Actual source code: sfbasic.c

  1: #include <../src/vec/is/sf/impls/basic/sfbasic.h>
  2: #include <../src/vec/is/sf/impls/basic/sfpack.h>
  3: #include <petsc/private/viewerimpl.h>

  5: /*===================================================================================*/
  6: /*              SF public interface implementations                                  */
  7: /*===================================================================================*/
  8: PETSC_INTERN PetscErrorCode PetscSFSetUp_Basic(PetscSF sf)
  9: {
 10:   PetscSF_Basic  *bas = (PetscSF_Basic*)sf->data;
 11:   PetscInt       *rlengths,*ilengths,i,nRemoteRootRanks,nRemoteLeafRanks;
 12:   PetscMPIInt    rank,niranks,*iranks,tag;
 13:   MPI_Comm       comm;
 14:   MPI_Group      group;
 15:   MPI_Request    *rootreqs,*leafreqs;

 17:   MPI_Comm_group(PETSC_COMM_SELF,&group);
 18:   PetscSFSetUpRanks(sf,group);
 19:   MPI_Group_free(&group);
 20:   PetscObjectGetComm((PetscObject)sf,&comm);
 21:   PetscObjectGetNewTag((PetscObject)sf,&tag);
 22:   MPI_Comm_rank(comm,&rank);
 23:   /*
 24:    * Inform roots about how many leaves and from which ranks
 25:    */
 26:   PetscMalloc1(sf->nranks,&rlengths);
 27:   /* Determine number, sending ranks and length of incoming */
 28:   for (i=0; i<sf->nranks; i++) {
 29:     rlengths[i] = sf->roffset[i+1] - sf->roffset[i]; /* Number of roots referenced by my leaves; for rank sf->ranks[i] */
 30:   }
 31:   nRemoteRootRanks = sf->nranks-sf->ndranks;
 32:   PetscCommBuildTwoSided(comm,1,MPIU_INT,nRemoteRootRanks,sf->ranks+sf->ndranks,rlengths+sf->ndranks,&niranks,&iranks,(void**)&ilengths);

 34:   /* Sort iranks. See use of VecScatterGetRemoteOrdered_Private() in MatGetBrowsOfAoCols_MPIAIJ() on why.
 35:      We could sort ranks there at the price of allocating extra working arrays. Presumably, niranks is
 36:      small and the sorting is cheap.
 37:    */
 38:   PetscSortMPIIntWithIntArray(niranks,iranks,ilengths);

 40:   /* Partition into distinguished and non-distinguished incoming ranks */
 41:   bas->ndiranks = sf->ndranks;
 42:   bas->niranks = bas->ndiranks + niranks;
 43:   PetscMalloc2(bas->niranks,&bas->iranks,bas->niranks+1,&bas->ioffset);
 44:   bas->ioffset[0] = 0;
 45:   for (i=0; i<bas->ndiranks; i++) {
 46:     bas->iranks[i] = sf->ranks[i];
 47:     bas->ioffset[i+1] = bas->ioffset[i] + rlengths[i];
 48:   }
 50:   for (; i<bas->niranks; i++) {
 51:     bas->iranks[i] = iranks[i-bas->ndiranks];
 52:     bas->ioffset[i+1] = bas->ioffset[i] + ilengths[i-bas->ndiranks];
 53:   }
 54:   bas->itotal = bas->ioffset[i];
 55:   PetscFree(rlengths);
 56:   PetscFree(iranks);
 57:   PetscFree(ilengths);

 59:   /* Send leaf identities to roots */
 60:   nRemoteLeafRanks = bas->niranks-bas->ndiranks;
 61:   PetscMalloc1(bas->itotal,&bas->irootloc);
 62:   PetscMalloc2(nRemoteLeafRanks,&rootreqs,nRemoteRootRanks,&leafreqs);
 63:   for (i=bas->ndiranks; i<bas->niranks; i++) {
 64:     MPIU_Irecv(bas->irootloc+bas->ioffset[i],bas->ioffset[i+1]-bas->ioffset[i],MPIU_INT,bas->iranks[i],tag,comm,&rootreqs[i-bas->ndiranks]);
 65:   }
 66:   for (i=0; i<sf->nranks; i++) {
 67:     PetscInt npoints = sf->roffset[i+1] - sf->roffset[i];
 68:     if (i < sf->ndranks) {
 72:       PetscArraycpy(bas->irootloc+bas->ioffset[0],sf->rremote+sf->roffset[i],npoints);
 73:       continue;
 74:     }
 75:     MPIU_Isend(sf->rremote+sf->roffset[i],npoints,MPIU_INT,sf->ranks[i],tag,comm,&leafreqs[i-sf->ndranks]);
 76:   }
 77:   MPI_Waitall(nRemoteLeafRanks,rootreqs,MPI_STATUSES_IGNORE);
 78:   MPI_Waitall(nRemoteRootRanks,leafreqs,MPI_STATUSES_IGNORE);

