Actual source code: vscat.c
1: #include "petscsf.h"
2: #include "petscsystypes.h"
3: #include "petscvec.h"
4: #include <petsc/private/sfimpl.h>
5: #include <../src/vec/is/sf/impls/basic/sfbasic.h>
6: #include <../src/vec/is/sf/impls/basic/sfpack.h>
7: #include <petsc/private/vecimpl.h>
9: typedef enum {IS_INVALID, IS_GENERAL, IS_BLOCK, IS_STRIDE} ISTypeID;
11: PETSC_STATIC_INLINE PetscErrorCode ISGetTypeID_Private(IS is,ISTypeID *id)
12: {
14: PetscBool same;
17: *id = IS_INVALID;
18: PetscObjectTypeCompare((PetscObject)is,ISGENERAL,&same);
19: if (same) {*id = IS_GENERAL; goto functionend;}
20: PetscObjectTypeCompare((PetscObject)is,ISBLOCK,&same);
21: if (same) {*id = IS_BLOCK; goto functionend;}
22: PetscObjectTypeCompare((PetscObject)is,ISSTRIDE,&same);
23: if (same) {*id = IS_STRIDE; goto functionend;}
24: functionend:
25: return(0);
26: }
28: static PetscErrorCode VecScatterBegin_Internal(VecScatter sf,Vec x,Vec y,InsertMode addv,ScatterMode mode)
29: {
31: PetscSF wsf=NULL; /* either sf or its local part */
32: MPI_Op mop=MPI_OP_NULL;
33: PetscMPIInt size;
34: PetscMemType xmtype=PETSC_MEMTYPE_HOST,ymtype=PETSC_MEMTYPE_HOST;
37: if (x != y) {VecLockReadPush(x);}
38: if (sf->use_gpu_aware_mpi || sf->vscat.packongpu) {
39: VecGetArrayReadAndMemType(x,&sf->vscat.xdata,&xmtype);
40: } else {
41: VecGetArrayRead(x,&sf->vscat.xdata);
42: }
44: if (x != y) {
45: if (sf->use_gpu_aware_mpi || sf->vscat.packongpu) {VecGetArrayAndMemType(y,&sf->vscat.ydata,&ymtype);}
46: else {VecGetArray(y,&sf->vscat.ydata);}
47: } else {
48: sf->vscat.ydata = (PetscScalar *)sf->vscat.xdata;
49: ymtype = xmtype;
50: }
51: VecLockWriteSet_Private(y,PETSC_TRUE);
53: /* SCATTER_LOCAL indicates ignoring inter-process communication */
54: MPI_Comm_size(PetscObjectComm((PetscObject)sf),&size);
55: if ((mode & SCATTER_LOCAL) && size > 1) { /* Lazy creation of sf->vscat.lsf since SCATTER_LOCAL is uncommon */
56: if (!sf->vscat.lsf) {PetscSFCreateLocalSF_Private(sf,&sf->vscat.lsf);}
57: wsf = sf->vscat.lsf;
58: } else {
59: wsf = sf;
60: }
62: /* Note xdata/ydata is always recorded on sf (not lsf) above */
63: if (addv == INSERT_VALUES) mop = MPI_REPLACE;
64: else if (addv == ADD_VALUES) mop = MPIU_SUM; /* Petsc defines its own MPI datatype and SUM operation for __float128 etc. */
65: else if (addv == MAX_VALUES) mop = MPIU_MAX;
66: else if (addv == MIN_VALUES) mop = MPIU_MIN;
67: else SETERRQ1(PetscObjectComm((PetscObject)sf),PETSC_ERR_SUP,"Unsupported InsertMode %D in VecScatterBegin/End",addv);
69: if (mode & SCATTER_REVERSE) { /* REVERSE indicates leaves to root scatter. Note that x and y are swapped in input */
70: PetscSFReduceWithMemTypeBegin(wsf,sf->vscat.unit,xmtype,sf->vscat.xdata,ymtype,sf->vscat.ydata,mop);
71: } else { /* FORWARD indicates x to y scatter, where x is root and y is leaf */
72: PetscSFBcastWithMemTypeBegin(wsf,sf->vscat.unit,xmtype,sf->vscat.xdata,ymtype,sf->vscat.ydata,mop);
73: }
74: return(0);
75: }
77: static PetscErrorCode VecScatterEnd_Internal(VecScatter sf,Vec x,Vec y,InsertMode addv,ScatterMode mode)
78: {
80: PetscSF wsf=NULL;
81: MPI_Op mop=MPI_OP_NULL;
82: PetscMPIInt size;
85: /* SCATTER_LOCAL indicates ignoring inter-process communication */
86: MPI_Comm_size(PetscObjectComm((PetscObject)sf),&size);
87: wsf = ((mode & SCATTER_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 SETERRQ1(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: 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: PetscSFBcastEnd(wsf,sf->vscat.unit,sf->vscat.xdata,sf->vscat.ydata,mop);
99: }
101: if (x != y) {
102: if (sf->use_gpu_aware_mpi || sf->vscat.packongpu) {VecRestoreArrayReadAndMemType(x,&sf->vscat.xdata);}
103: else {VecRestoreArrayRead(x,&sf->vscat.xdata);}
104: VecLockReadPop(x);
105: }
107: if (sf->use_gpu_aware_mpi || sf->vscat.packongpu) {VecRestoreArrayAndMemType(y,&sf->vscat.ydata);}
108: else {VecRestoreArray(y,&sf->vscat.ydata);}
109: VecLockWriteSet_Private(y,PETSC_FALSE);
111: return(0);
112: }
114: /* VecScatterRemap provides a light way to slightly modify a VecScatter. Suppose the input sf scatters
115: x[i] to y[j], tomap gives a plan to change vscat to scatter x[tomap[i]] to y[j]. Note that in SF,
116: x is roots. That means we need to change incoming stuffs such as bas->irootloc[].
117: */
118: static PetscErrorCode VecScatterRemap_Internal(VecScatter sf,const PetscInt *tomap,const PetscInt *frommap)
119: {
120: PetscInt i,bs = sf->vscat.bs;
121: PetscMPIInt size;
122: PetscBool ident = PETSC_TRUE,isbasic,isneighbor;
123: PetscSFType type;
124: PetscSF_Basic *bas = NULL;
128: /* check if it is an identity map. If it is, do nothing */
129: if (tomap) {
130: for (i=0; i<sf->nroots*bs; i++) {if (i != tomap[i]) {ident = PETSC_FALSE; break; } }
131: if (ident) return(0);
132: }
133: if (frommap) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Unable to remap the FROM in scatters yet");
134: if (!tomap) return(0);
136: MPI_Comm_size(PetscObjectComm((PetscObject)sf),&size);
138: /* Since the indices changed, we must also update the local SF. But we do not do it since
139: lsf is rarely used. We just destroy lsf and rebuild it on demand from updated sf.
140: */
141: if (sf->vscat.lsf) {PetscSFDestroy(&sf->vscat.lsf);}
143: PetscSFGetType(sf,&type);
144: PetscObjectTypeCompare((PetscObject)sf,PETSCSFBASIC,&isbasic);
145: PetscObjectTypeCompare((PetscObject)sf,PETSCSFNEIGHBOR,&isneighbor);
146: if (!isbasic && !isneighbor) SETERRQ1(PetscObjectComm((PetscObject)sf),PETSC_ERR_SUP,"VecScatterRemap on SF type %s is not supported",type);
148: PetscSFSetUp(sf); /* to bulid sf->irootloc if SetUp is not yet called */
150: /* Root indices are going to be remapped. This is tricky for SF. Root indices are used in sf->rremote,
151: sf->remote and bas->irootloc. The latter one is cheap to remap, but the former two are not.
152: To remap them, we have to do a bcast from roots to leaves, to let leaves know their updated roots.
