscCallMPI(MPI_Irecv(frame->scalars, hdr->count, MPIU_SCALAR, rank, tag[1], comm, &req[1]));
132: frame->pendings = 2;
133: } else {
134: frame->ints = NULL;
135: frame->scalars = NULL;
136: frame->pendings = 0;
137: }
139: if (hdr->bcount) {
140: PetscCall(PetscSegBufferGet(x->segrecvint, hdr->bcount, &frame->intb));
141: PetscCallMPI(MPI_Irecv(frame->intb, hdr->bcount, MPIU_INT, rank, tag[2], comm, &req[2]));
142: PetscCall(PetscSegBufferGet(x->segrecvscalar, hdr->bcount * bs, &frame->scalarb));
143: PetscCallMPI(MPI_Irecv(frame->scalarb, hdr->bcount * bs, MPIU_SCALAR, rank, tag[3], comm, &req[3]));
144: frame->pendingb = 2;
145: } else {
146: frame->intb = NULL;
147: frame->scalarb = NULL;
148: frame->pendingb = 0;
149: }
150: PetscFunctionReturn(PETSC_SUCCESS);
151: }
153: static PetscErrorCode VecAssemblyBegin_MPI_BTS(Vec X)
154: {
155: Vec_MPI *x = (Vec_MPI *)X->data;
156: MPI_Comm comm;
157: PetscInt i, j, jb, bs;
159: PetscFunctionBegin;
160: if (X->stash.donotstash) PetscFunctionReturn(PETSC_SUCCESS);
162: PetscCall(PetscObjectGetComm((PetscObject)X, &comm));
163: PetscCall(VecGetBlockSize(X, &bs));
164: if (PetscDefined(USE_DEBUG)) {
165: InsertMode addv;
166: PetscCall(MPIU_Allreduce((PetscEnum *)&X->stash.insertmode, (PetscEnum *)&addv, 1, MPIU_ENUM, MPI_BOR, comm));
167: PetscCheck(addv != (ADD_VALUES | INSERT_VALUES), comm, PETSC_ERR_ARG_NOTSAMETYPE, "Some processors inserted values while others added");
168: }
169: X->bstash.insertmode = X->stash.insertmode; /* Block stash implicitly tracks InsertMode of scalar stash */
171: PetscCall(VecStashSortCompress_Private(&X->stash));
172: PetscCall(VecStashSortCompress_Private(&X->bstash));
174: if (!x->sendranks) {
175: PetscMPIInt nowners, bnowners, *owners, *bowners;
176: PetscInt ntmp;
177: PetscCall(VecStashGetOwnerList_Private(&X->stash, X->map, &nowners, &owners));
178: PetscCall(VecStashGetOwnerList_Private(&X->bstash, X->map, &bnowners, &bowners));
179: PetscCall(PetscMergeMPIIntArray(nowners, owners, bnowners, bowners, &ntmp, &x->sendranks));
180: x->nsendranks = ntmp;
181: PetscCall(PetscFree(owners));
182: PetscCall(PetscFree(bowners));
183: PetscCall(PetscMalloc1(x->nsendranks, &x->sendhdr));
184: PetscCall(PetscCalloc1(x->nsendranks, &x->sendptrs));
185: }
186: for (i = 0, j = 0, jb = 0; i < x->nsendranks; i++) {
187: PetscMPIInt rank = x->sendranks[i];
188: x->sendhdr[i].insertmode = X->stash.insertmode;
189: /* Initialize pointers for non-empty stashes the first time around. Subsequent assemblies with
190: * VEC_SUBSET_OFF_PROC_ENTRIES will leave the old pointers (dangling because the stash has been collected) when
191: * there is nothing new to send, so that size-zero messages get sent instead. */
192: x->sendhdr[i].count = 0;
193: if (X->stash.n) {
194: x->sendptrs[i].ints = &X->stash.idx[j];
195: x->sendptrs[i].scalars = &X->stash.array[j];
196: for (; j < X->stash.n && X->stash.idx[j] < X->map->range[rank + 1]; j++) x->sendhdr[i].count++;
197: }
198: x->sendhdr[i].bcount = 0;
199: if (X->bstash.n) {
200: x->sendptrs[i].intb = &X->bstash.idx[jb];
201: x->sendptrs[i].scalarb = &X->bstash.array[jb * bs];
202: for (; jb < X->bstash.n && X->bstash.idx[jb] * bs < X->map->range[rank + 1]; jb++) x->sendhdr[i].bcount++;
203: }
204: }
206: if (!x->segrecvint) PetscCall(PetscSegBufferCreate(sizeof(PetscInt), 1000, &x->segrecvint));
207: if (!x->segrecvscalar) PetscCall(PetscSegBufferCreate(sizeof(PetscScalar), 1000, &x->segrecvscalar));
208: if (!x->segrecvframe) PetscCall(PetscSegBufferCreate(sizeof(VecAssemblyFrame), 50, &x->segrecvframe));
209: if (x->first_assembly_done) { /* this is not the first assembly */
210: PetscMPIInt tag[4];
211: for (i = 0; i < 4; i++) PetscCall(PetscCommGetNewTag(comm, &tag[i]));
212: for (i = 0; i < x->nsendranks; i++) PetscCall(VecAssemblySend_MPI_Private(comm, tag, i, x->sendranks[i], x->sendhdr + i, x->sendreqs + 4 * i, X));
213: for (i = 0; i < x->nrecvranks; i++) PetscCall(VecAssemblyRecv_MPI_Private(comm, tag, x->recvranks[i], x->recvhdr + i, x->recvreqs + 4 * i, X));
214: x->use_status = PETSC_TRUE;
215: } else { /* First time assembly */
216: PetscCall(PetscCommBuildTwoSidedFReq(comm, 3, MPIU_INT, x->nsendranks, x->sendranks, (PetscInt *)x->sendhdr, &x->nrecvranks, &x->recvranks, &x->recvhdr, 4, &x->sendreqs, &x->recvreqs, VecAssemblySend_MPI_Private, VecAssemblyRecv_MPI_Private, X));
217: x->use_status = PETSC_FALSE;
218: }
220: /* The first_assembly_done flag is only meaningful when x->assembly_subset is set.