 80:   sf->nleafreqs  = nRemoteRootRanks;
 81:   bas->nrootreqs = nRemoteLeafRanks;
 82:   sf->persistent = PETSC_TRUE;

 84:   /* Setup fields related to packing, such as rootbuflen[] */
 85:   PetscSFSetUpPackFields(sf);
 86:   PetscFree2(rootreqs,leafreqs);
 87:   return 0;
 88: }

 90: PETSC_INTERN PetscErrorCode PetscSFReset_Basic(PetscSF sf)
 91: {
 92:   PetscSF_Basic     *bas = (PetscSF_Basic*)sf->data;
 93:   PetscSFLink       link = bas->avail,next;

 96:   PetscFree2(bas->iranks,bas->ioffset);
 97:   PetscFree(bas->irootloc);

 99:  #if defined(PETSC_HAVE_DEVICE)
100:   for (PetscInt i=0; i<2; i++) PetscSFFree(sf,PETSC_MEMTYPE_DEVICE,bas->irootloc_d[i]);
101:  #endif

103:  #if defined(PETSC_HAVE_NVSHMEM)
104:   PetscSFReset_Basic_NVSHMEM(sf);
105:  #endif

107:   for (; link; link=next) {next = link->next; PetscSFLinkDestroy(sf,link);}
108:   bas->avail = NULL;
109:   PetscSFResetPackFields(sf);
110:   return 0;
111: }

113: PETSC_INTERN PetscErrorCode PetscSFDestroy_Basic(PetscSF sf)
114: {
115:   PetscSFReset_Basic(sf);
116:   PetscFree(sf->data);
117:   return 0;
118: }

120: #if defined(PETSC_USE_SINGLE_LIBRARY)
121: #include <petscmat.h>

123: PETSC_INTERN PetscErrorCode PetscSFView_Basic_PatternAndSizes(PetscSF sf,PetscViewer viewer)
124: {
125:   PetscSF_Basic        *bas = (PetscSF_Basic*)sf->data;
126:   PetscInt             i,nrootranks,ndrootranks;
127:   const PetscInt       *rootoffset;
128:   PetscMPIInt          rank,size;
129:   const PetscMPIInt    *rootranks;
130:   MPI_Comm             comm = PetscObjectComm((PetscObject)sf);
131:   PetscScalar          unitbytes;
132:   Mat                  A;

134:   MPI_Comm_size(comm,&size);
135:   MPI_Comm_rank(comm,&rank);
136:   /* PetscSFView is most useful for the SF used in VecScatterBegin/End in MatMult etc, where we do
137:     PetscSFBcast, i.e., roots send data to leaves.  We dump the communication pattern into a matrix
138:     in senders' view point: how many bytes I will send to my neighbors.

140:     Looking at a column of the matrix, one can also know how many bytes the rank will receive from others.

142:     If PetscSFLink bas->inuse is available, we can use that to get tree vertex size. But that would give
143:     different interpretations for the same SF for different data types. Since we most care about VecScatter,
144:     we uniformly treat each vertex as a PetscScalar.
145:   */
146:   unitbytes = (PetscScalar)sizeof(PetscScalar);

148:   PetscSFGetRootInfo_Basic(sf,&nrootranks,&ndrootranks,&rootranks,&rootoffset,NULL);
149:   MatCreateAIJ(comm,1,1,size,size,1,NULL,nrootranks-ndrootranks,NULL,&A);
150:   MatSetOptionsPrefix(A,"__petsc_internal__"); /* To prevent the internal A from taking any command line options */
151:   for (i=0; i<nrootranks; i++) {
152:     MatSetValue(A,(PetscInt)rank,bas->iranks[i],(rootoffset[i+1]-rootoffset[i])*unitbytes,INSERT_VALUES);
153:   }
154:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
155:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
156:   MatView(A,viewer);
157:   MatDestroy(&A);
158:   return 0;
159: }
160: #endif