153: Since VecScatterRemap is supposed to be a cheap routine to adapt a vecscatter by only changing where
154: x[] data is taken, we do not remap sf->rremote, sf->remote. The consequence is that operations
155: accessing them (such as PetscSFCompose) may get stale info. Considering VecScatter does not need
156: that complicated SF operations, we do not remap sf->rremote, sf->remote, instead we destroy them
157: so that code accessing them (if any) will crash (instead of get silent errors). Note that BcastAndOp/Reduce,
158: which are used by VecScatter and only rely on bas->irootloc, are updated and correct.
159: */
160: sf->remote = NULL;
161: PetscFree(sf->remote_alloc);
162: /* Not easy to free sf->rremote since it was allocated with PetscMalloc4(), so just give it crazy values */
163: for (i=0; i<sf->roffset[sf->nranks]; i++) sf->rremote[i] = PETSC_MIN_INT;
165: /* Indices in tomap[] are for each indivisual vector entry. But indices in sf are for each
166: block in the vector. So before the remapping, we have to expand indices in sf by bs, and
167: after the remapping, we have to shrink them back.
168: */
169: bas = (PetscSF_Basic*)sf->data;
170: for (i=0; i<bas->ioffset[bas->niranks]; i++) bas->irootloc[i] = tomap[bas->irootloc[i]*bs]/bs;
171: #if defined(PETSC_HAVE_DEVICE)
172: /* Free the irootloc copy on device. We allocate a new copy and get the updated value on demand. See PetscSFLinkGetRootPackOptAndIndices() */
173: for (i=0; i<2; i++) {PetscSFFree(sf,PETSC_MEMTYPE_DEVICE,bas->irootloc_d[i]);}
174: #endif
175: /* Destroy and then rebuild root packing optimizations since indices are changed */
176: PetscSFResetPackFields(sf);
177: PetscSFSetUpPackFields(sf);
178: return(0);
179: }
181: /* Given a parallel VecScatter context, return number of procs and vector entries involved in remote (i.e., off-process) communication
183: Input Parameters:
184: + sf - the context (must be a parallel vecscatter)
185: - send - true to select the send info (i.e., todata), otherwise to select the recv info (i.e., fromdata)
187: Output parameters:
188: + num_procs - number of remote processors
189: - num_entries - number of vector entries to send or recv
192: .seealso: VecScatterGetRemote_Private(), VecScatterGetRemoteOrdered_Private()
194: Notes:
195: Sometimes PETSc internally needs to use the matrix-vector-multiply vecscatter context for other purposes. The client code
196: usually only uses MPI_Send/Recv. This group of subroutines provides info needed for such uses.
197: */
198: PetscErrorCode VecScatterGetRemoteCount_Private(VecScatter sf,PetscBool send,PetscInt *num_procs,PetscInt *num_entries)
199: {
200: PetscErrorCode ierr;
201: PetscInt nranks,remote_start;
202: PetscMPIInt rank;
203: const PetscInt *offset;
204: const PetscMPIInt *ranks;
207: PetscSFSetUp(sf);
208: MPI_Comm_rank(PetscObjectComm((PetscObject)sf),&rank);
210: /* This routine is mainly used for MatMult's Mvctx. In Mvctx, we scatter an MPI vector x to a sequential vector lvec.
211: Remember x is roots and lvec is leaves. 'send' means roots to leaves communication. If 'send' is true, we need to
212: get info about which ranks this processor needs to send to. In other words, we need to call PetscSFGetLeafRanks().
213: If send is false, we do the opposite, calling PetscSFGetRootRanks().
214: */
215: if (send) {PetscSFGetLeafRanks(sf,&nranks,&ranks,&offset,NULL);}
216: else {PetscSFGetRootRanks(sf,&nranks,&ranks,&offset,NULL,NULL);}
217: if (nranks) {
218: remote_start = (rank == ranks[0])? 1 : 0;
219: if (num_procs) *num_procs = nranks - remote_start;
220: if (num_entries) *num_entries = offset[nranks] - offset[remote_start];
221: } else {
222: if (num_procs) *num_procs = 0;
223: if (num_entries) *num_entries = 0;
224: }
225: return(0);
226: }
228: /* Given a parallel VecScatter context, return a plan that represents the remote communication.
229: Any output parameter can be NULL.
231: Input Parameters:
232: + sf - the context
233: - send - true to select the send info (i.e., todata), otherwise to select the recv info (i.e., fromdata)
235: Output parameters:
236: + n - number of remote processors
237: . starts - starting point in indices for each proc. ATTENTION: starts[0] is not necessarily zero.
238: Therefore, expressions like starts[i+1]-starts[i] and indices[starts[i]+j] work as
239: expected for a CSR structure but buf[starts[i]+j] may be out of range if buf was allocated
240: with length starts[n]-starts[0]. One should use buf[starts[i]-starts[0]+j] instead.
241: . indices - indices of entries to send/recv
242: . procs - ranks of remote processors
243: - bs - block size
245: .seealso: VecScatterRestoreRemote_Private(), VecScatterGetRemoteOrdered_Private()
246: */
247: PetscErrorCode VecScatterGetRemote_Private(VecScatter sf,PetscBool send,PetscInt *n,const PetscInt **starts,const PetscInt **indices,const PetscMPIInt **procs,PetscInt *bs)
248: {
249: PetscErrorCode ierr;
250: PetscInt nranks,remote_start;
251: PetscMPIInt rank;
252: const PetscInt *offset,*location;
253: const PetscMPIInt *ranks;
256: PetscSFSetUp(sf);
257: MPI_Comm_rank(PetscObjectComm((PetscObject)sf),&rank);
259: if (send) {PetscSFGetLeafRanks(sf,&nranks,&ranks,&offset,&location);}
260: else {PetscSFGetRootRanks(sf,&nranks,&ranks,&offset,&location,NULL);}
262: if (nranks) {
263: remote_start = (rank == ranks[0])? 1 : 0;
264: if (n) *n = nranks - remote_start;
265: if (starts) *starts = &offset[remote_start];
266: if (indices) *indices = location; /* not &location[offset[remote_start]]. Starts[0] may point to the middle of indices[] */
267: if (procs) *procs = &ranks[remote_start];
268: } else {
269: if (n) *n = 0;
270: if (starts) *starts = NULL;
271: if (indices) *indices = NULL;
272: if (procs) *procs = NULL;
273: }
275: if (bs) *bs = 1;
276: return(0);
277: }
279: /* Given a parallel VecScatter context, return a plan that represents the remote communication. Ranks of remote
280: processors returned in procs must be sorted in ascending order. Any output parameter can be NULL.
282: Input Parameters:
283: + sf - the context
284: - send - true to select the send info (i.e., todata), otherwise to select the recv info (i.e., fromdata)
286: Output parameters:
287: + n - number of remote processors
288: . starts - starting point in indices for each proc. ATTENTION: starts[0] is not necessarily zero.
289: Therefore, expressions like starts[i+1]-starts[i] and indices[starts[i]+j] work as
290: expected for a CSR structure but buf[starts[i]+j] may be out of range if buf was allocated
291: with length starts[n]-starts[0]. One should use buf[starts[i]-starts[0]+j] instead.
292: . indices - indices of entries to send/recv
293: . procs - ranks of remote processors
294: - bs - block size
296: .seealso: VecScatterRestoreRemoteOrdered_Private(), VecScatterGetRemote_Private()
298: Notes:
299: Output parameters like starts, indices must also be adapted according to the sorted ranks.
