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;
233: PetscFunctionBegin;
234: PetscCall(PetscLogEventBegin(PETSCSF_DistSect, sf, 0, 0, 0));
235: PetscCall(PetscSectionGetNumFields(rootSection, &numFields));
236: if (numFields) {
237: IS perm;
239: /* PetscSectionSetNumFields() calls PetscSectionReset(), which destroys
240: leafSection->perm. To keep this permutation set by the user, we grab
241: the reference before calling PetscSectionSetNumFields() and set it
242: back after. */
243: PetscCall(PetscSectionGetPermutation(leafSection, &perm));
244: PetscCall(PetscObjectReference((PetscObject)perm));
245: PetscCall(PetscSectionSetNumFields(leafSection, numFields));
246: PetscCall(PetscSectionSetPermutation(leafSection, perm));
247: PetscCall(ISDestroy(&perm));
248: }
249: PetscCall(PetscMalloc1(numFields + 2, &sub));
250: sub[1] = rootSection->bc ? PETSC_TRUE : PETSC_FALSE;
251: for (f = 0; f < numFields; ++f) {
252: PetscSectionSym sym, dsym = NULL;
253: const char *name = NULL;
254: PetscInt numComp = 0;
256: sub[2 + f] = rootSection->field[f]->bc ? PETSC_TRUE : PETSC_FALSE;
257: PetscCall(PetscSectionGetFieldComponents(rootSection, f, &numComp));
258: PetscCall(PetscSectionGetFieldName(rootSection, f, &name));
259: PetscCall(PetscSectionGetFieldSym(rootSection, f, &sym));
260: if (sym) PetscCall(PetscSectionSymDistribute(sym, sf, &dsym));
261: PetscCall(PetscSectionSetFieldComponents(leafSection, f, numComp));
262: PetscCall(PetscSectionSetFieldName(leafSection, f, name));
263: PetscCall(PetscSectionSetFieldSym(leafSection, f, dsym));
264: PetscCall(PetscSectionSymDestroy(&dsym));
265: for (c = 0; c < rootSection->numFieldComponents[f]; ++c) {
266: PetscCall(PetscSectionGetComponentName(rootSection, f, c, &name));
267: PetscCall(PetscSectionSetComponentName(leafSection, f, c, name));
268: }
269: }
270: PetscCall(PetscSectionGetChart(rootSection, &rpStart, &rpEnd));
271: PetscCall(PetscSFGetGraph(sf, &nroots, NULL, NULL, NULL));
272: rpEnd = PetscMin(rpEnd, nroots);
273: rpEnd = PetscMax(rpStart, rpEnd);
274: /* see if we can avoid creating the embedded SF, since it can cost more than an allreduce */
275: sub[0] = (PetscBool)(nroots != rpEnd - rpStart);
276: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, sub, (PetscMPIInt)(2 + numFields), MPIU_BOOL, MPI_LOR, PetscObjectComm((PetscObject)sf)));
277: if (sub[0]) {
278: PetscCall(ISCreateStride(PETSC_COMM_SELF, rpEnd - rpStart, rpStart, 1, &selected));
279: PetscCall(ISGetIndices(selected, &indices));
280: PetscCall(PetscSFCreateEmbeddedRootSF(sf, rpEnd - rpStart, indices, &embedSF));
281: PetscCall(ISRestoreIndices(selected, &indices));
282: PetscCall(ISDestroy(&selected));
283: } else {
284: PetscCall(PetscObjectReference((PetscObject)sf));
285: embedSF = sf;
286: }
287: PetscCall(PetscSFGetLeafRange(embedSF, &lpStart, &lpEnd));
288: lpEnd++;
290: PetscCall(PetscSectionSetChart(leafSection, lpStart, lpEnd));
292: /* Constrained dof section */
293: hasc = sub[1];
294: for (f = 0; f < numFields; ++f) hasc = (PetscBool)(hasc || sub[2 + f]);
296: /* Could fuse these at the cost of copies and extra allocation */
297: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->atlasDof, -lpStart), MPI_REPLACE));
298: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->atlasDof, -lpStart), MPI_REPLACE));
299: if (sub[1]) {
300: PetscCall(PetscSectionCheckConstraints_Private(rootSection));
301: PetscCall(PetscSectionCheckConstraints_Private(leafSection));
302: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->bc->atlasDof[-rpStart], &leafSection->bc->atlasDof[-lpStart], MPI_REPLACE));
303: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->bc->atlasDof[-rpStart], &leafSection->bc->atlasDof[-lpStart], MPI_REPLACE));
304: }
305: for (f = 0; f < numFields; ++f) {
306: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->field[f]->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->field[f]->atlasDof, -lpStart), MPI_REPLACE));
