Actual source code: sfutils.c
1: #include <petsc/private/sfimpl.h>
2: #include <petsc/private/sectionimpl.h>
4: /*@
5: PetscSFSetGraphLayout - Set a parallel star forest via global indices and a `PetscLayout`
7: Collective
9: Input Parameters:
10: + sf - star forest
11: . layout - `PetscLayout` defining the global space for roots
12: . nleaves - number of leaf vertices on the current process, each of these references a root on any process
13: . ilocal - locations of leaves in leafdata buffers, pass NULL for contiguous storage
14: . localmode - copy mode for ilocal
15: - gremote - root vertices in global numbering corresponding to leaves in ilocal
17: Level: intermediate
19: Note:
20: Global indices must lie in [0, N) where N is the global size of layout.
21: Leaf indices in ilocal get sorted; this means the user-provided array gets sorted if localmode is `PETSC_OWN_POINTER`.
23: Developer Notes:
24: Local indices which are the identity permutation in the range [0,nleaves) are discarded as they
25: encode contiguous storage. In such case, if localmode is `PETSC_OWN_POINTER`, the memory is deallocated as it is not
26: needed
28: .seealso: `PetscSF`, `PetscSFGetGraphLayout()`, `PetscSFCreate()`, `PetscSFView()`, `PetscSFSetGraph()`, `PetscSFGetGraph()`
29: @*/
30: PetscErrorCode PetscSFSetGraphLayout(PetscSF sf, PetscLayout layout, PetscInt nleaves, PetscInt *ilocal, PetscCopyMode localmode, const PetscInt *gremote)
31: {
32: const PetscInt *range;
33: PetscInt i, nroots, ls = -1, ln = -1;
34: PetscMPIInt lr = -1;
35: PetscSFNode *remote;
37: PetscFunctionBegin;
39: PetscCall(PetscLayoutSetUp(layout));
40: PetscCall(PetscLayoutGetLocalSize(layout, &nroots));
41: PetscCall(PetscLayoutGetRanges(layout, &range));
42: PetscCall(PetscMalloc1(nleaves, &remote));
43: if (nleaves) ls = gremote[0] + 1;
44: for (i = 0; i < nleaves; i++) {
45: const PetscInt idx = gremote[i] - ls;
46: if (idx < 0 || idx >= ln) { /* short-circuit the search */
47: PetscCall(PetscLayoutFindOwnerIndex(layout, gremote[i], &lr, &remote[i].index));
48: remote[i].rank = lr;
49: ls = range[lr];
50: ln = range[lr + 1] - ls;
51: } else {
52: remote[i].rank = lr;
53: remote[i].index = idx;
54: }
55: }
56: PetscCall(PetscSFSetGraph(sf, nroots, nleaves, ilocal, localmode, remote, PETSC_OWN_POINTER));
57: PetscFunctionReturn(PETSC_SUCCESS);
58: }
60: /*@C
61: PetscSFGetGraphLayout - Get the global indices and `PetscLayout` that describe this star forest
63: Collective
65: Input Parameter:
66: . sf - star forest
68: Output Parameters:
69: + layout - `PetscLayout` defining the global space for roots
70: . nleaves - number of leaf vertices on the current process, each of these references a root on any process
71: . ilocal - locations of leaves in leafdata buffers, or NULL for contiguous storage
72: - gremote - root vertices in global numbering corresponding to leaves in ilocal
74: Level: intermediate
76: Notes:
77: The outputs are such that passing them as inputs to `PetscSFSetGraphLayout()` would lead to the same star forest.
78: The outputs layout and gremote are freshly created each time this function is called,
79: so they need to be freed by user and cannot be qualified as const.
81: .seealso: `PetscSF`, `PetscSFSetGraphLayout()`, `PetscSFCreate()`, `PetscSFView()`, `PetscSFSetGraph()`, `PetscSFGetGraph()`
82: @*/
83: PetscErrorCode PetscSFGetGraphLayout(PetscSF sf, PetscLayout *layout, PetscInt *nleaves, const PetscInt *ilocal[], PetscInt *gremote[])
84: {
85: PetscInt nr, nl;
86: const PetscSFNode *ir;
87: PetscLayout lt;
89: PetscFunctionBegin;
90: PetscCall(PetscSFGetGraph(sf, &nr, &nl, ilocal, &ir));
91: PetscCall(PetscLayoutCreateFromSizes(PetscObjectComm((PetscObject)sf), nr, PETSC_DECIDE, 1, <));
92: if (gremote) {
93: PetscInt i;
94: const PetscInt *range;
95: PetscInt *gr;
97: PetscCall(PetscLayoutGetRanges(lt, &range));
98: PetscCall(PetscMalloc1(nl, &gr));
99: for (i = 0; i < nl; i++) gr[i] = range[ir[i].rank] + ir[i].index;
100: *gremote = gr;
101: }
102: if (nleaves) *nleaves = nl;
103: if (layout) *layout = lt;
104: else PetscCall(PetscLayoutDestroy(<));
105: PetscFunctionReturn(PETSC_SUCCESS);
106: }
108: /*@
109: PetscSFSetGraphSection - Sets the `PetscSF` graph encoding the parallel dof overlap based upon the `PetscSection` describing the data layout.
