Actual source code: vscat.c
1: #include <petsc/private/sfimpl.h>
2: #include <../src/vec/is/sf/impls/basic/sfbasic.h>
3: #include <../src/vec/is/sf/impls/basic/sfpack.h>
4: #include <petsc/private/vecimpl.h>
6: PETSC_EXTERN PetscErrorCode PetscGatherNumberOfMessages_Private(MPI_Comm, const PetscMPIInt[], const PetscInt[], PetscMPIInt *);
7: PETSC_EXTERN PetscErrorCode PetscGatherMessageLengths_Private(MPI_Comm, PetscMPIInt, PetscMPIInt, const PetscInt[], PetscMPIInt **, PetscInt **);
9: typedef enum {
10: IS_INVALID,
11: IS_GENERAL,
12: IS_BLOCK,
13: IS_STRIDE
14: } ISTypeID;
16: static inline PetscErrorCode ISGetTypeID_Private(IS is, ISTypeID *id)
17: {
18: PetscBool same;
20: PetscFunctionBegin;
21: *id = IS_INVALID;
22: PetscCall(PetscObjectTypeCompare((PetscObject)is, ISGENERAL, &same));
23: if (same) {
24: *id = IS_GENERAL;
25: goto functionend;
26: }
27: PetscCall(PetscObjectTypeCompare((PetscObject)is, ISBLOCK, &same));
28: if (same) {
29: *id = IS_BLOCK;
30: goto functionend;
31: }
32: PetscCall(PetscObjectTypeCompare((PetscObject)is, ISSTRIDE, &same));
33: if (same) {
34: *id = IS_STRIDE;
35: goto functionend;
36: }
37: functionend:
38: PetscFunctionReturn(PETSC_SUCCESS);
39: }
41: static PetscErrorCode VecScatterBegin_Internal(VecScatter sf, Vec x, Vec y, InsertMode addv, ScatterMode mode)
42: {
43: PetscSF wsf = NULL; /* either sf or its local part */
44: MPI_Op mop = MPI_OP_NULL;
45: PetscMPIInt size;
46: PetscMemType xmtype = PETSC_MEMTYPE_HOST, ymtype = PETSC_MEMTYPE_HOST;
48: PetscFunctionBegin;
49: if (x != y) PetscCall(VecLockReadPush(x));
50: PetscCall(VecGetArrayReadAndMemType(x, &sf->vscat.xdata, &xmtype));
51: PetscCall(VecGetArrayAndMemType(y, &sf->vscat.ydata, &ymtype));
52: PetscCall(VecLockWriteSet(y, PETSC_TRUE));
54: /* SCATTER_FORWARD_LOCAL indicates ignoring inter-process communication */
55: PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)sf), &size));
56: if ((mode & SCATTER_FORWARD_LOCAL) && size > 1) { /* Lazy creation of sf->vscat.lsf since SCATTER_FORWARD_LOCAL is uncommon */
57: if (!sf->vscat.lsf) PetscCall(PetscSFCreateLocalSF_Private(sf, &sf->vscat.lsf));
58: wsf = sf->vscat.lsf;
59: } else {
60: wsf = sf;
61: }
63: /* Note xdata/ydata is always recorded on sf (not lsf) above */
64: if (addv == INSERT_VALUES) mop = MPI_REPLACE;
65: else if (addv == ADD_VALUES) mop = MPIU_SUM; /* Petsc defines its own MPI datatype and SUM operation for __float128 etc. */
66: else if (addv == MAX_VALUES) mop = MPIU_MAX;
67: else if (addv == MIN_VALUES) mop = MPIU_MIN;
68: else SETERRQ(PetscObjectComm((PetscObject)sf), PETSC_ERR_SUP, "Unsupported InsertMode %d in VecScatterBegin/End", addv);
70: if (mode & SCATTER_REVERSE) { /* REVERSE indicates leaves to root scatter. Note that x and y are swapped in input */
71: PetscCall(PetscSFReduceWithMemTypeBegin(wsf, sf->vscat.unit, xmtype, sf->vscat.xdata, ymtype, sf->vscat.ydata, mop));
72: } else { /* FORWARD indicates x to y scatter, where x is root and y is leaf */
73: PetscCall(PetscSFBcastWithMemTypeBegin(wsf, sf->vscat.unit, xmtype, sf->vscat.xdata, ymtype, sf->vscat.ydata, mop));
74: }
75: PetscFunctionReturn(PETSC_SUCCESS);
76: }
78: static PetscErrorCode VecScatterEnd_Internal(VecScatter sf, Vec x, Vec y, InsertMode addv, ScatterMode mode)
79: {
80: PetscSF wsf = NULL;
81: MPI_Op mop = MPI_OP_NULL;
82: PetscMPIInt size;
84: PetscFunctionBegin;
85: /* SCATTER_FORWARD_LOCAL indicates ignoring inter-process communication */
86: PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)sf), &size));
87: wsf = ((mode & SCATTER_FORWARD_LOCAL) && size > 1) ? sf->vscat.lsf : sf;
89: if (addv == INSERT_VALUES) mop = MPI_REPLACE;
90: else if (addv == ADD_VALUES) mop = MPIU_SUM;
91: else if (addv == MAX_VALUES) mop = MPIU_MAX;
92: else if (addv == MIN_VALUES) mop = MPIU_MIN;
93: else SETERRQ(PetscObjectComm((PetscObject)sf), PETSC_ERR_SUP, "Unsupported InsertMode %d in VecScatterBegin/End", addv);
95: if (mode & SCATTER_REVERSE) { /* reverse scatter sends leaves to roots. Note that x and y are swapped in input */
96: PetscCall(PetscSFReduceEnd(wsf, sf->vscat.unit, sf->vscat.xdata, sf->vscat.ydata, mop));
97: } else { /* forward scatter sends roots to leaves, i.e., x to y */
98: PetscCall(PetscSFBcastEnd(wsf, sf->vscat.unit, sf->vscat.xdata, sf->vscat.ydata, mop));
99: }
101: PetscCall(VecRestoreArrayReadAndMemType(x, &sf->vscat.xdata));
102: if (x != y) PetscCall(VecLockReadPop(x));
103: PetscCall(VecRestoreArrayAndMemType(y, &sf->vscat.ydata));
104: PetscCall(VecLockWriteSet(y, PETSC_FALSE));
105: PetscFunctionReturn(PETSC_SUCCESS);
106: }
108: /* VecScatterRemap provides a light way to slightly modify a VecScatter. Suppose the input sf scatters
109: x[i] to y[j], tomap gives a plan to change vscat to scatter x[tomap[i]] to y[j]. Note that in SF,
110: x is roots. That means we need to change incoming stuffs such as bas->irootloc[].
111: */
112: static PetscErrorCode VecScatterRemap_Internal(VecScatter sf, const PetscInt *tomap, const PetscInt *frommap)
113: {
114: PetscInt i, bs = sf->vscat.bs;
115: PetscMPIInt size;
116: PetscBool ident = PETSC_TRUE, isbasic, isneighbor;
117: PetscSFType type;
118: PetscSF_Basic *bas = NULL;
120: PetscFunctionBegin;
121: /* check if it is an identity map. If it is, do nothing */
122: if (tomap) {
123: for (i = 0; i < sf->nroots * bs; i++) {
124: if (i != tomap[i]) {
125: ident = PETSC_FALSE;
126: break;
127: }
128: }
129: if (ident) PetscFunctionReturn(PETSC_SUCCESS);
130: }
131: PetscCheck(!frommap, PETSC_COMM_SELF, PETSC_ERR_SUP, "Unable to remap the FROM in scatters yet");
132: if (!tomap) PetscFunctionReturn(PETSC_SUCCESS);
134: PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)sf), &size));
136: /* Since the indices changed, we must also update the local SF. But we do not do it since
137: lsf is rarely used. We just destroy lsf and rebuild it on demand from updated sf.
138: */
139: if (sf->vscat.lsf) PetscCall(PetscSFDestroy(&sf->vscat.lsf));
141: PetscCall(PetscSFGetType(sf, &type));
142: PetscCall(PetscObjectTypeCompare((PetscObject)sf, PETSCSFBASIC, &isbasic));
143: PetscCall(PetscObjectTypeCompare((PetscObject)sf, PETSCSFNEIGHBOR, &isneighbor));
144: PetscCheck(isbasic || isneighbor, PetscObjectComm((PetscObject)sf), PETSC_ERR_SUP, "VecScatterRemap on SF type %s is not supported", type);
146: PetscCall(PetscSFSetUp(sf)); /* to build sf->irootloc if SetUp is not yet called */
148: /* Root indices are going to be remapped. This is tricky for SF. Root indices are used in sf->rremote,
149: sf->remote and bas->irootloc. The latter one is cheap to remap, but the former two are not.