221: This line says when assembly_subset is set, then we mark that the first assembly is done.
222: */
223: x->first_assembly_done = x->assembly_subset;
225: {
226: PetscInt nstash, reallocs;
227: PetscCall(VecStashGetInfo_Private(&X->stash, &nstash, &reallocs));
228: PetscCall(PetscInfo(X, "Stash has %" PetscInt_FMT " entries, uses %" PetscInt_FMT " mallocs.\n", nstash, reallocs));
229: PetscCall(VecStashGetInfo_Private(&X->bstash, &nstash, &reallocs));
230: PetscCall(PetscInfo(X, "Block-Stash has %" PetscInt_FMT " entries, uses %" PetscInt_FMT " mallocs.\n", nstash, reallocs));
231: }
232: PetscFunctionReturn(PETSC_SUCCESS);
233: }
235: static PetscErrorCode VecAssemblyEnd_MPI_BTS(Vec X)
236: {
237: Vec_MPI *x = (Vec_MPI *)X->data;
238: PetscInt bs = X->map->bs;
239: PetscMPIInt npending, *some_indices, r;
240: MPI_Status *some_statuses;
241: PetscScalar *xarray;
242: VecAssemblyFrame *frame;
244: PetscFunctionBegin;
245: if (X->stash.donotstash) {
246: X->stash.insertmode = NOT_SET_VALUES;
247: X->bstash.insertmode = NOT_SET_VALUES;
248: PetscFunctionReturn(PETSC_SUCCESS);
249: }
251: PetscCheck(x->segrecvframe, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Missing segrecvframe! Probably you forgot to call VecAssemblyBegin first");
252: PetscCall(VecGetArray(X, &xarray));
253: PetscCall(PetscSegBufferExtractInPlace(x->segrecvframe, &frame));
254: PetscCall(PetscMalloc2(4 * x->nrecvranks, &some_indices, x->use_status ? 4 * x->nrecvranks : 0, &some_statuses));
255: for (r = 0, npending = 0; r < x->nrecvranks; r++) npending += frame[r].pendings + frame[r].pendingb;
256: while (npending > 0) {
257: PetscMPIInt ndone = 0, ii;
258: /* Filling MPI_Status fields requires some resources from the MPI library. We skip it on the first assembly, or
259: * when VEC_SUBSET_OFF_PROC_ENTRIES has not been set, because we could exchange exact sizes in the initial
260: * rendezvous. When the rendezvous is elided, however, we use MPI_Status to get actual message lengths, so that
261: * subsequent assembly can set a proper subset of the values. */
262: PetscCallMPI(MPI_Waitsome(4 * x->nrecvranks, x->recvreqs, &ndone, some_indices, x->use_status ? some_statuses : MPI_STATUSES_IGNORE));
263: for (ii = 0; ii < ndone; ii++) {
264: PetscInt i = some_indices[ii] / 4, j, k;
265: InsertMode imode = (InsertMode)x->recvhdr[i].insertmode;
266: PetscInt *recvint;
267: PetscScalar *recvscalar;
268: PetscBool intmsg = (PetscBool)(some_indices[ii] % 2 == 0);
269: PetscBool blockmsg = (PetscBool)((some_indices[ii] % 4) / 2 == 1);
270: npending--;
271: if (!blockmsg) { /* Scalar stash */
272: PetscMPIInt count;
273: if (--frame[i].pendings > 0) continue;
274: if (x->use_status) {
275: PetscCallMPI(MPI_Get_count(&some_statuses[ii], intmsg ? MPIU_INT : MPIU_SCALAR, &count));
276: } else count = x->recvhdr[i].count;
277: for (j = 0, recvint = frame[i].ints, recvscalar = frame[i].scalars; j < count; j++, recvint++) {
278: PetscInt loc = *recvint - X->map->rstart;
279: PetscCheck(*recvint >= X->map->rstart && X->map->rend > *recvint, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Received vector entry %" PetscInt_FMT " out of local range [%" PetscInt_FMT ",%" PetscInt_FMT ")]", *recvint, X->map->rstart, X->map->rend);
280: switch (imode) {
281: case ADD_VALUES:
282: xarray[loc] += *recvscalar++;
283: break;
284: case INSERT_VALUES:
285: xarray[loc] = *recvscalar++;
286: break;
287: default:
288: SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Insert mode not supported 0x%x", imode);
289: }
290: }
291: } else { /* Block stash */
292: PetscMPIInt count;
293: if (--frame[i].pendingb > 0) continue;
294: if (x->use_status) {
295: PetscCallMPI(MPI_Get_count(&some_statuses[ii], intmsg ? MPIU_INT : MPIU_SCALAR, &count));
296: if (!intmsg) count /= bs; /* Convert from number of scalars to number of blocks */
297: } else count = x->recvhdr[i].bcount;
298: for (j = 0, recvint = frame[i].intb, recvscalar = frame[i].scalarb; j < count; j++, recvint++) {
299: PetscInt loc = (*recvint) * bs - X->map->rstart;
300: switch (imode) {
301: case ADD_VALUES:
302: for (k = loc; k < loc + bs; k++) xarray[k] += *recvscalar++;
303: break;
304: case INSERT_VALUES:
305: for (k = loc; k < loc + bs; k++) xarray[k] = *recvscalar++;
306: break;
307: default:
308: SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Insert mode not supported 0x%x", imode);
309: }
310: }
311: }
312: }
313: }
314: PetscCall(VecRestoreArray(X, &xarray));
315: PetscCallMPI(MPI_Waitall(4 * x->nsendranks, x->sendreqs, MPI_STATUSES_IGNORE));
316: PetscCall(PetscFree2(some_indices, some_statuses));
317: if (x->assembly_subset) {
318: PetscCall(PetscSegBufferExtractInPlace(x->segrecvint, NULL));
319: PetscCall(PetscSegBufferExtractInPlace(x->segrecvscalar, NULL));
320: } else {
321: PetscCall(VecAssemblyReset_MPI(X));
322: }
324: X->stash.insertmode = NOT_SET_VALUES;
325: X->bstash.insertmode = NOT_SET_VALUES;
326: PetscCall(VecStashScatterEnd_Private(&X->stash));
327: PetscCall(VecStashScatterEnd_Private(&X->bstash));
328: PetscFunctionReturn(PETSC_SUCCESS);
329: }
331: PetscErrorCode VecAssemblyReset_MPI(Vec X)
332: {
333: Vec_MPI *x = (Vec_MPI *)X->data;
335: PetscFunctionBegin;
336: PetscCall(PetscFree(x->sendreqs));
337: PetscCall(PetscFree(x->recvreqs));
338: PetscCall(PetscFree(x->sendranks));
339: PetscCall(PetscFree(x->recvranks));
340: PetscCall(PetscFree(x->sendhdr));
341: PetscCall(PetscFree(x->recvhdr));
342: PetscCall(PetscFree(x->sendptrs));
343: PetscCall(PetscSegBufferDestroy(&x->segrecvint));
344: PetscCall(PetscSegBufferDestroy(&x->segrecvscalar));
345: PetscCall(PetscSegBufferDestroy(&x->segrecvframe));
346: PetscFunctionReturn(PETSC_SUCCESS);
347: }
349: static PetscErrorCode VecSetFromOptions_MPI(Vec X, PetscOptionItems *PetscOptionsObject)
350: {
351: #if !defined(PETSC_HAVE_MPIUNI)
352: PetscBool flg = PETSC_FALSE, set;
354: PetscFunctionBegin;
355: PetscOptionsHeadBegin(PetscOptionsObject, "VecMPI Options");
356: PetscCall(PetscOptionsBool("-vec_assembly_legacy", "Use MPI 1 version of assembly", "", flg, &flg, &set));
357: if (set) {
358: X->ops->assemblybegin = flg ? VecAssemblyBegin_MPI : VecAssemblyBegin_MPI_BTS;
359: X->ops->assemblyend = flg ? VecAssemblyEnd_MPI : VecAssemblyEnd_MPI_BTS;
360: }
361: PetscOptionsHeadEnd();
362: #else
363: PetscFunctionBegin;
364: X->ops->assemblybegin = VecAssemblyBegin_MPI;
365: X->ops->assemblyend = VecAssemblyEnd_MPI;
366: #endif
367: PetscFunctionReturn(PETSC_SUCCESS);
368: }
370: static struct _VecOps DvOps = {PetscDesignatedInitializer(duplicate, VecDuplicate_MPI), /* 1 */
371: PetscDesignatedInitializer(duplicatevecs, VecDuplicateVecs_Default),
372: PetscDesignatedInitializer(destroyvecs, VecDestroyVecs_Default),
373: PetscDesignatedInitializer(dot, VecDot_MPI),
374: PetscDesignatedInitializer(mdot, VecMDot_MPI),
375: PetscDesignatedInitializer(norm, VecNorm_MPI),
376: PetscDesignatedInitializer(tdot, VecTDot_MPI),
377: PetscDesignatedInitializer(mtdot, VecMTDot_MPI),
378: PetscDesignatedInitializer(scale, VecScale_Seq),
379: PetscDesignatedInitializer(copy, VecCopy_Seq), /* 10 */
380: PetscDesignatedInitializer(set, VecSet_Seq),
381: PetscDesignatedInitializer(swap, VecSwap_Seq),
382: PetscDesignatedInitializer(axpy, VecAXPY_Seq),
383: PetscDesignatedInitializer(axpby, VecAXPBY_Seq),
384: PetscDesignatedInitializer(maxpy, VecMAXPY_Seq),
385: PetscDesignatedInitializer(aypx, VecAYPX_Seq),
386: PetscDesignatedInitializer(waxpy, VecWAXPY_Seq),
387: PetscDesignatedInitializer(axpbypcz, VecAXPBYPCZ_Seq),
388: PetscDesignatedInitializer(pointwisemult, VecPointwiseMult_Seq),
389: PetscDesignatedInitializer(pointwisedivide, VecPointwiseDivide_Seq),
390: PetscDesignatedInitializer(setvalues, VecSetValues_MPI), /* 20 */
391: PetscDesignatedInitializer(assemblybegin, VecAssemblyBegin_MPI_BTS),
392: PetscDesignatedInitializer(assemblyend, VecAssemblyEnd_MPI_BTS),
393: PetscDesignatedInitializer(getarray, NULL),
394: PetscDesignatedInitializer(getsize, VecGetSize_MPI),
395: PetscDesignatedInitializer(getlocalsize, VecGetSize_Seq),
396: PetscDesignatedInitializer(restorearray, NULL),
397: PetscDesignatedInitializer(max, VecMax_MPI),