111: Input Parameters:
112: + sf - The `PetscSF`
113: . localSection - `PetscSection` describing the local data layout
114: - globalSection - `PetscSection` describing the global data layout
116: Level: developer
118: .seealso: `PetscSF`, `PetscSFSetGraph()`, `PetscSFSetGraphLayout()`
119: @*/
120: PetscErrorCode PetscSFSetGraphSection(PetscSF sf, PetscSection localSection, PetscSection globalSection)
121: {
122: MPI_Comm comm;
123: PetscLayout layout;
124: const PetscInt *ranges;
125: PetscInt *local;
126: PetscSFNode *remote;
127: PetscInt pStart, pEnd, p, nroots, nleaves = 0, l;
128: PetscMPIInt size, rank;
130: PetscFunctionBegin;
135: PetscCall(PetscObjectGetComm((PetscObject)sf, &comm));
136: PetscCallMPI(MPI_Comm_size(comm, &size));
137: PetscCallMPI(MPI_Comm_rank(comm, &rank));
138: PetscCall(PetscSectionGetChart(globalSection, &pStart, &pEnd));
139: PetscCall(PetscSectionGetConstrainedStorageSize(globalSection, &nroots));
140: PetscCall(PetscLayoutCreate(comm, &layout));
141: PetscCall(PetscLayoutSetBlockSize(layout, 1));
142: PetscCall(PetscLayoutSetLocalSize(layout, nroots));
143: PetscCall(PetscLayoutSetUp(layout));
144: PetscCall(PetscLayoutGetRanges(layout, &ranges));
145: for (p = pStart; p < pEnd; ++p) {
146: PetscInt gdof, gcdof;
148: PetscCall(PetscSectionGetDof(globalSection, p, &gdof));
149: PetscCall(PetscSectionGetConstraintDof(globalSection, p, &gcdof));
150: PetscCheck(gcdof <= (gdof < 0 ? -(gdof + 1) : gdof), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Point %" PetscInt_FMT " has %" PetscInt_FMT " constraints > %" PetscInt_FMT " dof", p, gcdof, (gdof < 0 ? -(gdof + 1) : gdof));
151: nleaves += gdof < 0 ? -(gdof + 1) - gcdof : gdof - gcdof;
152: }
153: PetscCall(PetscMalloc1(nleaves, &local));
154: PetscCall(PetscMalloc1(nleaves, &remote));
155: for (p = pStart, l = 0; p < pEnd; ++p) {
156: const PetscInt *cind;
157: PetscInt dof, cdof, off, gdof, gcdof, goff, gsize, d, c;
159: PetscCall(PetscSectionGetDof(localSection, p, &dof));
160: PetscCall(PetscSectionGetOffset(localSection, p, &off));
161: PetscCall(PetscSectionGetConstraintDof(localSection, p, &cdof));
162: PetscCall(PetscSectionGetConstraintIndices(localSection, p, &cind));
163: PetscCall(PetscSectionGetDof(globalSection, p, &gdof));
164: PetscCall(PetscSectionGetConstraintDof(globalSection, p, &gcdof));
165: PetscCall(PetscSectionGetOffset(globalSection, p, &goff));
166: if (!gdof) continue; /* Censored point */
167: gsize = gdof < 0 ? -(gdof + 1) - gcdof : gdof - gcdof;
168: if (gsize != dof - cdof) {
169: PetscCheck(gsize == dof, comm, PETSC_ERR_ARG_WRONG, "Global dof %" PetscInt_FMT " for point %" PetscInt_FMT " is neither the constrained size %" PetscInt_FMT ", nor the unconstrained %" PetscInt_FMT, gsize, p, dof - cdof, dof);
170: cdof = 0; /* Ignore constraints */
171: }
172: for (d = 0, c = 0; d < dof; ++d) {
173: if ((c < cdof) && (cind[c] == d)) {
174: ++c;
175: continue;
176: }
177: local[l + d - c] = off + d;
178: }
179: PetscCheck(d - c == gsize, comm, PETSC_ERR_ARG_WRONG, "Point %" PetscInt_FMT ": Global dof %" PetscInt_FMT " != %" PetscInt_FMT " size - number of constraints", p, gsize, d - c);
180: if (gdof < 0) {
181: for (d = 0; d < gsize; ++d, ++l) {
182: PetscInt offset = -(goff + 1) + d, r;
184: PetscCall(PetscFindInt(offset, size + 1, ranges, &r));
185: if (r < 0) r = -(r + 2);
186: PetscCheck(!(r < 0) && !(r >= size), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Point %" PetscInt_FMT " mapped to invalid process %" PetscInt_FMT " (%" PetscInt_FMT ", %" PetscInt_FMT ")", p, r, gdof, goff);
187: remote[l].rank = r;
188: remote[l].index = offset - ranges[r];
189: }
190: } else {
191: for (d = 0; d < gsize; ++d, ++l) {
192: remote[l].rank = rank;
193: remote[l].index = goff + d - ranges[rank];
194: }
195: }
196: }
197: PetscCheck(l == nleaves, comm, PETSC_ERR_PLIB, "Iteration error, l %" PetscInt_FMT " != nleaves %" PetscInt_FMT, l, nleaves);
198: PetscCall(PetscLayoutDestroy(&layout));
199: PetscCall(PetscSFSetGraph(sf, nroots, nleaves, local, PETSC_OWN_POINTER, remote, PETSC_OWN_POINTER));
200: PetscFunctionReturn(PETSC_SUCCESS);
201: }
203: /*@C
204: PetscSFDistributeSection - Create a new `PetscSection` reorganized, moving from the root to the leaves of the `PetscSF`
206: Collective
208: Input Parameters:
209: + sf - The `PetscSF`
210: - rootSection - Section defined on root space
212: Output Parameters:
213: + remoteOffsets - root offsets in leaf storage, or NULL
214: - leafSection - Section defined on the leaf space
216: Level: advanced
218: Fortran Notes:
219: In Fortran, use PetscSFDistributeSectionF90()
221: .seealso: `PetscSF`, `PetscSFCreate()`
222: @*/
223: PetscErrorCode PetscSFDistributeSection(PetscSF sf, PetscSection rootSection, PetscInt **remoteOffsets, PetscSection leafSection)
224: {
225: PetscSF embedSF;
226: const PetscInt *indices;
227: IS selected;
228: PetscInt numFields, nroots, rpStart, rpEnd, lpStart = PETSC_MAX_INT, lpEnd = -1, f, c;
229: PetscBool *sub, hasc;
231: PetscFunctionBegin;
232: PetscCall(PetscLogEventBegin(PETSCSF_DistSect, sf, 0, 0, 0));
233: PetscCall(PetscSectionGetNumFields(rootSection, &numFields));
234: if (numFields) {
235: IS perm;