150: To remap them, we have to do a bcast from roots to leaves, to let leaves know their updated roots.
151: Since VecScatterRemap is supposed to be a cheap routine to adapt a vecscatter by only changing where
152: x[] data is taken, we do not remap sf->rremote, sf->remote. The consequence is that operations
153: accessing them (such as PetscSFCompose) may get stale info. Considering VecScatter does not need
154: that complicated SF operations, we do not remap sf->rremote, sf->remote, instead we destroy them
155: so that code accessing them (if any) will crash (instead of get silent errors). Note that BcastAndOp/Reduce,
156: which are used by VecScatter and only rely on bas->irootloc, are updated and correct.
157: */
158: sf->remote = NULL;
159: PetscCall(PetscFree(sf->remote_alloc));
160: /* Not easy to free sf->rremote since it was allocated with PetscMalloc4(), so just give it crazy values */
161: for (i = 0; i < sf->roffset[sf->nranks]; i++) sf->rremote[i] = PETSC_INT_MIN;
163: /* Indices in tomap[] are for each individual vector entry. But indices in sf are for each
164: block in the vector. So before the remapping, we have to expand indices in sf by bs, and
165: after the remapping, we have to shrink them back.
166: */
167: bas = (PetscSF_Basic *)sf->data;
168: for (i = 0; i < bas->ioffset[bas->niranks]; i++) bas->irootloc[i] = tomap[bas->irootloc[i] * bs] / bs;
169: #if defined(PETSC_HAVE_DEVICE)
170: /* Free the irootloc copy on device. We allocate a new copy and get the updated value on demand. See PetscSFLinkGetRootPackOptAndIndices() */
171: for (i = 0; i < 2; i++) PetscCall(PetscSFFree(sf, PETSC_MEMTYPE_DEVICE, bas->irootloc_d[i]));
172: #endif
173: /* Destroy and then rebuild root packing optimizations since indices are changed */
174: PetscCall(PetscSFResetPackFields(sf));
175: PetscCall(PetscSFSetUpPackFields(sf));
176: PetscFunctionReturn(PETSC_SUCCESS);
177: }
179: /*
180: Given a parallel VecScatter context, return number of procs and vector entries involved in remote (i.e., off-process) communication
182: Input Parameters:
183: + sf - the context (must be a parallel vecscatter)
184: - send - true to select the send info (i.e., todata), otherwise to select the recv info (i.e., fromdata)
186: Output parameters:
187: + num_procs - number of remote processors
188: - num_entries - number of vector entries to send or recv
190: Notes:
191: Sometimes PETSc internally needs to use the matrix-vector-multiply vecscatter context for other purposes. The client code
192: usually only uses MPI_Send/Recv. This group of subroutines provides info needed for such uses.
194: .seealso: [](sec_scatter), `VecScatterGetRemote_Private()`, `VecScatterGetRemoteOrdered_Private()`
195: */
196: PetscErrorCode VecScatterGetRemoteCount_Private(VecScatter sf, PetscBool send, PetscInt *num_procs, PetscInt *num_entries)
197: {
198: PetscMPIInt nranks, remote_start;
199: PetscMPIInt rank;
200: const PetscInt *offset;
201: const PetscMPIInt *ranks;
203: PetscFunctionBegin;
204: PetscCall(PetscSFSetUp(sf));
205: PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)sf), &rank));
207: /* This routine is mainly used for MatMult's Mvctx. In Mvctx, we scatter an MPI vector x to a sequential vector lvec.
208: Remember x is roots and lvec is leaves. 'send' means roots to leaves communication. If 'send' is true, we need to
209: get info about which ranks this processor needs to send to. In other words, we need to call PetscSFGetLeafRanks().
210: If send is false, we do the opposite, calling PetscSFGetRootRanks().
211: */
212: if (send) PetscCall(PetscSFGetLeafRanks(sf, &nranks, &ranks, &offset, NULL));
213: else PetscCall(PetscSFGetRootRanks(sf, &nranks, &ranks, &offset, NULL, NULL));
214: if (nranks) {
215: remote_start = (rank == ranks[0]) ? 1 : 0;
216: if (num_procs) *num_procs = nranks - remote_start;
217: if (num_entries) *num_entries = offset[nranks] - offset[remote_start];
218: } else {
219: if (num_procs) *num_procs = 0;
220: if (num_entries) *num_entries = 0;
221: }
222: PetscFunctionReturn(PETSC_SUCCESS);
223: }
225: /* Given a parallel VecScatter context, return a plan that represents the remote communication.
226: Any output parameter can be NULL.
228: Input Parameters:
229: + sf - the context
230: - send - true to select the send info (i.e., todata), otherwise to select the recv info (i.e., fromdata)
232: Output parameters:
233: + n - number of remote processors
234: . starts - starting point in indices for each proc. ATTENTION: starts[0] is not necessarily zero.
235: Therefore, expressions like starts[i+1]-starts[i] and indices[starts[i]+j] work as
236: expected for a CSR structure but buf[starts[i]+j] may be out of range if buf was allocated
237: with length starts[n]-starts[0]. One should use buf[starts[i]-starts[0]+j] instead.
238: . indices - indices of entries to send/recv
239: . procs - ranks of remote processors
240: - bs - block size
242: .seealso: `VecScatterRestoreRemote_Private()`, `VecScatterGetRemoteOrdered_Private()`
243: */
244: PetscErrorCode VecScatterGetRemote_Private(VecScatter sf, PetscBool send, PetscMPIInt *n, const PetscInt **starts, const PetscInt **indices, const PetscMPIInt **procs, PetscInt *bs)
245: {
246: PetscMPIInt nranks, remote_start;
247: PetscMPIInt rank;
248: const PetscInt *offset, *location;
249: const PetscMPIInt *ranks;
251: PetscFunctionBegin;
252: PetscCall(PetscSFSetUp(sf));
253: PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)sf), &rank));
255: if (send) PetscCall(PetscSFGetLeafRanks(sf, &nranks, &ranks, &offset, &location));
256: else PetscCall(PetscSFGetRootRanks(sf, &nranks, &ranks, &offset, &location, NULL));
258: if (nranks) {
259: remote_start = (rank == ranks[0]) ? 1 : 0;
260: if (n) *n = nranks - remote_start;
261: if (starts) *starts = &offset[remote_start];
262: if (indices) *indices = location; /* not &location[offset[remote_start]]. Starts[0] may point to the middle of indices[] */
263: if (procs) *procs = &ranks[remote_start];
264: } else {
265: if (n) *n = 0;
266: if (starts) *starts = NULL;
267: if (indices) *indices = NULL;
268: if (procs) *procs = NULL;
269: }
271: if (bs) *bs = 1;
272: PetscFunctionReturn(PETSC_SUCCESS);
273: }
275: /* Given a parallel VecScatter context, return a plan that represents the remote communication. Ranks of remote
276: processors returned in procs must be sorted in ascending order. Any output parameter can be NULL.
278: Input Parameters:
279: + sf - the context
280: - send - true to select the send info (i.e., todata), otherwise to select the recv info (i.e., fromdata)
282: Output parameters:
283: + n - number of remote processors
284: . starts - starting point in indices for each proc. ATTENTION: starts[0] is not necessarily zero.
285: Therefore, expressions like starts[i+1]-starts[i] and indices[starts[i]+j] work as
286: expected for a CSR structure but buf[starts[i]+j] may be out of range if buf was allocated
287: with length starts[n]-starts[0]. One should use buf[starts[i]-starts[0]+j] instead.
288: . indices - indices of entries to send/recv
289: . procs - ranks of remote processors
290: - bs - block size
292: Notes:
293: Output parameters like starts, indices must also be adapted according to the sorted ranks.
295: .seealso: `VecScatterRestoreRemoteOrdered_Private()`, `VecScatterGetRemote_Private()`
296: */
297: PetscErrorCode VecScatterGetRemoteOrdered_Private(VecScatter sf, PetscBool send, PetscMPIInt *n, const PetscInt **starts, const PetscInt **indices, const PetscMPIInt **procs, PetscInt *bs)
298: {
299: PetscFunctionBegin;
300: PetscCall(VecScatterGetRemote_Private(sf, send, n, starts, indices, procs, bs));
301: if (PetscUnlikelyDebug(n && procs)) {
302: PetscMPIInt i;
303: /* from back to front to also handle cases *n=0 */
304: for (i = *n - 1; i > 0; i--) PetscCheck((*procs)[i - 1] <= (*procs)[i], PETSC_COMM_SELF, PETSC_ERR_PLIB, "procs[] are not ordered");
305: }
306: PetscFunctionReturn(PETSC_SUCCESS);
307: }
309: /* Given a parallel VecScatter context, restore the plan returned by VecScatterGetRemote_Private. This gives a chance for
310: an implementation to free memory allocated in the VecScatterGetRemote_Private call.