300: */
301: PetscErrorCode VecScatterGetRemoteOrdered_Private(VecScatter sf,PetscBool send,PetscInt *n,const PetscInt **starts,const PetscInt **indices,const PetscMPIInt **procs,PetscInt *bs)
302: {
306: VecScatterGetRemote_Private(sf,send,n,starts,indices,procs,bs);
307: if (PetscUnlikelyDebug(n && procs)) {
308: PetscInt i;
309: /* from back to front to also handle cases *n=0 */
310: for (i=*n-1; i>0; i--) { if ((*procs)[i-1] > (*procs)[i]) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"procs[] are not ordered"); }
311: }
312: return(0);
313: }
315: /* Given a parallel VecScatter context, restore the plan returned by VecScatterGetRemote_Private. This gives a chance for
316: an implementation to free memory allocated in the VecScatterGetRemote_Private call.
318: Input Parameters:
319: + sf - the context
320: - send - true to select the send info (i.e., todata), otherwise to select the recv info (i.e., fromdata)
322: Output parameters:
323: + n - number of remote processors
324: . starts - starting point in indices for each proc
325: . indices - indices of entries to send/recv
326: . procs - ranks of remote processors
327: - bs - block size
329: .seealso: VecScatterGetRemote_Private()
330: */
331: PetscErrorCode VecScatterRestoreRemote_Private(VecScatter sf,PetscBool send,PetscInt *n,const PetscInt **starts,const PetscInt **indices,const PetscMPIInt **procs,PetscInt *bs)
332: {
334: if (starts) *starts = NULL;
335: if (indices) *indices = NULL;
336: if (procs) *procs = NULL;
337: return(0);
338: }
340: /* Given a parallel VecScatter context, restore the plan returned by VecScatterGetRemoteOrdered_Private. This gives a chance for
341: an implementation to free memory allocated in the VecScatterGetRemoteOrdered_Private call.
343: Input Parameters:
344: + sf - the context
345: - send - true to select the send info (i.e., todata), otherwise to select the recv info (i.e., fromdata)
347: Output parameters:
348: + n - number of remote processors
349: . starts - starting point in indices for each proc
350: . indices - indices of entries to send/recv
351: . procs - ranks of remote processors
352: - bs - block size
354: .seealso: VecScatterGetRemoteOrdered_Private()
355: */
356: PetscErrorCode VecScatterRestoreRemoteOrdered_Private(VecScatter sf,PetscBool send,PetscInt *n,const PetscInt **starts,const PetscInt **indices,const PetscMPIInt **procs,PetscInt *bs)
357: {
360: VecScatterRestoreRemote_Private(sf,send,n,starts,indices,procs,bs);
361: return(0);
362: }
364: /*@
365: VecScatterSetUp - Sets up the VecScatter to be able to actually scatter information between vectors
367: Collective on VecScatter
369: Input Parameter:
370: . sf - the scatter context
372: Level: intermediate
374: .seealso: VecScatterCreate(), VecScatterCopy()
375: @*/
376: PetscErrorCode VecScatterSetUp(VecScatter sf)
377: {
380: PetscSFSetUp(sf);
381: return(0);
382: }
384: /*@C
385: VecScatterSetType - Builds a vector scatter, for a particular vector scatter implementation.
387: Collective on VecScatter
389: Input Parameters:
390: + sf - The VecScatter (SF) object
391: - type - The name of the vector scatter type
393: Options Database Key:
394: . -sf_type <type> - Sets the VecScatter (SF) type
396: Notes:
397: Use VecScatterDuplicate() to form additional vectors scatter of the same type as an existing vector scatter.
399: Level: intermediate
401: .seealso: VecScatterGetType(), VecScatterCreate()
402: @*/
403: PetscErrorCode VecScatterSetType(VecScatter sf, VecScatterType type)
404: {
408: PetscSFSetType(sf,type);
409: return(0);
410: }
412: /*@C
413: VecScatterGetType - Gets the vector scatter type name (as a string) from the VecScatter.
415: Not Collective
417: Input Parameter:
418: . sf - The vector scatter (SF)
420: Output Parameter:
421: . type - The vector scatter type name
423: Level: intermediate
425: .seealso: VecScatterSetType(), VecScatterCreate()
426: @*/
427: PetscErrorCode VecScatterGetType(VecScatter sf, VecScatterType *type)
428: {
431: PetscSFGetType(sf,type);
432: return(0);
433: }
435: /*@C
436: VecScatterRegister - Adds a new vector scatter component implementation
438: Not Collective
440: Input Parameters:
441: + name - The name of a new user-defined creation routine
442: - create_func - The creation routine itself
444: Level: advanced
446: .seealso: VecRegister()
447: @*/
448: PetscErrorCode VecScatterRegister(const char sname[], PetscErrorCode (*function)(VecScatter))
449: {
452: PetscSFRegister(sname,function);
453: return(0);
454: }
456: /* ------------------------------------------------------------------*/
457: /*@
458: VecScatterGetMerged - Returns true if the scatter is completed in the VecScatterBegin()
459: and the VecScatterEnd() does nothing
461: Not Collective
463: Input Parameter:
464: . sf - scatter context created with VecScatterCreate()
466: Output Parameter:
467: . flg - PETSC_TRUE if the VecScatterBegin/End() are all done during the VecScatterBegin()
469: Level: developer
471: .seealso: VecScatterCreate(), VecScatterEnd(), VecScatterBegin()
472: @*/
473: PetscErrorCode VecScatterGetMerged(VecScatter sf,PetscBool *flg)
474: {
477: if (flg) *flg = sf->vscat.beginandendtogether;
478: return(0);
479: }
480: /*@C
481: VecScatterDestroy - Destroys a scatter context created by VecScatterCreate()
483: Collective on VecScatter
485: Input Parameter:
486: . sf - the scatter context
488: Level: intermediate
490: .seealso: VecScatterCreate(), VecScatterCopy()
491: @*/
492: PetscErrorCode VecScatterDestroy(VecScatter *sf)
493: {
497: PetscSFDestroy(sf);
498: return(0);
499: }
501: /*@
502: VecScatterCopy - Makes a copy of a scatter context.
504: Collective on VecScatter
506: Input Parameter:
507: . sf - the scatter context
509: Output Parameter:
510: . newsf - the context copy
512: Level: advanced
514: .seealso: VecScatterCreate(), VecScatterDestroy()
515: @*/
516: PetscErrorCode VecScatterCopy(VecScatter sf,VecScatter *newsf)
517: {
522: PetscSFDuplicate(sf,PETSCSF_DUPLICATE_GRAPH,newsf);
523: PetscSFSetUp(*newsf);
524: return(0);
525: }
527: /*@C
528: VecScatterViewFromOptions - View from Options
530: Collective on VecScatter
532: Input Parameters:
533: + sf - the scatter context
534: . obj - Optional object
535: - name - command line option
537: Level: intermediate
538: .seealso: VecScatter, VecScatterView, PetscObjectViewFromOptions(), VecScatterCreate()
539: @*/
540: PetscErrorCode VecScatterViewFromOptions(VecScatter sf,PetscObject obj,const char name[])
541: {
546: PetscObjectViewFromOptions((PetscObject)sf,obj,name);
547: return(0);
548: }
550: /* ------------------------------------------------------------------*/
551: /*@C
552: VecScatterView - Views a vector scatter context.
554: Collective on VecScatter
556: Input Parameters:
557: + sf - the scatter context
558: - viewer - the viewer for displaying the context
560: Level: intermediate
562: @*/
563: PetscErrorCode VecScatterView(VecScatter sf,PetscViewer viewer)
564: {
568: PetscSFView(sf,viewer);
569: return(0);
570: }
572: /*@C
573: VecScatterRemap - Remaps the "from" and "to" indices in a
574: vector scatter context. FOR EXPERTS ONLY!
576: Collective on VecScatter
578: Input Parameters:
579: + sf - vector scatter context
580: . tomap - remapping plan for "to" indices (may be NULL).
581: - frommap - remapping plan for "from" indices (may be NULL)
583: Level: developer
585: Notes:
586: In the parallel case the todata contains indices from where the data is taken
587: (and then sent to others)! The fromdata contains indices from where the received
588: data is finally put locally.