237: /* PetscSectionSetNumFields() calls PetscSectionReset(), which destroys
238: leafSection->perm. To keep this permutation set by the user, we grab
239: the reference before calling PetscSectionSetNumFields() and set it
240: back after. */
241: PetscCall(PetscSectionGetPermutation(leafSection, &perm));
242: PetscCall(PetscObjectReference((PetscObject)perm));
243: PetscCall(PetscSectionSetNumFields(leafSection, numFields));
244: PetscCall(PetscSectionSetPermutation(leafSection, perm));
245: PetscCall(ISDestroy(&perm));
246: }
247: PetscCall(PetscMalloc1(numFields + 2, &sub));
248: sub[1] = rootSection->bc ? PETSC_TRUE : PETSC_FALSE;
249: for (f = 0; f < numFields; ++f) {
250: PetscSectionSym sym, dsym = NULL;
251: const char *name = NULL;
252: PetscInt numComp = 0;
254: sub[2 + f] = rootSection->field[f]->bc ? PETSC_TRUE : PETSC_FALSE;
255: PetscCall(PetscSectionGetFieldComponents(rootSection, f, &numComp));
256: PetscCall(PetscSectionGetFieldName(rootSection, f, &name));
257: PetscCall(PetscSectionGetFieldSym(rootSection, f, &sym));
258: if (sym) PetscCall(PetscSectionSymDistribute(sym, sf, &dsym));
259: PetscCall(PetscSectionSetFieldComponents(leafSection, f, numComp));
260: PetscCall(PetscSectionSetFieldName(leafSection, f, name));
261: PetscCall(PetscSectionSetFieldSym(leafSection, f, dsym));
262: PetscCall(PetscSectionSymDestroy(&dsym));
263: for (c = 0; c < rootSection->numFieldComponents[f]; ++c) {
264: PetscCall(PetscSectionGetComponentName(rootSection, f, c, &name));
265: PetscCall(PetscSectionSetComponentName(leafSection, f, c, name));
266: }
267: }
268: PetscCall(PetscSectionGetChart(rootSection, &rpStart, &rpEnd));
269: PetscCall(PetscSFGetGraph(sf, &nroots, NULL, NULL, NULL));
270: rpEnd = PetscMin(rpEnd, nroots);
271: rpEnd = PetscMax(rpStart, rpEnd);
272: /* see if we can avoid creating the embedded SF, since it can cost more than an allreduce */
273: sub[0] = (PetscBool)(nroots != rpEnd - rpStart);
274: PetscCall(MPIU_Allreduce(MPI_IN_PLACE, sub, 2 + numFields, MPIU_BOOL, MPI_LOR, PetscObjectComm((PetscObject)sf)));
275: if (sub[0]) {
276: PetscCall(ISCreateStride(PETSC_COMM_SELF, rpEnd - rpStart, rpStart, 1, &selected));
277: PetscCall(ISGetIndices(selected, &indices));
278: PetscCall(PetscSFCreateEmbeddedRootSF(sf, rpEnd - rpStart, indices, &embedSF));
279: PetscCall(ISRestoreIndices(selected, &indices));
280: PetscCall(ISDestroy(&selected));
281: } else {
282: PetscCall(PetscObjectReference((PetscObject)sf));
283: embedSF = sf;
284: }
285: PetscCall(PetscSFGetLeafRange(embedSF, &lpStart, &lpEnd));
286: lpEnd++;
288: PetscCall(PetscSectionSetChart(leafSection, lpStart, lpEnd));
290: /* Constrained dof section */
291: hasc = sub[1];
292: for (f = 0; f < numFields; ++f) hasc = (PetscBool)(hasc || sub[2 + f]);
294: /* Could fuse these at the cost of copies and extra allocation */
295: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->atlasDof, -lpStart), MPI_REPLACE));
296: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->atlasDof, -lpStart), MPI_REPLACE));
297: if (sub[1]) {
298: PetscCall(PetscSectionCheckConstraints_Private(rootSection));
299: PetscCall(PetscSectionCheckConstraints_Private(leafSection));
300: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->bc->atlasDof[-rpStart], &leafSection->bc->atlasDof[-lpStart], MPI_REPLACE));
301: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->bc->atlasDof[-rpStart], &leafSection->bc->atlasDof[-lpStart], MPI_REPLACE));
302: }
303: for (f = 0; f < numFields; ++f) {
304: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->field[f]->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->field[f]->atlasDof, -lpStart), MPI_REPLACE));
305: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->field[f]->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->field[f]->atlasDof, -lpStart), MPI_REPLACE));
306: if (sub[2 + f]) {
307: PetscCall(PetscSectionCheckConstraints_Private(rootSection->field[f]));
308: PetscCall(PetscSectionCheckConstraints_Private(leafSection->field[f]));
309: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasDof[-rpStart], &leafSection->field[f]->bc->atlasDof[-lpStart], MPI_REPLACE));
310: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasDof[-rpStart], &leafSection->field[f]->bc->atlasDof[-lpStart], MPI_REPLACE));
311: }
312: }
313: if (remoteOffsets) {
314: PetscCall(PetscMalloc1(lpEnd - lpStart, remoteOffsets));
315: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
316: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
317: }
318: PetscCall(PetscSectionInvalidateMaxDof_Internal(leafSection));
319: PetscCall(PetscSectionSetUp(leafSection));
320: if (hasc) { /* need to communicate bcIndices */
321: PetscSF bcSF;
322: PetscInt *rOffBc;
324: PetscCall(PetscMalloc1(lpEnd - lpStart, &rOffBc));
325: if (sub[1]) {
326: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
327: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
328: PetscCall(PetscSFCreateSectionSF(embedSF, rootSection->bc, rOffBc, leafSection->bc, &bcSF));
329: PetscCall(PetscSFBcastBegin(bcSF, MPIU_INT, rootSection->bcIndices, leafSection->bcIndices, MPI_REPLACE));
330: PetscCall(PetscSFBcastEnd(bcSF, MPIU_INT, rootSection->bcIndices, leafSection->bcIndices, MPI_REPLACE));