312: Input Parameters:
313: + sf - the context
314: - send - true to select the send info (i.e., todata), otherwise to select the recv info (i.e., fromdata)
316: Output parameters:
317: + n - number of remote processors
318: . starts - starting point in indices for each proc
319: . indices - indices of entries to send/recv
320: . procs - ranks of remote processors
321: - bs - block size
323: .seealso: `VecScatterGetRemote_Private()`
324: */
325: PetscErrorCode VecScatterRestoreRemote_Private(VecScatter sf, PetscBool send, PetscMPIInt *n, const PetscInt **starts, const PetscInt **indices, const PetscMPIInt **procs, PetscInt *bs)
326: {
327: PetscFunctionBegin;
328: if (starts) *starts = NULL;
329: if (indices) *indices = NULL;
330: if (procs) *procs = NULL;
331: PetscFunctionReturn(PETSC_SUCCESS);
332: }
334: /* Given a parallel VecScatter context, restore the plan returned by VecScatterGetRemoteOrdered_Private. This gives a chance for
335: an implementation to free memory allocated in the VecScatterGetRemoteOrdered_Private call.
337: Input Parameters:
338: + sf - the context
339: - send - true to select the send info (i.e., todata), otherwise to select the recv info (i.e., fromdata)
341: Output parameters:
342: + n - number of remote processors
343: . starts - starting point in indices for each proc
344: . indices - indices of entries to send/recv
345: . procs - ranks of remote processors
346: - bs - block size
348: .seealso: `VecScatterGetRemoteOrdered_Private()`
349: */
350: PetscErrorCode VecScatterRestoreRemoteOrdered_Private(VecScatter sf, PetscBool send, PetscMPIInt *n, const PetscInt **starts, const PetscInt **indices, const PetscMPIInt **procs, PetscInt *bs)
351: {
352: PetscFunctionBegin;
353: PetscCall(VecScatterRestoreRemote_Private(sf, send, n, starts, indices, procs, bs));
354: PetscFunctionReturn(PETSC_SUCCESS);
355: }
357: /*@
358: VecScatterSetUp - Sets up the `VecScatter` to be able to actually scatter information between vectors
360: Collective
362: Input Parameter:
363: . sf - the scatter context
365: Level: intermediate
367: .seealso: [](sec_scatter), `VecScatter`, `VecScatterCreate()`, `VecScatterCopy()`
368: @*/
369: PetscErrorCode VecScatterSetUp(VecScatter sf)
370: {
371: PetscFunctionBegin;
372: PetscCall(PetscSFSetUp(sf));
373: PetscFunctionReturn(PETSC_SUCCESS);
374: }
376: /*@
377: VecScatterSetType - Builds a vector scatter, for a particular vector scatter implementation.
379: Collective
381: Input Parameters:
382: + sf - The `VecScatter` object
383: - type - The name of the vector scatter type
385: Options Database Key:
386: . -sf_type <type> - Sets the `VecScatterType`
388: Level: intermediate
390: Note:
391: Use `VecScatterDuplicate()` to form additional vectors scatter of the same type as an existing vector scatter.
393: .seealso: [](sec_scatter), `VecScatter`, `VecScatterType`, `VecScatterGetType()`, `VecScatterCreate()`
394: @*/
395: PetscErrorCode VecScatterSetType(VecScatter sf, VecScatterType type)
396: {
397: PetscFunctionBegin;
398: PetscCall(PetscSFSetType(sf, type));
399: PetscFunctionReturn(PETSC_SUCCESS);
400: }
402: /*@
403: VecScatterGetType - Gets the vector scatter type name (as a string) from the `VecScatter`.
405: Not Collective
407: Input Parameter:
408: . sf - The vector scatter
410: Output Parameter:
411: . type - The vector scatter type name
413: Level: intermediate
415: .seealso: [](sec_scatter), `VecScatter`, `VecScatterType`, `VecScatterSetType()`, `VecScatterCreate()`
416: @*/
417: PetscErrorCode VecScatterGetType(VecScatter sf, VecScatterType *type)
418: {
419: PetscFunctionBegin;
420: PetscCall(PetscSFGetType(sf, type));
421: PetscFunctionReturn(PETSC_SUCCESS);
422: }
424: /*@C
425: VecScatterRegister - Adds a new vector scatter component implementation
427: Not Collective
429: Input Parameters:
430: + sname - The name of a new user-defined creation routine
431: - function - The creation routine
433: Level: advanced
435: .seealso: [](sec_scatter), `VecScatter`, `VecScatterType`, `VecRegister()`
436: @*/
437: PetscErrorCode VecScatterRegister(const char sname[], PetscErrorCode (*function)(VecScatter))
438: {
439: PetscFunctionBegin;
440: PetscCall(PetscSFRegister(sname, function));
441: PetscFunctionReturn(PETSC_SUCCESS);
442: }
444: /*@
445: VecScatterGetMerged - Returns true if the scatter is completed in the `VecScatterBegin()`
446: and the `VecScatterEnd()` does nothing
448: Not Collective
450: Input Parameter:
451: . sf - scatter context created with `VecScatterCreate()`
453: Output Parameter:
454: . flg - `PETSC_TRUE` if the `VecScatterBegin()`/`VecScatterEnd()` are all done during the `VecScatterBegin()`
456: Level: developer
458: .seealso: [](sec_scatter), `VecScatter`, `VecScatterCreate()`, `VecScatterEnd()`, `VecScatterBegin()`
459: @*/
460: PetscErrorCode VecScatterGetMerged(VecScatter sf, PetscBool *flg)
461: {
462: PetscFunctionBegin;
464: if (flg) *flg = sf->vscat.beginandendtogether;
465: PetscFunctionReturn(PETSC_SUCCESS);
466: }
467: /*@
468: VecScatterDestroy - Destroys a scatter context created by `VecScatterCreate()`
470: Collective
472: Input Parameter:
473: . sf - the scatter context
475: Level: intermediate
477: .seealso: [](sec_scatter), `VecScatter`, `VecScatterCreate()`, `VecScatterCopy()`
478: @*/
479: PetscErrorCode VecScatterDestroy(VecScatter *sf)
480: {
481: PetscFunctionBegin;
482: PetscCall(PetscSFDestroy(sf));
483: PetscFunctionReturn(PETSC_SUCCESS);
484: }
486: /*@
487: VecScatterCopy - Makes a copy of a scatter context.
489: Collective
491: Input Parameter:
492: . sf - the scatter context
494: Output Parameter:
495: . newsf - the context copy
497: Level: advanced
499: .seealso: [](sec_scatter), `VecScatter`, `VecScatterType`, `VecScatterCreate()`, `VecScatterDestroy()`
500: @*/
501: PetscErrorCode VecScatterCopy(VecScatter sf, VecScatter *newsf)
502: {
503: PetscFunctionBegin;
504: PetscAssertPointer(newsf, 2);
505: PetscCall(PetscSFDuplicate(sf, PETSCSF_DUPLICATE_GRAPH, newsf));
506: PetscCall(PetscSFSetUp(*newsf));
507: PetscFunctionReturn(PETSC_SUCCESS);
508: }
510: /*@
511: VecScatterViewFromOptions - View a `VecScatter` object based on values in the options database
513: Collective
515: Input Parameters:
516: + sf - the scatter context
517: . obj - Optional object
518: - name - command line option
520: Level: intermediate
522: Note:
523: See `PetscObjectViewFromOptions()` for available `PetscViewer` and `PetscViewerFormat` values
525: .seealso: [](sec_scatter), `VecScatter`, `VecScatterView()`, `PetscObjectViewFromOptions()`, `VecScatterCreate()`
526: @*/
527: PetscErrorCode VecScatterViewFromOptions(VecScatter sf, PetscObject obj, const char name[])
528: {
529: PetscFunctionBegin;
531: PetscCall(PetscObjectViewFromOptions((PetscObject)sf, obj, name));
532: PetscFunctionReturn(PETSC_SUCCESS);
533: }
535: /*@
536: VecScatterView - Views a vector scatter context.
538: Collective
540: Input Parameters:
541: + sf - the scatter context
542: - viewer - the viewer for displaying the context
544: Level: intermediate
546: .seealso: [](sec_scatter), `VecScatter`, `PetscViewer`, `VecScatterViewFromOptions()`, `PetscObjectViewFromOptions()`, `VecScatterCreate()`
547: @*/
548: PetscErrorCode VecScatterView(VecScatter sf, PetscViewer viewer)
549: {
550: PetscFunctionBegin;
551: PetscCall(PetscSFView(sf, viewer));
552: PetscFunctionReturn(PETSC_SUCCESS);
553: }
555: /*@
556: VecScatterRemap - Remaps the "from" and "to" indices in a
557: vector scatter context.
