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 (with `PetscLayoutDestroy()` and `PetscFree()`) by the user.
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, ir;
183: PetscMPIInt r;
185: PetscCall(PetscFindInt(offset, size + 1, ranges, &ir));
186: PetscCall(PetscMPIIntCast(ir, &r));
187: if (r < 0) r = -(r + 2);
188: PetscCheck(!(r < 0) && !(r >= size), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Point %" PetscInt_FMT " mapped to invalid process %d (%" PetscInt_FMT ", %" PetscInt_FMT ")", p, r, gdof, goff);
189: remote[l].rank = r;
190: remote[l].index = offset - ranges[r];
191: }
192: } else {
193: for (d = 0; d < gsize; ++d, ++l) {
194: remote[l].rank = rank;
195: remote[l].index = goff + d - ranges[rank];
196: }
197: }
198: }
199: PetscCheck(l == nleaves, comm, PETSC_ERR_PLIB, "Iteration error, l %" PetscInt_FMT " != nleaves %" PetscInt_FMT, l, nleaves);
200: PetscCall(PetscLayoutDestroy(&layout));
201: PetscCall(PetscSFSetGraph(sf, nroots, nleaves, local, PETSC_OWN_POINTER, remote, PETSC_OWN_POINTER));
202: PetscFunctionReturn(PETSC_SUCCESS);
203: }
205: /*@C
206: PetscSFDistributeSection - Create a new `PetscSection` reorganized, moving from the root to the leaves of the `PetscSF`
208: Collective
210: Input Parameters:
211: + sf - The `PetscSF`
212: - rootSection - Section defined on root space
214: Output Parameters:
215: + remoteOffsets - root offsets in leaf storage, or `NULL`
216: - leafSection - Section defined on the leaf space
218: Level: advanced
220: Fortran Notes:
221: In Fortran, use PetscSFDistributeSectionF90()
223: .seealso: `PetscSF`, `PetscSFCreate()`
224: @*/
225: PetscErrorCode PetscSFDistributeSection(PetscSF sf, PetscSection rootSection, PetscInt **remoteOffsets, PetscSection leafSection)
226: {
227: PetscSF embedSF;
228: const PetscInt *indices;
229: IS selected;
230: PetscInt numFields, nroots, rpStart, rpEnd, lpStart = PETSC_INT_MAX, lpEnd = -1, f, c;
231: PetscBool *sub, hasc;
232: PetscMPIInt msize;
234: PetscFunctionBegin;
235: PetscCall(PetscLogEventBegin(PETSCSF_DistSect, sf, 0, 0, 0));
236: PetscCall(PetscSectionGetNumFields(rootSection, &numFields));
237: if (numFields) {
238: IS perm;
240: /* PetscSectionSetNumFields() calls PetscSectionReset(), which destroys
241: leafSection->perm. To keep this permutation set by the user, we grab
242: the reference before calling PetscSectionSetNumFields() and set it
243: back after. */
244: PetscCall(PetscSectionGetPermutation(leafSection, &perm));
245: PetscCall(PetscObjectReference((PetscObject)perm));
246: PetscCall(PetscSectionSetNumFields(leafSection, numFields));
247: PetscCall(PetscSectionSetPermutation(leafSection, perm));
248: PetscCall(ISDestroy(&perm));
249: }
250: PetscCall(PetscMalloc1(numFields + 2, &sub));
251: sub[1] = rootSection->bc ? PETSC_TRUE : PETSC_FALSE;
252: for (f = 0; f < numFields; ++f) {
253: PetscSectionSym sym, dsym = NULL;
254: const char *name = NULL;
255: PetscInt numComp = 0;
257: sub[2 + f] = rootSection->field[f]->bc ? PETSC_TRUE : PETSC_FALSE;
258: PetscCall(PetscSectionGetFieldComponents(rootSection, f, &numComp));
259: PetscCall(PetscSectionGetFieldName(rootSection, f, &name));
260: PetscCall(PetscSectionGetFieldSym(rootSection, f, &sym));
261: if (sym) PetscCall(PetscSectionSymDistribute(sym, sf, &dsym));
262: PetscCall(PetscSectionSetFieldComponents(leafSection, f, numComp));
263: PetscCall(PetscSectionSetFieldName(leafSection, f, name));
264: PetscCall(PetscSectionSetFieldSym(leafSection, f, dsym));
265: PetscCall(PetscSectionSymDestroy(&dsym));
266: for (c = 0; c < rootSection->numFieldComponents[f]; ++c) {
267: PetscCall(PetscSectionGetComponentName(rootSection, f, c, &name));
268: PetscCall(PetscSectionSetComponentName(leafSection, f, c, name));
269: }
270: }
271: PetscCall(PetscSectionGetChart(rootSection, &rpStart, &rpEnd));
272: PetscCall(PetscSFGetGraph(sf, &nroots, NULL, NULL, NULL));
273: rpEnd = PetscMin(rpEnd, nroots);
274: rpEnd = PetscMax(rpStart, rpEnd);
275: /* see if we can avoid creating the embedded SF, since it can cost more than an allreduce */
276: sub[0] = (PetscBool)(nroots != rpEnd - rpStart);
