Actual source code: sfutils.c
1: #include <petsc/private/sfimpl.h>
2: #include <petsc/private/sectionimpl.h>
4: /*@
5: PetscSFSetGraphLayout - Set a `PetscSF` communication pattern using global indices and a `PetscLayout`
7: Collective
9: Input Parameters:
10: + sf - star forest
11: . layout - `PetscLayout` defining the global space for roots, i.e. which roots are owned by each MPI process
12: . nleaves - number of leaf vertices on the current process, each of these references a root on any MPI process
13: . ilocal - locations of leaves in leafdata buffers, pass `NULL` for contiguous storage, that is the locations are in [0,`nleaves`)
14: . localmode - copy mode for `ilocal`
15: - gremote - root vertices in global numbering corresponding to the leaves
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: [](sec_petscsf), `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: PetscAssertPointer(layout, 2);
40: if (nleaves > 0 && ilocal) PetscAssertPointer(ilocal, 4);
41: if (nleaves > 0) PetscAssertPointer(gremote, 6);
42: PetscCall(PetscLayoutSetUp(layout));
43: PetscCall(PetscLayoutGetLocalSize(layout, &nroots));
44: PetscCall(PetscLayoutGetRanges(layout, &range));
45: PetscCall(PetscMalloc1(nleaves, &remote));
46: if (nleaves) ls = gremote[0] + 1;
47: for (i = 0; i < nleaves; i++) {
48: const PetscInt idx = gremote[i] - ls;
49: if (idx < 0 || idx >= ln) { /* short-circuit the search */
50: PetscCall(PetscLayoutFindOwnerIndex(layout, gremote[i], &lr, &remote[i].index));
51: remote[i].rank = lr;
52: ls = range[lr];
53: ln = range[lr + 1] - ls;
54: } else {
55: remote[i].rank = lr;
56: remote[i].index = idx;
57: }
58: }
59: PetscCall(PetscSFSetGraph(sf, nroots, nleaves, ilocal, localmode, remote, PETSC_OWN_POINTER));
60: PetscFunctionReturn(PETSC_SUCCESS);
61: }
63: /*@C
64: PetscSFGetGraphLayout - Get the global indices and `PetscLayout` that describe a `PetscSF`
66: Collective
68: Input Parameter:
69: . sf - star forest
71: Output Parameters:
72: + layout - `PetscLayout` defining the global space for roots
73: . nleaves - number of leaf vertices on the current process, each of these references a root on any process
74: . ilocal - locations of leaves in leafdata buffers, or `NULL` for contiguous storage
75: - gremote - root vertices in global numbering corresponding to the leaves
77: Level: intermediate
79: Notes:
80: The outputs are such that passing them as inputs to `PetscSFSetGraphLayout()` would lead to the same star forest.
81: The outputs `layout` and `gremote` are freshly created each time this function is called,
82: so they need to be freed (with `PetscLayoutDestroy()` and `PetscFree()`) by the user.
84: .seealso: [](sec_petscsf), `PetscSF`, `PetscSFSetGraphLayout()`, `PetscSFCreate()`, `PetscSFView()`, `PetscSFSetGraph()`, `PetscSFGetGraph()`
85: @*/
86: PetscErrorCode PetscSFGetGraphLayout(PetscSF sf, PetscLayout *layout, PetscInt *nleaves, const PetscInt *ilocal[], PetscInt *gremote[])
87: {
88: PetscInt nr, nl;
89: const PetscSFNode *ir;
90: PetscLayout lt;
92: PetscFunctionBegin;
94: if (layout) PetscAssertPointer(layout, 2);
95: if (nleaves) PetscAssertPointer(nleaves, 3);
96: if (ilocal) PetscAssertPointer(ilocal, 4);
97: if (gremote) PetscAssertPointer(gremote, 5);
98: PetscCall(PetscSFGetGraph(sf, &nr, &nl, ilocal, &ir));
99: PetscCall(PetscLayoutCreateFromSizes(PetscObjectComm((PetscObject)sf), nr, PETSC_DECIDE, 1, <));
100: if (gremote) {
101: const PetscInt *range;
102: PetscInt *gr;
104: PetscCall(PetscLayoutGetRanges(lt, &range));
105: PetscCall(PetscMalloc1(nl, &gr));
106: for (PetscInt i = 0; i < nl; i++) gr[i] = range[ir[i].rank] + ir[i].index;
107: *gremote = gr;
108: }
109: if (nleaves) *nleaves = nl;
110: if (layout) *layout = lt;
111: else PetscCall(PetscLayoutDestroy(<));
112: PetscFunctionReturn(PETSC_SUCCESS);
113: }
115: /*@
116: PetscSFSetGraphSection - Sets the `PetscSF` graph (communication pattern) encoding the parallel dof overlap based upon the `PetscSection` describing the data layout.