398: PetscDesignatedInitializer(min, VecMin_MPI),
399: PetscDesignatedInitializer(setrandom, VecSetRandom_Seq),
400: PetscDesignatedInitializer(setoption, VecSetOption_MPI),
401: PetscDesignatedInitializer(setvaluesblocked, VecSetValuesBlocked_MPI),
402: PetscDesignatedInitializer(destroy, VecDestroy_MPI),
403: PetscDesignatedInitializer(view, VecView_MPI),
404: PetscDesignatedInitializer(placearray, VecPlaceArray_MPI),
405: PetscDesignatedInitializer(replacearray, VecReplaceArray_Seq),
406: PetscDesignatedInitializer(dot_local, VecDot_Seq),
407: PetscDesignatedInitializer(tdot_local, VecTDot_Seq),
408: PetscDesignatedInitializer(norm_local, VecNorm_Seq),
409: PetscDesignatedInitializer(mdot_local, VecMDot_Seq),
410: PetscDesignatedInitializer(mtdot_local, VecMTDot_Seq),
411: PetscDesignatedInitializer(load, VecLoad_Default),
412: PetscDesignatedInitializer(reciprocal, VecReciprocal_Default),
413: PetscDesignatedInitializer(conjugate, VecConjugate_Seq),
414: PetscDesignatedInitializer(setlocaltoglobalmapping, NULL),
415: PetscDesignatedInitializer(setvalueslocal, NULL),
416: PetscDesignatedInitializer(resetarray, VecResetArray_MPI),
417: PetscDesignatedInitializer(setfromoptions, VecSetFromOptions_MPI), /*set from options */
418: PetscDesignatedInitializer(maxpointwisedivide, VecMaxPointwiseDivide_Seq),
419: PetscDesignatedInitializer(pointwisemax, VecPointwiseMax_Seq),
420: PetscDesignatedInitializer(pointwisemaxabs, VecPointwiseMaxAbs_Seq),
421: PetscDesignatedInitializer(pointwisemin, VecPointwiseMin_Seq),
422: PetscDesignatedInitializer(getvalues, VecGetValues_MPI),
423: PetscDesignatedInitializer(sqrt, NULL),
424: PetscDesignatedInitializer(abs, NULL),
425: PetscDesignatedInitializer(exp, NULL),
426: PetscDesignatedInitializer(log, NULL),
427: PetscDesignatedInitializer(shift, NULL),
428: PetscDesignatedInitializer(create, NULL), /* really? */
429: PetscDesignatedInitializer(stridegather, VecStrideGather_Default),
430: PetscDesignatedInitializer(stridescatter, VecStrideScatter_Default),
431: PetscDesignatedInitializer(dotnorm2, NULL),
432: PetscDesignatedInitializer(getsubvector, NULL),
433: PetscDesignatedInitializer(restoresubvector, NULL),
434: PetscDesignatedInitializer(getarrayread, NULL),
435: PetscDesignatedInitializer(restorearrayread, NULL),
436: PetscDesignatedInitializer(stridesubsetgather, VecStrideSubSetGather_Default),
437: PetscDesignatedInitializer(stridesubsetscatter, VecStrideSubSetScatter_Default),
438: PetscDesignatedInitializer(viewnative, VecView_MPI),
439: PetscDesignatedInitializer(loadnative, NULL),
440: PetscDesignatedInitializer(createlocalvector, NULL),
441: PetscDesignatedInitializer(getlocalvector, NULL),
442: PetscDesignatedInitializer(restorelocalvector, NULL),
443: PetscDesignatedInitializer(getlocalvectorread, NULL),
444: PetscDesignatedInitializer(restorelocalvectorread, NULL),
445: PetscDesignatedInitializer(bindtocpu, NULL),
446: PetscDesignatedInitializer(getarraywrite, NULL),
447: PetscDesignatedInitializer(restorearraywrite, NULL),
448: PetscDesignatedInitializer(getarrayandmemtype, NULL),
449: PetscDesignatedInitializer(restorearrayandmemtype, NULL),
450: PetscDesignatedInitializer(getarrayreadandmemtype, NULL),
451: PetscDesignatedInitializer(restorearrayreadandmemtype, NULL),
452: PetscDesignatedInitializer(getarraywriteandmemtype, NULL),
453: PetscDesignatedInitializer(restorearraywriteandmemtype, NULL),
454: PetscDesignatedInitializer(concatenate, NULL),
455: PetscDesignatedInitializer(sum, NULL),
456: PetscDesignatedInitializer(setpreallocationcoo, VecSetPreallocationCOO_MPI),
457: PetscDesignatedInitializer(setvaluescoo, VecSetValuesCOO_MPI)};
459: /*
460: VecCreate_MPI_Private - Basic create routine called by VecCreate_MPI() (i.e. VecCreateMPI()),
461: VecCreateMPIWithArray(), VecCreate_Shared() (i.e. VecCreateShared()), VecCreateGhost(),
462: VecDuplicate_MPI(), VecCreateGhostWithArray(), VecDuplicate_MPI(), and VecDuplicate_Shared()
464: If alloc is true and array is NULL then this routine allocates the space, otherwise
465: no space is allocated.