559: Collective
561: Input Parameters:
562: + sf - vector scatter context
563: . tomap - remapping plan for "to" indices (may be `NULL`).
564: - frommap - remapping plan for "from" indices (may be `NULL`)
566: Level: developer
568: Notes:
569: In the parallel case the todata contains indices from where the data is taken
570: (and then sent to others)! The fromdata contains indices from where the received
571: data is finally put locally.
573: In the sequential case the todata contains indices from where the data is put
574: and the fromdata contains indices from where the data is taken from.
575: This is backwards from the parallel case!
577: .seealso: [](sec_scatter), `VecScatter`, `VecScatterCreate()`
578: @*/
579: PetscErrorCode VecScatterRemap(VecScatter sf, PetscInt tomap[], PetscInt frommap[])
580: {
581: PetscFunctionBegin;
582: if (tomap) PetscAssertPointer(tomap, 2);
583: if (frommap) PetscAssertPointer(frommap, 3);
584: PetscCall(VecScatterRemap_Internal(sf, tomap, frommap));
585: PetscCheck(!frommap, PETSC_COMM_SELF, PETSC_ERR_SUP, "Unable to remap the FROM in scatters yet");
586: /* Mark then vector lengths as unknown because we do not know the lengths of the remapped vectors */
587: sf->vscat.from_n = -1;
588: sf->vscat.to_n = -1;
589: PetscFunctionReturn(PETSC_SUCCESS);
590: }
592: /*@
593: VecScatterSetFromOptions - Configures the vector scatter from values in the options database.
595: Collective
597: Input Parameter:
598: . sf - The vector scatter
600: Notes:
601: To see all options, run your program with the -help option, or consult the users manual.
603: Must be called before `VecScatterSetUp()` and before the vector scatter is used.
605: Level: beginner
607: .seealso: [](sec_scatter), `VecScatter`, `VecScatterCreate()`, `VecScatterDestroy()`, `VecScatterSetUp()`
608: @*/
609: PetscErrorCode VecScatterSetFromOptions(VecScatter sf)
610: {
611: PetscFunctionBegin;
613: PetscObjectOptionsBegin((PetscObject)sf);
615: sf->vscat.beginandendtogether = PETSC_FALSE;
616: PetscCall(PetscOptionsBool("-vecscatter_merge", "Use combined (merged) vector scatter begin and end", "VecScatterCreate", sf->vscat.beginandendtogether, &sf->vscat.beginandendtogether, NULL));
617: if (sf->vscat.beginandendtogether) PetscCall(PetscInfo(sf, "Using combined (merged) vector scatter begin and end\n"));
618: PetscOptionsEnd();
619: PetscFunctionReturn(PETSC_SUCCESS);
620: }
622: /*@
623: VecScatterCreate - Creates a vector scatter context.
625: Collective
627: Input Parameters:
628: + x - a vector that defines the shape (parallel data layout of the vector) of vectors from
629: which we scatter
630: . y - a vector that defines the shape (parallel data layout of the vector) of vectors to which
631: we scatter
632: . ix - the indices of xin to scatter (if `NULL` scatters all values)
633: - iy - the indices of yin to hold results (if `NULL` fills entire vector `yin` in order)
635: Output Parameter:
636: . newsf - location to store the new scatter context
638: Options Database Keys:
639: + -vecscatter_view - Prints detail of communications
640: . -vecscatter_view ::ascii_info - Print less details about communication
641: - -vecscatter_merge - `VecScatterBegin()` handles all of the communication, `VecScatterEnd()` is a nop
642: eliminates the chance for overlap of computation and communication
644: Level: intermediate
646: Notes:
647: If both `xin` and `yin` are parallel, their communicator must be on the same
648: set of processes, but their process order can be different.
649: In calls to the scatter options you can use different vectors than the `xin` and
650: `yin` you used above; BUT they must have the same parallel data layout, for example,
651: they could be obtained from `VecDuplicate()`.
652: A `VecScatter` context CANNOT be used in two or more simultaneous scatters;
653: that is you cannot call a second `VecScatterBegin()` with the same scatter
654: context until the `VecScatterEnd()` has been called on the first `VecScatterBegin()`.
655: In this case a separate `VecScatter` is needed for each concurrent scatter.
657: Both `ix` and `iy` cannot be `NULL` at the same time.
659: Use `VecScatterCreateToAll()` to create a vecscatter that copies an MPI vector to sequential vectors on all MPI ranks.
660: Use `VecScatterCreateToZero()` to create a vecscatter that copies an MPI vector to a sequential vector on MPI rank 0.
661: These special vecscatters have better performance than general ones.
663: .seealso: [](sec_scatter), `VecScatter`, `VecScatterDestroy()`, `VecScatterCreateToAll()`, `VecScatterCreateToZero()`, `PetscSFCreate()`
664: @*/
665: PetscErrorCode VecScatterCreate(Vec x, IS ix, Vec y, IS iy, VecScatter *newsf)
666: {
667: MPI_Comm xcomm, ycomm, bigcomm;
668: Vec xx, yy;
669: IS ix_old = ix, iy_old = iy, ixx, iyy;
670: PetscMPIInt xcommsize, ycommsize, rank, result;
671: PetscInt i, n, N, nroots, nleaves, *ilocal, xstart, ystart, ixsize, iysize, xlen, ylen;
672: const PetscInt *xindices, *yindices;
673: PetscSFNode *iremote;
674: PetscLayout xlayout, ylayout;
675: ISTypeID ixid, iyid;
676: PetscInt bs, bsx, bsy, min, max, m[2], mg[2], ixfirst, ixstep, iyfirst, iystep;
677: PetscBool can_do_block_opt = PETSC_FALSE;
678: PetscSF sf;
680: PetscFunctionBegin;
681: PetscAssertPointer(newsf, 5);
682: PetscCheck(ix || iy, PetscObjectComm((PetscObject)x), PETSC_ERR_SUP, "Cannot pass default in for both input and output indices");
684: /* Get comm from x and y */
685: PetscCall(PetscObjectGetComm((PetscObject)x, &xcomm));
686: PetscCallMPI(MPI_Comm_size(xcomm, &xcommsize));
687: PetscCall(PetscObjectGetComm((PetscObject)y, &ycomm));
688: PetscCallMPI(MPI_Comm_size(ycomm, &ycommsize));
689: if (xcommsize > 1 && ycommsize > 1) {
690: PetscCallMPI(MPI_Comm_compare(xcomm, ycomm, &result));
691: PetscCheck(result != MPI_UNEQUAL, PETSC_COMM_SELF, PETSC_ERR_ARG_NOTSAMECOMM, "VecScatterCreate: parallel vectors x and y must have identical/congruent/similar communicators");
692: }
693: bs = 1; /* default, no blocking */
695: /*
696: Let P and S stand for parallel and sequential vectors respectively. There are four combinations of vecscatters: PtoP, PtoS,
697: StoP and StoS. The assumption of VecScatterCreate(Vec x,IS ix,Vec y,IS iy,VecScatter *newctx) is: if x is parallel, then ix
698: contains global indices of x. If x is sequential, ix contains local indices of x. Similarly for y and iy.
700: SF builds around concepts of local leaves and remote roots. We treat source vector x as roots and destination vector y as
701: leaves. A PtoS scatter can be naturally mapped to SF. We transform PtoP and StoP to PtoS, and treat StoS as trivial PtoS.