162: PETSC_INTERN PetscErrorCode PetscSFView_Basic(PetscSF sf,PetscViewer viewer)
163: {
164:   PetscBool      isascii;

166:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isascii);
167:   if (isascii && viewer->format != PETSC_VIEWER_ASCII_MATLAB) PetscViewerASCIIPrintf(viewer,"  MultiSF sort=%s\n",sf->rankorder ? "rank-order" : "unordered");
168: #if defined(PETSC_USE_SINGLE_LIBRARY)
169:   else {
170:     PetscBool  isdraw,isbinary;
171:     PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
172:     PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
173:     if ((isascii && viewer->format == PETSC_VIEWER_ASCII_MATLAB) || isdraw || isbinary) {
174:       PetscSFView_Basic_PatternAndSizes(sf,viewer);
175:     }
176:   }
177: #endif
178:   return 0;
179: }

181: static PetscErrorCode PetscSFBcastBegin_Basic(PetscSF sf,MPI_Datatype unit,PetscMemType rootmtype,const void *rootdata,PetscMemType leafmtype,void *leafdata,MPI_Op op)
182: {
183:   PetscSFLink       link = NULL;

185:   /* Create a communication link, which provides buffers, MPI requests etc (if MPI is used) */
186:   PetscSFLinkCreate(sf,unit,rootmtype,rootdata,leafmtype,leafdata,op,PETSCSF_BCAST,&link);
187:   /* Pack rootdata to rootbuf for remote communication */
188:   PetscSFLinkPackRootData(sf,link,PETSCSF_REMOTE,rootdata);
189:   /* Start communcation, e.g., post MPI_Isend */
190:   PetscSFLinkStartCommunication(sf,link,PETSCSF_../../../../../..2LEAF);
191:   /* Do local scatter (i.e., self to self communication), which overlaps with the remote communication above */
192:   PetscSFLinkScatterLocal(sf,link,PETSCSF_../../../../../..2LEAF,(void*)rootdata,leafdata,op);
193:   return 0;
194: }

196: PETSC_INTERN PetscErrorCode PetscSFBcastEnd_Basic(PetscSF sf,MPI_Datatype unit,const void *rootdata,void *leafdata,MPI_Op op)
197: {
198:   PetscSFLink       link = NULL;

200:   /* Retrieve the link used in XxxBegin() with root/leafdata as key */
201:   PetscSFLinkGetInUse(sf,unit,rootdata,leafdata,PETSC_OWN_POINTER,&link);
202:   /* Finish remote communication, e.g., post MPI_Waitall */
203:   PetscSFLinkFinishCommunication(sf,link,PETSCSF_../../../../../..2LEAF);
204:   /* Unpack data in leafbuf to leafdata for remote communication */
205:   PetscSFLinkUnpackLeafData(sf,link,PETSCSF_REMOTE,leafdata,op);
206:   /* Recycle the link */
207:   PetscSFLinkReclaim(sf,&link);
208:   return 0;
209: }

211: /* Shared by ReduceBegin and FetchAndOpBegin */
212: static inline PetscErrorCode PetscSFLeafToRootBegin_Basic(PetscSF sf,MPI_Datatype unit,PetscMemType leafmtype,const void *leafdata,PetscMemType rootmtype,void *rootdata,MPI_Op op,PetscSFOperation sfop,PetscSFLink *out)
213: {
214:   PetscSFLink       link = NULL;

216:   PetscSFLinkCreate(sf,unit,rootmtype,rootdata,leafmtype,leafdata,op,sfop,&link);
217:   PetscSFLinkPackLeafData(sf,link,PETSCSF_REMOTE,leafdata);
218:   PetscSFLinkStartCommunication(sf,link,PETSCSF_LEAF2../../../../../..);
219:   *out = link;
220:   return 0;
221: }

223: /* leaf -> root with reduction */
224: static PetscErrorCode PetscSFReduceBegin_Basic(PetscSF sf,MPI_Datatype unit,PetscMemType leafmtype,const void *leafdata,PetscMemType rootmtype,void *rootdata,MPI_Op op)
225: {
226:   PetscSFLink       link = NULL;