466: */
467: PetscErrorCode VecCreate_MPI_Private(Vec v, PetscBool alloc, PetscInt nghost, const PetscScalar array[])
468: {
469: Vec_MPI *s;
471: PetscFunctionBegin;
472: PetscCall(PetscNew(&s));
473: v->data = (void *)s;
474: PetscCall(PetscMemcpy(v->ops, &DvOps, sizeof(DvOps)));
475: s->nghost = nghost;
476: v->petscnative = PETSC_TRUE;
477: if (array) v->offloadmask = PETSC_OFFLOAD_CPU;
479: PetscCall(PetscLayoutSetUp(v->map));
481: s->array = (PetscScalar *)array;
482: s->array_allocated = NULL;
483: if (alloc && !array) {
484: PetscInt n = v->map->n + nghost;
485: PetscCall(PetscCalloc1(n, &s->array));
486: s->array_allocated = s->array;
487: }
489: /* By default parallel vectors do not have local representation */
490: s->localrep = NULL;
491: s->localupdate = NULL;
493: v->stash.insertmode = NOT_SET_VALUES;
494: v->bstash.insertmode = NOT_SET_VALUES;
495: /* create the stashes. The block-size for bstash is set later when
496: VecSetValuesBlocked is called.
497: */
498: PetscCall(VecStashCreate_Private(PetscObjectComm((PetscObject)v), 1, &v->stash));
499: PetscCall(VecStashCreate_Private(PetscObjectComm((PetscObject)v), PetscAbs(v->map->bs), &v->bstash));
501: #if defined(PETSC_HAVE_MATLAB)
502: PetscCall(PetscObjectComposeFunction((PetscObject)v, "PetscMatlabEnginePut_C", VecMatlabEnginePut_Default));
503: PetscCall(PetscObjectComposeFunction((PetscObject)v, "PetscMatlabEngineGet_C", VecMatlabEngineGet_Default));
504: #endif
505: PetscCall(PetscObjectChangeTypeName((PetscObject)v, VECMPI));
506: PetscFunctionReturn(PETSC_SUCCESS);
507: }
509: /*MC
510: VECMPI - VECMPI = "mpi" - The basic parallel vector
512: Options Database Key:
513: . -vec_type mpi - sets the vector type to `VECMPI` during a call to `VecSetFromOptions()`
515: Level: beginner
517: .seealso: [](ch_vectors), `Vec`, `VecType`, `VecCreate()`, `VecSetType()`, `VecSetFromOptions()`, `VecCreateMPIWithArray()`, `VECMPI`, `VecType`, `VecCreateMPI()`, `VecCreateMPI()`
518: M*/
520: PetscErrorCode VecCreate_MPI(Vec vv)
521: {
522: PetscFunctionBegin;
523: PetscCall(VecCreate_MPI_Private(vv, PETSC_TRUE, 0, NULL));
524: PetscFunctionReturn(PETSC_SUCCESS);
525: }
527: /*MC
528: VECSTANDARD = "standard" - A `VECSEQ` on one process and `VECMPI` on more than one process
530: Options Database Key:
531: . -vec_type standard - sets a vector type to standard on calls to `VecSetFromOptions()`
533: Level: beginner
535: .seealso: [](ch_vectors), `Vec`, `VecType`, `VecCreateSeq()`, `VecCreateMPI()`
536: M*/
538: PETSC_EXTERN PetscErrorCode VecCreate_Standard(Vec v)
539: {
540: PetscMPIInt size;
542: PetscFunctionBegin;
543: PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)v), &size));
544: if (size == 1) {
545: PetscCall(VecSetType(v, VECSEQ));
546: } else {
547: PetscCall(VecSetType(v, VECMPI));
548: }
549: PetscFunctionReturn(PETSC_SUCCESS);
550: }
552: /*@C
553: VecCreateMPIWithArray - Creates a parallel, array-style vector,
554: where the user provides the array space to store the vector values.
556: Collective
558: Input Parameters:
559: + comm - the MPI communicator to use
560: . bs - block size, same meaning as `VecSetBlockSize()`
561: . n - local vector length, cannot be `PETSC_DECIDE`
562: . N - global vector length (or `PETSC_DETERMINE` to have calculated)
563: - array - the user provided array to store the vector values
565: Output Parameter:
566: . vv - the vector
568: Level: intermediate
570: Notes:
571: Use `VecDuplicate()` or `VecDuplicateVecs()` to form additional vectors of the
572: same type as an existing vector.
574: If the user-provided array is `NULL`, then `VecPlaceArray()` can be used
575: at a later stage to SET the array for storing the vector values.
577: PETSc does NOT free `array` when the vector is destroyed via `VecDestroy()`.
579: The user should not free `array` until the vector is destroyed.
581: .seealso: [](ch_vectors), `Vec`, `VecType`, `VecCreateSeqWithArray()`, `VecCreate()`, `VecDuplicate()`, `VecDuplicateVecs()`, `VecCreateGhost()`,
582: `VecCreateMPI()`, `VecCreateGhostWithArray()`, `VecPlaceArray()`
583: @*/
584: PetscErrorCode VecCreateMPIWithArray(MPI_Comm comm, PetscInt bs, PetscInt n, PetscInt N, const PetscScalar array[], Vec *vv)
585: {
586: PetscFunctionBegin;
587: PetscCheck(n != PETSC_DECIDE, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Must set local size of vector");
588: PetscCall(PetscSplitOwnership(comm, &n, &N));
589: PetscCall(VecCreate(comm, vv));
590: PetscCall(VecSetSizes(*vv, n, N));
591: PetscCall(VecSetBlockSize(*vv, bs));
592: PetscCall(VecCreate_MPI_Private(*vv, PETSC_FALSE, 0, array));
593: PetscFunctionReturn(PETSC_SUCCESS);
594: }
596: /*@C
597: VecCreateGhostWithArray - Creates a parallel vector with ghost padding on each processor;
598: the caller allocates the array space.