702: */
704: /* NULL ix or iy in VecScatterCreate(x,ix,y,iy,newctx) has special meaning. Recover them for these cases */
705: if (!ix) {
706: if (xcommsize > 1 && ycommsize == 1) { /* PtoS: null ix means the whole x will be scattered to each seq y */
707: PetscCall(VecGetSize(x, &N));
708: PetscCall(ISCreateStride(PETSC_COMM_SELF, N, 0, 1, &ix));
709: } else { /* PtoP, StoP or StoS: null ix means the whole local part of x will be scattered */
710: PetscCall(VecGetLocalSize(x, &n));
711: PetscCall(VecGetOwnershipRange(x, &xstart, NULL));
712: PetscCall(ISCreateStride(PETSC_COMM_SELF, n, xstart, 1, &ix));
713: }
714: }
716: if (!iy) {
717: if (xcommsize == 1 && ycommsize > 1) { /* StoP: null iy means the whole y will be scattered to from each seq x */
718: PetscCall(VecGetSize(y, &N));
719: PetscCall(ISCreateStride(PETSC_COMM_SELF, N, 0, 1, &iy));
720: } else { /* PtoP, StoP or StoS: null iy means the whole local part of y will be scattered to */
721: PetscCall(VecGetLocalSize(y, &n));
722: PetscCall(VecGetOwnershipRange(y, &ystart, NULL));
723: PetscCall(ISCreateStride(PETSC_COMM_SELF, n, ystart, 1, &iy));
724: }
725: }
727: /* Do error checking immediately after we have non-empty ix, iy */
728: PetscCall(ISGetLocalSize(ix, &ixsize));
729: PetscCall(ISGetLocalSize(iy, &iysize));
730: PetscCall(VecGetSize(x, &xlen));
731: PetscCall(VecGetSize(y, &ylen));
732: PetscCheck(ixsize == iysize, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Scatter sizes of ix and iy don't match locally ix=%" PetscInt_FMT " iy=%" PetscInt_FMT, ixsize, iysize);
733: PetscCall(ISGetMinMax(ix, &min, &max));
734: PetscCheck(min >= 0 && max < xlen, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Scatter indices in ix are out of range: found [%" PetscInt_FMT ",%" PetscInt_FMT "), expected in [0,%" PetscInt_FMT ")", min, max, xlen);
735: PetscCall(ISGetMinMax(iy, &min, &max));
736: PetscCheck(min >= 0 && max < ylen, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Scatter indices in iy are out of range: found [%" PetscInt_FMT ",%" PetscInt_FMT "), expected in [0,%" PetscInt_FMT ")", min, max, ylen);
738: /* Extract info about ix, iy for further test */
739: PetscCall(ISGetTypeID_Private(ix, &ixid));
740: PetscCall(ISGetTypeID_Private(iy, &iyid));
741: if (ixid == IS_BLOCK) PetscCall(ISGetBlockSize(ix, &bsx));
742: else if (ixid == IS_STRIDE) PetscCall(ISStrideGetInfo(ix, &ixfirst, &ixstep));
744: if (iyid == IS_BLOCK) PetscCall(ISGetBlockSize(iy, &bsy));
745: else if (iyid == IS_STRIDE) PetscCall(ISStrideGetInfo(iy, &iyfirst, &iystep));
747: /* Check if a PtoS is special ToAll/ToZero scatters, which can be results of VecScatterCreateToAll/Zero.
748: ToAll means a whole MPI vector is copied to a seq vector on every process. ToZero means a whole MPI
749: vector is copied to a seq vector on rank 0 and other processes do nothing(i.e.,they input empty ix,iy).
751: We can optimize these scatters with MPI collectives. We can also avoid costly analysis used for general scatters.
752: */
753: if (xcommsize > 1 && ycommsize == 1) { /* Ranks do not diverge at this if-test */
754: PetscInt pattern[2] = {0, 0}; /* A boolean array with pattern[0] for allgather-like (ToAll) and pattern[1] for gather-like (ToZero) */
755: PetscLayout map;
757: PetscCallMPI(MPI_Comm_rank(xcomm, &rank));
758: PetscCall(VecGetLayout(x, &map));
759: if (rank == 0) {
760: if (ixid == IS_STRIDE && iyid == IS_STRIDE && ixsize == xlen && ixfirst == 0 && ixstep == 1 && iyfirst == 0 && iystep == 1) {
761: /* Rank 0 scatters the whole mpi x to seq y, so it is either a ToAll or a ToZero candidate in its view */
762: pattern[0] = pattern[1] = 1;
763: }
764: } else {
765: if (ixid == IS_STRIDE && iyid == IS_STRIDE && ixsize == xlen && ixfirst == 0 && ixstep == 1 && iyfirst == 0 && iystep == 1) {
766: /* Other ranks also scatter the whole mpi x to seq y, so it is a ToAll candidate in their view */
767: pattern[0] = 1;
768: } else if (ixsize == 0) {
769: /* Other ranks do nothing, so it is a ToZero candidate */
770: pattern[1] = 1;
771: }
772: }
774: /* One stone (the expensive allreduce) two birds: pattern[] tells if it is ToAll or ToZero */
775: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, pattern, 2, MPIU_INT, MPI_LAND, xcomm));
777: if (pattern[0] || pattern[1]) {
778: PetscCall(PetscSFCreate(xcomm, &sf));
779: PetscCall(PetscSFSetFromOptions(sf));
780: PetscCall(PetscSFSetGraphWithPattern(sf, map, pattern[0] ? PETSCSF_PATTERN_ALLGATHER : PETSCSF_PATTERN_GATHER));
781: goto functionend; /* No further analysis needed. What a big win! */
782: }
783: }
785: /* Continue ...
786: Do block optimization by taking advantage of high level info available in ix, iy.
787: The block optimization is valid when all of the following conditions are met:
788: 1) ix, iy are blocked or can be blocked (i.e., strided with step=1);
789: 2) ix, iy have the same block size;
790: 3) all processors agree on one block size;
791: 4) no blocks span more than one process;
792: */
793: bigcomm = (xcommsize == 1) ? ycomm : xcomm;
795: /* Processors could go through different path in this if-else test */
796: m[0] = PETSC_INT_MAX;
797: m[1] = PETSC_INT_MIN;
798: if (ixid == IS_BLOCK && iyid == IS_BLOCK) {
799: m[0] = PetscMin(bsx, bsy);
800: m[1] = PetscMax(bsx, bsy);
801: } else if (ixid == IS_BLOCK && iyid == IS_STRIDE && iystep == 1 && iyfirst % bsx == 0) {
802: m[0] = bsx;
803: m[1] = bsx;
804: } else if (ixid == IS_STRIDE && iyid == IS_BLOCK && ixstep == 1 && ixfirst % bsy == 0) {
805: m[0] = bsy;
806: m[1] = bsy;
807: }
808: /* Get max and min of bsx,bsy over all processes in one allreduce */
809: PetscCall(PetscGlobalMinMaxInt(bigcomm, m, mg));
811: /* Since we used allreduce above, all ranks will have the same min and max. min==max
812: implies all ranks have the same bs. Do further test to see if local vectors are dividable
813: by bs on ALL ranks. If they are, we are ensured that no blocks span more than one processor.
814: */
815: if (mg[0] == mg[1] && mg[0] > 1) {
816: PetscCall(VecGetLocalSize(x, &xlen));
817: PetscCall(VecGetLocalSize(y, &ylen));
818: m[0] = xlen % mg[0];
819: m[1] = ylen % mg[0];
820: PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, m, 2, MPIU_INT, MPI_LOR, bigcomm));
821: if (!m[0] && !m[1]) can_do_block_opt = PETSC_TRUE;
822: }
824: /* If can_do_block_opt, then shrink x, y, ix and iy by bs to get xx, yy, ixx and iyy, whose indices
825: and layout are actually used in building SF. Suppose blocked ix representing {0,1,2,6,7,8} has
826: indices {0,2} and bs=3, then ixx = {0,2}; suppose strided iy={3,4,5,6,7,8}, then iyy={1,2}.
828: xx is a little special. If x is seq, then xx is the concatenation of seq x's on ycomm. In this way,
829: we can treat PtoP and StoP uniformly as PtoS.
830: */
831: if (can_do_block_opt) {
832: const PetscInt *indices;
834: /* Shrink x and ix */
835: bs = mg[0];
836: PetscCall(VecCreateMPIWithArray(bigcomm, 1, xlen / bs, PETSC_DECIDE, NULL, &xx)); /* We only care xx's layout */
837: if (ixid == IS_BLOCK) {
838: PetscCall(ISBlockGetIndices(ix, &indices));
839: PetscCall(ISBlockGetLocalSize(ix, &ixsize));
840: PetscCall(ISCreateGeneral(PETSC_COMM_SELF, ixsize, indices, PETSC_COPY_VALUES, &ixx));
841: PetscCall(ISBlockRestoreIndices(ix, &indices));
842: } else { /* ixid == IS_STRIDE */
843: PetscCall(ISGetLocalSize(ix, &ixsize));
844: PetscCall(ISCreateStride(PETSC_COMM_SELF, ixsize / bs, ixfirst / bs, 1, &ixx));
845: }
847: /* Shrink y and iy */
848: PetscCall(VecCreateMPIWithArray(ycomm, 1, ylen / bs, PETSC_DECIDE, NULL, &yy));
849: if (iyid == IS_BLOCK) {
850: PetscCall(ISBlockGetIndices(iy, &indices));
851: PetscCall(ISBlockGetLocalSize(iy, &iysize));
852: PetscCall(ISCreateGeneral(PETSC_COMM_SELF, iysize, indices, PETSC_COPY_VALUES, &iyy));
853: PetscCall(ISBlockRestoreIndices(iy, &indices));
854: } else { /* iyid == IS_STRIDE */
855: PetscCall(ISGetLocalSize(iy, &iysize));
856: PetscCall(ISCreateStride(PETSC_COMM_SELF, iysize / bs, iyfirst / bs, 1, &iyy));
857: }
858: } else {
859: ixx = ix;
860: iyy = iy;
861: yy = y;
862: if (xcommsize == 1) PetscCall(VecCreateMPIWithArray(bigcomm, 1, xlen, PETSC_DECIDE, NULL, &xx));
863: else xx = x;
864: }
866: /* Now it is ready to build SF with preprocessed (xx, yy) and (ixx, iyy) */
867: PetscCall(ISGetIndices(ixx, &xindices));
868: PetscCall(ISGetIndices(iyy, &yindices));
869: PetscCall(VecGetLayout(xx, &xlayout));
871: if (ycommsize > 1) {
872: /* PtoP or StoP */
874: /* Below is a piece of complex code with a very simple goal: move global index pairs (xindices[i], yindices[i]),
875: to owner process of yindices[i] according to ylayout, i = 0..n.