331: PetscCall(PetscSFDestroy(&bcSF));
332: }
333: for (f = 0; f < numFields; ++f) {
334: if (sub[2 + f]) {
335: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
336: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
337: PetscCall(PetscSFCreateSectionSF(embedSF, rootSection->field[f]->bc, rOffBc, leafSection->field[f]->bc, &bcSF));
338: PetscCall(PetscSFBcastBegin(bcSF, MPIU_INT, rootSection->field[f]->bcIndices, leafSection->field[f]->bcIndices, MPI_REPLACE));
339: PetscCall(PetscSFBcastEnd(bcSF, MPIU_INT, rootSection->field[f]->bcIndices, leafSection->field[f]->bcIndices, MPI_REPLACE));
340: PetscCall(PetscSFDestroy(&bcSF));
341: }
342: }
343: PetscCall(PetscFree(rOffBc));
344: }
345: PetscCall(PetscSFDestroy(&embedSF));
346: PetscCall(PetscFree(sub));
347: PetscCall(PetscLogEventEnd(PETSCSF_DistSect, sf, 0, 0, 0));
348: PetscFunctionReturn(PETSC_SUCCESS);
349: }
351: /*@C
352: PetscSFCreateRemoteOffsets - Create offsets for point data on remote processes
354: Collective
356: Input Parameters:
357: + sf - The `PetscSF`
358: . rootSection - Data layout of remote points for outgoing data (this is layout for SF roots)
359: - leafSection - Data layout of local points for incoming data (this is layout for SF leaves)
361: Output Parameter:
362: . remoteOffsets - Offsets for point data on remote processes (these are offsets from the root section), or NULL
364: Level: developer
366: Fortran Notes:
367: In Fortran, use PetscSFCreateRemoteOffsetsF90()
369: .seealso: `PetscSF`, `PetscSFCreate()`
370: @*/
371: PetscErrorCode PetscSFCreateRemoteOffsets(PetscSF sf, PetscSection rootSection, PetscSection leafSection, PetscInt **remoteOffsets)
372: {
373: PetscSF embedSF;
374: const PetscInt *indices;
375: IS selected;
376: PetscInt numRoots, rpStart = 0, rpEnd = 0, lpStart = 0, lpEnd = 0;
378: PetscFunctionBegin;
379: *remoteOffsets = NULL;
380: PetscCall(PetscSFGetGraph(sf, &numRoots, NULL, NULL, NULL));
381: if (numRoots < 0) PetscFunctionReturn(PETSC_SUCCESS);
382: PetscCall(PetscLogEventBegin(PETSCSF_RemoteOff, sf, 0, 0, 0));
383: PetscCall(PetscSectionGetChart(rootSection, &rpStart, &rpEnd));
384: PetscCall(PetscSectionGetChart(leafSection, &lpStart, &lpEnd));
385: PetscCall(ISCreateStride(PETSC_COMM_SELF, rpEnd - rpStart, rpStart, 1, &selected));
386: PetscCall(ISGetIndices(selected, &indices));
387: PetscCall(PetscSFCreateEmbeddedRootSF(sf, rpEnd - rpStart, indices, &embedSF));
388: PetscCall(ISRestoreIndices(selected, &indices));
389: PetscCall(ISDestroy(&selected));
390: PetscCall(PetscCalloc1(lpEnd - lpStart, remoteOffsets));
391: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
392: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
393: PetscCall(PetscSFDestroy(&embedSF));
394: PetscCall(PetscLogEventEnd(PETSCSF_RemoteOff, sf, 0, 0, 0));
395: PetscFunctionReturn(PETSC_SUCCESS);
396: }
398: /*@C
399: PetscSFCreateSectionSF - Create an expanded `PetscSF` of dofs, assuming the input `PetscSF` relates points
401: Collective
403: Input Parameters:
404: + sf - The `PetscSF`
405: . rootSection - Data layout of remote points for outgoing data (this is usually the serial section)
406: . remoteOffsets - Offsets for point data on remote processes (these are offsets from the root section), or NULL
407: - leafSection - Data layout of local points for incoming data (this is the distributed section)
409: Output Parameter:
410: . sectionSF - The new `PetscSF`
412: Level: advanced
414: Notes:
415: Either rootSection or remoteOffsets can be specified
417: Fortran Notes:
418: In Fortran, use PetscSFCreateSectionSFF90()
420: .seealso: `PetscSF`, `PetscSFCreate()`
421: @*/
422: PetscErrorCode PetscSFCreateSectionSF(PetscSF sf, PetscSection rootSection, PetscInt remoteOffsets[], PetscSection leafSection, PetscSF *sectionSF)
423: {
424: MPI_Comm comm;
425: const PetscInt *localPoints;
426: const PetscSFNode *remotePoints;
427: PetscInt lpStart, lpEnd;
428: PetscInt numRoots, numSectionRoots, numPoints, numIndices = 0;
429: PetscInt *localIndices;
430: PetscSFNode *remoteIndices;
431: PetscInt i, ind;
433: PetscFunctionBegin;
435: PetscAssertPointer(rootSection, 2);
436: /* Cannot check PetscAssertPointer(remoteOffsets,3) because it can be NULL if sf does not reference any points in leafSection */
437: PetscAssertPointer(leafSection, 4);
438: PetscAssertPointer(sectionSF, 5);
439: PetscCall(PetscObjectGetComm((PetscObject)sf, &comm));
440: PetscCall(PetscSFCreate(comm, sectionSF));
441: PetscCall(PetscSectionGetChart(leafSection, &lpStart, &lpEnd));
442: PetscCall(PetscSectionGetStorageSize(rootSection, &numSectionRoots));
443: PetscCall(PetscSFGetGraph(sf, &numRoots, &numPoints, &localPoints, &remotePoints));
444: if (numRoots < 0) PetscFunctionReturn(PETSC_SUCCESS);
445: PetscCall(PetscLogEventBegin(PETSCSF_SectSF, sf, 0, 0, 0));
446: for (i = 0; i < numPoints; ++i) {
447: PetscInt localPoint = localPoints ? localPoints[i] : i;
448: PetscInt dof;
450: if ((localPoint >= lpStart) && (localPoint < lpEnd)) {
451: PetscCall(PetscSectionGetDof(leafSection, localPoint, &dof));
452: numIndices += dof < 0 ? 0 : dof;
453: }
454: }
455: PetscCall(PetscMalloc1(numIndices, &localIndices));
456: PetscCall(PetscMalloc1(numIndices, &remoteIndices));