600: Collective
602: Input Parameters:
603: + comm - the MPI communicator to use
604: . n - local vector length
605: . N - global vector length (or `PETSC_DETERMINE` to have calculated if `n` is given)
606: . nghost - number of local ghost points
607: . ghosts - global indices of ghost points (or `NULL` if not needed), these do not need to be in increasing order (sorted)
608: - array - the space to store the vector values (as long as n + nghost)
610: Output Parameter:
611: . vv - the global vector representation (without ghost points as part of vector)
613: Level: advanced
615: Notes:
616: Use `VecGhostGetLocalForm()` to access the local, ghosted representation
617: of the vector.
619: This also automatically sets the `ISLocalToGlobalMapping()` for this vector.
621: .seealso: [](ch_vectors), `Vec`, `VecType`, `VecCreate()`, `VecGhostGetLocalForm()`, `VecGhostRestoreLocalForm()`,
622: `VecCreateGhost()`, `VecCreateSeqWithArray()`, `VecCreateMPIWithArray()`,
623: `VecCreateGhostBlock()`, `VecCreateGhostBlockWithArray()`, `VecMPISetGhost()`
624: @*/
625: PetscErrorCode VecCreateGhostWithArray(MPI_Comm comm, PetscInt n, PetscInt N, PetscInt nghost, const PetscInt ghosts[], const PetscScalar array[], Vec *vv)
626: {
627: Vec_MPI *w;
628: PetscScalar *larray;
629: IS from, to;
630: ISLocalToGlobalMapping ltog;
631: PetscInt rstart, i, *indices;
633: PetscFunctionBegin;
634: *vv = NULL;
636: PetscCheck(n != PETSC_DECIDE, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Must set local size");
637: PetscCheck(nghost != PETSC_DECIDE, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Must set local ghost size");
638: PetscCheck(nghost >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Ghost length must be >= 0");
639: PetscCall(PetscSplitOwnership(comm, &n, &N));
640: /* Create global representation */
641: PetscCall(VecCreate(comm, vv));
642: PetscCall(VecSetSizes(*vv, n, N));
643: PetscCall(VecCreate_MPI_Private(*vv, PETSC_TRUE, nghost, array));
644: w = (Vec_MPI *)(*vv)->data;
645: /* Create local representation */
646: PetscCall(VecGetArray(*vv, &larray));
647: PetscCall(VecCreateSeqWithArray(PETSC_COMM_SELF, 1, n + nghost, larray, &w->localrep));
648: PetscCall(VecRestoreArray(*vv, &larray));
650: /*
651: Create scatter context for scattering (updating) ghost values
652: */
653: PetscCall(ISCreateGeneral(comm, nghost, ghosts, PETSC_COPY_VALUES, &from));
654: PetscCall(ISCreateStride(PETSC_COMM_SELF, nghost, n, 1, &to));
655: PetscCall(VecScatterCreate(*vv, from, w->localrep, to, &w->localupdate));
656: PetscCall(ISDestroy(&to));
657: PetscCall(ISDestroy(&from));
659: /* set local to global mapping for ghosted vector */
660: PetscCall(PetscMalloc1(n + nghost, &indices));
661: PetscCall(VecGetOwnershipRange(*vv, &rstart, NULL));
662: for (i = 0; i < n; i++) indices[i] = rstart + i;
663: for (i = 0; i < nghost; i++) indices[n + i] = ghosts[i];
664: PetscCall(ISLocalToGlobalMappingCreate(comm, 1, n + nghost, indices, PETSC_OWN_POINTER, <og));
665: PetscCall(VecSetLocalToGlobalMapping(*vv, ltog));
666: PetscCall(ISLocalToGlobalMappingDestroy(<og));
667: PetscFunctionReturn(PETSC_SUCCESS);
668: }
670: /*@
671: VecCreateGhost - Creates a parallel vector with ghost padding on each processor.
673: Collective
675: Input Parameters:
676: + comm - the MPI communicator to use
677: . n - local vector length
678: . N - global vector length (or `PETSC_DETERMEINE` to have calculated if `n` is given)
679: . nghost - number of local ghost points
680: - ghosts - global indices of ghost points, these do not need to be in increasing order (sorted)
682: Output Parameter:
683: . vv - the global vector representation (without ghost points as part of vector)
685: Level: advanced
687: Notes:
688: Use `VecGhostGetLocalForm()` to access the local, ghosted representation
689: of the vector.
691: This also automatically sets the `ISLocalToGlobalMapping()` for this vector.