118: Input Parameters:
119: + sf - The `PetscSF`
120: . localSection - `PetscSection` describing the local data layout
121: - globalSection - `PetscSection` describing the global data layout
123: Level: developer
125: .seealso: [](sec_petscsf), `PetscSF`, `PetscSFSetGraph()`, `PetscSFSetGraphLayout()`
126: @*/
127: PetscErrorCode PetscSFSetGraphSection(PetscSF sf, PetscSection localSection, PetscSection globalSection)
128: {
129: MPI_Comm comm;
130: PetscLayout layout;
131: const PetscInt *ranges;
132: PetscInt *local;
133: PetscSFNode *remote;
134: PetscInt pStart, pEnd, p, nroots, nleaves = 0, l;
135: PetscMPIInt size, rank;
137: PetscFunctionBegin;
142: PetscCall(PetscObjectGetComm((PetscObject)sf, &comm));
143: PetscCallMPI(MPI_Comm_size(comm, &size));
144: PetscCallMPI(MPI_Comm_rank(comm, &rank));
145: PetscCall(PetscSectionGetChart(globalSection, &pStart, &pEnd));
146: PetscCall(PetscSectionGetConstrainedStorageSize(globalSection, &nroots));
147: PetscCall(PetscLayoutCreate(comm, &layout));
148: PetscCall(PetscLayoutSetBlockSize(layout, 1));
149: PetscCall(PetscLayoutSetLocalSize(layout, nroots));
150: PetscCall(PetscLayoutSetUp(layout));
151: PetscCall(PetscLayoutGetRanges(layout, &ranges));
152: for (p = pStart; p < pEnd; ++p) {
153: PetscInt gdof, gcdof;
155: PetscCall(PetscSectionGetDof(globalSection, p, &gdof));
156: PetscCall(PetscSectionGetConstraintDof(globalSection, p, &gcdof));
157: 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);
158: nleaves += gdof < 0 ? -(gdof + 1) - gcdof : gdof - gcdof;
159: }
160: PetscCall(PetscMalloc1(nleaves, &local));
161: PetscCall(PetscMalloc1(nleaves, &remote));
162: for (p = pStart, l = 0; p < pEnd; ++p) {
163: const PetscInt *cind;
164: PetscInt dof, cdof, off, gdof, gcdof, goff, gsize, d, c;
166: PetscCall(PetscSectionGetDof(localSection, p, &dof));
167: PetscCall(PetscSectionGetOffset(localSection, p, &off));
168: PetscCall(PetscSectionGetConstraintDof(localSection, p, &cdof));
169: PetscCall(PetscSectionGetConstraintIndices(localSection, p, &cind));
170: PetscCall(PetscSectionGetDof(globalSection, p, &gdof));
171: PetscCall(PetscSectionGetConstraintDof(globalSection, p, &gcdof));
172: PetscCall(PetscSectionGetOffset(globalSection, p, &goff));
173: if (!gdof) continue; /* Censored point */
174: gsize = gdof < 0 ? -(gdof + 1) - gcdof : gdof - gcdof;
175: if (gsize != dof - cdof) {
176: 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);
177: cdof = 0; /* Ignore constraints */
178: }
179: for (d = 0, c = 0; d < dof; ++d) {
180: if ((c < cdof) && (cind[c] == d)) {
181: ++c;
182: continue;
183: }
184: local[l + d - c] = off + d;
185: }
186: 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);
187: if (gdof < 0) {
188: for (d = 0; d < gsize; ++d, ++l) {
189: PetscInt offset = -(goff + 1) + d, ir;
190: PetscMPIInt r;
192: PetscCall(PetscFindInt(offset, size + 1, ranges, &ir));
193: PetscCall(PetscMPIIntCast(ir, &r));
194: if (r < 0) r = -(r + 2);
195: 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);
196: remote[l].rank = r;
197: remote[l].index = offset - ranges[r];
198: }
199: } else {
200: for (d = 0; d < gsize; ++d, ++l) {
201: remote[l].rank = rank;
202: remote[l].index = goff + d - ranges[rank];
203: }
204: }
205: }
206: PetscCheck(l == nleaves, comm, PETSC_ERR_PLIB, "Iteration error, l %" PetscInt_FMT " != nleaves %" PetscInt_FMT, l, nleaves);
207: PetscCall(PetscLayoutDestroy(&layout));
208: PetscCall(PetscSFSetGraph(sf, nroots, nleaves, local, PETSC_OWN_POINTER, remote, PETSC_OWN_POINTER));
209: PetscFunctionReturn(PETSC_SUCCESS);
210: }
212: /*@C
213: PetscSFDistributeSection - Create a new `PetscSection` reorganized, moving from the root to the leaves of the `PetscSF`
215: Collective
217: Input Parameters:
218: + sf - The `PetscSF`
219: - rootSection - Section defined on root space
221: Output Parameters:
222: + remoteOffsets - root offsets in leaf storage, or `NULL`, its length will be the size of the chart of `leafSection`
223: - leafSection - Section defined on the leaf space
225: Level: advanced
227: Note:
228: Caller must `PetscFree()` `remoteOffsets` if it was requested
230: To distribute data from the `rootSection` to the `leafSection`, see `PetscSFCreateSectionSF()` or `PetscSectionMigrateData()`.
232: Fortran Note:
233: Use `PetscSFDestroyRemoteOffsets()` when `remoteOffsets` is no longer needed.
235: .seealso: [](sec_petscsf), `PetscSF`, `PetscSFCreate()`, `PetscSFCreateSectionSF()`
236: @*/
237: PetscErrorCode PetscSFDistributeSection(PetscSF sf, PetscSection rootSection, PetscInt *remoteOffsets[], PetscSection leafSection)
238: {
239: PetscSF embedSF;
240: const PetscInt *indices;
241: IS selected;
242: PetscInt numFields, nroots, rpStart, rpEnd, lpStart = PETSC_INT_MAX, lpEnd = -1, f, c;
243: PetscBool *sub, hasc;
245: PetscFunctionBegin;
248: if (remoteOffsets) PetscAssertPointer(remoteOffsets, 3);
250: PetscCall(PetscLogEventBegin(PETSCSF_DistSect, sf, 0, 0, 0));
251: PetscCall(PetscSectionGetNumFields(rootSection, &numFields));
252: if (numFields) {
253: IS perm;
255: /* PetscSectionSetNumFields() calls PetscSectionReset(), which destroys
256: leafSection->perm. To keep this permutation set by the user, we grab
257: the reference before calling PetscSectionSetNumFields() and set it
258: back after. */
259: PetscCall(PetscSectionGetPermutation(leafSection, &perm));
260: PetscCall(PetscObjectReference((PetscObject)perm));
261: PetscCall(PetscSectionSetNumFields(leafSection, numFields));
262: PetscCall(PetscSectionSetPermutation(leafSection, perm));
263: PetscCall(ISDestroy(&perm));
264: }
265: PetscCall(PetscMalloc1(numFields + 2, &sub));
266: sub[1] = rootSection->bc ? PETSC_TRUE : PETSC_FALSE;
267: for (f = 0; f < numFields; ++f) {
268: PetscSectionSym sym, dsym = NULL;
269: const char *name = NULL;
270: PetscInt numComp = 0;
272: sub[2 + f] = rootSection->field[f]->bc ? PETSC_TRUE : PETSC_FALSE;
273: PetscCall(PetscSectionGetFieldComponents(rootSection, f, &numComp));