457: /* Create new index graph */
458: for (i = 0, ind = 0; i < numPoints; ++i) {
459: PetscInt localPoint = localPoints ? localPoints[i] : i;
460: PetscInt rank = remotePoints[i].rank;
462: if ((localPoint >= lpStart) && (localPoint < lpEnd)) {
463: PetscInt remoteOffset = remoteOffsets[localPoint - lpStart];
464: PetscInt loff, dof, d;
466: PetscCall(PetscSectionGetOffset(leafSection, localPoint, &loff));
467: PetscCall(PetscSectionGetDof(leafSection, localPoint, &dof));
468: for (d = 0; d < dof; ++d, ++ind) {
469: localIndices[ind] = loff + d;
470: remoteIndices[ind].rank = rank;
471: remoteIndices[ind].index = remoteOffset + d;
472: }
473: }
474: }
475: PetscCheck(numIndices == ind, comm, PETSC_ERR_PLIB, "Inconsistency in indices, %" PetscInt_FMT " should be %" PetscInt_FMT, ind, numIndices);
476: PetscCall(PetscSFSetGraph(*sectionSF, numSectionRoots, numIndices, localIndices, PETSC_OWN_POINTER, remoteIndices, PETSC_OWN_POINTER));
477: PetscCall(PetscSFSetUp(*sectionSF));
478: PetscCall(PetscLogEventEnd(PETSCSF_SectSF, sf, 0, 0, 0));
479: PetscFunctionReturn(PETSC_SUCCESS);
480: }
482: /*@C
483: PetscSFCreateFromLayouts - Creates a parallel star forest mapping two `PetscLayout` objects
485: Collective
487: Input Parameters:
488: + rmap - `PetscLayout` defining the global root space
489: - lmap - `PetscLayout` defining the global leaf space
491: Output Parameter:
492: . sf - The parallel star forest
494: Level: intermediate
496: .seealso: `PetscSF`, `PetscSFCreate()`, `PetscLayoutCreate()`, `PetscSFSetGraphLayout()`
497: @*/
498: PetscErrorCode PetscSFCreateFromLayouts(PetscLayout rmap, PetscLayout lmap, PetscSF *sf)
499: {
500: PetscInt i, nroots, nleaves = 0;
501: PetscInt rN, lst, len;
502: PetscMPIInt owner = -1;
503: PetscSFNode *remote;
504: MPI_Comm rcomm = rmap->comm;
505: MPI_Comm lcomm = lmap->comm;
506: PetscMPIInt flg;
508: PetscFunctionBegin;
509: PetscAssertPointer(sf, 3);
510: PetscCheck(rmap->setupcalled, rcomm, PETSC_ERR_ARG_WRONGSTATE, "Root layout not setup");
511: PetscCheck(lmap->setupcalled, lcomm, PETSC_ERR_ARG_WRONGSTATE, "Leaf layout not setup");
512: PetscCallMPI(MPI_Comm_compare(rcomm, lcomm, &flg));
513: PetscCheck(flg == MPI_CONGRUENT || flg == MPI_IDENT, rcomm, PETSC_ERR_SUP, "cannot map two layouts with non-matching communicators");
514: PetscCall(PetscSFCreate(rcomm, sf));
515: PetscCall(PetscLayoutGetLocalSize(rmap, &nroots));
516: PetscCall(PetscLayoutGetSize(rmap, &rN));
517: PetscCall(PetscLayoutGetRange(lmap, &lst, &len));
518: PetscCall(PetscMalloc1(len - lst, &remote));
519: for (i = lst; i < len && i < rN; i++) {
520: if (owner < -1 || i >= rmap->range[owner + 1]) PetscCall(PetscLayoutFindOwner(rmap, i, &owner));
521: remote[nleaves].rank = owner;
522: remote[nleaves].index = i - rmap->range[owner];
523: nleaves++;
524: }
525: PetscCall(PetscSFSetGraph(*sf, nroots, nleaves, NULL, PETSC_OWN_POINTER, remote, PETSC_COPY_VALUES));
526: PetscCall(PetscFree(remote));
527: PetscFunctionReturn(PETSC_SUCCESS);
528: }
530: /* TODO: handle nooffprocentries like MatZeroRowsMapLocal_Private, since this code is the same */
531: PetscErrorCode PetscLayoutMapLocal(PetscLayout map, PetscInt N, const PetscInt idxs[], PetscInt *on, PetscInt **oidxs, PetscInt **ogidxs)
532: {
533: PetscInt *owners = map->range;
534: PetscInt n = map->n;
535: PetscSF sf;
536: PetscInt *lidxs, *work = NULL;
537: PetscSFNode *ridxs;
538: PetscMPIInt rank, p = 0;
539: PetscInt r, len = 0;
541: PetscFunctionBegin;
542: if (on) *on = 0; /* squelch -Wmaybe-uninitialized */
543: /* Create SF where leaves are input idxs and roots are owned idxs */
544: PetscCallMPI(MPI_Comm_rank(map->comm, &rank));
545: PetscCall(PetscMalloc1(n, &lidxs));
546: for (r = 0; r < n; ++r) lidxs[r] = -1;
547: PetscCall(PetscMalloc1(N, &ridxs));
548: for (r = 0; r < N; ++r) {
549: const PetscInt idx = idxs[r];
550: PetscCheck(idx >= 0 && idx < map->N, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Index %" PetscInt_FMT " out of range [0,%" PetscInt_FMT ")", idx, map->N);
551: if (idx < owners[p] || owners[p + 1] <= idx) { /* short-circuit the search if the last p owns this idx too */
552: PetscCall(PetscLayoutFindOwner(map, idx, &p));
553: }
554: ridxs[r].rank = p;
555: ridxs[r].index = idxs[r] - owners[p];
556: }
557: PetscCall(PetscSFCreate(map->comm, &sf));
558: PetscCall(PetscSFSetGraph(sf, n, N, NULL, PETSC_OWN_POINTER, ridxs, PETSC_OWN_POINTER));
559: PetscCall(PetscSFReduceBegin(sf, MPIU_INT, (PetscInt *)idxs, lidxs, MPI_LOR));
560: PetscCall(PetscSFReduceEnd(sf, MPIU_INT, (PetscInt *)idxs, lidxs, MPI_LOR));
561: if (ogidxs) { /* communicate global idxs */
562: PetscInt cum = 0, start, *work2;
564: PetscCall(PetscMalloc1(n, &work));
565: PetscCall(PetscCalloc1(N, &work2));
566: for (r = 0; r < N; ++r)
567: if (idxs[r] >= 0) cum++;
568: PetscCallMPI(MPI_Scan(&cum, &start, 1, MPIU_INT, MPI_SUM, map->comm));
569: start -= cum;
570: cum = 0;
571: for (r = 0; r < N; ++r)
572: if (idxs[r] >= 0) work2[r] = start + cum++;
573: PetscCall(PetscSFReduceBegin(sf, MPIU_INT, work2, work, MPI_REPLACE));
574: PetscCall(PetscSFReduceEnd(sf, MPIU_INT, work2, work, MPI_REPLACE));
575: PetscCall(PetscFree(work2));
576: }