693: .seealso: [](ch_vectors), `Vec`, `VecType`, `VecCreateSeq()`, `VecCreate()`, `VecDuplicate()`, `VecDuplicateVecs()`, `VecCreateMPI()`,
694: `VecGhostGetLocalForm()`, `VecGhostRestoreLocalForm()`, `VecGhostUpdateBegin()`,
695: `VecCreateGhostWithArray()`, `VecCreateMPIWithArray()`, `VecGhostUpdateEnd()`,
696: `VecCreateGhostBlock()`, `VecCreateGhostBlockWithArray()`, `VecMPISetGhost()`
698: @*/
699: PetscErrorCode VecCreateGhost(MPI_Comm comm, PetscInt n, PetscInt N, PetscInt nghost, const PetscInt ghosts[], Vec *vv)
700: {
701: PetscFunctionBegin;
702: PetscCall(VecCreateGhostWithArray(comm, n, N, nghost, ghosts, NULL, vv));
703: PetscFunctionReturn(PETSC_SUCCESS);
704: }
706: /*@
707: VecMPISetGhost - Sets the ghost points for an MPI ghost vector
709: Collective
711: Input Parameters:
712: + vv - the MPI vector
713: . nghost - number of local ghost points
714: - ghosts - global indices of ghost points, these do not need to be in increasing order (sorted)
716: Level: advanced
718: Notes:
719: Use `VecGhostGetLocalForm()` to access the local, ghosted representation
720: of the vector.
722: This also automatically sets the `ISLocalToGlobalMapping()` for this vector.
724: You must call this AFTER you have set the type of the vector (with` VecSetType()`) and the size (with `VecSetSizes()`).
726: .seealso: [](ch_vectors), `Vec`, `VecType`, `VecCreateSeq()`, `VecCreate()`, `VecDuplicate()`, `VecDuplicateVecs()`, `VecCreateMPI()`,
727: `VecGhostGetLocalForm()`, `VecGhostRestoreLocalForm()`, `VecGhostUpdateBegin()`,
728: `VecCreateGhostWithArray()`, `VecCreateMPIWithArray()`, `VecGhostUpdateEnd()`,
729: `VecCreateGhostBlock()`, `VecCreateGhostBlockWithArray()`
730: @*/
731: PetscErrorCode VecMPISetGhost(Vec vv, PetscInt nghost, const PetscInt ghosts[])
732: {
733: PetscBool flg;
735: PetscFunctionBegin;
736: PetscCall(PetscObjectTypeCompare((PetscObject)vv, VECMPI, &flg));
737: /* if already fully existent VECMPI then basically destroy it and rebuild with ghosting */
738: if (flg) {
739: PetscInt n, N;
740: Vec_MPI *w;
741: PetscScalar *larray;
742: IS from, to;
743: ISLocalToGlobalMapping ltog;
744: PetscInt rstart, i, *indices;
745: MPI_Comm comm;
747: PetscCall(PetscObjectGetComm((PetscObject)vv, &comm));
748: n = vv->map->n;
749: N = vv->map->N;
750: PetscUseTypeMethod(vv, destroy);
751: PetscCall(VecSetSizes(vv, n, N));
752: PetscCall(VecCreate_MPI_Private(vv, PETSC_TRUE, nghost, NULL));
753: w = (Vec_MPI *)(vv)->data;
754: /* Create local representation */
755: PetscCall(VecGetArray(vv, &larray));
756: PetscCall(VecCreateSeqWithArray(PETSC_COMM_SELF, 1, n + nghost, larray, &w->localrep));
757: PetscCall(VecRestoreArray(vv, &larray));
759: /*
760: Create scatter context for scattering (updating) ghost values
761: */
762: PetscCall(ISCreateGeneral(comm, nghost, ghosts, PETSC_COPY_VALUES, &from));
763: PetscCall(ISCreateStride(PETSC_COMM_SELF, nghost, n, 1, &to));
764: PetscCall(VecScatterCreate(vv, from, w->localrep, to, &w->localupdate));
765: PetscCall(ISDestroy(&to));
766: PetscCall(ISDestroy(&from));
768: /* set local to global mapping for ghosted vector */
769: PetscCall(PetscMalloc1(n + nghost, &indices));
770: PetscCall(VecGetOwnershipRange(vv, &rstart, NULL));
772: for (i = 0; i < n; i++) indices[i] = rstart + i;
773: for (i = 0; i < nghost; i++) indices[n + i] = ghosts[i];
775: PetscCall(ISLocalToGlobalMappingCreate(comm, 1, n + nghost, indices, PETSC_OWN_POINTER, <og));
776: PetscCall(VecSetLocalToGlobalMapping(vv, ltog));
777: PetscCall(ISLocalToGlobalMappingDestroy(<og));
778: } else {
779: PetscCheck(vv->ops->create != VecCreate_MPI, PetscObjectComm((PetscObject)vv), PETSC_ERR_ARG_WRONGSTATE, "Must set local or global size before setting ghosting");
780: PetscCheck(((PetscObject)vv)->type_name, PetscObjectComm((PetscObject)vv), PETSC_ERR_ARG_WRONGSTATE, "Must set type to VECMPI before ghosting");
781: }
782: PetscFunctionReturn(PETSC_SUCCESS);
783: }
785: /* ------------------------------------------------------------------------------------------*/
786: /*@C
787: VecCreateGhostBlockWithArray - Creates a parallel vector with ghost padding on each processor;
788: the caller allocates the array space. Indices in the ghost region are based on blocks.
790: Collective
792: Input Parameters:
793: + comm - the MPI communicator to use
794: . bs - block size
795: . n - local vector length
796: . N - global vector length (or `PETSC_DETERMINE` to have calculated if `n` is given)
797: . nghost - number of local ghost blocks
798: . ghosts - global indices of ghost blocks (or `NULL` if not needed), counts are by block not by index, these do not need to be in increasing order (sorted)
799: - array - the space to store the vector values (as long as `n + nghost*bs`)
801: Output Parameter:
802: . vv - the global vector representation (without ghost points as part of vector)
804: Level: advanced
806: Notes:
807: Use `VecGhostGetLocalForm()` to access the local, ghosted representation
808: of the vector.