274: PetscCall(PetscSectionGetFieldName(rootSection, f, &name));
275: PetscCall(PetscSectionGetFieldSym(rootSection, f, &sym));
276: if (sym) PetscCall(PetscSectionSymDistribute(sym, sf, &dsym));
277: PetscCall(PetscSectionSetFieldComponents(leafSection, f, numComp));
278: PetscCall(PetscSectionSetFieldName(leafSection, f, name));
279: PetscCall(PetscSectionSetFieldSym(leafSection, f, dsym));
280: PetscCall(PetscSectionSymDestroy(&dsym));
281: for (c = 0; c < rootSection->numFieldComponents[f]; ++c) {
282: PetscCall(PetscSectionGetComponentName(rootSection, f, c, &name));
283: PetscCall(PetscSectionSetComponentName(leafSection, f, c, name));
284: }
285: }
286: PetscCall(PetscSectionGetChart(rootSection, &rpStart, &rpEnd));
287: PetscCall(PetscSFGetGraph(sf, &nroots, NULL, NULL, NULL));
288: rpEnd = PetscMin(rpEnd, nroots);
289: rpEnd = PetscMax(rpStart, rpEnd);
290: /* see if we can avoid creating the embedded SF, since it can cost more than an allreduce */
291: sub[0] = (PetscBool)(nroots != rpEnd - rpStart);
292: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, sub, 2 + numFields, MPI_C_BOOL, MPI_LOR, PetscObjectComm((PetscObject)sf)));
293: if (sub[0]) {
294: PetscCall(ISCreateStride(PETSC_COMM_SELF, rpEnd - rpStart, rpStart, 1, &selected));
295: PetscCall(ISGetIndices(selected, &indices));
296: PetscCall(PetscSFCreateEmbeddedRootSF(sf, rpEnd - rpStart, indices, &embedSF));
297: PetscCall(ISRestoreIndices(selected, &indices));
298: PetscCall(ISDestroy(&selected));
299: } else {
300: PetscCall(PetscObjectReference((PetscObject)sf));
301: embedSF = sf;
302: }
303: PetscCall(PetscSFGetLeafRange(embedSF, &lpStart, &lpEnd));
304: lpEnd++;
306: PetscCall(PetscSectionSetChart(leafSection, lpStart, lpEnd));
308: /* Constrained dof section */
309: hasc = sub[1];
310: for (f = 0; f < numFields; ++f) hasc = (PetscBool)(hasc || sub[2 + f]);
312: /* Could fuse these at the cost of copies and extra allocation */
313: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->atlasDof, -lpStart), MPI_REPLACE));
314: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->atlasDof, -lpStart), MPI_REPLACE));
315: if (sub[1]) {
316: PetscCall(PetscSectionCheckConstraints_Private(rootSection));
317: PetscCall(PetscSectionCheckConstraints_Private(leafSection));
318: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->bc->atlasDof[-rpStart], &leafSection->bc->atlasDof[-lpStart], MPI_REPLACE));
319: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->bc->atlasDof[-rpStart], &leafSection->bc->atlasDof[-lpStart], MPI_REPLACE));
320: }
321: for (f = 0; f < numFields; ++f) {
322: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->field[f]->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->field[f]->atlasDof, -lpStart), MPI_REPLACE));
323: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->field[f]->atlasDof, -rpStart), PetscSafePointerPlusOffset(leafSection->field[f]->atlasDof, -lpStart), MPI_REPLACE));
324: if (sub[2 + f]) {
325: PetscCall(PetscSectionCheckConstraints_Private(rootSection->field[f]));
326: PetscCall(PetscSectionCheckConstraints_Private(leafSection->field[f]));
327: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasDof[-rpStart], &leafSection->field[f]->bc->atlasDof[-lpStart], MPI_REPLACE));
328: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasDof[-rpStart], &leafSection->field[f]->bc->atlasDof[-lpStart], MPI_REPLACE));
329: }
330: }
331: if (remoteOffsets) {
332: PetscCall(PetscMalloc1(lpEnd - lpStart, remoteOffsets));
333: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
334: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
335: }
336: PetscCall(PetscSectionInvalidateMaxDof_Internal(leafSection));
337: PetscCall(PetscSectionSetUp(leafSection));
338: if (hasc) { /* need to communicate bcIndices */
339: PetscSF bcSF;
340: PetscInt *rOffBc;
342: PetscCall(PetscMalloc1(lpEnd - lpStart, &rOffBc));
343: if (sub[1]) {
344: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
345: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
346: PetscCall(PetscSFCreateSectionSF(embedSF, rootSection->bc, rOffBc, leafSection->bc, &bcSF));
347: PetscCall(PetscSFBcastBegin(bcSF, MPIU_INT, rootSection->bcIndices, leafSection->bcIndices, MPI_REPLACE));
348: PetscCall(PetscSFBcastEnd(bcSF, MPIU_INT, rootSection->bcIndices, leafSection->bcIndices, MPI_REPLACE));
349: PetscCall(PetscSFDestroy(&bcSF));
350: }
351: for (f = 0; f < numFields; ++f) {
352: if (sub[2 + f]) {
353: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
354: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, &rootSection->field[f]->bc->atlasOff[-rpStart], &rOffBc[-lpStart], MPI_REPLACE));
355: PetscCall(PetscSFCreateSectionSF(embedSF, rootSection->field[f]->bc, rOffBc, leafSection->field[f]->bc, &bcSF));
356: PetscCall(PetscSFBcastBegin(bcSF, MPIU_INT, rootSection->field[f]->bcIndices, leafSection->field[f]->bcIndices, MPI_REPLACE));
357: PetscCall(PetscSFBcastEnd(bcSF, MPIU_INT, rootSection->field[f]->bcIndices, leafSection->field[f]->bcIndices, MPI_REPLACE));
358: PetscCall(PetscSFDestroy(&bcSF));
359: }
360: }
361: PetscCall(PetscFree(rOffBc));
362: }
363: PetscCall(PetscSFDestroy(&embedSF));
364: PetscCall(PetscFree(sub));
365: PetscCall(PetscLogEventEnd(PETSCSF_DistSect, sf, 0, 0, 0));
366: PetscFunctionReturn(PETSC_SUCCESS);
367: }
369: /*@C
370: PetscSFCreateRemoteOffsets - Create offsets for point data on remote processes
372: Collective
374: Input Parameters:
375: + sf - The `PetscSF`
376: . rootSection - Data layout of remote points for outgoing data (this is layout for roots)
377: - leafSection - Data layout of local points for incoming data (this is layout for leaves)
379: Output Parameter:
380: . remoteOffsets - Offsets for point data on remote processes (these are offsets from the root section), or `NULL`
382: Level: developer
384: Note:
385: Caller must `PetscFree()` `remoteOffsets` if it was requested
387: Fortran Note:
388: Use `PetscSFDestroyRemoteOffsets()` when `remoteOffsets` is no longer needed.