277: PetscCall(PetscMPIIntCast(2 + numFields, &msize));
278: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, sub, msize, MPIU_BOOL, MPI_LOR, PetscObjectComm((PetscObject)sf)));
279: if (sub[0]) {
280: PetscCall(ISCreateStride(PETSC_COMM_SELF, rpEnd - rpStart, rpStart, 1, &selected));
281: PetscCall(ISGetIndices(selected, &indices));
282: PetscCall(PetscSFCreateEmbeddedRootSF(sf, rpEnd - rpStart, indices, &embedSF));
283: PetscCall(ISRestoreIndices(selected, &indices));
284: PetscCall(ISDestroy(&selected));
285: } else {
286: PetscCall(PetscObjectReference((PetscObject)sf));
287: embedSF = sf;
288: }
289: PetscCall(PetscSFGetLeafRange(embedSF, &lpStart, &lpEnd));
290: lpEnd++;
292: PetscCall(PetscSectionSetChart(leafSection, lpStart, lpEnd));
294: /* Constrained dof section */
295: hasc = sub[1];
296: for (f = 0; f < numFields; ++f) hasc = (PetscBool)(hasc || sub[2 + f]);
298: /* Could fuse these at the cost of copies and extra allocation */
299: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->atlasDof, -lpStart), MPI_REPLACE));
300: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->atlasDof, -lpStart), MPI_REPLACE));
301: if (sub[1]) {
302: PetscCall(PetscSectionCheckConstraints_Private(rootSection));
303: PetscCall(PetscSectionCheckConstraints_Private(leafSection));
304: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->bc->atlasDof[-rpStart], &leafSection->bc->atlasDof[-lpStart], MPI_REPLACE));
305: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->bc->atlasDof[-rpStart], &leafSection->bc->atlasDof[-lpStart], MPI_REPLACE));
306: }
307: for (f = 0; f < numFields; ++f) {
308: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->field[f]->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->field[f]->atlasDof, -lpStart), MPI_REPLACE));
309: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->field[f]->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->field[f]->atlasDof, -lpStart), MPI_REPLACE));
310: if (sub[2 + f]) {
311: PetscCall(PetscSectionCheckConstraints_Private(rootSection->field[f]));
312: PetscCall(PetscSectionCheckConstraints_Private(leafSection->field[f]));
313: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasDof[-rpStart], &leafSection->field[f]->bc->atlasDof[-lpStart], MPI_REPLACE));
314: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasDof[-rpStart], &leafSection->field[f]->bc->atlasDof[-lpStart], MPI_REPLACE));
315: }
316: }
317: if (remoteOffsets) {
318: PetscCall(PetscMalloc1(lpEnd - lpStart, remoteOffsets));
319: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
320: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
321: }
322: PetscCall(PetscSectionInvalidateMaxDof_Internal(leafSection));
323: PetscCall(PetscSectionSetUp(leafSection));
324: if (hasc) { /* need to communicate bcIndices */
325: PetscSF bcSF;
326: PetscInt *rOffBc;
328: PetscCall(PetscMalloc1(lpEnd - lpStart, &rOffBc));
329: if (sub[1]) {
330: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
331: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
332: PetscCall(PetscSFCreateSectionSF(embedSF, rootSection->bc, rOffBc, leafSection->bc, &bcSF));
333: PetscCall(PetscSFBcastBegin(bcSF, MPIU_INT, rootSection->bcIndices, leafSection->bcIndices, MPI_REPLACE));
334: PetscCall(PetscSFBcastEnd(bcSF, MPIU_INT, rootSection->bcIndices, leafSection->bcIndices, MPI_REPLACE));
335: PetscCall(PetscSFDestroy(&bcSF));
336: }
337: for (f = 0; f < numFields; ++f) {
338: if (sub[2 + f]) {
339: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
340: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
341: PetscCall(PetscSFCreateSectionSF(embedSF, rootSection->field[f]->bc, rOffBc, leafSection->field[f]->bc, &bcSF));
342: PetscCall(PetscSFBcastBegin(bcSF, MPIU_INT, rootSection->field[f]->bcIndices, leafSection->field[f]->bcIndices, MPI_REPLACE));
343: PetscCall(PetscSFBcastEnd(bcSF, MPIU_INT, rootSection->field[f]->bcIndices, leafSection->field[f]->bcIndices, MPI_REPLACE));
344: PetscCall(PetscSFDestroy(&bcSF));
345: }
346: }
347: PetscCall(PetscFree(rOffBc));
348: }
349: PetscCall(PetscSFDestroy(&embedSF));