810: n is the local vector size (total local size not the number of blocks) while nghost
811: is the number of blocks in the ghost portion, i.e. the number of elements in the ghost
812: portion is bs*nghost
814: .seealso: [](ch_vectors), `Vec`, `VecType`, `VecCreate()`, `VecGhostGetLocalForm()`, `VecGhostRestoreLocalForm()`,
815: `VecCreateGhost()`, `VecCreateSeqWithArray()`, `VecCreateMPIWithArray()`,
816: `VecCreateGhostWithArray()`, `VecCreateGhostBlock()`
817: @*/
818: PetscErrorCode VecCreateGhostBlockWithArray(MPI_Comm comm, PetscInt bs, PetscInt n, PetscInt N, PetscInt nghost, const PetscInt ghosts[], const PetscScalar array[], Vec *vv)
819: {
820: Vec_MPI *w;
821: PetscScalar *larray;
822: IS from, to;
823: ISLocalToGlobalMapping ltog;
824: PetscInt rstart, i, nb, *indices;
826: PetscFunctionBegin;
827: *vv = NULL;
829: PetscCheck(n != PETSC_DECIDE, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Must set local size");
830: PetscCheck(nghost != PETSC_DECIDE, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Must set local ghost size");
831: PetscCheck(nghost >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Ghost length must be >= 0");
832: PetscCheck(n % bs == 0, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Local size must be a multiple of block size");
833: PetscCall(PetscSplitOwnership(comm, &n, &N));
834: /* Create global representation */
835: PetscCall(VecCreate(comm, vv));
836: PetscCall(VecSetSizes(*vv, n, N));
837: PetscCall(VecSetBlockSize(*vv, bs));
838: PetscCall(VecCreate_MPI_Private(*vv, PETSC_TRUE, nghost * bs, array));
839: w = (Vec_MPI *)(*vv)->data;
840: /* Create local representation */
841: PetscCall(VecGetArray(*vv, &larray));
842: PetscCall(VecCreateSeqWithArray(PETSC_COMM_SELF, bs, n + bs * nghost, larray, &w->localrep));
843: PetscCall(VecRestoreArray(*vv, &larray));
845: /*
846: Create scatter context for scattering (updating) ghost values
847: */
848: PetscCall(ISCreateBlock(comm, bs, nghost, ghosts, PETSC_COPY_VALUES, &from));
849: PetscCall(ISCreateStride(PETSC_COMM_SELF, bs * nghost, n, 1, &to));
850: PetscCall(VecScatterCreate(*vv, from, w->localrep, to, &w->localupdate));
851: PetscCall(ISDestroy(&to));
852: PetscCall(ISDestroy(&from));
854: /* set local to global mapping for ghosted vector */
855: nb = n / bs;
856: PetscCall(PetscMalloc1(nb + nghost, &indices));
857: PetscCall(VecGetOwnershipRange(*vv, &rstart, NULL));
858: rstart = rstart / bs;
860: for (i = 0; i < nb; i++) indices[i] = rstart + i;
861: for (i = 0; i < nghost; i++) indices[nb + i] = ghosts[i];
863: PetscCall(ISLocalToGlobalMappingCreate(comm, bs, nb + nghost, indices, PETSC_OWN_POINTER, <og));
864: PetscCall(VecSetLocalToGlobalMapping(*vv, ltog));
865: PetscCall(ISLocalToGlobalMappingDestroy(<og));
866: PetscFunctionReturn(PETSC_SUCCESS);
867: }
869: /*@
870: VecCreateGhostBlock - Creates a parallel vector with ghost padding on each processor.
871: The indicing of the ghost points is done with blocks.
873: Collective
875: Input Parameters:
876: + comm - the MPI communicator to use
877: . bs - the block size
878: . n - local vector length
879: . N - global vector length (or `PETSC_DETERMINE` to have calculated if `n` is given)
880: . nghost - number of local ghost blocks
881: - ghosts - global indices of ghost blocks, counts are by block, not by individual index, these do not need to be in increasing order (sorted)
883: Output Parameter:
884: . vv - the global vector representation (without ghost points as part of vector)
886: Level: advanced
888: Notes:
889: Use `VecGhostGetLocalForm()` to access the local, ghosted representation
890: of the vector.
892: `n` is the local vector size (total local size not the number of blocks) while `nghost`
893: is the number of blocks in the ghost portion, i.e. the number of elements in the ghost
894: portion is `bs*nghost`
896: .seealso: [](ch_vectors), `Vec`, `VecType`, `VecCreateSeq()`, `VecCreate()`, `VecDuplicate()`, `VecDuplicateVecs()`, `VecCreateMPI()`,
897: `VecGhostGetLocalForm()`, `VecGhostRestoreLocalForm()`,
898: `VecCreateGhostWithArray()`, `VecCreateMPIWithArray()`, `VecCreateGhostBlockWithArray()`
899: @*/
900: PetscErrorCode VecCreateGhostBlock(MPI_Comm comm, PetscInt bs, PetscInt n, PetscInt N, PetscInt nghost, const PetscInt ghosts[], Vec *vv)
901: {
902: PetscFunctionBegin;
903: PetscCall(VecCreateGhostBlockWithArray(comm, bs, n, N, nghost, ghosts, NULL, vv));
904: PetscFunctionReturn(PETSC_SUCCESS);
905: }