307: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->field[f]->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->field[f]->atlasDof, -lpStart), MPI_REPLACE));
308: if (sub[2 + f]) {
309: PetscCall(PetscSectionCheckConstraints_Private(rootSection->field[f]));
310: PetscCall(PetscSectionCheckConstraints_Private(leafSection->field[f]));
311: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasDof[-rpStart], &leafSection->field[f]->bc->atlasDof[-lpStart], MPI_REPLACE));
312: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasDof[-rpStart], &leafSection->field[f]->bc->atlasDof[-lpStart], MPI_REPLACE));
313: }
314: }
315: if (remoteOffsets) {
316: PetscCall(PetscMalloc1(lpEnd - lpStart, remoteOffsets));
317: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
318: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
319: }
320: PetscCall(PetscSectionInvalidateMaxDof_Internal(leafSection));
321: PetscCall(PetscSectionSetUp(leafSection));
322: if (hasc) { /* need to communicate bcIndices */
323: PetscSF bcSF;
324: PetscInt *rOffBc;
326: PetscCall(PetscMalloc1(lpEnd - lpStart, &rOffBc));
327: if (sub[1]) {
328: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
329: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
330: PetscCall(PetscSFCreateSectionSF(embedSF, rootSection->bc, rOffBc, leafSection->bc, &bcSF));
331: PetscCall(PetscSFBcastBegin(bcSF, MPIU_INT, rootSection->bcIndices, leafSection->bcIndices, MPI_REPLACE));
332: PetscCall(PetscSFBcastEnd(bcSF, MPIU_INT, rootSection->bcIndices, leafSection->bcIndices, MPI_REPLACE));
333: PetscCall(PetscSFDestroy(&bcSF));
334: }
335: for (f = 0; f < numFields; ++f) {
336: if (sub[2 + f]) {
337: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
338: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
339: PetscCall(PetscSFCreateSectionSF(embedSF, rootSection->field[f]->bc, rOffBc, leafSection->field[f]->bc, &bcSF));
340: PetscCall(PetscSFBcastBegin(bcSF, MPIU_INT, rootSection->field[f]->bcIndices, leafSection->field[f]->bcIndices, MPI_REPLACE));
341: PetscCall(PetscSFBcastEnd(bcSF, MPIU_INT, rootSection->field[f]->bcIndices, leafSection->field[f]->bcIndices, MPI_REPLACE));
342: PetscCall(PetscSFDestroy(&bcSF));
343: }
344: }
345: PetscCall(PetscFree(rOffBc));
346: }
347: PetscCall(PetscSFDestroy(&embedSF));
348: PetscCall(PetscFree(sub));
349: PetscCall(PetscLogEventEnd(PETSCSF_DistSect, sf, 0, 0, 0));
350: PetscFunctionReturn(PETSC_SUCCESS);
351: }
353: /*@C
354: PetscSFCreateRemoteOffsets - Create offsets for point data on remote processes
356: Collective
358: Input Parameters:
359: + sf - The `PetscSF`
360: . rootSection - Data layout of remote points for outgoing data (this is layout for SF roots)
361: - leafSection - Data layout of local points for incoming data (this is layout for SF leaves)
363: Output Parameter:
364: . remoteOffsets - Offsets for point data on remote processes (these are offsets from the root section), or NULL
366: Level: developer
368: Fortran Notes:
369: In Fortran, use PetscSFCreateRemoteOffsetsF90()
371: .seealso: `PetscSF`, `PetscSFCreate()`
372: @*/
373: PetscErrorCode PetscSFCreateRemoteOffsets(PetscSF sf, PetscSection rootSection, PetscSection leafSection, PetscInt **remoteOffsets)
374: {
375: PetscSF embedSF;
376: const PetscInt *indices;
377: IS selected;
378: PetscInt numRoots, rpStart = 0, rpEnd = 0, lpStart = 0, lpEnd = 0;
380: PetscFunctionBegin;
381: *remoteOffsets = NULL;
382: PetscCall(PetscSFGetGraph(sf, &numRoots, NULL, NULL, NULL));
383: if (numRoots < 0) PetscFunctionReturn(PETSC_SUCCESS);
384: PetscCall(PetscLogEventBegin(PETSCSF_RemoteOff, sf, 0, 0, 0));
385: PetscCall(PetscSectionGetChart(rootSection, &rpStart, &rpEnd));
386: PetscCall(PetscSectionGetChart(leafSection, &lpStart, &lpEnd));
387: PetscCall(ISCreateStride(PETSC_COMM_SELF, rpEnd - rpStart, rpStart, 1, &selected));
388: PetscCall(ISGetIndices(selected, &indices));
389: PetscCall(PetscSFCreateEmbeddedRootSF(sf, rpEnd - rpStart, indices, &embedSF));