350: PetscCall(PetscFree(sub));
351: PetscCall(PetscLogEventEnd(PETSCSF_DistSect, sf, 0, 0, 0));
352: PetscFunctionReturn(PETSC_SUCCESS);
353: }
355: /*@C
356: PetscSFCreateRemoteOffsets - Create offsets for point data on remote processes
358: Collective
360: Input Parameters:
361: + sf - The `PetscSF`
362: . rootSection - Data layout of remote points for outgoing data (this is layout for SF roots)
363: - leafSection - Data layout of local points for incoming data (this is layout for SF leaves)
365: Output Parameter:
366: . remoteOffsets - Offsets for point data on remote processes (these are offsets from the root section), or NULL
368: Level: developer
370: Fortran Notes:
371: In Fortran, use PetscSFCreateRemoteOffsetsF90()
373: .seealso: `PetscSF`, `PetscSFCreate()`
374: @*/
375: PetscErrorCode PetscSFCreateRemoteOffsets(PetscSF sf, PetscSection rootSection, PetscSection leafSection, PetscInt **remoteOffsets)
376: {
377: PetscSF embedSF;
378: const PetscInt *indices;
379: IS selected;
380: PetscInt numRoots, rpStart = 0, rpEnd = 0, lpStart = 0, lpEnd = 0;
382: PetscFunctionBegin;
383: *remoteOffsets = NULL;
384: PetscCall(PetscSFGetGraph(sf, &numRoots, NULL, NULL, NULL));
385: if (numRoots < 0) PetscFunctionReturn(PETSC_SUCCESS);
386: PetscCall(PetscLogEventBegin(PETSCSF_RemoteOff, sf, 0, 0, 0));
387: PetscCall(PetscSectionGetChart(rootSection, &rpStart, &rpEnd));
388: PetscCall(PetscSectionGetChart(leafSection, &lpStart, &lpEnd));
389: PetscCall(ISCreateStride(PETSC_COMM_SELF, rpEnd - rpStart, rpStart, 1, &selected));
390: PetscCall(ISGetIndices(selected, &indices));
391: PetscCall(PetscSFCreateEmbeddedRootSF(sf, rpEnd - rpStart, indices, &embedSF));
392: PetscCall(ISRestoreIndices(selected, &indices));
393: PetscCall(ISDestroy(&selected));
394: PetscCall(PetscCalloc1(lpEnd - lpStart, remoteOffsets));
395: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
396: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
397: PetscCall(PetscSFDestroy(&embedSF));
398: PetscCall(PetscLogEventEnd(PETSCSF_RemoteOff, sf, 0, 0, 0));
399: PetscFunctionReturn(PETSC_SUCCESS);
400: }
402: /*@C
403: PetscSFCreateSectionSF - Create an expanded `PetscSF` of dofs, assuming the input `PetscSF` relates points
405: Collective
407: Input Parameters:
408: + sf - The `PetscSF`
409: . rootSection - Data layout of remote points for outgoing data (this is usually the serial section)
410: . remoteOffsets - Offsets for point data on remote processes (these are offsets from the root section), or NULL
411: - leafSection - Data layout of local points for incoming data (this is the distributed section)
413: Output Parameter:
414: . sectionSF - The new `PetscSF`
416: Level: advanced
418: Notes:
419: `remoteOffsets` can be NULL if `sf` does not reference any points in leafSection
421: Fortran Notes:
422: In Fortran, use PetscSFCreateSectionSFF90()
424: .seealso: `PetscSF`, `PetscSFCreate()`
425: @*/
426: PetscErrorCode PetscSFCreateSectionSF(PetscSF sf, PetscSection rootSection, PetscInt remoteOffsets[], PetscSection leafSection, PetscSF *sectionSF)
427: {
428: MPI_Comm comm;
429: const PetscInt *localPoints;
430: const PetscSFNode *remotePoints;
431: PetscInt lpStart, lpEnd;
432: PetscInt numRoots, numSectionRoots, numPoints, numIndices = 0;
433: PetscInt *localIndices;
434: PetscSFNode *remoteIndices;
435: PetscInt i, ind;
437: PetscFunctionBegin;
439: PetscAssertPointer(rootSection, 2);
440: /* Cannot check PetscAssertPointer(remoteOffsets,3) because it can be NULL if sf does not reference any points in leafSection */
441: PetscAssertPointer(leafSection, 4);
442: PetscAssertPointer(sectionSF, 5);
443: PetscCall(PetscObjectGetComm((PetscObject)sf, &comm));
444: PetscCall(PetscSFCreate(comm, sectionSF));
445: PetscCall(PetscSectionGetChart(leafSection, &lpStart, &lpEnd));
446: PetscCall(PetscSectionGetStorageSize(rootSection, &numSectionRoots));
447: PetscCall(PetscSFGetGraph(sf, &numRoots, &numPoints, &localPoints, &remotePoints));
448: if (numRoots < 0) PetscFunctionReturn(PETSC_SUCCESS);
449: PetscCall(PetscLogEventBegin(PETSCSF_SectSF, sf, 0, 0, 0));
450: for (i = 0; i < numPoints; ++i) {