877: I did it through a temp sf, but later I thought the old design was inefficient and also distorted log view.
878: We want to map one VecScatterCreate() call to one PetscSFCreate() call. The old design mapped to three
879: PetscSFCreate() calls. This code is on critical path of VecScatterSetUp and is used by every VecScatterCreate.
880: So I commented it out and did another optimized implementation. The commented code is left here for reference.
881: */
882: #if 0
883: const PetscInt *degree;
884: PetscSF tmpsf;
885: PetscInt inedges=0,*leafdata,*rootdata;
887: PetscCall(VecGetOwnershipRange(xx,&xstart,NULL));
888: PetscCall(VecGetLayout(yy,&ylayout));
889: PetscCall(VecGetOwnershipRange(yy,&ystart,NULL));
891: PetscCall(VecGetLocalSize(yy,&nroots));
892: PetscCall(ISGetLocalSize(iyy,&nleaves));
893: PetscCall(PetscMalloc2(nleaves,&iremote,nleaves*2,&leafdata));
895: for (i=0; i<nleaves; i++) {
896: PetscCall(PetscLayoutFindOwnerIndex(ylayout,yindices[i],&iremote[i].rank,&iremote[i].index));
897: leafdata[2*i] = yindices[i];
898: leafdata[2*i+1] = (xcommsize > 1)? xindices[i] : xindices[i] + xstart;
899: }
901: PetscCall(PetscSFCreate(ycomm,&tmpsf));
902: PetscCall(PetscSFSetGraph(tmpsf,nroots,nleaves,NULL,PETSC_USE_POINTER,iremote,PETSC_USE_POINTER));
904: PetscCall(PetscSFComputeDegreeBegin(tmpsf,°ree));
905: PetscCall(PetscSFComputeDegreeEnd(tmpsf,°ree));
907: for (i=0; i<nroots; i++) inedges += degree[i];
908: PetscCall(PetscMalloc1(inedges*2,&rootdata));
909: PetscCall(PetscSFGatherBegin(tmpsf,MPIU_2INT,leafdata,rootdata));
910: PetscCall(PetscSFGatherEnd(tmpsf,MPIU_2INT,leafdata,rootdata));
912: PetscCall(PetscFree2(iremote,leafdata));
913: PetscCall(PetscSFDestroy(&tmpsf));
915: /* rootdata contains global index pairs (i, j). j's are owned by the current process, but i's can point to anywhere.
916: We convert j to local, and convert i to (rank, index). In the end, we get an PtoS suitable for building SF.
917: */
918: nleaves = inedges;
919: PetscCall(VecGetLocalSize(xx,&nroots));
920: PetscCall(PetscMalloc1(nleaves,&ilocal));
921: PetscCall(PetscMalloc1(nleaves,&iremote));
923: for (i=0; i<inedges; i++) {
924: ilocal[i] = rootdata[2*i] - ystart; /* convert y's global index to local index */
925: PetscCall(PetscLayoutFindOwnerIndex(xlayout,rootdata[2*i+1],&iremote[i].rank,&iremote[i].index)); /* convert x's global index to (rank, index) */
926: }
927: PetscCall(PetscFree(rootdata));
928: #else
929: PetscInt j, k, n, disp, rlentotal, *sstart, *xindices_sorted, *yindices_sorted;
930: const PetscInt *yrange;
931: PetscMPIInt nsend, nrecv, nreq, yrank, *sendto, *recvfrom, tag1, tag2;
932: PetscInt *slens, *rlens, count;
933: PetscInt *rxindices, *ryindices;
934: MPI_Request *reqs, *sreqs, *rreqs;
936: /* Sorting makes code simpler, faster and also helps getting rid of many O(P) arrays, which hurt scalability at large scale
937: yindices_sorted - sorted yindices
938: xindices_sorted - xindices sorted along with yindces
939: */
940: PetscCall(ISGetLocalSize(ixx, &n)); /*ixx, iyy have the same local size */
941: PetscCall(PetscMalloc2(n, &xindices_sorted, n, &yindices_sorted));
942: PetscCall(PetscArraycpy(xindices_sorted, xindices, n));
943: PetscCall(PetscArraycpy(yindices_sorted, yindices, n));
944: PetscCall(PetscSortIntWithArray(n, yindices_sorted, xindices_sorted));
945: PetscCall(VecGetOwnershipRange(xx, &xstart, NULL));
946: if (xcommsize == 1) {
947: for (i = 0; i < n; i++) xindices_sorted[i] += xstart;
948: } /* Convert to global indices */
950: /*
951: Calculate info about messages I need to send
952: nsend - number of non-empty messages to send
953: sendto - [nsend] ranks I will send messages to
954: sstart - [nsend+1] sstart[i] is the start index in xsindices_sorted[] I send to rank sendto[i]
955: slens - [ycommsize] I want to send slens[i] entries to rank i.
956: */
957: PetscCall(VecGetLayout(yy, &ylayout));
958: PetscCall(PetscLayoutGetRanges(ylayout, &yrange));
959: PetscCall(PetscCalloc1(ycommsize, &slens)); /* The only O(P) array in this algorithm */
961: i = j = nsend = 0;
962: while (i < n) {
963: if (yindices_sorted[i] >= yrange[j + 1]) { /* If i-th index is out of rank j's bound */
964: do {
965: j++;
966: } while (yindices_sorted[i] >= yrange[j + 1] && j < ycommsize); /* Increase j until i-th index falls in rank j's bound */
967: PetscCheck(j != ycommsize, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Index %" PetscInt_FMT " not owned by any process, upper bound %" PetscInt_FMT, yindices_sorted[i], yrange[ycommsize]);
968: }
969: i++;
970: if (!slens[j]++) nsend++;
971: }
973: PetscCall(PetscMalloc2(nsend + 1, &sstart, nsend, &sendto));
975: sstart[0] = 0;
976: for (i = j = 0; i < ycommsize; i++) {
977: if (slens[i]) {
978: sendto[j] = (PetscMPIInt)i;
979: sstart[j + 1] = sstart[j] + slens[i];
980: j++;
981: }
982: }
984: /*
985: Calculate the reverse info about messages I will recv
986: nrecv - number of messages I will recv
987: recvfrom - [nrecv] ranks I recv from
988: rlens - [nrecv] I will recv rlens[i] entries from rank recvfrom[i]
989: rlentotal - sum of rlens[]
990: rxindices - [rlentotal] recv buffer for xindices_sorted
991: ryindices - [rlentotal] recv buffer for yindices_sorted
992: */
993: PetscCall(PetscGatherNumberOfMessages_Private(ycomm, NULL, slens, &nrecv));
994: PetscCall(PetscGatherMessageLengths_Private(ycomm, nsend, nrecv, slens, &recvfrom, &rlens));
995: PetscCall(PetscFree(slens)); /* Free the O(P) array ASAP */
996: rlentotal = 0;
997: for (i = 0; i < nrecv; i++) rlentotal += rlens[i];
999: /*
1000: Communicate with processors in recvfrom[] to populate rxindices and ryindices
1001: */
1002: PetscCall(PetscCommGetNewTag(ycomm, &tag1));
1003: PetscCall(PetscCommGetNewTag(ycomm, &tag2));
1004: PetscCall(PetscMalloc2(rlentotal, &rxindices, rlentotal, &ryindices));
1005: PetscCall(PetscMPIIntCast((nsend + nrecv) * 2, &nreq));
1006: PetscCall(PetscMalloc1(nreq, &reqs));
1007: sreqs = reqs;
1008: rreqs = PetscSafePointerPlusOffset(reqs, nsend * 2);
1010: for (i = disp = 0; i < nrecv; i++) {
1011: count = rlens[i];
1012: PetscCallMPI(MPIU_Irecv(rxindices + disp, count, MPIU_INT, recvfrom[i], tag1, ycomm, rreqs + i));
1013: PetscCallMPI(MPIU_Irecv(ryindices + disp, count, MPIU_INT, recvfrom[i], tag2, ycomm, rreqs + nrecv + i));
1014: disp += rlens[i];
1015: }
1017: for (i = 0; i < nsend; i++) {
1018: count = sstart[i + 1] - sstart[i];
1019: PetscCallMPI(MPIU_Isend(xindices_sorted + sstart[i], count, MPIU_INT, sendto[i], tag1, ycomm, sreqs + i));
1020: PetscCallMPI(MPIU_Isend(yindices_sorted + sstart[i], count, MPIU_INT, sendto[i], tag2, ycomm, sreqs + nsend + i));