577: PetscCall(PetscSFDestroy(&sf));
578: /* Compress and put in indices */
579: for (r = 0; r < n; ++r)
580: if (lidxs[r] >= 0) {
581: if (work) work[len] = work[r];
582: lidxs[len++] = r;
583: }
584: if (on) *on = len;
585: if (oidxs) *oidxs = lidxs;
586: if (ogidxs) *ogidxs = work;
587: PetscFunctionReturn(PETSC_SUCCESS);
588: }
590: /*@
591: PetscSFCreateByMatchingIndices - Create `PetscSF` by matching root and leaf indices
593: Collective
595: Input Parameters:
596: + layout - `PetscLayout` defining the global index space and the rank that brokers each index
597: . numRootIndices - size of rootIndices
598: . rootIndices - `PetscInt` array of global indices of which this process requests ownership
599: . rootLocalIndices - root local index permutation (NULL if no permutation)
600: . rootLocalOffset - offset to be added to root local indices
601: . numLeafIndices - size of leafIndices
602: . leafIndices - `PetscInt` array of global indices with which this process requires data associated
603: . leafLocalIndices - leaf local index permutation (NULL if no permutation)
604: - leafLocalOffset - offset to be added to leaf local indices
606: Output Parameters:
607: + sfA - star forest representing the communication pattern from the layout space to the leaf space (NULL if not needed)
608: - sf - star forest representing the communication pattern from the root space to the leaf space
610: Level: advanced
612: Example 1:
613: .vb
614: rank : 0 1 2
615: rootIndices : [1 0 2] [3] [3]
616: rootLocalOffset : 100 200 300
617: layout : [0 1] [2] [3]
618: leafIndices : [0] [2] [0 3]
619: leafLocalOffset : 400 500 600
621: would build the following PetscSF
623: [0] 400 <- (0,101)
624: [1] 500 <- (0,102)
625: [2] 600 <- (0,101)
626: [2] 601 <- (2,300)
627: .ve
629: Example 2:
630: .vb
631: rank : 0 1 2
632: rootIndices : [1 0 2] [3] [3]
633: rootLocalOffset : 100 200 300
634: layout : [0 1] [2] [3]
635: leafIndices : rootIndices rootIndices rootIndices
636: leafLocalOffset : rootLocalOffset rootLocalOffset rootLocalOffset
638: would build the following PetscSF
640: [1] 200 <- (2,300)
641: .ve
643: Example 3:
644: .vb
645: No process requests ownership of global index 1, but no process needs it.
647: rank : 0 1 2
648: numRootIndices : 2 1 1
649: rootIndices : [0 2] [3] [3]
650: rootLocalOffset : 100 200 300
651: layout : [0 1] [2] [3]
652: numLeafIndices : 1 1 2
653: leafIndices : [0] [2] [0 3]
654: leafLocalOffset : 400 500 600
656: would build the following PetscSF
658: [0] 400 <- (0,100)
659: [1] 500 <- (0,101)
660: [2] 600 <- (0,100)
661: [2] 601 <- (2,300)
662: .ve
664: Notes:
665: The layout parameter represents any partitioning of [0, N), where N is the total number of global indices, and its
666: local size can be set to `PETSC_DECIDE`.
668: If a global index x lies in the partition owned by process i, each process whose rootIndices contains x requests
669: ownership of x and sends its own rank and the local index of x to process i.
670: If multiple processes request ownership of x, the one with the highest rank is to own x.
671: Process i then broadcasts the ownership information, so that each process whose leafIndices contains x knows the
672: ownership information of x.
673: The output sf is constructed by associating each leaf point to a root point in this way.
675: Suppose there is point data ordered according to the global indices and partitioned according to the given layout.
676: The optional output `PetscSF` object sfA can be used to push such data to leaf points.
678: All indices in rootIndices and leafIndices must lie in the layout range. The union (over all processes) of rootIndices
679: must cover that of leafIndices, but need not cover the entire layout.
681: If (leafIndices, leafLocalIndices, leafLocalOffset) == (rootIndices, rootLocalIndices, rootLocalOffset), the output
682: star forest is almost identity, so will only include non-trivial part of the map.
684: Developer Notes:
685: Current approach of a process of the highest rank gaining the ownership may cause load imbalance; consider using
686: hash(rank, root_local_index) as the bid for the ownership determination.
688: .seealso: `PetscSF`, `PetscSFCreate()`
689: @*/
690: PetscErrorCode PetscSFCreateByMatchingIndices(PetscLayout layout, PetscInt numRootIndices, const PetscInt *rootIndices, const PetscInt *rootLocalIndices, PetscInt rootLocalOffset, PetscInt numLeafIndices, const PetscInt *leafIndices, const PetscInt *leafLocalIndices, PetscInt leafLocalOffset, PetscSF *sfA, PetscSF *sf)
691: {
692: MPI_Comm comm = layout->comm;
693: PetscMPIInt size, rank;
694: PetscSF sf1;
695: PetscSFNode *owners, *buffer, *iremote;
696: PetscInt *ilocal, nleaves, N, n, i;
697: #if defined(PETSC_USE_DEBUG)
698: PetscInt N1;
699: #endif
700: PetscBool flag;
702: PetscFunctionBegin;
703: if (rootIndices) PetscAssertPointer(rootIndices, 3);
704: if (rootLocalIndices) PetscAssertPointer(rootLocalIndices, 4);
705: if (leafIndices) PetscAssertPointer(leafIndices, 7);
706: if (leafLocalIndices) PetscAssertPointer(leafLocalIndices, 8);
707: if (sfA) PetscAssertPointer(sfA, 10);
708: PetscAssertPointer(sf, 11);