228:   PetscSFLeafToRootBegin_Basic(sf,unit,leafmtype,leafdata,rootmtype,rootdata,op,PETSCSF_REDUCE,&link);
229:   PetscSFLinkScatterLocal(sf,link,PETSCSF_LEAF2../../../../../..,rootdata,(void*)leafdata,op);
230:   return 0;
231: }

233: PETSC_INTERN PetscErrorCode PetscSFReduceEnd_Basic(PetscSF sf,MPI_Datatype unit,const void *leafdata,void *rootdata,MPI_Op op)
234: {
235:   PetscSFLink       link = NULL;

237:   PetscSFLinkGetInUse(sf,unit,rootdata,leafdata,PETSC_OWN_POINTER,&link);
238:   PetscSFLinkFinishCommunication(sf,link,PETSCSF_LEAF2../../../../../..);
239:   PetscSFLinkUnpackRootData(sf,link,PETSCSF_REMOTE,rootdata,op);
240:   PetscSFLinkReclaim(sf,&link);
241:   return 0;
242: }

244: PETSC_INTERN PetscErrorCode PetscSFFetchAndOpBegin_Basic(PetscSF sf,MPI_Datatype unit,PetscMemType rootmtype,void *rootdata,PetscMemType leafmtype,const void *leafdata,void *leafupdate,MPI_Op op)
245: {
246:   PetscSFLink       link = NULL;

248:   PetscSFLeafToRootBegin_Basic(sf,unit,leafmtype,leafdata,rootmtype,rootdata,op,PETSCSF_FETCH,&link);
249:   PetscSFLinkFetchAndOpLocal(sf,link,rootdata,leafdata,leafupdate,op);
250:   return 0;
251: }

253: static PetscErrorCode PetscSFFetchAndOpEnd_Basic(PetscSF sf,MPI_Datatype unit,void *rootdata,const void *leafdata,void *leafupdate,MPI_Op op)
254: {
255:   PetscSFLink       link = NULL;

257:   PetscSFLinkGetInUse(sf,unit,rootdata,leafdata,PETSC_OWN_POINTER,&link);
258:   /* This implementation could be changed to unpack as receives arrive, at the cost of non-determinism */
259:   PetscSFLinkFinishCommunication(sf,link,PETSCSF_LEAF2../../../../../..);
260:   /* Do fetch-and-op, the (remote) update results are in rootbuf */
261:   PetscSFLinkFetchAndOpRemote(sf,link,rootdata,op);
262:   /* Bcast rootbuf to leafupdate */
263:   PetscSFLinkStartCommunication(sf,link,PETSCSF_../../../../../..2LEAF);
264:   PetscSFLinkFinishCommunication(sf,link,PETSCSF_../../../../../..2LEAF);
265:   /* Unpack and insert fetched data into leaves */
266:   PetscSFLinkUnpackLeafData(sf,link,PETSCSF_REMOTE,leafupdate,MPI_REPLACE);
267:   PetscSFLinkReclaim(sf,&link);
268:   return 0;
269: }

271: PETSC_INTERN PetscErrorCode PetscSFGetLeafRanks_Basic(PetscSF sf,PetscInt *niranks,const PetscMPIInt **iranks,const PetscInt **ioffset,const PetscInt **irootloc)
272: {
273:   PetscSF_Basic *bas = (PetscSF_Basic*)sf->data;

275:   if (niranks)  *niranks  = bas->niranks;
276:   if (iranks)   *iranks   = bas->iranks;
277:   if (ioffset)  *ioffset  = bas->ioffset;
278:   if (irootloc) *irootloc = bas->irootloc;
279:   return 0;
280: }

282: /* An optimized PetscSFCreateEmbeddedRootSF. We aggresively make use of the established communication on sf.
283:    We need one bcast on sf, and no communication anymore to build the embedded sf. Note that selected[]
284:    was sorted before calling the routine.
285:  */
286: PETSC_INTERN PetscErrorCode PetscSFCreateEmbeddedRootSF_Basic(PetscSF sf,PetscInt nselected,const PetscInt *selected,PetscSF *newsf)
287: {
288:   PetscSF           esf;
289:   PetscInt          esf_nranks,esf_ndranks,*esf_roffset,*esf_rmine,*esf_rremote;
290:   PetscInt          i,j,p,q,nroots,esf_nleaves,*new_ilocal,nranks,ndranks,niranks,ndiranks,minleaf,maxleaf,maxlocal;
291:   char              *rootdata,*leafdata,*leafmem; /* Only stores 0 or 1, so we can save memory with char */
292:   PetscMPIInt       *esf_ranks;
293:   const PetscMPIInt *ranks,*iranks;
294:   const PetscInt    *roffset,*rmine,*rremote,*ioffset,*irootloc;
295:   PetscBool         connected;
296:   PetscSFNode       *new_iremote;
297:   PetscSF_Basic     *bas;