451: PetscInt localPoint = localPoints ? localPoints[i] : i;
452: PetscInt dof;
454: if ((localPoint >= lpStart) && (localPoint < lpEnd)) {
455: PetscCall(PetscSectionGetDof(leafSection, localPoint, &dof));
456: numIndices += dof < 0 ? 0 : dof;
457: }
458: }
459: PetscCall(PetscMalloc1(numIndices, &localIndices));
460: PetscCall(PetscMalloc1(numIndices, &remoteIndices));
461: /* Create new index graph */
462: for (i = 0, ind = 0; i < numPoints; ++i) {
463: PetscInt localPoint = localPoints ? localPoints[i] : i;
464: PetscInt rank = remotePoints[i].rank;
466: if ((localPoint >= lpStart) && (localPoint < lpEnd)) {
467: PetscInt remoteOffset = remoteOffsets[localPoint - lpStart];
468: PetscInt loff, dof, d;
470: PetscCall(PetscSectionGetOffset(leafSection, localPoint, &loff));
471: PetscCall(PetscSectionGetDof(leafSection, localPoint, &dof));
472: for (d = 0; d < dof; ++d, ++ind) {
473: localIndices[ind] = loff + d;
474: remoteIndices[ind].rank = rank;
475: remoteIndices[ind].index = remoteOffset + d;
476: }
477: }
478: }
479: PetscCheck(numIndices == ind, comm, PETSC_ERR_PLIB, "Inconsistency in indices, %" PetscInt_FMT " should be %" PetscInt_FMT, ind, numIndices);
480: PetscCall(PetscSFSetGraph(*sectionSF, numSectionRoots, numIndices, localIndices, PETSC_OWN_POINTER, remoteIndices, PETSC_OWN_POINTER));
481: PetscCall(PetscSFSetUp(*sectionSF));
482: PetscCall(PetscLogEventEnd(PETSCSF_SectSF, sf, 0, 0, 0));
483: PetscFunctionReturn(PETSC_SUCCESS);
484: }
486: /*@C
487: PetscSFCreateFromLayouts - Creates a parallel star forest mapping two `PetscLayout` objects
489: Collective
491: Input Parameters:
492: + rmap - `PetscLayout` defining the global root space
493: - lmap - `PetscLayout` defining the global leaf space
495: Output Parameter:
496: . sf - The parallel star forest
498: Level: intermediate
500: .seealso: `PetscSF`, `PetscSFCreate()`, `PetscLayoutCreate()`, `PetscSFSetGraphLayout()`
501: @*/
502: PetscErrorCode PetscSFCreateFromLayouts(PetscLayout rmap, PetscLayout lmap, PetscSF *sf)
503: {
504: PetscInt i, nroots, nleaves = 0;
505: PetscInt rN, lst, len;
506: PetscMPIInt owner = -1;
507: PetscSFNode *remote;
508: MPI_Comm rcomm = rmap->comm;
509: MPI_Comm lcomm = lmap->comm;
510: PetscMPIInt flg;
512: PetscFunctionBegin;
513: PetscAssertPointer(sf, 3);
514: PetscCheck(rmap->setupcalled, rcomm, PETSC_ERR_ARG_WRONGSTATE, "Root layout not setup");
515: PetscCheck(lmap->setupcalled, lcomm, PETSC_ERR_ARG_WRONGSTATE, "Leaf layout not setup");
516: PetscCallMPI(MPI_Comm_compare(rcomm, lcomm, &flg));
517: PetscCheck(flg == MPI_CONGRUENT || flg == MPI_IDENT, rcomm, PETSC_ERR_SUP, "cannot map two layouts with non-matching communicators");
518: PetscCall(PetscSFCreate(rcomm, sf));
519: PetscCall(PetscLayoutGetLocalSize(rmap, &nroots));
520: PetscCall(PetscLayoutGetSize(rmap, &rN));
521: PetscCall(PetscLayoutGetRange(lmap, &lst, &len));
522: PetscCall(PetscMalloc1(len - lst, &remote));
523: for (i = lst; i < len && i < rN; i++) {
524: if (owner < -1 || i >= rmap->range[owner + 1]) PetscCall(PetscLayoutFindOwner(rmap, i, &owner));
525: remote[nleaves].rank = owner;
526: remote[nleaves].index = i - rmap->range[owner];
527: nleaves++;
528: }
529: PetscCall(PetscSFSetGraph(*sf, nroots, nleaves, NULL, PETSC_OWN_POINTER, remote, PETSC_COPY_VALUES));
530: PetscCall(PetscFree(remote));
531: PetscFunctionReturn(PETSC_SUCCESS);
532: }
534: /* TODO: handle nooffprocentries like MatZeroRowsMapLocal_Private, since this code is the same */
535: PetscErrorCode PetscLayoutMapLocal(PetscLayout map, PetscInt N, const PetscInt idxs[], PetscInt *on, PetscInt **oidxs, PetscInt **ogidxs)
536: {
537: PetscInt *owners = map->range;
538: PetscInt n = map->n;
539: PetscSF sf;
540: PetscInt *lidxs, *work = NULL;
541: PetscSFNode *ridxs;
542: PetscMPIInt rank, p = 0;
543: PetscInt r, len = 0;
545: PetscFunctionBegin;
546: if (on) *on = 0; /* squelch -Wmaybe-uninitialized */
547: /* Create SF where leaves are input idxs and roots are owned idxs */
548: PetscCallMPI(MPI_Comm_rank(map->comm, &rank));
549: PetscCall(PetscMalloc1(n, &lidxs));
550: for (r = 0; r < n; ++r) lidxs[r] = -1;