390: PetscCall(ISRestoreIndices(selected, &indices));
391: PetscCall(ISDestroy(&selected));
392: PetscCall(PetscCalloc1(lpEnd - lpStart, remoteOffsets));
393: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
394: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
395: PetscCall(PetscSFDestroy(&embedSF));
396: PetscCall(PetscLogEventEnd(PETSCSF_RemoteOff, sf, 0, 0, 0));
397: PetscFunctionReturn(PETSC_SUCCESS);
398: }
400: /*@C
401: PetscSFCreateSectionSF - Create an expanded `PetscSF` of dofs, assuming the input `PetscSF` relates points
403: Collective
405: Input Parameters:
406: + sf - The `PetscSF`
407: . rootSection - Data layout of remote points for outgoing data (this is usually the serial section)
408: . remoteOffsets - Offsets for point data on remote processes (these are offsets from the root section), or NULL
409: - leafSection - Data layout of local points for incoming data (this is the distributed section)
411: Output Parameter:
412: . sectionSF - The new `PetscSF`
414: Level: advanced
416: Notes:
417: `remoteOffsets` can be NULL if `sf` does not reference any points in leafSection
419: Fortran Notes:
420: In Fortran, use PetscSFCreateSectionSFF90()
422: .seealso: `PetscSF`, `PetscSFCreate()`
423: @*/
424: PetscErrorCode PetscSFCreateSectionSF(PetscSF sf, PetscSection rootSection, PetscInt remoteOffsets[], PetscSection leafSection, PetscSF *sectionSF)
425: {
426: MPI_Comm comm;
427: const PetscInt *localPoints;
428: const PetscSFNode *remotePoints;
429: PetscInt lpStart, lpEnd;
430: PetscInt numRoots, numSectionRoots, numPoints, numIndices = 0;
431: PetscInt *localIndices;
432: PetscSFNode *remoteIndices;
433: PetscInt i, ind;
435: PetscFunctionBegin;
437: PetscAssertPointer(rootSection, 2);
438: /* Cannot check PetscAssertPointer(remoteOffsets,3) because it can be NULL if sf does not reference any points in leafSection */
439: PetscAssertPointer(leafSection, 4);
440: PetscAssertPointer(sectionSF, 5);
441: PetscCall(PetscObjectGetComm((PetscObject)sf, &comm));
442: PetscCall(PetscSFCreate(comm, sectionSF));
443: PetscCall(PetscSectionGetChart(leafSection, &lpStart, &lpEnd));
444: PetscCall(PetscSectionGetStorageSize(rootSection, &numSectionRoots));
445: PetscCall(PetscSFGetGraph(sf, &numRoots, &numPoints, &localPoints, &remotePoints));
446: if (numRoots < 0) PetscFunctionReturn(PETSC_SUCCESS);
447: PetscCall(PetscLogEventBegin(PETSCSF_SectSF, sf, 0, 0, 0));
448: for (i = 0; i < numPoints; ++i) {
449: PetscInt localPoint = localPoints ? localPoints[i] : i;
450: PetscInt dof;
452: if ((localPoint >= lpStart) && (localPoint < lpEnd)) {
453: PetscCall(PetscSectionGetDof(leafSection, localPoint, &dof));
454: numIndices += dof < 0 ? 0 : dof;
455: }
456: }
457: PetscCall(PetscMalloc1(numIndices, &localIndices));
458: PetscCall(PetscMalloc1(numIndices, &remoteIndices));
459: /* Create new index graph */
460: for (i = 0, ind = 0; i < numPoints; ++i) {
461: PetscInt localPoint = localPoints ? localPoints[i] : i;
462: PetscMPIInt rank = (PetscMPIInt)remotePoints[i].rank;
464: if ((localPoint >= lpStart) && (localPoint < lpEnd)) {
465: PetscInt remoteOffset = remoteOffsets[localPoint - lpStart];
466: PetscInt loff, dof, d;
468: PetscCall(PetscSectionGetOffset(leafSection, localPoint, &loff));
469: PetscCall(PetscSectionGetDof(leafSection, localPoint, &dof));
470: for (d = 0; d < dof; ++d, ++ind) {
471: localIndices[ind] = loff + d;
472: remoteIndices[ind].rank = rank;
473: remoteIndices[ind].index = remoteOffset + d;
474: }
475: }
476: }
477: PetscCheck(numIndices == ind, comm, PETSC_ERR_PLIB, "Inconsistency in indices, %" PetscInt_FMT " should be %" PetscInt_FMT, ind, numIndices);
478: PetscCall(PetscSFSetGraph(*sectionSF, numSectionRoots, numIndices, localIndices, PETSC_OWN_POINTER, remoteIndices, PETSC_OWN_POINTER));
479: PetscCall(PetscSFSetUp(*sectionSF));
480: PetscCall(PetscLogEventEnd(PETSCSF_SectSF, sf, 0, 0, 0));
481: PetscFunctionReturn(PETSC_SUCCESS);