590: In the sequential case the todata contains indices from where the data is put
591: and the fromdata contains indices from where the data is taken from.
592: This is backwards from the paralllel case!
594: @*/
595: PetscErrorCode VecScatterRemap(VecScatter sf,PetscInt tomap[],PetscInt frommap[])
596: {
597: PetscInt ierr;
602: VecScatterRemap_Internal(sf,tomap,frommap);
603: if (frommap) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Unable to remap the FROM in scatters yet");
604: /* Mark then vector lengths as unknown because we do not know the lengths of the remapped vectors */
605: sf->vscat.from_n = -1;
606: sf->vscat.to_n = -1;
607: return(0);
608: }
610: /*@
611: VecScatterSetFromOptions - Configures the vector scatter from the options database.
613: Collective on VecScatter
615: Input Parameter:
616: . sf - The vector scatter
618: Notes:
619: To see all options, run your program with the -help option, or consult the users manual.
620: Must be called before VecScatterSetUp() but before the vector scatter is used.
622: Level: beginner
625: .seealso: VecScatterCreate(), VecScatterDestroy(), VecScatterSetUp()
626: @*/
627: PetscErrorCode VecScatterSetFromOptions(VecScatter sf)
628: {
633: PetscObjectOptionsBegin((PetscObject)sf);
635: sf->vscat.beginandendtogether = PETSC_FALSE;
636: PetscOptionsBool("-vecscatter_merge","Use combined (merged) vector scatter begin and end","VecScatterCreate",sf->vscat.beginandendtogether,&sf->vscat.beginandendtogether,NULL);
637: if (sf->vscat.beginandendtogether) {PetscInfo(sf,"Using combined (merged) vector scatter begin and end\n");}
639: sf->vscat.packongpu = PETSC_TRUE;
640: PetscOptionsBool("-vecscatter_packongpu","For GPU vectors, pack needed entries on GPU, then copy packed data to CPU, then do MPI","VecScatterCreate",sf->vscat.packongpu,&sf->vscat.packongpu,NULL);
641: if (sf->vscat.packongpu) {PetscInfo(sf,"For GPU vectors, pack needed entries on GPU, then copy packed data to CPU, then do MPI\n");}
642: PetscOptionsEnd();
643: return(0);
644: }
646: /* ---------------------------------------------------------------- */
647: /*@
648: VecScatterCreate - Creates a vector scatter context.
650: Collective on Vec
652: Input Parameters:
653: + xin - a vector that defines the shape (parallel data layout of the vector)
654: of vectors from which we scatter
655: . yin - a vector that defines the shape (parallel data layout of the vector)
656: of vectors to which we scatter
657: . ix - the indices of xin to scatter (if NULL scatters all values)
658: - iy - the indices of yin to hold results (if NULL fills entire vector yin)
660: Output Parameter:
661: . newsf - location to store the new scatter (SF) context
663: Options Database Keys:
664: + -vecscatter_view - Prints detail of communications
665: . -vecscatter_view ::ascii_info - Print less details about communication
666: . -vecscatter_merge - VecScatterBegin() handles all of the communication, VecScatterEnd() is a nop
667: eliminates the chance for overlap of computation and communication
668: - -vecscatter_packongpu - For GPU vectors, pack needed entries on GPU, then copy packed data to CPU, then do MPI.
669: Otherwise, we might copy a segment encompassing needed entries. Default is TRUE.
671: Level: intermediate
673: Notes:
674: If both xin and yin are parallel, their communicator must be on the same
675: set of processes, but their process order can be different.
676: In calls to VecScatter() you can use different vectors than the xin and
677: yin you used above; BUT they must have the same parallel data layout, for example,
678: they could be obtained from VecDuplicate().
679: A VecScatter context CANNOT be used in two or more simultaneous scatters;
680: that is you cannot call a second VecScatterBegin() with the same scatter
681: context until the VecScatterEnd() has been called on the first VecScatterBegin().
682: In this case a separate VecScatter is needed for each concurrent scatter.
684: Currently the MPI_Send() use PERSISTENT versions.
685: (this unfortunately requires that the same in and out arrays be used for each use, this
686: is why we always need to pack the input into the work array before sending
687: and unpack upon receiving instead of using MPI datatypes to avoid the packing/unpacking).
689: Both ix and iy cannot be NULL at the same time.
691: Use VecScatterCreateToAll() to create a vecscatter that copies an MPI vector to sequential vectors on all MPI ranks.
692: Use VecScatterCreateToZero() to create a vecscatter that copies an MPI vector to a sequential vector on MPI rank 0.
693: These special vecscatters have better performance than general ones.
695: .seealso: VecScatterDestroy(), VecScatterCreateToAll(), VecScatterCreateToZero(), PetscSFCreate()
696: @*/
697: PetscErrorCode VecScatterCreate(Vec x,IS ix,Vec y,IS iy,VecScatter *newsf)
698: {
700: MPI_Comm xcomm,ycomm,bigcomm;
701: Vec xx,yy;
702: IS ix_old=ix,iy_old=iy,ixx,iyy;
703: PetscMPIInt xcommsize,ycommsize,rank,result;
704: PetscInt i,n,N,nroots,nleaves,*ilocal,xstart,ystart,ixsize,iysize,xlen,ylen;
705: const PetscInt *xindices,*yindices;
706: PetscSFNode *iremote;
707: PetscLayout xlayout,ylayout;
708: ISTypeID ixid,iyid;
709: PetscInt bs,bsx,bsy,min,max,m[2],ixfirst,ixstep,iyfirst,iystep;
710: PetscBool can_do_block_opt=PETSC_FALSE;
711: PetscSF sf;
715: if (!ix && !iy) SETERRQ(PetscObjectComm((PetscObject)x),PETSC_ERR_SUP,"Cannot pass default in for both input and output indices");
717: /* Get comm from x and y */
718: PetscObjectGetComm((PetscObject)x,&xcomm);
719: MPI_Comm_size(xcomm,&xcommsize);
720: PetscObjectGetComm((PetscObject)y,&ycomm);
721: MPI_Comm_size(ycomm,&ycommsize);
722: if (xcommsize > 1 && ycommsize > 1) {
723: MPI_Comm_compare(xcomm,ycomm,&result);
724: if (result == MPI_UNEQUAL) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NOTSAMECOMM,"VecScatterCreate: parallel vectors x and y must have identical/congruent/similar communicators");
725: }
726: bs = 1; /* default, no blocking */
728: /*
729: Let P and S stand for parallel and sequential vectors respectively. There are four combinations of vecscatters: PtoP, PtoS,
730: StoP and StoS. The assumption of VecScatterCreate(Vec x,IS ix,Vec y,IS iy,VecScatter *newctx) is: if x is parallel, then ix
731: contains global indices of x. If x is sequential, ix contains local indices of x. Similarily for y and iy.
733: SF builds around concepts of local leaves and remote roots. We treat source vector x as roots and destination vector y as
734: leaves. A PtoS scatter can be naturally mapped to SF. We transform PtoP and StoP to PtoS, and treat StoS as trivial PtoS.