390: .seealso: [](sec_petscsf), `PetscSF`, `PetscSFCreate()`
391: @*/
392: PetscErrorCode PetscSFCreateRemoteOffsets(PetscSF sf, PetscSection rootSection, PetscSection leafSection, PetscInt *remoteOffsets[])
393: {
394: PetscSF embedSF;
395: const PetscInt *indices;
396: IS selected;
397: PetscInt numRoots, rpStart = 0, rpEnd = 0, lpStart = 0, lpEnd = 0;
399: PetscFunctionBegin;
403: PetscAssertPointer(remoteOffsets, 4);
404: *remoteOffsets = NULL;
405: PetscCall(PetscSFGetGraph(sf, &numRoots, NULL, NULL, NULL));
406: if (numRoots < 0) PetscFunctionReturn(PETSC_SUCCESS);
407: PetscCall(PetscLogEventBegin(PETSCSF_RemoteOff, sf, 0, 0, 0));
408: PetscCall(PetscSectionGetChart(rootSection, &rpStart, &rpEnd));
409: PetscCall(PetscSectionGetChart(leafSection, &lpStart, &lpEnd));
410: PetscCall(ISCreateStride(PETSC_COMM_SELF, rpEnd - rpStart, rpStart, 1, &selected));
411: PetscCall(ISGetIndices(selected, &indices));
412: PetscCall(PetscSFCreateEmbeddedRootSF(sf, rpEnd - rpStart, indices, &embedSF));
413: PetscCall(ISRestoreIndices(selected, &indices));
414: PetscCall(ISDestroy(&selected));
415: PetscCall(PetscCalloc1(lpEnd - lpStart, remoteOffsets));
416: PetscCall(PetscSFBcastBegin(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
417: PetscCall(PetscSFBcastEnd(embedSF, MPIU_INT, PetscSafePointerPlusOffset(rootSection->atlasOff, -rpStart), PetscSafePointerPlusOffset(*remoteOffsets, -lpStart), MPI_REPLACE));
418: PetscCall(PetscSFDestroy(&embedSF));
419: PetscCall(PetscLogEventEnd(PETSCSF_RemoteOff, sf, 0, 0, 0));
420: PetscFunctionReturn(PETSC_SUCCESS);
421: }
423: /*@
424: PetscSFCreateSectionSF - Create an expanded `PetscSF` of dofs, assuming the input `PetscSF` relates points
426: Collective
428: Input Parameters:
429: + sf - The `PetscSF`
430: . rootSection - Data layout of remote points for outgoing data (this is usually the serial section)
431: . remoteOffsets - Offsets for point data on remote processes (these are offsets from the root section), or `NULL`
432: - leafSection - Data layout of local points for incoming data (this is the distributed section)
434: Output Parameter:
435: . sectionSF - The new `PetscSF`
437: Level: advanced
439: Notes:
440: `remoteOffsets` can be `NULL` if `sf` does not reference any points in `leafSection`
442: .seealso: [](sec_petscsf), `PetscSF`, `PetscSFCreate()`, `PetscSFDistributeSection()`
443: @*/
444: PetscErrorCode PetscSFCreateSectionSF(PetscSF sf, PetscSection rootSection, PetscInt remoteOffsets[], PetscSection leafSection, PetscSF *sectionSF)
445: {
446: MPI_Comm comm;
447: const PetscInt *localPoints;
448: const PetscSFNode *remotePoints;
449: PetscInt lpStart, lpEnd;
450: PetscInt numRoots, numSectionRoots, numPoints, numIndices = 0;
451: PetscInt *localIndices;
452: PetscSFNode *remoteIndices;
453: PetscInt i, ind;
455: PetscFunctionBegin;
457: PetscAssertPointer(rootSection, 2);
458: /* Cannot check PetscAssertPointer(remoteOffsets,3) because it can be NULL if sf does not reference any points in leafSection */
459: PetscAssertPointer(leafSection, 4);
460: PetscAssertPointer(sectionSF, 5);
461: PetscCall(PetscObjectGetComm((PetscObject)sf, &comm));
462: PetscCall(PetscSFCreate(comm, sectionSF));
463: PetscCall(PetscSectionGetChart(leafSection, &lpStart, &lpEnd));
464: PetscCall(PetscSectionGetStorageSize(rootSection, &numSectionRoots));
465: PetscCall(PetscSFGetGraph(sf, &numRoots, &numPoints, &localPoints, &remotePoints));
466: if (numRoots < 0) PetscFunctionReturn(PETSC_SUCCESS);
467: PetscCall(PetscLogEventBegin(PETSCSF_SectSF, sf, 0, 0, 0));
468: for (i = 0; i < numPoints; ++i) {
469: PetscInt localPoint = localPoints ? localPoints[i] : i;
470: PetscInt dof;
472: if ((localPoint >= lpStart) && (localPoint < lpEnd)) {
473: PetscCall(PetscSectionGetDof(leafSection, localPoint, &dof));
474: numIndices += dof < 0 ? 0 : dof;
475: }
476: }
477: PetscCall(PetscMalloc1(numIndices, &localIndices));
478: PetscCall(PetscMalloc1(numIndices, &remoteIndices));
479: /* Create new index graph */
480: for (i = 0, ind = 0; i < numPoints; ++i) {
481: PetscInt localPoint = localPoints ? localPoints[i] : i;
482: PetscInt rank = remotePoints[i].rank;
484: if ((localPoint >= lpStart) && (localPoint < lpEnd)) {
485: PetscInt remoteOffset = remoteOffsets[localPoint - lpStart];
486: PetscInt loff, dof, d;
488: PetscCall(PetscSectionGetOffset(leafSection, localPoint, &loff));
489: PetscCall(PetscSectionGetDof(leafSection, localPoint, &dof));
490: for (d = 0; d < dof; ++d, ++ind) {
491: localIndices[ind] = loff + d;
492: remoteIndices[ind].rank = rank;
493: remoteIndices[ind].index = remoteOffset + d;
494: }
495: }
496: }
497: PetscCheck(numIndices == ind, comm, PETSC_ERR_PLIB, "Inconsistency in indices, %" PetscInt_FMT " should be %" PetscInt_FMT, ind, numIndices);
498: PetscCall(PetscSFSetGraph(*sectionSF, numSectionRoots, numIndices, localIndices, PETSC_OWN_POINTER, remoteIndices, PETSC_OWN_POINTER));
499: PetscCall(PetscSFSetUp(*sectionSF));
500: PetscCall(PetscLogEventEnd(PETSCSF_SectSF, sf, 0, 0, 0));
501: PetscFunctionReturn(PETSC_SUCCESS);
502: }
504: /*@C
505: PetscSFCreateFromLayouts - Creates a parallel star forest mapping between two `PetscLayout` objects
507: Collective
509: Input Parameters:
510: + rmap - `PetscLayout` defining the global root space
511: - lmap - `PetscLayout` defining the global leaf space
513: Output Parameter:
514: . sf - The parallel star forest
516: Level: intermediate
518: Notes:
519: If the global length of `lmap` differs from the global length of `rmap` then the excess entries are ignored.