482: }
484: /*@C
485: PetscSFCreateFromLayouts - Creates a parallel star forest mapping two `PetscLayout` objects
487: Collective
489: Input Parameters:
490: + rmap - `PetscLayout` defining the global root space
491: - lmap - `PetscLayout` defining the global leaf space
493: Output Parameter:
494: . sf - The parallel star forest
496: Level: intermediate
498: .seealso: `PetscSF`, `PetscSFCreate()`, `PetscLayoutCreate()`, `PetscSFSetGraphLayout()`
499: @*/
500: PetscErrorCode PetscSFCreateFromLayouts(PetscLayout rmap, PetscLayout lmap, PetscSF *sf)
501: {
502: PetscInt i, nroots, nleaves = 0;
503: PetscInt rN, lst, len;
504: PetscMPIInt owner = -1;
505: PetscSFNode *remote;
506: MPI_Comm rcomm = rmap->comm;
507: MPI_Comm lcomm = lmap->comm;
508: PetscMPIInt flg;
510: PetscFunctionBegin;
511: PetscAssertPointer(sf, 3);
512: PetscCheck(rmap->setupcalled, rcomm, PETSC_ERR_ARG_WRONGSTATE, "Root layout not setup");
513: PetscCheck(lmap->setupcalled, lcomm, PETSC_ERR_ARG_WRONGSTATE, "Leaf layout not setup");
514: PetscCallMPI(MPI_Comm_compare(rcomm, lcomm, &flg));
515: PetscCheck(flg == MPI_CONGRUENT || flg == MPI_IDENT, rcomm, PETSC_ERR_SUP, "cannot map two layouts with non-matching communicators");
516: PetscCall(PetscSFCreate(rcomm, sf));
517: PetscCall(PetscLayoutGetLocalSize(rmap, &nroots));
518: PetscCall(PetscLayoutGetSize(rmap, &rN));
519: PetscCall(PetscLayoutGetRange(lmap, &lst, &len));
520: PetscCall(PetscMalloc1(len - lst, &remote));
521: for (i = lst; i < len && i < rN; i++) {
522: if (owner < -1 || i >= rmap->range[owner + 1]) PetscCall(PetscLayoutFindOwner(rmap, i, &owner));
523: remote[nleaves].rank = owner;
524: remote[nleaves].index = i - rmap->range[owner];
525: nleaves++;
526: }
527: PetscCall(PetscSFSetGraph(*sf, nroots, nleaves, NULL, PETSC_OWN_POINTER, remote, PETSC_COPY_VALUES));
528: PetscCall(PetscFree(remote));
529: PetscFunctionReturn(PETSC_SUCCESS);
530: }
532: /* TODO: handle nooffprocentries like MatZeroRowsMapLocal_Private, since this code is the same */
533: PetscErrorCode PetscLayoutMapLocal(PetscLayout map, PetscInt N, const PetscInt idxs[], PetscInt *on, PetscInt **oidxs, PetscInt **ogidxs)
534: {
535: PetscInt *owners = map->range;
536: PetscInt n = map->n;
537: PetscSF sf;
538: PetscInt *lidxs, *work = NULL;
539: PetscSFNode *ridxs;
540: PetscMPIInt rank, p = 0;
541: PetscInt r, len = 0;
543: PetscFunctionBegin;
544: if (on) *on = 0; /* squelch -Wmaybe-uninitialized */
545: /* Create SF where leaves are input idxs and roots are owned idxs */
546: PetscCallMPI(MPI_Comm_rank(map->comm, &rank));
547: PetscCall(PetscMalloc1(n, &lidxs));
548: for (r = 0; r < n; ++r) lidxs[r] = -1;
549: PetscCall(PetscMalloc1(N, &ridxs));
550: for (r = 0; r < N; ++r) {
551: const PetscInt idx = idxs[r];
552: 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);
553: if (idx < owners[p] || owners[p + 1] <= idx) { /* short-circuit the search if the last p owns this idx too */
554: PetscCall(PetscLayoutFindOwner(map, idx, &p));
555: }
556: ridxs[r].rank = p;
557: ridxs[r].index = idxs[r] - owners[p];
558: }
559: PetscCall(PetscSFCreate(map->comm, &sf));
560: PetscCall(PetscSFSetGraph(sf, n, N, NULL, PETSC_OWN_POINTER, ridxs, PETSC_OWN_POINTER));
561: PetscCall(PetscSFReduceBegin(sf, MPIU_INT, (PetscInt *)idxs, lidxs, MPI_LOR));
562: PetscCall(PetscSFReduceEnd(sf, MPIU_INT, (PetscInt *)idxs, lidxs, MPI_LOR));
563: if (ogidxs) { /* communicate global idxs */
564: PetscInt cum = 0, start, *work2;
566: PetscCall(PetscMalloc1(n, &work));
567: PetscCall(PetscCalloc1(N, &work2));
568: for (r = 0; r < N; ++r)
569: if (idxs[r] >= 0) cum++;
570: PetscCallMPI(MPI_Scan(&cum, &start, 1, MPIU_INT, MPI_SUM, map->comm));
571: start -= cum;
572: cum = 0;
573: for (r = 0; r < N; ++r)
574: if (idxs[r] >= 0) work2[r] = start + cum++;
575: PetscCall(PetscSFReduceBegin(sf, MPIU_INT, work2, work, MPI_REPLACE));
576: PetscCall(PetscSFReduceEnd(sf, MPIU_INT, work2, work, MPI_REPLACE));