299:   PetscSFCreate(PetscObjectComm((PetscObject)sf),&esf);
300:   PetscSFSetFromOptions(esf);
301:   PetscSFSetType(esf,PETSCSFBASIC); /* This optimized routine can only create a basic sf */

303:   /* Find out which leaves are still connected to roots in the embedded sf by doing a Bcast */
304:   PetscSFGetGraph(sf,&nroots,NULL,NULL,NULL);
305:   PetscSFGetLeafRange(sf,&minleaf,&maxleaf);
306:   maxlocal = maxleaf - minleaf + 1;
307:   PetscCalloc2(nroots,&rootdata,maxlocal,&leafmem);
308:   leafdata = leafmem - minleaf;
309:   /* Tag selected roots */
310:   for (i=0; i<nselected; ++i) rootdata[selected[i]] = 1;

312:   PetscSFBcastBegin(sf,MPI_CHAR,rootdata,leafdata,MPI_REPLACE);
313:   PetscSFBcastEnd(sf,MPI_CHAR,rootdata,leafdata,MPI_REPLACE);
314:   PetscSFGetLeafInfo_Basic(sf,&nranks,&ndranks,&ranks,&roffset,&rmine,&rremote); /* Get send info */
315:   esf_nranks = esf_ndranks = esf_nleaves = 0;
316:   for (i=0; i<nranks; i++) {
317:     connected = PETSC_FALSE; /* Is this process still connected to this remote root rank? */
318:     for (j=roffset[i]; j<roffset[i+1]; j++) {if (leafdata[rmine[j]]) {esf_nleaves++; connected = PETSC_TRUE;}}
319:     if (connected) {esf_nranks++; if (i < ndranks) esf_ndranks++;}
320:   }

322:   /* Set graph of esf and also set up its outgoing communication (i.e., send info), which is usually done by PetscSFSetUpRanks */
323:   PetscMalloc1(esf_nleaves,&new_ilocal);
324:   PetscMalloc1(esf_nleaves,&new_iremote);
325:   PetscMalloc4(esf_nranks,&esf_ranks,esf_nranks+1,&esf_roffset,esf_nleaves,&esf_rmine,esf_nleaves,&esf_rremote);
326:   p    = 0; /* Counter for connected root ranks */
327:   q    = 0; /* Counter for connected leaves */
328:   esf_roffset[0] = 0;
329:   for (i=0; i<nranks; i++) { /* Scan leaf data again to fill esf arrays */
330:     connected = PETSC_FALSE;
331:     for (j=roffset[i]; j<roffset[i+1]; j++) {
332:       if (leafdata[rmine[j]]) {
333:         esf_rmine[q]         = new_ilocal[q] = rmine[j];
334:         esf_rremote[q]       = rremote[j];
335:         new_iremote[q].index = rremote[j];
336:         new_iremote[q].rank  = ranks[i];
337:         connected            = PETSC_TRUE;
338:         q++;
339:       }
340:     }
341:     if (connected) {
342:       esf_ranks[p]     = ranks[i];
343:       esf_roffset[p+1] = q;
344:       p++;
345:     }
346:   }

348:   /* SetGraph internally resets the SF, so we only set its fields after the call */
349:   PetscSFSetGraph(esf,nroots,esf_nleaves,new_ilocal,PETSC_OWN_POINTER,new_iremote,PETSC_OWN_POINTER);
350:   esf->nranks    = esf_nranks;
351:   esf->ndranks   = esf_ndranks;
352:   esf->ranks     = esf_ranks;
353:   esf->roffset   = esf_roffset;
354:   esf->rmine     = esf_rmine;
355:   esf->rremote   = esf_rremote;
356:   esf->nleafreqs = esf_nranks - esf_ndranks;