521: The resulting `sf` used with `PetscSFBcastBegin()` and `PetscSFBcastEnd()` merely copies the array entries of `rootdata` to
522: `leafdata`; moving them between MPI processes if needed. For example,
523: if rmap is [0, 3, 5) and lmap is [0, 2, 6) and `rootdata` is (1, 2, 3) on MPI rank 0 and (4, 5) on MPI rank 1 then the
524: `leafdata` would become (1, 2) on MPI rank 0 and (3, 4, 5, x) on MPI rank 1.
526: .seealso: [](sec_petscsf), `PetscSF`, `PetscLayout`, `PetscSFCreate()`, `PetscSFSetGraph()`, `PetscLayoutCreate()`, `PetscSFSetGraphLayout()`
527: @*/
528: PetscErrorCode PetscSFCreateFromLayouts(PetscLayout rmap, PetscLayout lmap, PetscSF *sf)
529: {
530: PetscInt i, nroots, nleaves = 0;
531: PetscInt rN, lst, len;
532: PetscMPIInt owner = -1;
533: PetscSFNode *remote;
534: MPI_Comm rcomm = rmap->comm;
535: MPI_Comm lcomm = lmap->comm;
536: PetscMPIInt flg;
538: PetscFunctionBegin;
539: PetscAssertPointer(rmap, 1);
540: PetscAssertPointer(lmap, 2);
541: PetscAssertPointer(sf, 3);
542: PetscCheck(rmap->setupcalled, rcomm, PETSC_ERR_ARG_WRONGSTATE, "Root layout not setup");
543: PetscCheck(lmap->setupcalled, lcomm, PETSC_ERR_ARG_WRONGSTATE, "Leaf layout not setup");
544: PetscCallMPI(MPI_Comm_compare(rcomm, lcomm, &flg));
545: PetscCheck(flg == MPI_CONGRUENT || flg == MPI_IDENT, rcomm, PETSC_ERR_SUP, "cannot map two layouts with non-matching communicators");
546: PetscCall(PetscSFCreate(rcomm, sf));
547: PetscCall(PetscLayoutGetLocalSize(rmap, &nroots));
548: PetscCall(PetscLayoutGetSize(rmap, &rN));
549: PetscCall(PetscLayoutGetRange(lmap, &lst, &len));
550: PetscCall(PetscMalloc1(len - lst, &remote));
551: for (i = lst; i < len && i < rN; i++) {
552: if (owner < -1 || i >= rmap->range[owner + 1]) PetscCall(PetscLayoutFindOwner(rmap, i, &owner));
553: remote[nleaves].rank = owner;
554: remote[nleaves].index = i - rmap->range[owner];
555: nleaves++;
556: }
557: PetscCall(PetscSFSetGraph(*sf, nroots, nleaves, NULL, PETSC_OWN_POINTER, remote, PETSC_COPY_VALUES));
558: PetscCall(PetscFree(remote));
559: PetscFunctionReturn(PETSC_SUCCESS);
560: }
562: /* TODO: handle nooffprocentries like MatZeroRowsMapLocal_Private, since this code is the same */
563: PetscErrorCode PetscLayoutMapLocal(PetscLayout map, PetscInt N, const PetscInt idxs[], PetscInt *on, PetscInt *oidxs[], PetscInt *ogidxs[])
564: {
565: PetscInt *owners = map->range;
566: PetscInt n = map->n;
567: PetscSF sf;
568: PetscInt *lidxs, *work = NULL, *ilocal;
569: PetscSFNode *ridxs;
570: PetscMPIInt rank, p = 0;
571: PetscInt r, len = 0, nleaves = 0;
573: PetscFunctionBegin;
574: if (on) *on = 0; /* squelch -Wmaybe-uninitialized */
575: /* Create SF where leaves are input idxs and roots are owned idxs */
576: PetscCallMPI(MPI_Comm_rank(map->comm, &rank));
577: PetscCall(PetscMalloc1(n, &lidxs));
578: for (r = 0; r < n; ++r) lidxs[r] = -1;
579: PetscCall(PetscMalloc1(N, &ridxs));
580: PetscCall(PetscMalloc1(N, &ilocal));
581: for (r = 0; r < N; ++r) {
582: const PetscInt idx = idxs[r];
584: if (idx < 0) continue;
585: PetscCheck(idx < map->N, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Index %" PetscInt_FMT " out of range [0,%" PetscInt_FMT ")", idx, map->N);
586: if (idx < owners[p] || owners[p + 1] <= idx) { /* short-circuit the search if the last p owns this idx too */
587: PetscCall(PetscLayoutFindOwner(map, idx, &p));
588: }
589: ridxs[nleaves].rank = p;
590: ridxs[nleaves].index = idxs[r] - owners[p];
591: ilocal[nleaves] = r;
592: nleaves++;
593: }
594: PetscCall(PetscSFCreate(map->comm, &sf));
595: PetscCall(PetscSFSetGraph(sf, n, nleaves, ilocal, PETSC_OWN_POINTER, ridxs, PETSC_OWN_POINTER));
596: PetscCall(PetscSFReduceBegin(sf, MPIU_INT, (PetscInt *)idxs, lidxs, MPI_LOR));
597: PetscCall(PetscSFReduceEnd(sf, MPIU_INT, (PetscInt *)idxs, lidxs, MPI_LOR));
598: if (ogidxs) { /* communicate global idxs */
599: PetscInt cum = 0, start, *work2;
601: PetscCall(PetscMalloc1(n, &work));
602: PetscCall(PetscCalloc1(N, &work2));
603: for (r = 0; r < N; ++r)
604: if (idxs[r] >= 0) cum++;
605: PetscCallMPI(MPI_Scan(&cum, &start, 1, MPIU_INT, MPI_SUM, map->comm));
606: start -= cum;
607: cum = 0;
608: for (r = 0; r < N; ++r)
609: if (idxs[r] >= 0) work2[r] = start + cum++;
610: PetscCall(PetscSFReduceBegin(sf, MPIU_INT, work2, work, MPI_REPLACE));
611: PetscCall(PetscSFReduceEnd(sf, MPIU_INT, work2, work, MPI_REPLACE));
612: PetscCall(PetscFree(work2));
613: }
614: PetscCall(PetscSFDestroy(&sf));
615: /* Compress and put in indices */
616: for (r = 0; r < n; ++r)
617: if (lidxs[r] >= 0) {
618: if (work) work[len] = work[r];
619: lidxs[len++] = r;
620: }
621: if (on) *on = len;
622: if (oidxs) *oidxs = lidxs;
623: if (ogidxs) *ogidxs = work;
624: PetscFunctionReturn(PETSC_SUCCESS);
625: }
627: /*@
628: PetscSFCreateByMatchingIndices - Create `PetscSF` by matching root and leaf indices
630: Collective
632: Input Parameters:
633: + layout - `PetscLayout` defining the global index space and the MPI rank that brokers each index
634: . numRootIndices - size of `rootIndices`
635: . rootIndices - array of global indices of which this process requests ownership
636: . rootLocalIndices - root local index permutation (`NULL` if no permutation)
637: . rootLocalOffset - offset to be added to `rootLocalIndices`
638: . numLeafIndices - size of `leafIndices`
639: . leafIndices - array of global indices with which this process requires data associated