735: */
737: /* NULL ix or iy in VecScatterCreate(x,ix,y,iy,newctx) has special meaning. Recover them for these cases */
738: if (!ix) {
739: if (xcommsize > 1 && ycommsize == 1) { /* PtoS: null ix means the whole x will be scattered to each seq y */
740: VecGetSize(x,&N);
741: ISCreateStride(PETSC_COMM_SELF,N,0,1,&ix);
742: } else { /* PtoP, StoP or StoS: null ix means the whole local part of x will be scattered */
743: VecGetLocalSize(x,&n);
744: VecGetOwnershipRange(x,&xstart,NULL);
745: ISCreateStride(PETSC_COMM_SELF,n,xstart,1,&ix);
746: }
747: }
749: if (!iy) {
750: if (xcommsize == 1 && ycommsize > 1) { /* StoP: null iy means the whole y will be scattered to from each seq x */
751: VecGetSize(y,&N);
752: ISCreateStride(PETSC_COMM_SELF,N,0,1,&iy);
753: } else { /* PtoP, StoP or StoS: null iy means the whole local part of y will be scattered to */
754: VecGetLocalSize(y,&n);
755: VecGetOwnershipRange(y,&ystart,NULL);
756: ISCreateStride(PETSC_COMM_SELF,n,ystart,1,&iy);
757: }
758: }
760: /* Do error checking immediately after we have non-empty ix, iy */
761: ISGetLocalSize(ix,&ixsize);
762: ISGetLocalSize(iy,&iysize);
763: VecGetSize(x,&xlen);
764: VecGetSize(y,&ylen);
765: if (ixsize != iysize) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Scatter sizes of ix and iy don't match locally");
766: ISGetMinMax(ix,&min,&max);
767: if (min < 0 || max >= xlen) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Scatter indices in ix are out of range");
768: ISGetMinMax(iy,&min,&max);
769: if (min < 0 || max >= ylen) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Scatter indices in iy are out of range");
771: /* Extract info about ix, iy for further test */
772: ISGetTypeID_Private(ix,&ixid);
773: ISGetTypeID_Private(iy,&iyid);
774: if (ixid == IS_BLOCK) {ISGetBlockSize(ix,&bsx);}
775: else if (ixid == IS_STRIDE) {ISStrideGetInfo(ix,&ixfirst,&ixstep);}
777: if (iyid == IS_BLOCK) {ISGetBlockSize(iy,&bsy);}
778: else if (iyid == IS_STRIDE) {ISStrideGetInfo(iy,&iyfirst,&iystep);}
780: /* Check if a PtoS is special ToAll/ToZero scatters, which can be results of VecScatterCreateToAll/Zero.
781: ToAll means a whole MPI vector is copied to a seq vector on every process. ToZero means a whole MPI
782: vector is copied to a seq vector on rank 0 and other processes do nothing(i.e.,they input empty ix,iy).
784: We can optimize these scatters with MPI collectives. We can also avoid costly analysis used for general scatters.
785: */
786: if (xcommsize > 1 && ycommsize == 1) { /* Ranks do not diverge at this if-test */
787: PetscInt pattern[2] = {0, 0}; /* A boolean array with pattern[0] for allgather-like (ToAll) and pattern[1] for gather-like (ToZero) */
788: PetscLayout map;
790: MPI_Comm_rank(xcomm,&rank);
791: VecGetLayout(x,&map);
792: if (!rank) {
793: if (ixid == IS_STRIDE && iyid == IS_STRIDE && ixsize == xlen && ixfirst == 0 && ixstep == 1 && iyfirst == 0 && iystep == 1) {
794: /* Rank 0 scatters the whole mpi x to seq y, so it is either a ToAll or a ToZero candidate in its view */
795: pattern[0] = pattern[1] = 1;
796: }
797: } else {
798: if (ixid == IS_STRIDE && iyid == IS_STRIDE && ixsize == xlen && ixfirst == 0 && ixstep == 1 && iyfirst == 0 && iystep == 1) {
799: /* Other ranks also scatter the whole mpi x to seq y, so it is a ToAll candidate in their view */
800: pattern[0] = 1;
801: } else if (ixsize == 0) {
802: /* Other ranks do nothing, so it is a ToZero candiate */
803: pattern[1] = 1;
804: }
805: }
807: /* One stone (the expensive allreduce) two birds: pattern[] tells if it is ToAll or ToZero */
808: MPIU_Allreduce(MPI_IN_PLACE,pattern,2,MPIU_INT,MPI_LAND,xcomm);
810: if (pattern[0] || pattern[1]) {
811: PetscSFCreate(xcomm,&sf);
812: PetscSFSetFromOptions(sf);
813: PetscSFSetGraphWithPattern(sf,map,pattern[0] ? PETSCSF_PATTERN_ALLGATHER : PETSCSF_PATTERN_GATHER);
814: goto functionend; /* No further analysis needed. What a big win! */
815: }
816: }
818: /* Continue ...
819: Do block optimization by taking advantage of high level info available in ix, iy.
820: The block optimization is valid when all of the following conditions are met:
821: 1) ix, iy are blocked or can be blocked (i.e., strided with step=1);
822: 2) ix, iy have the same block size;
823: 3) all processors agree on one block size;
824: 4) no blocks span more than one process;
825: */
826: bigcomm = (xcommsize == 1) ? ycomm : xcomm;
828: /* Processors could go through different path in this if-else test */
829: m[0] = m[1] = PETSC_MPI_INT_MIN;
830: if (ixid == IS_BLOCK && iyid == IS_BLOCK) {
831: m[0] = PetscMax(bsx,bsy);
832: m[1] = -PetscMin(bsx,bsy);
833: } else if (ixid == IS_BLOCK && iyid == IS_STRIDE && iystep==1 && iyfirst%bsx==0) {
834: m[0] = bsx;
835: m[1] = -bsx;
836: } else if (ixid == IS_STRIDE && iyid == IS_BLOCK && ixstep==1 && ixfirst%bsy==0) {
837: m[0] = bsy;
838: m[1] = -bsy;
839: }
840: /* Get max and min of bsx,bsy over all processes in one allreduce */
841: MPIU_Allreduce(MPI_IN_PLACE,m,2,MPIU_INT,MPI_MAX,bigcomm);
842: max = m[0]; min = -m[1];
844: /* Since we used allreduce above, all ranks will have the same min and max. min==max
845: implies all ranks have the same bs. Do further test to see if local vectors are dividable
846: by bs on ALL ranks. If they are, we are ensured that no blocks span more than one processor.
847: */
848: if (min == max && min > 1) {
849: VecGetLocalSize(x,&xlen);
850: VecGetLocalSize(y,&ylen);
851: m[0] = xlen%min;
852: m[1] = ylen%min;
853: MPIU_Allreduce(MPI_IN_PLACE,m,2,MPIU_INT,MPI_LOR,bigcomm);
854: if (!m[0] && !m[1]) can_do_block_opt = PETSC_TRUE;
855: }
857: /* If can_do_block_opt, then shrink x, y, ix and iy by bs to get xx, yy, ixx and iyy, whose indices
858: and layout are actually used in building SF. Suppose blocked ix representing {0,1,2,6,7,8} has
859: indices {0,2} and bs=3, then ixx = {0,2}; suppose strided iy={3,4,5,6,7,8}, then iyy={1,2}.
861: xx is a little special. If x is seq, then xx is the concatenation of seq x's on ycomm. In this way,
862: we can treat PtoP and StoP uniformly as PtoS.