551: PetscCall(PetscMalloc1(N, &ridxs));
552: for (r = 0; r < N; ++r) {
553: const PetscInt idx = idxs[r];
554: 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);
555: if (idx < owners[p] || owners[p + 1] <= idx) { /* short-circuit the search if the last p owns this idx too */
556: PetscCall(PetscLayoutFindOwner(map, idx, &p));
557: }
558: ridxs[r].rank = p;
559: ridxs[r].index = idxs[r] - owners[p];
560: }
561: PetscCall(PetscSFCreate(map->comm, &sf));
562: PetscCall(PetscSFSetGraph(sf, n, N, NULL, PETSC_OWN_POINTER, ridxs, PETSC_OWN_POINTER));
563: PetscCall(PetscSFReduceBegin(sf, MPIU_INT, (PetscInt *)idxs, lidxs, MPI_LOR));
564: PetscCall(PetscSFReduceEnd(sf, MPIU_INT, (PetscInt *)idxs, lidxs, MPI_LOR));
565: if (ogidxs) { /* communicate global idxs */
566: PetscInt cum = 0, start, *work2;
568: PetscCall(PetscMalloc1(n, &work));
569: PetscCall(PetscCalloc1(N, &work2));
570: for (r = 0; r < N; ++r)
571: if (idxs[r] >= 0) cum++;
572: PetscCallMPI(MPI_Scan(&cum, &start, 1, MPIU_INT, MPI_SUM, map->comm));
573: start -= cum;
574: cum = 0;
575: for (r = 0; r < N; ++r)
576: if (idxs[r] >= 0) work2[r] = start + cum++;
577: PetscCall(PetscSFReduceBegin(sf, MPIU_INT, work2, work, MPI_REPLACE));
578: PetscCall(PetscSFReduceEnd(sf, MPIU_INT, work2, work, MPI_REPLACE));
579: PetscCall(PetscFree(work2));
580: }
581: PetscCall(PetscSFDestroy(&sf));
582: /* Compress and put in indices */
583: for (r = 0; r < n; ++r)
584: if (lidxs[r] >= 0) {
585: if (work) work[len] = work[r];
586: lidxs[len++] = r;
587: }
588: if (on) *on = len;
589: if (oidxs) *oidxs = lidxs;
590: if (ogidxs) *ogidxs = work;
591: PetscFunctionReturn(PETSC_SUCCESS);
592: }
594: /*@
595: PetscSFCreateByMatchingIndices - Create `PetscSF` by matching root and leaf indices
597: Collective
599: Input Parameters:
600: + layout - `PetscLayout` defining the global index space and the rank that brokers each index
601: . numRootIndices - size of rootIndices
602: . rootIndices - `PetscInt` array of global indices of which this process requests ownership
603: . rootLocalIndices - root local index permutation (NULL if no permutation)
604: . rootLocalOffset - offset to be added to root local indices
605: . numLeafIndices - size of leafIndices
606: . leafIndices - `PetscInt` array of global indices with which this process requires data associated
607: . leafLocalIndices - leaf local index permutation (NULL if no permutation)
608: - leafLocalOffset - offset to be added to leaf local indices
610: Output Parameters:
611: + sfA - star forest representing the communication pattern from the layout space to the leaf space (NULL if not needed)
612: - sf - star forest representing the communication pattern from the root space to the leaf space
614: Level: advanced
616: Example 1:
617: .vb
618: rank : 0 1 2
619: rootIndices : [1 0 2] [3] [3]
620: rootLocalOffset : 100 200 300
621: layout : [0 1] [2] [3]
622: leafIndices : [0] [2] [0 3]
623: leafLocalOffset : 400 500 600
625: would build the following PetscSF
627: [0] 400 <- (0,101)
628: [1] 500 <- (0,102)
629: [2] 600 <- (0,101)
630: [2] 601 <- (2,300)
631: .ve
633: Example 2:
634: .vb
635: rank : 0 1 2
636: rootIndices : [1 0 2] [3] [3]
637: rootLocalOffset : 100 200 300
638: layout : [0 1] [2] [3]
639: leafIndices : rootIndices rootIndices rootIndices
640: leafLocalOffset : rootLocalOffset rootLocalOffset rootLocalOffset
642: would build the following PetscSF
644: [1] 200 <- (2,300)
645: .ve
647: Example 3:
648: .vb
649: No process requests ownership of global index 1, but no process needs it.
651: rank : 0 1 2
652: numRootIndices : 2 1 1
653: rootIndices : [0 2] [3] [3]
654: rootLocalOffset : 100 200 300
655: layout : [0 1] [2] [3]
656: numLeafIndices : 1 1 2
657: leafIndices : [0] [2] [0 3]
658: leafLocalOffset : 400 500 600
660: would build the following PetscSF
662: [0] 400 <- (0,100)
663: [1] 500 <- (0,101)
664: [2] 600 <- (0,100)
665: [2] 601 <- (2,300)
666: .ve
668: Notes:
669: The layout parameter represents any partitioning of [0, N), where N is the total number of global indices, and its
670: local size can be set to `PETSC_DECIDE`.