358:   /* Set up the incoming communication (i.e., recv info) stored in esf->data, which is usually done by PetscSFSetUp_Basic */
359:   bas  = (PetscSF_Basic*)esf->data;
360:   PetscSFGetRootInfo_Basic(sf,&niranks,&ndiranks,&iranks,&ioffset,&irootloc); /* Get recv info */
361:   /* Embedded sf always has simpler communication than the original one. We might allocate longer arrays than needed here. But we
362:      we do not care since these arrays are usually short. The benefit is we can fill these arrays by just parsing irootloc once.
363:    */
364:   PetscMalloc2(niranks,&bas->iranks,niranks+1,&bas->ioffset);
365:   PetscMalloc1(ioffset[niranks],&bas->irootloc);
366:   bas->niranks = bas->ndiranks = bas->ioffset[0] = 0;
367:   p = 0; /* Counter for connected leaf ranks */
368:   q = 0; /* Counter for connected roots */
369:   for (i=0; i<niranks; i++) {
370:     connected = PETSC_FALSE; /* Is the current process still connected to this remote leaf rank? */
371:     for (j=ioffset[i]; j<ioffset[i+1]; j++) {
372:       if (rootdata[irootloc[j]]) {
373:         bas->irootloc[q++] = irootloc[j];
374:         connected = PETSC_TRUE;
375:       }
376:     }
377:     if (connected) {
378:       bas->niranks++;
379:       if (i<ndiranks) bas->ndiranks++; /* Note that order of ranks (including distinguished ranks) is kept */
380:       bas->iranks[p]    = iranks[i];
381:       bas->ioffset[p+1] = q;
382:       p++;
383:     }
384:   }
385:   bas->itotal     = q;
386:   bas->nrootreqs  = bas->niranks - bas->ndiranks;
387:   esf->persistent = PETSC_TRUE;
388:   /* Setup packing related fields */
389:   PetscSFSetUpPackFields(esf);

391:   /* Copy from PetscSFSetUp(), since this method wants to skip PetscSFSetUp(). */
392: #if defined(PETSC_HAVE_CUDA)
393:   if (esf->backend == PETSCSF_BACKEND_CUDA) {
394:     esf->ops->Malloc = PetscSFMalloc_CUDA;
395:     esf->ops->Free   = PetscSFFree_CUDA;
396:   }
397: #endif

399: #if defined(PETSC_HAVE_HIP)
400:   /* TODO: Needs debugging */
401:   if (esf->backend == PETSCSF_BACKEND_HIP) {
402:     esf->ops->Malloc = PetscSFMalloc_HIP;
403:     esf->ops->Free   = PetscSFFree_HIP;
404:   }
405: #endif

407: #if defined(PETSC_HAVE_KOKKOS)
408:   if (esf->backend == PETSCSF_BACKEND_KOKKOS) {
409:     esf->ops->Malloc = PetscSFMalloc_Kokkos;
410:     esf->ops->Free   = PetscSFFree_Kokkos;
411:   }
412: #endif
413:   esf->setupcalled = PETSC_TRUE; /* We have done setup ourselves! */
414:   PetscFree2(rootdata,leafmem);
415:   *newsf = esf;
416:   return 0;
417: }

419: PETSC_EXTERN PetscErrorCode PetscSFCreate_Basic(PetscSF sf)
420: {
421:   PetscSF_Basic  *dat;

423:   sf->ops->SetUp                = PetscSFSetUp_Basic;
424:   sf->ops->Reset                = PetscSFReset_Basic;
425:   sf->ops->Destroy              = PetscSFDestroy_Basic;
426:   sf->ops->View                 = PetscSFView_Basic;
427:   sf->ops->BcastBegin           = PetscSFBcastBegin_Basic;
428:   sf->ops->BcastEnd             = PetscSFBcastEnd_Basic;
429:   sf->ops->ReduceBegin          = PetscSFReduceBegin_Basic;
430:   sf->ops->ReduceEnd            = PetscSFReduceEnd_Basic;
431:   sf->ops->FetchAndOpBegin      = PetscSFFetchAndOpBegin_Basic;
432:   sf->ops->FetchAndOpEnd        = PetscSFFetchAndOpEnd_Basic;
433:   sf->ops->GetLeafRanks         = PetscSFGetLeafRanks_Basic;
434:   sf->ops->CreateEmbeddedRootSF = PetscSFCreateEmbeddedRootSF_Basic;

436:   PetscNewLog(sf,&dat);
437:   sf->data = (void*)dat;
438:   return 0;
439: }