863: */
864: if (can_do_block_opt) {
865: const PetscInt *indices;
867: /* Shrink x and ix */
868: bs = min;
869: VecCreateMPIWithArray(bigcomm,1,xlen/bs,PETSC_DECIDE,NULL,&xx); /* We only care xx's layout */
870: if (ixid == IS_BLOCK) {
871: ISBlockGetIndices(ix,&indices);
872: ISBlockGetLocalSize(ix,&ixsize);
873: ISCreateGeneral(PETSC_COMM_SELF,ixsize,indices,PETSC_COPY_VALUES,&ixx);
874: ISBlockRestoreIndices(ix,&indices);
875: } else { /* ixid == IS_STRIDE */
876: ISGetLocalSize(ix,&ixsize);
877: ISCreateStride(PETSC_COMM_SELF,ixsize/bs,ixfirst/bs,1,&ixx);
878: }
880: /* Shrink y and iy */
881: VecCreateMPIWithArray(ycomm,1,ylen/bs,PETSC_DECIDE,NULL,&yy);
882: if (iyid == IS_BLOCK) {
883: ISBlockGetIndices(iy,&indices);
884: ISBlockGetLocalSize(iy,&iysize);
885: ISCreateGeneral(PETSC_COMM_SELF,iysize,indices,PETSC_COPY_VALUES,&iyy);
886: ISBlockRestoreIndices(iy,&indices);
887: } else { /* iyid == IS_STRIDE */
888: ISGetLocalSize(iy,&iysize);
889: ISCreateStride(PETSC_COMM_SELF,iysize/bs,iyfirst/bs,1,&iyy);
890: }
891: } else {
892: ixx = ix;
893: iyy = iy;
894: yy = y;
895: if (xcommsize == 1) {VecCreateMPIWithArray(bigcomm,1,xlen,PETSC_DECIDE,NULL,&xx);} else xx = x;
896: }
898: /* Now it is ready to build SF with preprocessed (xx, yy) and (ixx, iyy) */
899: ISGetIndices(ixx,&xindices);
900: ISGetIndices(iyy,&yindices);
901: VecGetLayout(xx,&xlayout);
903: if (ycommsize > 1) {
904: /* PtoP or StoP */
906: /* Below is a piece of complex code with a very simple goal: move global index pairs (xindices[i], yindices[i]),
907: to owner process of yindices[i] according to ylayout, i = 0..n.
909: I did it through a temp sf, but later I thought the old design was inefficient and also distorted log view.
910: We want to mape one VecScatterCreate() call to one PetscSFCreate() call. The old design mapped to three
911: PetscSFCreate() calls. This code is on critical path of VecScatterSetUp and is used by every VecScatterCreate.
912: So I commented it out and did another optimized implementation. The commented code is left here for reference.
913: */
914: #if 0
915: const PetscInt *degree;
916: PetscSF tmpsf;
917: PetscInt inedges=0,*leafdata,*rootdata;
919: VecGetOwnershipRange(xx,&xstart,NULL);
920: VecGetLayout(yy,&ylayout);
921: VecGetOwnershipRange(yy,&ystart,NULL);
923: VecGetLocalSize(yy,&nroots);
924: ISGetLocalSize(iyy,&nleaves);
925: PetscMalloc2(nleaves,&iremote,nleaves*2,&leafdata);
927: for (i=0; i<nleaves; i++) {
928: PetscLayoutFindOwnerIndex(ylayout,yindices[i],&iremote[i].rank,&iremote[i].index);
929: leafdata[2*i] = yindices[i];
930: leafdata[2*i+1] = (xcommsize > 1)? xindices[i] : xindices[i] + xstart;
931: }
933: PetscSFCreate(ycomm,&tmpsf);
934: PetscSFSetGraph(tmpsf,nroots,nleaves,NULL,PETSC_USE_POINTER,iremote,PETSC_USE_POINTER);
936: PetscSFComputeDegreeBegin(tmpsf,°ree);
937: PetscSFComputeDegreeEnd(tmpsf,°ree);
939: for (i=0; i<nroots; i++) inedges += degree[i];
940: PetscMalloc1(inedges*2,&rootdata);
941: PetscSFGatherBegin(tmpsf,MPIU_2INT,leafdata,rootdata);
942: PetscSFGatherEnd(tmpsf,MPIU_2INT,leafdata,rootdata);
944: PetscFree2(iremote,leafdata);
945: PetscSFDestroy(&tmpsf);
947: /* rootdata contains global index pairs (i, j). j's are owned by the current process, but i's can point to anywhere.
948: We convert j to local, and convert i to (rank, index). In the end, we get an PtoS suitable for building SF.
949: */
950: nleaves = inedges;
951: VecGetLocalSize(xx,&nroots);
952: PetscMalloc1(nleaves,&ilocal);
953: PetscMalloc1(nleaves,&iremote);
955: for (i=0; i<inedges; i++) {
956: ilocal[i] = rootdata[2*i] - ystart; /* covert y's global index to local index */
957: PetscLayoutFindOwnerIndex(xlayout,rootdata[2*i+1],&iremote[i].rank,&iremote[i].index); /* convert x's global index to (rank, index) */
958: }
959: PetscFree(rootdata);
960: #else
961: PetscInt j,k,n,disp,rlentotal,*sstart,*xindices_sorted,*yindices_sorted;
962: const PetscInt *yrange;
963: PetscMPIInt nsend,nrecv,nreq,count,yrank,*slens,*rlens,*sendto,*recvfrom,tag1,tag2;
964: PetscInt *rxindices,*ryindices;
965: MPI_Request *reqs,*sreqs,*rreqs;
967: /* Sorting makes code simpler, faster and also helps getting rid of many O(P) arrays, which hurt scalability at large scale
968: yindices_sorted - sorted yindices
969: xindices_sorted - xindices sorted along with yindces
970: */
971: ISGetLocalSize(ixx,&n); /*ixx, iyy have the same local size */
972: PetscMalloc2(n,&xindices_sorted,n,&yindices_sorted);
973: PetscArraycpy(xindices_sorted,xindices,n);
974: PetscArraycpy(yindices_sorted,yindices,n);
975: PetscSortIntWithArray(n,yindices_sorted,xindices_sorted);
976: VecGetOwnershipRange(xx,&xstart,NULL);
977: if (xcommsize == 1) {for (i=0; i<n; i++) xindices_sorted[i] += xstart;} /* Convert to global indices */
979: /*=============================================================================
980: Calculate info about messages I need to send
981: =============================================================================*/
982: /* nsend - number of non-empty messages to send
983: sendto - [nsend] ranks I will send messages to
984: sstart - [nsend+1] sstart[i] is the start index in xsindices_sorted[] I send to rank sendto[i]
985: slens - [ycommsize] I want to send slens[i] entries to rank i.