672: If a global index x lies in the partition owned by process i, each process whose rootIndices contains x requests
673: ownership of x and sends its own rank and the local index of x to process i.
674: If multiple processes request ownership of x, the one with the highest rank is to own x.
675: Process i then broadcasts the ownership information, so that each process whose leafIndices contains x knows the
676: ownership information of x.
677: The output sf is constructed by associating each leaf point to a root point in this way.
679: Suppose there is point data ordered according to the global indices and partitioned according to the given layout.
680: The optional output `PetscSF` object sfA can be used to push such data to leaf points.
682: All indices in rootIndices and leafIndices must lie in the layout range. The union (over all processes) of rootIndices
683: must cover that of leafIndices, but need not cover the entire layout.
685: If (leafIndices, leafLocalIndices, leafLocalOffset) == (rootIndices, rootLocalIndices, rootLocalOffset), the output
686: star forest is almost identity, so will only include non-trivial part of the map.
688: Developer Notes:
689: Current approach of a process of the highest rank gaining the ownership may cause load imbalance; consider using
690: hash(rank, root_local_index) as the bid for the ownership determination.
692: .seealso: `PetscSF`, `PetscSFCreate()`
693: @*/
694: 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)
695: {
696: MPI_Comm comm = layout->comm;
697: PetscMPIInt size, rank;
698: PetscSF sf1;
699: PetscSFNode *owners, *buffer, *iremote;
700: PetscInt *ilocal, nleaves, N, n, i;
701: #if defined(PETSC_USE_DEBUG)
702: PetscInt N1;
703: #endif
704: PetscBool flag;
706: PetscFunctionBegin;
707: if (rootIndices) PetscAssertPointer(rootIndices, 3);
708: if (rootLocalIndices) PetscAssertPointer(rootLocalIndices, 4);
709: if (leafIndices) PetscAssertPointer(leafIndices, 7);
710: if (leafLocalIndices) PetscAssertPointer(leafLocalIndices, 8);
711: if (sfA) PetscAssertPointer(sfA, 10);
712: PetscAssertPointer(sf, 11);
713: PetscCheck(numRootIndices >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "numRootIndices (%" PetscInt_FMT ") must be non-negative", numRootIndices);
714: PetscCheck(numLeafIndices >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "numLeafIndices (%" PetscInt_FMT ") must be non-negative", numLeafIndices);
715: PetscCallMPI(MPI_Comm_size(comm, &size));
716: PetscCallMPI(MPI_Comm_rank(comm, &rank));
717: PetscCall(PetscLayoutSetUp(layout));
718: PetscCall(PetscLayoutGetSize(layout, &N));
719: PetscCall(PetscLayoutGetLocalSize(layout, &n));
720: flag = (PetscBool)(leafIndices == rootIndices);
721: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &flag, 1, MPIU_BOOL, MPI_LAND, comm));
722: PetscCheck(!flag || numLeafIndices == numRootIndices, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "leafIndices == rootIndices, but numLeafIndices (%" PetscInt_FMT ") != numRootIndices(%" PetscInt_FMT ")", numLeafIndices, numRootIndices);
723: #if defined(PETSC_USE_DEBUG)
724: N1 = PETSC_INT_MIN;
725: for (i = 0; i < numRootIndices; i++)
726: if (rootIndices[i] > N1) N1 = rootIndices[i];
727: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &N1, 1, MPIU_INT, MPI_MAX, comm));
728: PetscCheck(N1 < N, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Max. root index (%" PetscInt_FMT ") out of layout range [0,%" PetscInt_FMT ")", N1, N);
729: if (!flag) {
730: N1 = PETSC_INT_MIN;
731: for (i = 0; i < numLeafIndices; i++)
732: if (leafIndices[i] > N1) N1 = leafIndices[i];
733: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &N1, 1, MPIU_INT, MPI_MAX, comm));
734: PetscCheck(N1 < N, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Max. leaf index (%" PetscInt_FMT ") out of layout range [0,%" PetscInt_FMT ")", N1, N);
735: }
736: #endif
737: /* Reduce: owners -> buffer */
738: PetscCall(PetscMalloc1(n, &buffer));
739: PetscCall(PetscSFCreate(comm, &sf1));
740: PetscCall(PetscSFSetFromOptions(sf1));
741: PetscCall(PetscSFSetGraphLayout(sf1, layout, numRootIndices, NULL, PETSC_OWN_POINTER, rootIndices));
742: PetscCall(PetscMalloc1(numRootIndices, &owners));
743: for (i = 0; i < numRootIndices; ++i) {
744: owners[i].rank = rank;
745: owners[i].index = rootLocalOffset + (rootLocalIndices ? rootLocalIndices[i] : i);
746: }
747: for (i = 0; i < n; ++i) {
748: buffer[i].index = -1;
749: buffer[i].rank = -1;
750: }
751: PetscCall(PetscSFReduceBegin(sf1, MPIU_SF_NODE, owners, buffer, MPI_MAXLOC));
752: PetscCall(PetscSFReduceEnd(sf1, MPIU_SF_NODE, owners, buffer, MPI_MAXLOC));
753: /* Bcast: buffer -> owners */
754: if (!flag) {
755: /* leafIndices is different from rootIndices */
756: PetscCall(PetscFree(owners));