577: PetscCall(PetscFree(work2));
578: }
579: PetscCall(PetscSFDestroy(&sf));
580: /* Compress and put in indices */
581: for (r = 0; r < n; ++r)
582: if (lidxs[r] >= 0) {
583: if (work) work[len] = work[r];
584: lidxs[len++] = r;
585: }
586: if (on) *on = len;
587: if (oidxs) *oidxs = lidxs;
588: if (ogidxs) *ogidxs = work;
589: PetscFunctionReturn(PETSC_SUCCESS);
590: }
592: /*@
593: PetscSFCreateByMatchingIndices - Create `PetscSF` by matching root and leaf indices
595: Collective
597: Input Parameters:
598: + layout - `PetscLayout` defining the global index space and the rank that brokers each index
599: . numRootIndices - size of rootIndices
600: . rootIndices - `PetscInt` array of global indices of which this process requests ownership
601: . rootLocalIndices - root local index permutation (NULL if no permutation)
602: . rootLocalOffset - offset to be added to root local indices
603: . numLeafIndices - size of leafIndices
604: . leafIndices - `PetscInt` array of global indices with which this process requires data associated
605: . leafLocalIndices - leaf local index permutation (NULL if no permutation)
606: - leafLocalOffset - offset to be added to leaf local indices
608: Output Parameters:
609: + sfA - star forest representing the communication pattern from the layout space to the leaf space (NULL if not needed)
610: - sf - star forest representing the communication pattern from the root space to the leaf space
612: Level: advanced
614: Example 1:
615: .vb
616: rank : 0 1 2
617: rootIndices : [1 0 2] [3] [3]
618: rootLocalOffset : 100 200 300
619: layout : [0 1] [2] [3]
620: leafIndices : [0] [2] [0 3]
621: leafLocalOffset : 400 500 600
623: would build the following PetscSF
625: [0] 400 <- (0,101)
626: [1] 500 <- (0,102)
627: [2] 600 <- (0,101)
628: [2] 601 <- (2,300)
629: .ve
631: Example 2:
632: .vb
633: rank : 0 1 2
634: rootIndices : [1 0 2] [3] [3]
635: rootLocalOffset : 100 200 300
636: layout : [0 1] [2] [3]
637: leafIndices : rootIndices rootIndices rootIndices
638: leafLocalOffset : rootLocalOffset rootLocalOffset rootLocalOffset
640: would build the following PetscSF
642: [1] 200 <- (2,300)
643: .ve
645: Example 3:
646: .vb
647: No process requests ownership of global index 1, but no process needs it.
649: rank : 0 1 2
650: numRootIndices : 2 1 1
651: rootIndices : [0 2] [3] [3]
652: rootLocalOffset : 100 200 300
653: layout : [0 1] [2] [3]
654: numLeafIndices : 1 1 2
655: leafIndices : [0] [2] [0 3]
656: leafLocalOffset : 400 500 600
658: would build the following PetscSF
660: [0] 400 <- (0,100)
661: [1] 500 <- (0,101)
662: [2] 600 <- (0,100)
663: [2] 601 <- (2,300)
664: .ve
666: Notes:
667: The layout parameter represents any partitioning of [0, N), where N is the total number of global indices, and its
668: local size can be set to `PETSC_DECIDE`.
670: If a global index x lies in the partition owned by process i, each process whose rootIndices contains x requests
671: ownership of x and sends its own rank and the local index of x to process i.
672: If multiple processes request ownership of x, the one with the highest rank is to own x.
673: Process i then broadcasts the ownership information, so that each process whose leafIndices contains x knows the
674: ownership information of x.
675: The output sf is constructed by associating each leaf point to a root point in this way.
677: Suppose there is point data ordered according to the global indices and partitioned according to the given layout.
678: The optional output `PetscSF` object sfA can be used to push such data to leaf points.
680: All indices in rootIndices and leafIndices must lie in the layout range. The union (over all processes) of rootIndices
681: must cover that of leafIndices, but need not cover the entire layout.
683: If (leafIndices, leafLocalIndices, leafLocalOffset) == (rootIndices, rootLocalIndices, rootLocalOffset), the output
684: star forest is almost identity, so will only include non-trivial part of the map.