640: . leafLocalIndices - leaf local index permutation (`NULL` if no permutation)
641: - leafLocalOffset - offset to be added to `leafLocalIndices`
643: Output Parameters:
644: + sfA - star forest representing the communication pattern from the layout space to the leaf space (`NULL` if not needed)
645: - sf - star forest representing the communication pattern from the root space to the leaf space
647: Level: advanced
649: Example 1:
650: .vb
651: rank : 0 1 2
652: rootIndices : [1 0 2] [3] [3]
653: rootLocalOffset : 100 200 300
654: layout : [0 1] [2] [3]
655: leafIndices : [0] [2] [0 3]
656: leafLocalOffset : 400 500 600
658: would build the following PetscSF
660: [0] 400 <- (0,101)
661: [1] 500 <- (0,102)
662: [2] 600 <- (0,101)
663: [2] 601 <- (2,300)
664: .ve
666: Example 2:
667: .vb
668: rank : 0 1 2
669: rootIndices : [1 0 2] [3] [3]
670: rootLocalOffset : 100 200 300
671: layout : [0 1] [2] [3]
672: leafIndices : rootIndices rootIndices rootIndices
673: leafLocalOffset : rootLocalOffset rootLocalOffset rootLocalOffset
675: would build the following PetscSF
677: [1] 200 <- (2,300)
678: .ve
680: Example 3:
681: .vb
682: No process requests ownership of global index 1, but no process needs it.
684: rank : 0 1 2
685: numRootIndices : 2 1 1
686: rootIndices : [0 2] [3] [3]
687: rootLocalOffset : 100 200 300
688: layout : [0 1] [2] [3]
689: numLeafIndices : 1 1 2
690: leafIndices : [0] [2] [0 3]
691: leafLocalOffset : 400 500 600
693: would build the following PetscSF
695: [0] 400 <- (0,100)
696: [1] 500 <- (0,101)
697: [2] 600 <- (0,100)
698: [2] 601 <- (2,300)
699: .ve
701: Notes:
702: `layout` represents any partitioning of [0, N), where N is the total number of global indices, and its
703: local size can be set to `PETSC_DECIDE`.
705: If a global index x lies in the partition owned by process i, each process whose `rootIndices` contains x requests
706: ownership of x and sends its own rank and the local index of x to process i.
707: If multiple processes request ownership of x, the one with the highest rank is to own x.
708: Process i then broadcasts the ownership information, so that each process whose `leafIndices` contains x knows the
709: ownership information of x.
710: The output `sf` is constructed by associating each leaf point to a root point in this way.
712: Suppose there is point data ordered according to the global indices and partitioned according to the given layout.
713: The optional output `sfA` can be used to push such data to leaf points.
715: All indices in `rootIndices` and `leafIndices` must lie in the layout range. The union (over all processes) of `rootIndices`
716: must cover that of `leafIndices`, but need not cover the entire layout.
718: If (leafIndices, leafLocalIndices, leafLocalOffset) == (rootIndices, rootLocalIndices, rootLocalOffset), the output
719: star forest is almost identity, so will only include non-trivial part of the map.
721: Developer Notes:
722: Current approach of a process of the highest rank gaining the ownership may cause load imbalance; consider using
723: hash(rank, root_local_index) as the bid for the ownership determination.
725: .seealso: [](sec_petscsf), `PetscSF`, `PetscSFCreate()`
726: @*/
727: 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)
728: {
729: MPI_Comm comm = layout->comm;
730: PetscMPIInt rank;
731: PetscSF sf1;
732: PetscSFNode *owners, *buffer, *iremote;
733: PetscInt *ilocal, nleaves, N, n, i;
734: PetscBool areIndicesSame;
736: PetscFunctionBegin;
737: PetscAssertPointer(layout, 1);
738: if (rootIndices) PetscAssertPointer(rootIndices, 3);
739: if (rootLocalIndices) PetscAssertPointer(rootLocalIndices, 4);
740: if (leafIndices) PetscAssertPointer(leafIndices, 7);
741: if (leafLocalIndices) PetscAssertPointer(leafLocalIndices, 8);
742: if (sfA) PetscAssertPointer(sfA, 10);
743: PetscAssertPointer(sf, 11);
744: PetscCheck(numRootIndices >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "numRootIndices (%" PetscInt_FMT ") must be non-negative", numRootIndices);
745: PetscCheck(numLeafIndices >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "numLeafIndices (%" PetscInt_FMT ") must be non-negative", numLeafIndices);
746: PetscCallMPI(MPI_Comm_rank(comm, &rank));
747: PetscCall(PetscLayoutSetUp(layout));
748: PetscCall(PetscLayoutGetSize(layout, &N));
749: PetscCall(PetscLayoutGetLocalSize(layout, &n));
750: areIndicesSame = (PetscBool)(leafIndices == rootIndices);
751: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &areIndicesSame, 1, MPI_C_BOOL, MPI_LAND, comm));
752: PetscCheck(!areIndicesSame || numLeafIndices == numRootIndices, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "leafIndices == rootIndices, but numLeafIndices (%" PetscInt_FMT ") != numRootIndices(%" PetscInt_FMT ")", numLeafIndices, numRootIndices);
753: if (PetscDefined(USE_DEBUG)) {
754: PetscInt N1 = PETSC_INT_MIN;
755: for (i = 0; i < numRootIndices; i++)
756: if (rootIndices[i] > N1) N1 = rootIndices[i];
757: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &N1, 1, MPIU_INT, MPI_MAX, comm));
758: PetscCheck(N1 < N, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Max. root index (%" PetscInt_FMT ") out of layout range [0,%" PetscInt_FMT ")", N1, N);
759: if (!areIndicesSame) {
760: N1 = PETSC_INT_MIN;
761: for (i = 0; i < numLeafIndices; i++)
762: if (leafIndices[i] > N1) N1 = leafIndices[i];