757: PetscCall(PetscSFSetGraphLayout(sf1, layout, numLeafIndices, NULL, PETSC_OWN_POINTER, leafIndices));
758: PetscCall(PetscMalloc1(numLeafIndices, &owners));
759: }
760: PetscCall(PetscSFBcastBegin(sf1, MPIU_SF_NODE, buffer, owners, MPI_REPLACE));
761: PetscCall(PetscSFBcastEnd(sf1, MPIU_SF_NODE, buffer, owners, MPI_REPLACE));
762: 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]);
763: PetscCall(PetscFree(buffer));
764: if (sfA) {
765: *sfA = sf1;
766: } else PetscCall(PetscSFDestroy(&sf1));
767: /* Create sf */
768: if (flag && rootLocalIndices == leafLocalIndices && leafLocalOffset == rootLocalOffset) {
769: /* leaf space == root space */
770: for (i = 0, nleaves = 0; i < numLeafIndices; ++i)
771: if (owners[i].rank != rank) ++nleaves;
772: PetscCall(PetscMalloc1(nleaves, &ilocal));
773: PetscCall(PetscMalloc1(nleaves, &iremote));
774: for (i = 0, nleaves = 0; i < numLeafIndices; ++i) {
775: if (owners[i].rank != rank) {
776: ilocal[nleaves] = leafLocalOffset + i;
777: iremote[nleaves].rank = owners[i].rank;
778: iremote[nleaves].index = owners[i].index;
779: ++nleaves;
780: }
781: }
782: PetscCall(PetscFree(owners));
783: } else {
784: nleaves = numLeafIndices;
785: PetscCall(PetscMalloc1(nleaves, &ilocal));
786: for (i = 0; i < nleaves; ++i) ilocal[i] = leafLocalOffset + (leafLocalIndices ? leafLocalIndices[i] : i);
787: iremote = owners;
788: }
789: PetscCall(PetscSFCreate(comm, sf));
790: PetscCall(PetscSFSetFromOptions(*sf));
791: PetscCall(PetscSFSetGraph(*sf, rootLocalOffset + numRootIndices, nleaves, ilocal, PETSC_OWN_POINTER, iremote, PETSC_OWN_POINTER));
792: PetscFunctionReturn(PETSC_SUCCESS);
793: }
795: /*@
796: PetscSFMerge - append/merge indices of `sfb` into `sfa`, with preference for `sfb`
798: Collective
800: Input Parameters:
801: + sfa - default `PetscSF`
802: - sfb - additional edges to add/replace edges in sfa
804: Output Parameter:
805: . merged - new `PetscSF` with combined edges
807: Level: intermediate
809: .seealso: `PetscSFCompose()`
810: @*/
811: PetscErrorCode PetscSFMerge(PetscSF sfa, PetscSF sfb, PetscSF *merged)
812: {
813: PetscInt maxleaf;
815: PetscFunctionBegin;
818: PetscCheckSameComm(sfa, 1, sfb, 2);
819: PetscAssertPointer(merged, 3);
820: {
821: PetscInt aleaf, bleaf;
822: PetscCall(PetscSFGetLeafRange(sfa, NULL, &aleaf));
823: PetscCall(PetscSFGetLeafRange(sfb, NULL, &bleaf));
824: maxleaf = PetscMax(aleaf, bleaf) + 1; // One more than the last index
825: }
826: PetscInt *clocal, aroots, aleaves, broots, bleaves;
827: PetscSFNode *cremote;
828: const PetscInt *alocal, *blocal;
829: const PetscSFNode *aremote, *bremote;
830: PetscCall(PetscMalloc2(maxleaf, &clocal, maxleaf, &cremote));
831: for (PetscInt i = 0; i < maxleaf; i++) clocal[i] = -1;
832: PetscCall(PetscSFGetGraph(sfa, &aroots, &aleaves, &alocal, &aremote));
833: PetscCall(PetscSFGetGraph(sfb, &broots, &bleaves, &blocal, &bremote));
834: PetscCheck(aroots == broots, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Both sfa and sfb must have the same root space");
835: for (PetscInt i = 0; i < aleaves; i++) {
836: PetscInt a = alocal ? alocal[i] : i;
837: clocal[a] = a;
838: cremote[a] = aremote[i];
839: }
840: for (PetscInt i = 0; i < bleaves; i++) {
841: PetscInt b = blocal ? blocal[i] : i;
842: clocal[b] = b;
843: cremote[b] = bremote[i];
844: }
845: PetscInt nleaves = 0;
846: for (PetscInt i = 0; i < maxleaf; i++) {
847: if (clocal[i] < 0) continue;
848: clocal[nleaves] = clocal[i];
849: cremote[nleaves] = cremote[i];
850: nleaves++;
851: }
852: PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)sfa), merged));
853: PetscCall(PetscSFSetGraph(*merged, aroots, nleaves, clocal, PETSC_COPY_VALUES, cremote, PETSC_COPY_VALUES));
854: PetscCall(PetscFree2(clocal, cremote));
855: PetscFunctionReturn(PETSC_SUCCESS);
856: }
858: /*@
859: PetscSFCreateStridedSF - Create an `PetscSF` to communicate interleaved blocks of data
861: Collective
863: Input Parameters:
864: + sf - star forest
865: . bs - stride
866: . ldr - leading dimension of root space
867: - ldl - leading dimension of leaf space
869: Output Parameter:
870: . vsf - the new `PetscSF`
872: Level: intermediate
874: Notes:
875: This can be useful to perform communications on blocks of right-hand sides. For example, the calling sequence
876: .vb
877: c_datatype *roots, *leaves;
878: for i in [0,bs) do
879: PetscSFBcastBegin(sf, mpi_datatype, roots + i*ldr, leaves + i*ldl, op)
880: PetscSFBcastEnd(sf, mpi_datatype, roots + i*ldr, leaves + i*ldl, op)
881: .ve
882: is equivalent to
883: .vb
884: c_datatype *roots, *leaves;
885: PetscSFCreateStridedSF(sf, bs, ldr, ldl, &vsf)
886: PetscSFBcastBegin(vsf, mpi_datatype, roots, leaves, op)
887: PetscSFBcastEnd(vsf, mpi_datatype, roots, leaves, op)
888: .ve
890: Developer Notes:
891: Should this functionality be handled with a new API instead of creating a new object?