686: Developer Notes:
687: Current approach of a process of the highest rank gaining the ownership may cause load imbalance; consider using
688: hash(rank, root_local_index) as the bid for the ownership determination.
690: .seealso: `PetscSF`, `PetscSFCreate()`
691: @*/
692: 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)
693: {
694: MPI_Comm comm = layout->comm;
695: PetscMPIInt size, rank;
696: PetscSF sf1;
697: PetscSFNode *owners, *buffer, *iremote;
698: PetscInt *ilocal, nleaves, N, n, i;
699: #if defined(PETSC_USE_DEBUG)
700: PetscInt N1;
701: #endif
702: PetscBool flag;
704: PetscFunctionBegin;
705: if (rootIndices) PetscAssertPointer(rootIndices, 3);
706: if (rootLocalIndices) PetscAssertPointer(rootLocalIndices, 4);
707: if (leafIndices) PetscAssertPointer(leafIndices, 7);
708: if (leafLocalIndices) PetscAssertPointer(leafLocalIndices, 8);
709: if (sfA) PetscAssertPointer(sfA, 10);
710: PetscAssertPointer(sf, 11);
711: PetscCheck(numRootIndices >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "numRootIndices (%" PetscInt_FMT ") must be non-negative", numRootIndices);
712: PetscCheck(numLeafIndices >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "numLeafIndices (%" PetscInt_FMT ") must be non-negative", numLeafIndices);
713: PetscCallMPI(MPI_Comm_size(comm, &size));
714: PetscCallMPI(MPI_Comm_rank(comm, &rank));
715: PetscCall(PetscLayoutSetUp(layout));
716: PetscCall(PetscLayoutGetSize(layout, &N));
717: PetscCall(PetscLayoutGetLocalSize(layout, &n));
718: flag = (PetscBool)(leafIndices == rootIndices);
719: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &flag, 1, MPIU_BOOL, MPI_LAND, comm));
720: PetscCheck(!flag || numLeafIndices == numRootIndices, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "leafIndices == rootIndices, but numLeafIndices (%" PetscInt_FMT ") != numRootIndices(%" PetscInt_FMT ")", numLeafIndices, numRootIndices);
721: #if defined(PETSC_USE_DEBUG)
722: N1 = PETSC_INT_MIN;
723: for (i = 0; i < numRootIndices; i++)
724: if (rootIndices[i] > N1) N1 = rootIndices[i];
725: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &N1, 1, MPIU_INT, MPI_MAX, comm));
726: PetscCheck(N1 < N, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Max. root index (%" PetscInt_FMT ") out of layout range [0,%" PetscInt_FMT ")", N1, N);
727: if (!flag) {
728: N1 = PETSC_INT_MIN;
729: for (i = 0; i < numLeafIndices; i++)
730: if (leafIndices[i] > N1) N1 = leafIndices[i];
731: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &N1, 1, MPIU_INT, MPI_MAX, comm));
732: PetscCheck(N1 < N, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Max. leaf index (%" PetscInt_FMT ") out of layout range [0,%" PetscInt_FMT ")", N1, N);
733: }
734: #endif
735: /* Reduce: owners -> buffer */
736: PetscCall(PetscMalloc1(n, &buffer));
737: PetscCall(PetscSFCreate(comm, &sf1));
738: PetscCall(PetscSFSetFromOptions(sf1));
739: PetscCall(PetscSFSetGraphLayout(sf1, layout, numRootIndices, NULL, PETSC_OWN_POINTER, rootIndices));
740: PetscCall(PetscMalloc1(numRootIndices, &owners));
741: for (i = 0; i < numRootIndices; ++i) {
742: owners[i].rank = rank;
743: owners[i].index = rootLocalOffset + (rootLocalIndices ? rootLocalIndices[i] : i);
744: }
745: for (i = 0; i < n; ++i) {
746: buffer[i].index = -1;
747: buffer[i].rank = -1;
748: }
749: PetscCall(PetscSFReduceBegin(sf1, MPIU_SF_NODE, owners, buffer, MPI_MAXLOC));
750: PetscCall(PetscSFReduceEnd(sf1, MPIU_SF_NODE, owners, buffer, MPI_MAXLOC));
751: /* Bcast: buffer -> owners */
752: if (!flag) {
753: /* leafIndices is different from rootIndices */
754: PetscCall(PetscFree(owners));
755: PetscCall(PetscSFSetGraphLayout(sf1, layout, numLeafIndices, NULL, PETSC_OWN_POINTER, leafIndices));
756: PetscCall(PetscMalloc1(numLeafIndices, &owners));
757: }
758: PetscCall(PetscSFBcastBegin(sf1, MPIU_SF_NODE, buffer, owners, MPI_REPLACE));
759: PetscCall(PetscSFBcastEnd(sf1, MPIU_SF_NODE, buffer, owners, MPI_REPLACE));
760: 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]);
761: PetscCall(PetscFree(buffer));
762: if (sfA) {
763: *sfA = sf1;
764: } else PetscCall(PetscSFDestroy(&sf1));
765: /* Create sf */
766: if (flag && rootLocalIndices == leafLocalIndices && leafLocalOffset == rootLocalOffset) {