709: PetscCheck(numRootIndices >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "numRootIndices (%" PetscInt_FMT ") must be non-negative", numRootIndices);
710: PetscCheck(numLeafIndices >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "numLeafIndices (%" PetscInt_FMT ") must be non-negative", numLeafIndices);
711: PetscCallMPI(MPI_Comm_size(comm, &size));
712: PetscCallMPI(MPI_Comm_rank(comm, &rank));
713: PetscCall(PetscLayoutSetUp(layout));
714: PetscCall(PetscLayoutGetSize(layout, &N));
715: PetscCall(PetscLayoutGetLocalSize(layout, &n));
716: flag = (PetscBool)(leafIndices == rootIndices);
717: PetscCall(MPIU_Allreduce(MPI_IN_PLACE, &flag, 1, MPIU_BOOL, MPI_LAND, comm));
718: PetscCheck(!flag || numLeafIndices == numRootIndices, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "leafIndices == rootIndices, but numLeafIndices (%" PetscInt_FMT ") != numRootIndices(%" PetscInt_FMT ")", numLeafIndices, numRootIndices);
719: #if defined(PETSC_USE_DEBUG)
720: N1 = PETSC_MIN_INT;
721: for (i = 0; i < numRootIndices; i++)
722: if (rootIndices[i] > N1) N1 = rootIndices[i];
723: PetscCall(MPIU_Allreduce(MPI_IN_PLACE, &N1, 1, MPIU_INT, MPI_MAX, comm));
724: PetscCheck(N1 < N, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Max. root index (%" PetscInt_FMT ") out of layout range [0,%" PetscInt_FMT ")", N1, N);
725: if (!flag) {
726: N1 = PETSC_MIN_INT;
727: for (i = 0; i < numLeafIndices; i++)
728: if (leafIndices[i] > N1) N1 = leafIndices[i];
729: PetscCall(MPIU_Allreduce(MPI_IN_PLACE, &N1, 1, MPIU_INT, MPI_MAX, comm));
730: PetscCheck(N1 < N, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Max. leaf index (%" PetscInt_FMT ") out of layout range [0,%" PetscInt_FMT ")", N1, N);
731: }
732: #endif
733: /* Reduce: owners -> buffer */
734: PetscCall(PetscMalloc1(n, &buffer));
735: PetscCall(PetscSFCreate(comm, &sf1));
736: PetscCall(PetscSFSetFromOptions(sf1));
737: PetscCall(PetscSFSetGraphLayout(sf1, layout, numRootIndices, NULL, PETSC_OWN_POINTER, rootIndices));
738: PetscCall(PetscMalloc1(numRootIndices, &owners));
739: for (i = 0; i < numRootIndices; ++i) {
740: owners[i].rank = rank;
741: owners[i].index = rootLocalOffset + (rootLocalIndices ? rootLocalIndices[i] : i);
742: }
743: for (i = 0; i < n; ++i) {
744: buffer[i].index = -1;
745: buffer[i].rank = -1;
746: }
747: PetscCall(PetscSFReduceBegin(sf1, MPIU_2INT, owners, buffer, MPI_MAXLOC));
748: PetscCall(PetscSFReduceEnd(sf1, MPIU_2INT, owners, buffer, MPI_MAXLOC));
749: /* Bcast: buffer -> owners */
750: if (!flag) {
751: /* leafIndices is different from rootIndices */
752: PetscCall(PetscFree(owners));
753: PetscCall(PetscSFSetGraphLayout(sf1, layout, numLeafIndices, NULL, PETSC_OWN_POINTER, leafIndices));
754: PetscCall(PetscMalloc1(numLeafIndices, &owners));
755: }
756: PetscCall(PetscSFBcastBegin(sf1, MPIU_2INT, buffer, owners, MPI_REPLACE));
757: PetscCall(PetscSFBcastEnd(sf1, MPIU_2INT, buffer, owners, MPI_REPLACE));
758: for (i = 0; i < numLeafIndices; ++i) PetscCheck(owners[i].rank >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Global point %" PetscInt_FMT " was unclaimed", leafIndices[i]);
759: PetscCall(PetscFree(buffer));
760: if (sfA) {
761: *sfA = sf1;
762: } else PetscCall(PetscSFDestroy(&sf1));
763: /* Create sf */
764: if (flag && rootLocalIndices == leafLocalIndices && leafLocalOffset == rootLocalOffset) {
765: /* leaf space == root space */
766: for (i = 0, nleaves = 0; i < numLeafIndices; ++i)
767: if (owners[i].rank != rank) ++nleaves;
768: PetscCall(PetscMalloc1(nleaves, &ilocal));
769: PetscCall(PetscMalloc1(nleaves, &iremote));
770: for (i = 0, nleaves = 0; i < numLeafIndices; ++i) {
771: if (owners[i].rank != rank) {
772: ilocal[nleaves] = leafLocalOffset + i;
773: iremote[nleaves].rank = owners[i].rank;
774: iremote[nleaves].index = owners[i].index;
775: ++nleaves;
776: }
777: }
778: PetscCall(PetscFree(owners));
779: } else {
780: nleaves = numLeafIndices;
781: PetscCall(PetscMalloc1(nleaves, &ilocal));
782: for (i = 0; i < nleaves; ++i) ilocal[i] = leafLocalOffset + (leafLocalIndices ? leafLocalIndices[i] : i);
783: iremote = owners;
784: }
785: PetscCall(PetscSFCreate(comm, sf));
786: PetscCall(PetscSFSetFromOptions(*sf));
787: PetscCall(PetscSFSetGraph(*sf, rootLocalOffset + numRootIndices, nleaves, ilocal, PETSC_OWN_POINTER, iremote, PETSC_OWN_POINTER));
788: PetscFunctionReturn(PETSC_SUCCESS);
789: }
791: /*@
792: PetscSFMerge - append/merge indices of `sfb` into `sfa`, with preference for `sfb`
794: Collective
796: Input Parameters:
797: + sfa - default `PetscSF`
798: - sfb - additional edges to add/replace edges in sfa
800: Output Parameter:
801: . merged - new `PetscSF` with combined edges
803: Level: intermediate
805: .seealso: `PetscSFCompose()`
806: @*/
807: PetscErrorCode PetscSFMerge(PetscSF sfa, PetscSF sfb, PetscSF *merged)
808: {
809: PetscInt maxleaf;
811: PetscFunctionBegin;
814: PetscCheckSameComm(sfa, 1, sfb, 2);
815: PetscAssertPointer(merged, 3);
816: {
817: PetscInt aleaf, bleaf;
818: PetscCall(PetscSFGetLeafRange(sfa, NULL, &aleaf));
819: PetscCall(PetscSFGetLeafRange(sfb, NULL, &bleaf));
820: maxleaf = PetscMax(aleaf, bleaf) + 1; // One more than the last index
821: }
822: PetscInt *clocal, aroots, aleaves, broots, bleaves;
823: PetscSFNode *cremote;