986: */
987: VecGetLayout(yy,&ylayout);
988: PetscLayoutGetRanges(ylayout,&yrange);
989: PetscCalloc1(ycommsize,&slens); /* The only O(P) array in this algorithm */
991: i = j = nsend = 0;
992: while (i < n) {
993: if (yindices_sorted[i] >= yrange[j+1]) { /* If i-th index is out of rank j's bound */
994: do {j++;} while (yindices_sorted[i] >= yrange[j+1] && j < ycommsize); /* Increase j until i-th index falls in rank j's bound */
995: if (j == ycommsize) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Index %D not owned by any process, upper bound %D",yindices_sorted[i],yrange[ycommsize]);
996: }
997: i++;
998: if (!slens[j]++) nsend++;
999: }
1001: PetscMalloc2(nsend+1,&sstart,nsend,&sendto);
1003: sstart[0] = 0;
1004: for (i=j=0; i<ycommsize; i++) {
1005: if (slens[i]) {
1006: sendto[j] = (PetscMPIInt)i;
1007: sstart[j+1] = sstart[j] + slens[i];
1008: j++;
1009: }
1010: }
1012: /*=============================================================================
1013: Calculate the reverse info about messages I will recv
1014: =============================================================================*/
1015: /* nrecv - number of messages I will recv
1016: recvfrom - [nrecv] ranks I recv from
1017: rlens - [nrecv] I will recv rlens[i] entries from rank recvfrom[i]
1018: rlentotal - sum of rlens[]
1019: rxindices - [rlentotal] recv buffer for xindices_sorted
1020: ryindices - [rlentotal] recv buffer for yindices_sorted
1021: */
1022: PetscGatherNumberOfMessages(ycomm,NULL,slens,&nrecv);
1023: PetscGatherMessageLengths(ycomm,nsend,nrecv,slens,&recvfrom,&rlens);
1024: PetscFree(slens); /* Free the O(P) array ASAP */
1025: rlentotal = 0; for (i=0; i<nrecv; i++) rlentotal += rlens[i];
1027: /*=============================================================================
1028: Communicate with processors in recvfrom[] to populate rxindices and ryindices
1029: ============================================================================*/
1030: PetscCommGetNewTag(ycomm,&tag1);
1031: PetscCommGetNewTag(ycomm,&tag2);
1032: PetscMalloc2(rlentotal,&rxindices,rlentotal,&ryindices);
1033: PetscMPIIntCast((nsend+nrecv)*2,&nreq);
1034: PetscMalloc1(nreq,&reqs);
1035: sreqs = reqs;
1036: rreqs = reqs + nsend*2;
1038: for (i=disp=0; i<nrecv; i++) {
1039: count = rlens[i];
1040: MPI_Irecv(rxindices+disp,count,MPIU_INT,recvfrom[i],tag1,ycomm,rreqs+i);
1041: MPI_Irecv(ryindices+disp,count,MPIU_INT,recvfrom[i],tag2,ycomm,rreqs+nrecv+i);
1042: disp += rlens[i];
1043: }
1045: for (i=0; i<nsend; i++) {
1046: PetscMPIIntCast(sstart[i+1]-sstart[i],&count);
1047: MPI_Isend(xindices_sorted+sstart[i],count,MPIU_INT,sendto[i],tag1,ycomm,sreqs+i);
1048: MPI_Isend(yindices_sorted+sstart[i],count,MPIU_INT,sendto[i],tag2,ycomm,sreqs+nsend+i);
1049: }
1050: MPI_Waitall(nreq,reqs,MPI_STATUS_IGNORE);
1052: /* Transform VecScatter into SF */
1053: nleaves = rlentotal;
1054: PetscMalloc1(nleaves,&ilocal);
1055: PetscMalloc1(nleaves,&iremote);
1056: MPI_Comm_rank(ycomm,&yrank);
1057: for (i=disp=0; i<nrecv; i++) {
1058: for (j=0; j<rlens[i]; j++) {
1059: k = disp + j; /* k-th index pair */
1060: ilocal[k] = ryindices[k] - yrange[yrank]; /* Convert y's global index to local index */
1061: PetscLayoutFindOwnerIndex(xlayout,rxindices[k],&rank,&iremote[k].index); /* Convert x's global index to (rank, index) */
1062: iremote[k].rank = rank;
1063: }
1064: disp += rlens[i];
1065: }
1067: PetscFree2(sstart,sendto);
1068: PetscFree(slens);
1069: PetscFree(rlens);
1070: PetscFree(recvfrom);
1071: PetscFree(reqs);
1072: PetscFree2(rxindices,ryindices);
1073: PetscFree2(xindices_sorted,yindices_sorted);
1074: #endif
1075: } else {
1076: /* PtoS or StoS */
1077: ISGetLocalSize(iyy,&nleaves);
1078: PetscMalloc1(nleaves,&ilocal);
1079: PetscMalloc1(nleaves,&iremote);
1080: PetscArraycpy(ilocal,yindices,nleaves);
1081: for (i=0; i<nleaves; i++) {
1082: PetscLayoutFindOwnerIndex(xlayout,xindices[i],&rank,&iremote[i].index);
1083: iremote[i].rank = rank;
1084: }
1085: }
1087: /* MUST build SF on xx's comm, which is not necessarily identical to yy's comm.
1088: In SF's view, xx contains the roots (i.e., the remote) and iremote[].rank are ranks in xx's comm.
1089: yy contains leaves, which are local and can be thought as part of PETSC_COMM_SELF. */
1090: PetscSFCreate(PetscObjectComm((PetscObject)xx),&sf);
1091: PetscSFSetFromOptions(sf);
1092: VecGetLocalSize(xx,&nroots);
1093: PetscSFSetGraph(sf,nroots,nleaves,ilocal,PETSC_OWN_POINTER,iremote,PETSC_OWN_POINTER); /* Give ilocal/iremote to petsc and no need to free them here */
1095: /* Free memory no longer needed */
1096: ISRestoreIndices(ixx,&xindices);
1097: ISRestoreIndices(iyy,&yindices);
1098: if (can_do_block_opt) {
1099: VecDestroy(&xx);
1100: VecDestroy(&yy);
1101: ISDestroy(&ixx);
1102: ISDestroy(&iyy);
1103: } else if (xcommsize == 1) {
1104: VecDestroy(&xx);
1105: }
1107: functionend:
1108: sf->vscat.bs = bs;
1109: if (sf->vscat.bs > 1) {
1110: MPI_Type_contiguous(sf->vscat.bs,MPIU_SCALAR,&sf->vscat.unit);
1111: MPI_Type_commit(&sf->vscat.unit);
1112: } else {
1113: sf->vscat.unit = MPIU_SCALAR;
1114: }
1115: VecGetLocalSize(x,&sf->vscat.from_n);
1116: VecGetLocalSize(y,&sf->vscat.to_n);
1117: if (!ix_old) {ISDestroy(&ix);} /* We created helper ix, iy. Free them */
1118: if (!iy_old) {ISDestroy(&iy);}
1120: /* Set default */
1121: VecScatterSetFromOptions(sf);
1123: *newsf = sf;
1124: return(0);
1125: }
1127: /*@C
1128: VecScatterCreateToAll - Creates a vector and a scatter context that copies all
1129: vector values to each processor
1131: Collective on Vec
1133: Input Parameter:
1134: . vin - input MPIVEC
1136: Output Parameter:
1137: + ctx - scatter context
1138: - vout - output SEQVEC that is large enough to scatter into
1140: Level: intermediate
1142: Note: vout may be NULL [PETSC_NULL_VEC from fortran] if you do not
1143: need to have it created
1145: Usage:
1146: $ VecScatterCreateToAll(vin,&ctx,&vout);
1147: $
1148: $ // scatter as many times as you need
1149: $ VecScatterBegin(ctx,vin,vout,INSERT_VALUES,SCATTER_FORWARD);
1150: $ VecScatterEnd(ctx,vin,vout,INSERT_VALUES,SCATTER_FORWARD);
1151: $
1152: $ // destroy scatter context and local vector when no longer needed
1153: $ VecScatterDestroy(&ctx);
1154: $ VecDestroy(&vout);
1156: Do NOT create a vector and then pass it in as the final argument vout! vout is created by this routine
1157: automatically (unless you pass NULL in for that argument if you do not need it).
1159: .seealso VecScatterCreate(), VecScatterCreateToZero(), VecScatterBegin(), VecScatterEnd()
1161: @*/
1162: PetscErrorCode VecScatterCreateToAll(Vec vin,VecScatter *ctx,Vec *vout)
1163: {
1166: PetscInt N;
1167: IS is;
1168: Vec tmp;
1169: Vec *tmpv;
1170: PetscBool tmpvout = PETSC_FALSE;
1176: if (vout) {
1178: tmpv = vout;
1179: } else {
1180: tmpvout = PETSC_TRUE;
1181: tmpv = &tmp;
1182: }
1184: /* Create seq vec on each proc, with the same size of the original mpi vec */
1185: VecGetSize(vin,&N);
1186: VecCreateSeq(PETSC_COMM_SELF,N,tmpv);
1187: VecSetFromOptions(*tmpv);
1188: /* Create the VecScatter ctx with the communication info */
1189: ISCreateStride(PETSC_COMM_SELF,N,0,1,&is);
1190: VecScatterCreate(vin,is,*tmpv,is,ctx);
1191: ISDestroy(&is);
1192: if (tmpvout) {VecDestroy(tmpv);}
1193: return(0);
1194: }
1197: /*@C
1198: VecScatterCreateToZero - Creates an output vector and a scatter context used to
1199: copy all vector values into the output vector on the zeroth processor
1201: Collective on Vec
1203: Input Parameter:
1204: . vin - input MPIVEC
1206: Output Parameter:
1207: + ctx - scatter context
1208: - vout - output SEQVEC that is large enough to scatter into on processor 0 and
1209: of length zero on all other processors
1211: Level: intermediate
1213: Note: vout may be NULL [PETSC_NULL_VEC from fortran] if you do not
1214: need to have it created
1216: Usage:
1217: $ VecScatterCreateToZero(vin,&ctx,&vout);
1218: $
1219: $ // scatter as many times as you need
1220: $ VecScatterBegin(ctx,vin,vout,INSERT_VALUES,SCATTER_FORWARD);
1221: $ VecScatterEnd(ctx,vin,vout,INSERT_VALUES,SCATTER_FORWARD);
1222: $
1223: $ // destroy scatter context and local vector when no longer needed
1224: $ VecScatterDestroy(&ctx);
1225: $ VecDestroy(&vout);
1227: .seealso VecScatterCreate(), VecScatterCreateToAll(), VecScatterBegin(), VecScatterEnd()
1229: Do NOT create a vector and then pass it in as the final argument vout! vout is created by this routine
1230: automatically (unless you pass NULL in for that argument if you do not need it).