763: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &N1, 1, MPIU_INT, MPI_MAX, comm));
764: PetscCheck(N1 < N, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Max. leaf index (%" PetscInt_FMT ") out of layout range [0,%" PetscInt_FMT ")", N1, N);
765: }
766: }
768: /* Reduce: owners -> buffer */
769: PetscCall(PetscMalloc1(n, &buffer));
770: PetscCall(PetscSFCreate(comm, &sf1));
771: PetscCall(PetscSFSetFromOptions(sf1));
772: PetscCall(PetscSFSetGraphLayout(sf1, layout, numRootIndices, NULL, PETSC_OWN_POINTER, rootIndices));
773: PetscCall(PetscMalloc1(numRootIndices, &owners));
774: for (i = 0; i < numRootIndices; ++i) {
775: owners[i].rank = rank;
776: owners[i].index = rootLocalOffset + (rootLocalIndices ? rootLocalIndices[i] : i);
777: }
778: for (i = 0; i < n; ++i) {
779: buffer[i].index = -1;
780: buffer[i].rank = -1;
781: }
782: PetscCall(PetscSFReduceBegin(sf1, MPIU_SF_NODE, owners, buffer, MPI_MAXLOC));
783: PetscCall(PetscSFReduceEnd(sf1, MPIU_SF_NODE, owners, buffer, MPI_MAXLOC));
784: /* Bcast: buffer -> owners */
785: if (!areIndicesSame) {
786: PetscCall(PetscFree(owners));
787: PetscCall(PetscSFSetGraphLayout(sf1, layout, numLeafIndices, NULL, PETSC_OWN_POINTER, leafIndices));
788: PetscCall(PetscMalloc1(numLeafIndices, &owners));
789: }
790: PetscCall(PetscSFBcastBegin(sf1, MPIU_SF_NODE, buffer, owners, MPI_REPLACE));
791: PetscCall(PetscSFBcastEnd(sf1, MPIU_SF_NODE, buffer, owners, MPI_REPLACE));
792: 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]);
793: PetscCall(PetscFree(buffer));
794: if (sfA) *sfA = sf1;
795: else PetscCall(PetscSFDestroy(&sf1));
796: /* Create sf */
797: if (areIndicesSame && rootLocalIndices == leafLocalIndices && leafLocalOffset == rootLocalOffset) {
798: /* leaf space == root space */
799: for (i = 0, nleaves = 0; i < numLeafIndices; ++i)
800: if (owners[i].rank != rank) ++nleaves;
801: PetscCall(PetscMalloc1(nleaves, &ilocal));
802: PetscCall(PetscMalloc1(nleaves, &iremote));
803: for (i = 0, nleaves = 0; i < numLeafIndices; ++i) {
804: if (owners[i].rank != rank) {
805: ilocal[nleaves] = leafLocalOffset + i;
806: iremote[nleaves].rank = owners[i].rank;
807: iremote[nleaves].index = owners[i].index;
808: ++nleaves;
809: }
810: }
811: PetscCall(PetscFree(owners));
812: } else {
813: nleaves = numLeafIndices;
814: PetscCall(PetscMalloc1(nleaves, &ilocal));
815: for (i = 0; i < nleaves; ++i) ilocal[i] = leafLocalOffset + (leafLocalIndices ? leafLocalIndices[i] : i);
816: iremote = owners;
817: }
818: PetscCall(PetscSFCreate(comm, sf));
819: PetscCall(PetscSFSetFromOptions(*sf));
820: PetscCall(PetscSFSetGraph(*sf, rootLocalOffset + numRootIndices, nleaves, ilocal, PETSC_OWN_POINTER, iremote, PETSC_OWN_POINTER));
821: PetscFunctionReturn(PETSC_SUCCESS);
822: }
824: /*@
825: PetscSFMerge - append/merge indices of `sfb` into `sfa`, with preference for `sfb`
827: Collective
829: Input Parameters:
830: + sfa - default `PetscSF`
831: - sfb - additional edges to add/replace edges in `sfa`
833: Output Parameter:
834: . merged - new `PetscSF` with combined edges
836: Level: intermediate
838: .seealso: [](sec_petscsf), `PetscSF`, `PetscSFCompose()`
839: @*/
840: PetscErrorCode PetscSFMerge(PetscSF sfa, PetscSF sfb, PetscSF *merged)
841: {
842: PetscInt maxleaf;
844: PetscFunctionBegin;
847: PetscCheckSameComm(sfa, 1, sfb, 2);
848: PetscAssertPointer(merged, 3);
849: {
850: PetscInt aleaf, bleaf;
851: PetscCall(PetscSFGetLeafRange(sfa, NULL, &aleaf));
852: PetscCall(PetscSFGetLeafRange(sfb, NULL, &bleaf));
853: maxleaf = PetscMax(aleaf, bleaf) + 1; // One more than the last index
854: }
855: PetscInt *clocal, aroots, aleaves, broots, bleaves;
856: PetscSFNode *cremote;
857: const PetscInt *alocal, *blocal;
858: const PetscSFNode *aremote, *bremote;
859: PetscCall(PetscMalloc2(maxleaf, &clocal, maxleaf, &cremote));
860: for (PetscInt i = 0; i < maxleaf; i++) clocal[i] = -1;
861: PetscCall(PetscSFGetGraph(sfa, &aroots, &aleaves, &alocal, &aremote));
862: PetscCall(PetscSFGetGraph(sfb, &broots, &bleaves, &blocal, &bremote));
863: PetscCheck(aroots == broots, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Both sfa and sfb must have the same root space");
864: for (PetscInt i = 0; i < aleaves; i++) {
865: PetscInt a = alocal ? alocal[i] : i;
866: clocal[a] = a;
867: cremote[a] = aremote[i];
868: }
869: for (PetscInt i = 0; i < bleaves; i++) {
870: PetscInt b = blocal ? blocal[i] : i;
871: clocal[b] = b;
872: cremote[b] = bremote[i];
873: }
874: PetscInt nleaves = 0;
875: for (PetscInt i = 0; i < maxleaf; i++) {
876: if (clocal[i] < 0) continue;
877: clocal[nleaves] = clocal[i];
878: cremote[nleaves] = cremote[i];
879: nleaves++;
880: }
881: PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)sfa), merged));
882: PetscCall(PetscSFSetGraph(*merged, aroots, nleaves, clocal, PETSC_COPY_VALUES, cremote, PETSC_COPY_VALUES));
883: PetscCall(PetscFree2(clocal, cremote));
884: PetscFunctionReturn(PETSC_SUCCESS);
885: }
887: /*@
888: PetscSFCreateStridedSF - Create an `PetscSF` to communicate interleaved blocks of data
890: Collective
892: Input Parameters:
893: + sf - star forest
894: . bs - stride
895: . ldr - leading dimension of root space
896: - ldl - leading dimension of leaf space
898: Output Parameter:
899: . vsf - the new `PetscSF`
901: Level: intermediate
903: Notes:
904: This can be useful to perform communications on multiple right-hand sides stored in a Fortran-style two dimensional array.