767: /* leaf space == root space */
768: for (i = 0, nleaves = 0; i < numLeafIndices; ++i)
769: if (owners[i].rank != rank) ++nleaves;
770: PetscCall(PetscMalloc1(nleaves, &ilocal));
771: PetscCall(PetscMalloc1(nleaves, &iremote));
772: for (i = 0, nleaves = 0; i < numLeafIndices; ++i) {
773: if (owners[i].rank != rank) {
774: ilocal[nleaves] = leafLocalOffset + i;
775: iremote[nleaves].rank = owners[i].rank;
776: iremote[nleaves].index = owners[i].index;
777: ++nleaves;
778: }
779: }
780: PetscCall(PetscFree(owners));
781: } else {
782: nleaves = numLeafIndices;
783: PetscCall(PetscMalloc1(nleaves, &ilocal));
784: for (i = 0; i < nleaves; ++i) ilocal[i] = leafLocalOffset + (leafLocalIndices ? leafLocalIndices[i] : i);
785: iremote = owners;
786: }
787: PetscCall(PetscSFCreate(comm, sf));
788: PetscCall(PetscSFSetFromOptions(*sf));
789: PetscCall(PetscSFSetGraph(*sf, rootLocalOffset + numRootIndices, nleaves, ilocal, PETSC_OWN_POINTER, iremote, PETSC_OWN_POINTER));
790: PetscFunctionReturn(PETSC_SUCCESS);
791: }
793: /*@
794: PetscSFMerge - append/merge indices of `sfb` into `sfa`, with preference for `sfb`
796: Collective
798: Input Parameters:
799: + sfa - default `PetscSF`
800: - sfb - additional edges to add/replace edges in sfa
802: Output Parameter:
803: . merged - new `PetscSF` with combined edges
805: Level: intermediate
807: .seealso: `PetscSFCompose()`
808: @*/
809: PetscErrorCode PetscSFMerge(PetscSF sfa, PetscSF sfb, PetscSF *merged)
810: {
811: PetscInt maxleaf;
813: PetscFunctionBegin;
816: PetscCheckSameComm(sfa, 1, sfb, 2);
817: PetscAssertPointer(merged, 3);
818: {
819: PetscInt aleaf, bleaf;
820: PetscCall(PetscSFGetLeafRange(sfa, NULL, &aleaf));
821: PetscCall(PetscSFGetLeafRange(sfb, NULL, &bleaf));
822: maxleaf = PetscMax(aleaf, bleaf) + 1; // One more than the last index
823: }
824: PetscInt *clocal, aroots, aleaves, broots, bleaves;
825: PetscSFNode *cremote;
826: const PetscInt *alocal, *blocal;
827: const PetscSFNode *aremote, *bremote;
828: PetscCall(PetscMalloc2(maxleaf, &clocal, maxleaf, &cremote));
829: for (PetscInt i = 0; i < maxleaf; i++) clocal[i] = -1;
830: PetscCall(PetscSFGetGraph(sfa, &aroots, &aleaves, &alocal, &aremote));
831: PetscCall(PetscSFGetGraph(sfb, &broots, &bleaves, &blocal, &bremote));
832: PetscCheck(aroots == broots, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Both sfa and sfb must have the same root space");
833: for (PetscInt i = 0; i < aleaves; i++) {
834: PetscInt a = alocal ? alocal[i] : i;
835: clocal[a] = a;
836: cremote[a] = aremote[i];
837: }
838: for (PetscInt i = 0; i < bleaves; i++) {
839: PetscInt b = blocal ? blocal[i] : i;
840: clocal[b] = b;
841: cremote[b] = bremote[i];
842: }
843: PetscInt nleaves = 0;
844: for (PetscInt i = 0; i < maxleaf; i++) {
845: if (clocal[i] < 0) continue;
846: clocal[nleaves] = clocal[i];
847: cremote[nleaves] = cremote[i];
848: nleaves++;
849: }
850: PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)sfa), merged));
851: PetscCall(PetscSFSetGraph(*merged, aroots, nleaves, clocal, PETSC_COPY_VALUES, cremote, PETSC_COPY_VALUES));
852: PetscCall(PetscFree2(clocal, cremote));
853: PetscFunctionReturn(PETSC_SUCCESS);
854: }
856: /*@
857: PetscSFCreateStridedSF - Create an `PetscSF` to communicate interleaved blocks of data
859: Collective
861: Input Parameters:
862: + sf - star forest
863: . bs - stride
864: . ldr - leading dimension of root space
865: - ldl - leading dimension of leaf space
867: Output Parameter:
868: . vsf - the new `PetscSF`
870: Level: intermediate
872: Notes:
873: This can be useful to perform communications on blocks of right-hand sides. For example, the calling sequence
874: .vb
875: c_datatype *roots, *leaves;
876: for i in [0,bs) do
877: PetscSFBcastBegin(sf, mpi_datatype, roots + i*ldr, leaves + i*ldl, op)
878: PetscSFBcastEnd(sf, mpi_datatype, roots + i*ldr, leaves + i*ldl, op)
879: .ve
880: is equivalent to
881: .vb
882: c_datatype *roots, *leaves;
883: PetscSFCreateStridedSF(sf, bs, ldr, ldl, &vsf)
884: PetscSFBcastBegin(vsf, mpi_datatype, roots, leaves, op)
885: PetscSFBcastEnd(vsf, mpi_datatype, roots, leaves, op)
886: .ve
888: Developer Notes:
889: Should this functionality be handled with a new API instead of creating a new object?