1232: @*/
1233: PetscErrorCode VecScatterCreateToZero(Vec vin,VecScatter *ctx,Vec *vout)
1234: {
1237: PetscInt N;
1238: PetscMPIInt rank;
1239: IS is;
1240: Vec tmp;
1241: Vec *tmpv;
1242: PetscBool tmpvout = PETSC_FALSE;
1248: if (vout) {
1250: tmpv = vout;
1251: } else {
1252: tmpvout = PETSC_TRUE;
1253: tmpv = &tmp;
1254: }
1256: /* Create vec on each proc, with the same size of the original mpi vec (all on process 0)*/
1257: VecGetSize(vin,&N);
1258: MPI_Comm_rank(PetscObjectComm((PetscObject)vin),&rank);
1259: if (rank) N = 0;
1260: VecCreateSeq(PETSC_COMM_SELF,N,tmpv);
1261: VecSetFromOptions(*tmpv);
1262: /* Create the VecScatter ctx with the communication info */
1263: ISCreateStride(PETSC_COMM_SELF,N,0,1,&is);
1264: VecScatterCreate(vin,is,*tmpv,is,ctx);
1265: ISDestroy(&is);
1266: if (tmpvout) {VecDestroy(tmpv);}
1267: return(0);
1268: }
1270: /*@
1271: VecScatterBegin - Begins a generalized scatter from one vector to
1272: another. Complete the scattering phase with VecScatterEnd().
1274: Neighbor-wise Collective on VecScatter
1276: Input Parameters:
1277: + sf - scatter context generated by VecScatterCreate()
1278: . x - the vector from which we scatter
1279: . y - the vector to which we scatter
1280: . addv - either ADD_VALUES, MAX_VALUES, MIN_VALUES or INSERT_VALUES, with INSERT_VALUES mode any location
1281: not scattered to retains its old value; i.e. the vector is NOT first zeroed.
1282: - mode - the scattering mode, usually SCATTER_FORWARD. The available modes are:
1283: SCATTER_FORWARD or SCATTER_REVERSE
1286: Level: intermediate
1288: Options Database: See VecScatterCreate()
1290: Notes:
1291: The vectors x and y need not be the same vectors used in the call
1292: to VecScatterCreate(), but x must have the same parallel data layout
1293: as that passed in as the x to VecScatterCreate(), similarly for the y.
1294: Most likely they have been obtained from VecDuplicate().
1296: You cannot change the values in the input vector between the calls to VecScatterBegin()
1297: and VecScatterEnd().
1299: If you use SCATTER_REVERSE the two arguments x and y should be reversed, from
1300: the SCATTER_FORWARD.
1302: y[iy[i]] = x[ix[i]], for i=0,...,ni-1
1304: This scatter is far more general than the conventional
1305: scatter, since it can be a gather or a scatter or a combination,
1306: depending on the indices ix and iy. If x is a parallel vector and y
1307: is sequential, VecScatterBegin() can serve to gather values to a
1308: single processor. Similarly, if y is parallel and x sequential, the
1309: routine can scatter from one processor to many processors.
1312: .seealso: VecScatterCreate(), VecScatterEnd()
1313: @*/
1314: PetscErrorCode VecScatterBegin(VecScatter sf,Vec x,Vec y,InsertMode addv,ScatterMode mode)
1315: {
1317: PetscInt to_n,from_n;
1323: if (PetscDefined(USE_DEBUG)) {
1324: /*
1325: Error checking to make sure these vectors match the vectors used
1326: to create the vector scatter context. -1 in the from_n and to_n indicate the
1327: vector lengths are unknown (for example with mapped scatters) and thus
1328: no error checking is performed.
1329: */
1330: if (sf->vscat.from_n >= 0 && sf->vscat.to_n >= 0) {
1331: VecGetLocalSize(x,&from_n);
1332: VecGetLocalSize(y,&to_n);
1333: if (mode & SCATTER_REVERSE) {
1334: if (to_n != sf->vscat.from_n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Vector wrong size %D for scatter %D (scatter reverse and vector to != sf from size)",to_n,sf->vscat.from_n);
1335: if (from_n != sf->vscat.to_n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Vector wrong size %D for scatter %D (scatter reverse and vector from != sf to size)",from_n,sf->vscat.to_n);
1336: } else {
1337: if (to_n != sf->vscat.to_n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Vector wrong size %D for scatter %D (scatter forward and vector to != sf to size)",to_n,sf->vscat.to_n);
1338: if (from_n != sf->vscat.from_n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Vector wrong size %D for scatter %D (scatter forward and vector from != sf from size)",from_n,sf->vscat.from_n);
1339: }
1340: }
1341: }
1343: sf->vscat.logging = PETSC_TRUE;
1344: PetscLogEventBegin(VEC_ScatterBegin,sf,x,y,0);
1345: VecScatterBegin_Internal(sf,x,y,addv,mode);
1346: if (sf->vscat.beginandendtogether) {
1347: VecScatterEnd_Internal(sf,x,y,addv,mode);
1348: }
1349: PetscLogEventEnd(VEC_ScatterBegin,sf,x,y,0);
1350: sf->vscat.logging = PETSC_FALSE;
1351: return(0);
1352: }
1354: /*@
1355: VecScatterEnd - Ends a generalized scatter from one vector to another. Call
1356: after first calling VecScatterBegin().
1358: Neighbor-wise Collective on VecScatter
1360: Input Parameters:
1361: + sf - scatter context generated by VecScatterCreate()
1362: . x - the vector from which we scatter
1363: . y - the vector to which we scatter
1364: . addv - one of ADD_VALUES, MAX_VALUES, MIN_VALUES or INSERT_VALUES
1365: - mode - the scattering mode, usually SCATTER_FORWARD. The available modes are:
1366: SCATTER_FORWARD, SCATTER_REVERSE
1368: Level: intermediate
1370: Notes:
1371: If you use SCATTER_REVERSE the arguments x and y should be reversed, from the SCATTER_FORWARD.
1373: y[iy[i]] = x[ix[i]], for i=0,...,ni-1
1375: .seealso: VecScatterBegin(), VecScatterCreate()
1376: @*/
1377: PetscErrorCode VecScatterEnd(VecScatter sf,Vec x,Vec y,InsertMode addv,ScatterMode mode)
1378: {
1385: if (!sf->vscat.beginandendtogether) {
1386: sf->vscat.logging = PETSC_TRUE;
1387: PetscLogEventBegin(VEC_ScatterEnd,sf,x,y,0);
1388: VecScatterEnd_Internal(sf,x,y,addv,mode);
1389: PetscLogEventEnd(VEC_ScatterEnd,sf,x,y,0);
1390: sf->vscat.logging = PETSC_FALSE;
1391: }
1392: return(0);
1393: }