905: For example, the calling sequence
906: .vb
907: c_datatype *roots, *leaves;
908: for i in [0,bs) do
909: PetscSFBcastBegin(sf, mpi_datatype, roots + i*ldr, leaves + i*ldl, op)
910: PetscSFBcastEnd(sf, mpi_datatype, roots + i*ldr, leaves + i*ldl, op)
911: .ve
912: is equivalent to
913: .vb
914: c_datatype *roots, *leaves;
915: PetscSFCreateStridedSF(sf, bs, ldr, ldl, &vsf)
916: PetscSFBcastBegin(vsf, mpi_datatype, roots, leaves, op)
917: PetscSFBcastEnd(vsf, mpi_datatype, roots, leaves, op)
918: .ve
920: Developer Notes:
921: Should this functionality be handled with a new API instead of creating a new object?
923: .seealso: [](sec_petscsf), `PetscSF`, `PetscSFCreate()`, `PetscSFSetGraph()`
924: @*/
925: PetscErrorCode PetscSFCreateStridedSF(PetscSF sf, PetscInt bs, PetscInt ldr, PetscInt ldl, PetscSF *vsf)
926: {
927: PetscSF rankssf;
928: const PetscSFNode *iremote, *sfrremote;
929: PetscSFNode *viremote;
930: const PetscInt *ilocal;
931: PetscInt *vilocal = NULL, *ldrs;
932: PetscInt nranks, nr, nl, vnr, vnl, maxl;
933: PetscMPIInt rank;
934: MPI_Comm comm;
935: PetscSFType sftype;
937: PetscFunctionBegin;
940: PetscAssertPointer(vsf, 5);
941: if (bs == 1) {
942: PetscCall(PetscObjectReference((PetscObject)sf));
943: *vsf = sf;
944: PetscFunctionReturn(PETSC_SUCCESS);
945: }
946: PetscCall(PetscSFSetUp(sf));
947: PetscCall(PetscObjectGetComm((PetscObject)sf, &comm));
948: PetscCallMPI(MPI_Comm_rank(comm, &rank));
949: PetscCall(PetscSFGetGraph(sf, &nr, &nl, &ilocal, &iremote));
950: PetscCall(PetscSFGetLeafRange(sf, NULL, &maxl));
951: maxl += 1;
952: if (ldl == PETSC_DECIDE) ldl = maxl;
953: if (ldr == PETSC_DECIDE) ldr = nr;
954: ldl /= PetscMax(1, sf->vscat.bs); // SFs created from VecScatterCreate() may have a nonzero block size. If not 0, we need to scale ldl and ldr
955: ldr /= PetscMax(1, sf->vscat.bs);
956: 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);
957: 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);
958: vnr = nr * bs;
959: vnl = nl * bs;
960: PetscCall(PetscMalloc1(vnl, &viremote));
961: PetscCall(PetscMalloc1(vnl, &vilocal));
963: /* Communicate root leading dimensions to leaf ranks */
964: PetscCall(PetscSFGetRanksSF(sf, &rankssf));
965: PetscCall(PetscSFGetGraph(rankssf, NULL, &nranks, NULL, &sfrremote));
966: PetscCall(PetscMalloc1(nranks, &ldrs));
967: PetscCall(PetscSFBcastBegin(rankssf, MPIU_INT, &ldr, ldrs, MPI_REPLACE));
968: PetscCall(PetscSFBcastEnd(rankssf, MPIU_INT, &ldr, ldrs, MPI_REPLACE));
970: for (PetscInt i = 0, rold = -1, lda = -1; i < nl; i++) {
971: const PetscInt r = iremote[i].rank;
972: const PetscInt ii = iremote[i].index;
974: if (r == rank) lda = ldr;
975: else if (rold != r) {
976: PetscInt j;
978: for (j = 0; j < nranks; j++)
979: if (sfrremote[j].rank == r) break;
980: PetscCheck(j < nranks, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Unable to locate neighbor rank %" PetscInt_FMT, r);
981: lda = ldrs[j];
982: }
983: rold = r;
984: for (PetscInt v = 0; v < bs; v++) {
985: viremote[v * nl + i].rank = r;
986: viremote[v * nl + i].index = v * lda + ii;
987: vilocal[v * nl + i] = v * ldl + (ilocal ? ilocal[i] : i);
988: }
989: }
990: PetscCall(PetscFree(ldrs));
991: PetscCall(PetscSFCreate(comm, vsf));
992: if (sf->vscat.bs > 1) {
993: (*vsf)->vscat.bs = sf->vscat.bs;
994: PetscCallMPI(MPI_Type_dup(sf->vscat.unit, &(*vsf)->vscat.unit));
995: (*vsf)->vscat.to_n = bs * sf->vscat.to_n;
996: (*vsf)->vscat.from_n = bs * sf->vscat.from_n;
997: }
998: PetscCall(PetscSFGetType(sf, &sftype));
999: PetscCall(PetscSFSetType(*vsf, sftype));
1000: PetscCall(PetscSFSetGraph(*vsf, vnr, vnl, vilocal, PETSC_OWN_POINTER, viremote, PETSC_OWN_POINTER));
1001: PetscFunctionReturn(PETSC_SUCCESS);
1002: }