893: .seealso: `PetscSF`, `PetscSFCreate()`, `PetscSFSetGraph()`
894: @*/
895: PetscErrorCode PetscSFCreateStridedSF(PetscSF sf, PetscInt bs, PetscInt ldr, PetscInt ldl, PetscSF *vsf)
896: {
897: PetscSF rankssf;
898: const PetscSFNode *iremote, *sfrremote;
899: PetscSFNode *viremote;
900: const PetscInt *ilocal;
901: PetscInt *vilocal = NULL, *ldrs;
902: PetscInt nranks, nr, nl, vnr, vnl, maxl;
903: PetscMPIInt rank;
904: MPI_Comm comm;
905: PetscSFType sftype;
907: PetscFunctionBegin;
910: PetscAssertPointer(vsf, 5);
911: if (bs == 1) {
912: PetscCall(PetscObjectReference((PetscObject)sf));
913: *vsf = sf;
914: PetscFunctionReturn(PETSC_SUCCESS);
915: }
916: PetscCall(PetscSFSetUp(sf));
917: PetscCall(PetscObjectGetComm((PetscObject)sf, &comm));
918: PetscCallMPI(MPI_Comm_rank(comm, &rank));
919: PetscCall(PetscSFGetGraph(sf, &nr, &nl, &ilocal, &iremote));
920: PetscCall(PetscSFGetLeafRange(sf, NULL, &maxl));
921: maxl += 1;
922: if (ldl == PETSC_DECIDE) ldl = maxl;
923: if (ldr == PETSC_DECIDE) ldr = nr;
924: 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);
925: 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);
926: vnr = nr * bs;
927: vnl = nl * bs;
928: PetscCall(PetscMalloc1(vnl, &viremote));
929: PetscCall(PetscMalloc1(vnl, &vilocal));
931: /* Communicate root leading dimensions to leaf ranks */
932: PetscCall(PetscSFGetRanksSF(sf, &rankssf));
933: PetscCall(PetscSFGetGraph(rankssf, NULL, &nranks, NULL, &sfrremote));
934: PetscCall(PetscMalloc1(nranks, &ldrs));
935: PetscCall(PetscSFBcastBegin(rankssf, MPIU_INT, &ldr, ldrs, MPI_REPLACE));
936: PetscCall(PetscSFBcastEnd(rankssf, MPIU_INT, &ldr, ldrs, MPI_REPLACE));
938: for (PetscInt i = 0, rold = -1, lda = -1; i < nl; i++) {
939: const PetscInt r = iremote[i].rank;
940: const PetscInt ii = iremote[i].index;
942: if (r == rank) lda = ldr;
943: else if (rold != r) {
944: PetscInt j;
946: for (j = 0; j < nranks; j++)
947: if (sfrremote[j].rank == r) break;
948: PetscCheck(j < nranks, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Unable to locate neighbor rank %" PetscInt_FMT, r);
949: lda = ldrs[j];
950: }
951: rold = r;
952: for (PetscInt v = 0; v < bs; v++) {
953: viremote[v * nl + i].rank = r;
954: viremote[v * nl + i].index = v * lda + ii;
955: vilocal[v * nl + i] = v * ldl + (ilocal ? ilocal[i] : i);
956: }
957: }
958: PetscCall(PetscFree(ldrs));
959: PetscCall(PetscSFCreate(comm, vsf));
960: PetscCall(PetscSFGetType(sf, &sftype));
961: PetscCall(PetscSFSetType(*vsf, sftype));
962: PetscCall(PetscSFSetGraph(*vsf, vnr, vnl, vilocal, PETSC_OWN_POINTER, viremote, PETSC_OWN_POINTER));
963: PetscFunctionReturn(PETSC_SUCCESS);
964: }