1021: }
1022: PetscCallMPI(MPI_Waitall(nreq, reqs, MPI_STATUS_IGNORE));
1024: /* Transform VecScatter into SF */
1025: nleaves = rlentotal;
1026: PetscCall(PetscMalloc1(nleaves, &ilocal));
1027: PetscCall(PetscMalloc1(nleaves, &iremote));
1028: PetscCallMPI(MPI_Comm_rank(ycomm, &yrank));
1029: for (i = disp = 0; i < nrecv; i++) {
1030: for (j = 0; j < rlens[i]; j++) {
1031: k = disp + j; /* k-th index pair */
1032: ilocal[k] = ryindices[k] - yrange[yrank]; /* Convert y's global index to local index */
1033: PetscCall(PetscLayoutFindOwnerIndex(xlayout, rxindices[k], &rank, &iremote[k].index)); /* Convert x's global index to (rank, index) */
1034: iremote[k].rank = rank;
1035: }
1036: disp += rlens[i];
1037: }
1039: PetscCall(PetscFree2(sstart, sendto));
1040: PetscCall(PetscFree(rlens));
1041: PetscCall(PetscFree(recvfrom));
1042: PetscCall(PetscFree(reqs));
1043: PetscCall(PetscFree2(rxindices, ryindices));
1044: PetscCall(PetscFree2(xindices_sorted, yindices_sorted));
1045: #endif
1046: } else {
1047: /* PtoS or StoS */
1048: PetscCall(ISGetLocalSize(iyy, &nleaves));
1049: PetscCall(PetscMalloc1(nleaves, &ilocal));
1050: PetscCall(PetscMalloc1(nleaves, &iremote));
1051: PetscCall(PetscArraycpy(ilocal, yindices, nleaves));
1052: for (i = 0; i < nleaves; i++) {
1053: PetscCall(PetscLayoutFindOwnerIndex(xlayout, xindices[i], &rank, &iremote[i].index));
1054: iremote[i].rank = rank;
1055: }
1056: }
1058: /* MUST build SF on xx's comm, which is not necessarily identical to yy's comm.
1059: In SF's view, xx contains the roots (i.e., the remote) and iremote[].rank are ranks in xx's comm.
1060: yy contains leaves, which are local and can be thought as part of PETSC_COMM_SELF. */
1061: PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)xx), &sf));
1062: sf->allow_multi_leaves = PETSC_TRUE;
1063: PetscCall(PetscSFSetFromOptions(sf));
1064: PetscCall(VecGetLocalSize(xx, &nroots));
1065: PetscCall(PetscSFSetGraph(sf, nroots, nleaves, ilocal, PETSC_OWN_POINTER, iremote, PETSC_OWN_POINTER)); /* Give ilocal/iremote to petsc and no need to free them here */
1067: /* Free memory no longer needed */
1068: PetscCall(ISRestoreIndices(ixx, &xindices));
1069: PetscCall(ISRestoreIndices(iyy, &yindices));
1070: if (can_do_block_opt) {
1071: PetscCall(VecDestroy(&xx));
1072: PetscCall(VecDestroy(&yy));
1073: PetscCall(ISDestroy(&ixx));
1074: PetscCall(ISDestroy(&iyy));
1075: } else if (xcommsize == 1) {
1076: PetscCall(VecDestroy(&xx));
1077: }
1079: functionend:
1080: sf->vscat.bs = bs;
1081: if (sf->vscat.bs > 1) {
1082: PetscCallMPI(MPI_Type_contiguous((PetscMPIInt)sf->vscat.bs, MPIU_SCALAR, &sf->vscat.unit));
1083: PetscCallMPI(MPI_Type_commit(&sf->vscat.unit));
1084: } else {
1085: sf->vscat.unit = MPIU_SCALAR;
1086: }
1087: PetscCall(VecGetLocalSize(x, &sf->vscat.from_n));
1088: PetscCall(VecGetLocalSize(y, &sf->vscat.to_n));
1089: if (!ix_old) PetscCall(ISDestroy(&ix)); /* We created helper ix, iy. Free them */
1090: if (!iy_old) PetscCall(ISDestroy(&iy));
1092: /* Set default */
1093: PetscCall(VecScatterSetFromOptions(sf));
1094: PetscCall(PetscSFSetUp(sf));
1096: *newsf = sf;
1097: PetscFunctionReturn(PETSC_SUCCESS);
1098: }
1100: /*@
1101: VecScatterCreateToAll - Creates a vector and a scatter context that copies all
1102: vector values to each processor
1104: Collective
1106: Input Parameter:
1107: . vin - an `MPIVEC`
1109: Output Parameters:
1110: + ctx - scatter context
1111: - vout - output `SEQVEC` that is large enough to scatter into
1113: Level: intermediate
1115: Example Usage:
1116: .vb
1117: VecScatterCreateToAll(vin, &ctx, &vout);
1119: // scatter as many times as you need
1120: VecScatterBegin(ctx, vin, vout, INSERT_VALUES, SCATTER_FORWARD);
1121: VecScatterEnd(ctx, vin, vout, INSERT_VALUES, SCATTER_FORWARD);
1123: // destroy scatter context and local vector when no longer needed
1124: VecScatterDestroy(&ctx);
1125: VecDestroy(&vout);
1126: .ve
1128: Notes:
1129: `vout` may be `NULL` [`PETSC_NULL_VEC` from Fortran] if you do not
1130: need to have it created
1132: Do NOT create a vector and then pass it in as the final argument `vout`! `vout` is created by this routine
1133: automatically (unless you pass `NULL` in for that argument if you do not need it).
1135: .seealso: [](sec_scatter), `VecScatter`, `VecScatterCreate()`, `VecScatterCreateToZero()`, `VecScatterBegin()`, `VecScatterEnd()`
1136: @*/
1137: PetscErrorCode VecScatterCreateToAll(Vec vin, VecScatter *ctx, Vec *vout)
1138: {
1139: PetscInt N;
1140: IS is;
1141: Vec tmp;
1142: Vec *tmpv;
1143: PetscBool tmpvout = PETSC_FALSE;
1144: VecType roottype;
1146: PetscFunctionBegin;
1149: PetscAssertPointer(ctx, 2);
1150: if (vout) {
1151: PetscAssertPointer(vout, 3);
1152: tmpv = vout;
1153: } else {
1154: tmpvout = PETSC_TRUE;
1155: tmpv = &tmp;
1156: }
1158: /* Create seq vec on each proc, with the same size of the original vec */
1159: PetscCall(VecGetSize(vin, &N));
1160: PetscCall(VecGetRootType_Private(vin, &roottype));
1161: PetscCall(VecCreate(PETSC_COMM_SELF, tmpv));
1162: PetscCall(VecSetSizes(*tmpv, N, PETSC_DECIDE));
1163: PetscCall(VecSetType(*tmpv, roottype));
1164: /* Create the VecScatter ctx with the communication info */
1165: PetscCall(ISCreateStride(PETSC_COMM_SELF, N, 0, 1, &is));
1166: PetscCall(VecScatterCreate(vin, is, *tmpv, is, ctx));
1167: PetscCall(ISDestroy(&is));
1168: if (tmpvout) PetscCall(VecDestroy(tmpv));
1169: PetscFunctionReturn(PETSC_SUCCESS);
1170: }
1172: /*@
1173: VecScatterCreateToZero - Creates an output vector and a scatter context used to
1174: copy all vector values into the output vector on the zeroth processor
1176: Collective
1178: Input Parameter:
1179: . vin - `Vec` of type `MPIVEC`
1181: Output Parameters:
1182: + ctx - scatter context
1183: - vout - output `SEQVEC` that is large enough to scatter into on processor 0 and
1184: of length zero on all other processors
1186: Level: intermediate
1188: Example Usage:
1189: .vb
1190: VecScatterCreateToZero(vin, &ctx, &vout);
1192: // scatter as many times as you need
1193: VecScatterBegin(ctx, vin, vout, INSERT_VALUES, SCATTER_FORWARD);
1194: VecScatterEnd(ctx, vin, vout, INSERT_VALUES, SCATTER_FORWARD);
1196: // destroy scatter context and local vector when no longer needed
1197: VecScatterDestroy(&ctx);
1198: VecDestroy(&vout);
1199: .ve
1201: Notes:
1202: vout may be `NULL` [`PETSC_NULL_VEC` from Fortran] if you do not
1203: need to have it created
1205: Do NOT create a vector and then pass it in as the final argument `vout`! `vout` is created by this routine
1206: automatically (unless you pass `NULL` in for that argument if you do not need it).