824: const PetscInt *alocal, *blocal;
825: const PetscSFNode *aremote, *bremote;
826: PetscCall(PetscMalloc2(maxleaf, &clocal, maxleaf, &cremote));
827: for (PetscInt i = 0; i < maxleaf; i++) clocal[i] = -1;
828: PetscCall(PetscSFGetGraph(sfa, &aroots, &aleaves, &alocal, &aremote));
829: PetscCall(PetscSFGetGraph(sfb, &broots, &bleaves, &blocal, &bremote));
830: PetscCheck(aroots == broots, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Both sfa and sfb must have the same root space");
831: for (PetscInt i = 0; i < aleaves; i++) {
832: PetscInt a = alocal ? alocal[i] : i;
833: clocal[a] = a;
834: cremote[a] = aremote[i];
835: }
836: for (PetscInt i = 0; i < bleaves; i++) {
837: PetscInt b = blocal ? blocal[i] : i;
838: clocal[b] = b;
839: cremote[b] = bremote[i];
840: }
841: PetscInt nleaves = 0;
842: for (PetscInt i = 0; i < maxleaf; i++) {
843: if (clocal[i] < 0) continue;
844: clocal[nleaves] = clocal[i];
845: cremote[nleaves] = cremote[i];
846: nleaves++;
847: }
848: PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)sfa), merged));
849: PetscCall(PetscSFSetGraph(*merged, aroots, nleaves, clocal, PETSC_COPY_VALUES, cremote, PETSC_COPY_VALUES));
850: PetscCall(PetscFree2(clocal, cremote));
851: PetscFunctionReturn(PETSC_SUCCESS);
852: }
854: /*@
855: PetscSFCreateStridedSF - Create an `PetscSF` to communicate interleaved blocks of data
857: Collective
859: Input Parameters:
860: + sf - star forest
861: . bs - stride
862: . ldr - leading dimension of root space
863: - ldl - leading dimension of leaf space
865: Output Parameter:
866: . vsf - the new `PetscSF`
868: Level: intermediate
870: Notes:
871: This can be useful to perform communications on blocks of right-hand sides. For example, the calling sequence
872: .vb
873: c_datatype *roots, *leaves;
874: for i in [0,bs) do
875: PetscSFBcastBegin(sf, mpi_datatype, roots + i*ldr, leaves + i*ldl, op)
876: PetscSFBcastEnd(sf, mpi_datatype, roots + i*ldr, leaves + i*ldl, op)
877: .ve
878: is equivalent to
879: .vb
880: c_datatype *roots, *leaves;
881: PetscSFCreateStridedSF(sf, bs, ldr, ldl, &vsf)
882: PetscSFBcastBegin(vsf, mpi_datatype, roots, leaves, op)
883: PetscSFBcastEnd(vsf, mpi_datatype, roots, leaves, op)
884: .ve
886: Developer Notes:
887: Should this functionality be handled with a new API instead of creating a new object?
889: .seealso: `PetscSF`, `PetscSFCreate()`, `PetscSFSetGraph()`
890: @*/
891: PetscErrorCode PetscSFCreateStridedSF(PetscSF sf, PetscInt bs, PetscInt ldr, PetscInt ldl, PetscSF *vsf)
892: {
893: PetscSF rankssf;
894: const PetscSFNode *iremote, *sfrremote;
895: PetscSFNode *viremote;
896: const PetscInt *ilocal;
897: PetscInt *vilocal = NULL, *ldrs;
898: PetscInt nranks, nr, nl, vnr, vnl, maxl;
899: PetscMPIInt rank;
900: MPI_Comm comm;
901: PetscSFType sftype;
903: PetscFunctionBegin;
906: PetscAssertPointer(vsf, 5);
907: if (bs == 1) {
908: PetscCall(PetscObjectReference((PetscObject)sf));
909: *vsf = sf;
910: PetscFunctionReturn(PETSC_SUCCESS);
911: }
912: PetscCall(PetscSFSetUp(sf));
913: PetscCall(PetscObjectGetComm((PetscObject)sf, &comm));
914: PetscCallMPI(MPI_Comm_rank(comm, &rank));
915: PetscCall(PetscSFGetGraph(sf, &nr, &nl, &ilocal, &iremote));
916: PetscCall(PetscSFGetLeafRange(sf, NULL, &maxl));
917: maxl += 1;
918: if (ldl == PETSC_DECIDE) ldl = maxl;
919: if (ldr == PETSC_DECIDE) ldr = nr;
920: PetscCheck(ldr >= nr, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid leading dimension %" PetscInt_FMT " must be smaller than number of roots %" PetscInt_FMT, ldr, nr);
921: PetscCheck(ldl >= maxl, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid leading dimension %" PetscInt_FMT " must be larger than leaf range %" PetscInt_FMT, ldl, maxl - 1);
922: vnr = nr * bs;
923: vnl = nl * bs;
924: PetscCall(PetscMalloc1(vnl, &viremote));
925: PetscCall(PetscMalloc1(vnl, &vilocal));
927: /* Communicate root leading dimensions to leaf ranks */
928: PetscCall(PetscSFGetRanksSF(sf, &rankssf));
929: PetscCall(PetscSFGetGraph(rankssf, NULL, &nranks, NULL, &sfrremote));
930: PetscCall(PetscMalloc1(nranks, &ldrs));
931: PetscCall(PetscSFBcastBegin(rankssf, MPIU_INT, &ldr, ldrs, MPI_REPLACE));
932: PetscCall(PetscSFBcastEnd(rankssf, MPIU_INT, &ldr, ldrs, MPI_REPLACE));
934: for (PetscInt i = 0, rold = -1, lda = -1; i < nl; i++) {
935: const PetscInt r = iremote[i].rank;
936: const PetscInt ii = iremote[i].index;
938: if (r == rank) lda = ldr;
939: else if (rold != r) {
940: PetscInt j;
942: for (j = 0; j < nranks; j++)
943: if (sfrremote[j].rank == r) break;
944: PetscCheck(j < nranks, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Unable to locate neighbor rank %" PetscInt_FMT, r);
945: lda = ldrs[j];
946: }
947: rold = r;
948: for (PetscInt v = 0; v < bs; v++) {
949: viremote[v * nl + i].rank = r;
950: viremote[v * nl + i].index = v * lda + ii;
951: vilocal[v * nl + i] = v * ldl + (ilocal ? ilocal[i] : i);
952: }
953: }
954: PetscCall(PetscFree(ldrs));
955: PetscCall(PetscSFCreate(comm, vsf));
956: PetscCall(PetscSFGetType(sf, &sftype));
957: PetscCall(PetscSFSetType(*vsf, sftype));
958: PetscCall(PetscSFSetGraph(*vsf, vnr, vnl, vilocal, PETSC_OWN_POINTER, viremote, PETSC_OWN_POINTER));
959: PetscFunctionReturn(PETSC_SUCCESS);
960: }