891: .seealso: `PetscSF`, `PetscSFCreate()`, `PetscSFSetGraph()`
892: @*/
893: PetscErrorCode PetscSFCreateStridedSF(PetscSF sf, PetscInt bs, PetscInt ldr, PetscInt ldl, PetscSF *vsf)
894: {
895: PetscSF rankssf;
896: const PetscSFNode *iremote, *sfrremote;
897: PetscSFNode *viremote;
898: const PetscInt *ilocal;
899: PetscInt *vilocal = NULL, *ldrs;
900: PetscInt nranks, nr, nl, vnr, vnl, maxl;
901: PetscMPIInt rank;
902: MPI_Comm comm;
903: PetscSFType sftype;
905: PetscFunctionBegin;
908: PetscAssertPointer(vsf, 5);
909: if (bs == 1) {
910: PetscCall(PetscObjectReference((PetscObject)sf));
911: *vsf = sf;
912: PetscFunctionReturn(PETSC_SUCCESS);
913: }
914: PetscCall(PetscSFSetUp(sf));
915: PetscCall(PetscObjectGetComm((PetscObject)sf, &comm));
916: PetscCallMPI(MPI_Comm_rank(comm, &rank));
917: PetscCall(PetscSFGetGraph(sf, &nr, &nl, &ilocal, &iremote));
918: PetscCall(PetscSFGetLeafRange(sf, NULL, &maxl));
919: maxl += 1;
920: if (ldl == PETSC_DECIDE) ldl = maxl;
921: if (ldr == PETSC_DECIDE) ldr = nr;
922: 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);
923: 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);
924: vnr = nr * bs;
925: vnl = nl * bs;
926: PetscCall(PetscMalloc1(vnl, &viremote));
927: PetscCall(PetscMalloc1(vnl, &vilocal));
929: /* Communicate root leading dimensions to leaf ranks */
930: PetscCall(PetscSFGetRanksSF(sf, &rankssf));
931: PetscCall(PetscSFGetGraph(rankssf, NULL, &nranks, NULL, &sfrremote));
932: PetscCall(PetscMalloc1(nranks, &ldrs));
933: PetscCall(PetscSFBcastBegin(rankssf, MPIU_INT, &ldr, ldrs, MPI_REPLACE));
934: PetscCall(PetscSFBcastEnd(rankssf, MPIU_INT, &ldr, ldrs, MPI_REPLACE));
936: for (PetscInt i = 0, rold = -1, lda = -1; i < nl; i++) {
937: const PetscMPIInt r = (PetscMPIInt)iremote[i].rank;
938: const PetscInt ii = iremote[i].index;
940: if (r == rank) lda = ldr;
941: else if (rold != r) {
942: PetscInt j;
944: for (j = 0; j < nranks; j++)
945: if (sfrremote[j].rank == r) break;
946: PetscCheck(j < nranks, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Unable to locate neighbor rank %d", r);
947: lda = ldrs[j];
948: }
949: rold = r;
950: for (PetscInt v = 0; v < bs; v++) {
951: viremote[v * nl + i].rank = r;
952: viremote[v * nl + i].index = v * lda + ii;
953: vilocal[v * nl + i] = v * ldl + (ilocal ? ilocal[i] : i);
954: }
955: }
956: PetscCall(PetscFree(ldrs));
957: PetscCall(PetscSFCreate(comm, vsf));
958: PetscCall(PetscSFGetType(sf, &sftype));
959: PetscCall(PetscSFSetType(*vsf, sftype));
960: PetscCall(PetscSFSetGraph(*vsf, vnr, vnl, vilocal, PETSC_OWN_POINTER, viremote, PETSC_OWN_POINTER));
961: PetscFunctionReturn(PETSC_SUCCESS);
962: }