1208: .seealso: [](sec_scatter), `VecScatter`, `VecScatterCreate()`, `VecScatterCreateToAll()`, `VecScatterBegin()`, `VecScatterEnd()`
1209: @*/
1210: PetscErrorCode VecScatterCreateToZero(Vec vin, VecScatter *ctx, Vec *vout)
1211: {
1212: PetscInt N;
1213: PetscMPIInt rank;
1214: IS is;
1215: Vec tmp;
1216: Vec *tmpv;
1217: PetscBool tmpvout = PETSC_FALSE;
1218: VecType roottype;
1220: PetscFunctionBegin;
1223: PetscAssertPointer(ctx, 2);
1224: if (vout) {
1225: PetscAssertPointer(vout, 3);
1226: tmpv = vout;
1227: } else {
1228: tmpvout = PETSC_TRUE;
1229: tmpv = &tmp;
1230: }
1232: /* Create vec on each proc, with the same size of the original vec all on process 0 */
1233: PetscCall(VecGetSize(vin, &N));
1234: PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)vin), &rank));
1235: if (rank) N = 0;
1236: PetscCall(VecGetRootType_Private(vin, &roottype));
1237: PetscCall(VecCreate(PETSC_COMM_SELF, tmpv));
1238: PetscCall(VecSetSizes(*tmpv, N, PETSC_DECIDE));
1239: PetscCall(VecSetType(*tmpv, roottype));
1240: /* Create the VecScatter ctx with the communication info */
1241: PetscCall(ISCreateStride(PETSC_COMM_SELF, N, 0, 1, &is));
1242: PetscCall(VecScatterCreate(vin, is, *tmpv, is, ctx));
1243: PetscCall(ISDestroy(&is));
1244: if (tmpvout) PetscCall(VecDestroy(tmpv));
1245: PetscFunctionReturn(PETSC_SUCCESS);
1246: }
1248: /*@
1249: VecScatterBegin - Begins a generalized scatter from one vector to
1250: another. Complete the scattering phase with `VecScatterEnd()`.
1252: Neighbor-wise Collective
1254: Input Parameters:
1255: + sf - scatter context generated by `VecScatterCreate()`
1256: . x - the vector from which we scatter
1257: . y - the vector to which we scatter
1258: . addv - either `ADD_VALUES`, `MAX_VALUES`, `MIN_VALUES` or `INSERT_VALUES`, with `INSERT_VALUES` mode any location
1259: not scattered to retains its old value; i.e. the vector is NOT first zeroed.
1260: - mode - the scattering mode, usually `SCATTER_FORWARD`. The available modes are: `SCATTER_FORWARD` or `SCATTER_REVERSE`
1262: Level: intermediate
1264: Notes:
1265: The vectors `x` and `y` need not be the same vectors used in the call
1266: to `VecScatterCreate()`, but `x` must have the same parallel data layout
1267: as that passed in as the `x` to `VecScatterCreate()`, similarly for the `y`.
1268: Most likely they have been obtained from `VecDuplicate()`.
1270: You cannot change the values in the input vector between the calls to `VecScatterBegin()`
1271: and `VecScatterEnd()`.
1273: If you use `SCATTER_REVERSE` the two arguments `x` and `y` should be reversed, from
1274: the `SCATTER_FORWARD`.
1276: y[iy[i]] = x[ix[i]], for i=0,...,ni-1
1278: This scatter is far more general than the conventional
1279: scatter, since it can be a gather or a scatter or a combination,
1280: depending on the indices ix and iy. If x is a parallel vector and y
1281: is sequential, `VecScatterBegin()` can serve to gather values to a
1282: single processor. Similarly, if `y` is parallel and `x` sequential, the
1283: routine can scatter from one processor to many processors.
1285: .seealso: [](sec_scatter), `VecScatter`, `VecScatterCreate()`, `VecScatterEnd()`
1286: @*/
1287: PetscErrorCode VecScatterBegin(VecScatter sf, Vec x, Vec y, InsertMode addv, ScatterMode mode)
1288: {
1289: PetscInt to_n, from_n;
1291: PetscFunctionBegin;
1295: if (PetscDefined(USE_DEBUG)) {
1296: /*
1297: Error checking to make sure these vectors match the vectors used
1298: to create the vector scatter context. -1 in the from_n and to_n indicate the
1299: vector lengths are unknown (for example with mapped scatters) and thus
1300: no error checking is performed.
1301: */
1302: if (sf->vscat.from_n >= 0 && sf->vscat.to_n >= 0) {
1303: PetscCall(VecGetLocalSize(x, &from_n));
1304: PetscCall(VecGetLocalSize(y, &to_n));
1305: if (mode & SCATTER_REVERSE) {
1306: PetscCheck(to_n == sf->vscat.from_n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Vector wrong size %" PetscInt_FMT " for scatter %" PetscInt_FMT " (scatter reverse and vector to != sf from size)", to_n, sf->vscat.from_n);
1307: PetscCheck(from_n == sf->vscat.to_n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Vector wrong size %" PetscInt_FMT " for scatter %" PetscInt_FMT " (scatter reverse and vector from != sf to size)", from_n, sf->vscat.to_n);
1308: } else {
1309: PetscCheck(to_n == sf->vscat.to_n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Vector wrong size %" PetscInt_FMT " for scatter %" PetscInt_FMT " (scatter forward and vector to != sf to size)", to_n, sf->vscat.to_n);
1310: PetscCheck(from_n == sf->vscat.from_n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Vector wrong size %" PetscInt_FMT " for scatter %" PetscInt_FMT " (scatter forward and vector from != sf from size)", from_n, sf->vscat.from_n);
1311: }
1312: }
1313: }
1315: sf->vscat.logging = PETSC_TRUE;
1316: PetscCall(PetscLogEventBegin(VEC_ScatterBegin, sf, x, y, 0));
1317: PetscCall(VecScatterBegin_Internal(sf, x, y, addv, mode));
1318: if (sf->vscat.beginandendtogether) PetscCall(VecScatterEnd_Internal(sf, x, y, addv, mode));
1319: PetscCall(PetscLogEventEnd(VEC_ScatterBegin, sf, x, y, 0));
1320: sf->vscat.logging = PETSC_FALSE;
1321: PetscFunctionReturn(PETSC_SUCCESS);
1322: }
1324: /*@
1325: VecScatterEnd - Ends a generalized scatter from one vector to another. Call
1326: after first calling `VecScatterBegin()`.
1328: Neighbor-wise Collective
1330: Input Parameters:
1331: + sf - scatter context generated by `VecScatterCreate()`
1332: . x - the vector from which we scatter
1333: . y - the vector to which we scatter
1334: . addv - one of `ADD_VALUES`, `MAX_VALUES`, `MIN_VALUES` or `INSERT_VALUES`
1335: - mode - the scattering mode, usually `SCATTER_FORWARD`. The available modes are: `SCATTER_FORWARD`, `SCATTER_REVERSE`
1337: Level: intermediate
1339: Notes:
1340: If you use `SCATTER_REVERSE` the arguments `x` and `y` should be reversed, from the `SCATTER_FORWARD`.
1342: y[iy[i]] = x[ix[i]], for i=0,...,ni-1
1344: .seealso: [](sec_scatter), `VecScatter`, `VecScatterBegin()`, `VecScatterCreate()`
1345: @*/
1346: PetscErrorCode VecScatterEnd(VecScatter sf, Vec x, Vec y, InsertMode addv, ScatterMode mode)
1347: {
1348: PetscFunctionBegin;
1352: if (!sf->vscat.beginandendtogether) {
1353: sf->vscat.logging = PETSC_TRUE;
1354: PetscCall(PetscLogEventBegin(VEC_ScatterEnd, sf, x, y, 0));
1355: PetscCall(VecScatterEnd_Internal(sf, x, y, addv, mode));
1356: PetscCall(PetscLogEventEnd(VEC_ScatterEnd, sf, x, y, 0));
1357: sf->vscat.logging = PETSC_FALSE;
1358: }
1359: PetscFunctionReturn(PETSC_SUCCESS);
1360: }