Actual source code: hem.c

petsc-master 2018-10-22
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  2:  #include <petsc/private/matimpl.h>
  3:  #include <../src/mat/impls/aij/seq/aij.h>
  4:  #include <../src/mat/impls/aij/mpi/mpiaij.h>

  6: /* linked list methods
  7:  *
  8:  *  PetscCDCreate
  9:  */
 10: PetscErrorCode PetscCDCreate(PetscInt a_size, PetscCoarsenData **a_out)
 11: {
 12:   PetscErrorCode   ierr;
 13:   PetscCoarsenData *ail;

 16:   /* alocate pool, partially */
 17:   PetscNew(&ail);
 18:   *a_out               = ail;
 19:   ail->pool_list.next  = NULL;
 20:   ail->pool_list.array = NULL;
 21:   ail->chk_sz          = 0;
 22:   /* allocate array */
 23:   ail->size = a_size;
 24:   PetscCalloc1(a_size, &ail->array);
 25:   ail->extra_nodes = NULL;
 26:   ail->mat         = NULL;
 27:   return(0);
 28: }

 30: /* NPDestroy
 31:  */
 32: PetscErrorCode PetscCDDestroy(PetscCoarsenData *ail)
 33: {
 35:   PetscCDArrNd   *n = &ail->pool_list;

 38:   n = n->next;
 39:   while (n) {
 40:     PetscCDArrNd *lstn = n;
 41:     n    = n->next;
 42:     PetscFree(lstn);
 43:   }
 44:   if (ail->pool_list.array) {
 45:     PetscFree(ail->pool_list.array);
 46:   }
 47:   PetscFree(ail->array);
 48:   /* delete this (+agg+pool array) */
 49:   PetscFree(ail);
 50:   return(0);
 51: }

 53: /* PetscCDSetChuckSize
 54:  */
 55: PetscErrorCode PetscCDSetChuckSize(PetscCoarsenData *ail, PetscInt a_sz)
 56: {
 58:   ail->chk_sz = a_sz;
 59:   return(0);
 60: }

 62: /*  PetscCDGetNewNode
 63:  */
 64: PetscErrorCode PetscCDGetNewNode(PetscCoarsenData *ail, PetscCDIntNd **a_out, PetscInt a_id)
 65: {

 69:   *a_out = NULL;                /* squelch -Wmaybe-uninitialized */
 70:   if (ail->extra_nodes) {
 71:     PetscCDIntNd *node = ail->extra_nodes;
 72:     ail->extra_nodes = node->next;
 73:     node->gid        = a_id;
 74:     node->next       = NULL;
 75:     *a_out           = node;
 76:   } else {
 77:     if (!ail->pool_list.array) {
 78:       if (!ail->chk_sz) ail->chk_sz = 10; /* use a chuck size of ail->size? */
 79:       PetscMalloc1(ail->chk_sz, &ail->pool_list.array);
 80:       ail->new_node       = ail->pool_list.array;
 81:       ail->new_left       = ail->chk_sz;
 82:       ail->new_node->next = NULL;
 83:     } else if (!ail->new_left) {
 84:       PetscCDArrNd *node;
 85:       PetscMalloc(ail->chk_sz*sizeof(PetscCDIntNd) + sizeof(PetscCDArrNd), &node);
 86:       node->array         = (PetscCDIntNd*)(node + 1);
 87:       node->next          = ail->pool_list.next;
 88:       ail->pool_list.next = node;
 89:       ail->new_left       = ail->chk_sz;
 90:       ail->new_node       = node->array;
 91:     }
 92:     ail->new_node->gid  = a_id;
 93:     ail->new_node->next = NULL;
 94:     *a_out              = ail->new_node++; ail->new_left--;
 95:   }
 96:   return(0);
 97: }

 99: /* PetscCDIntNdSetID
100:  */
101: PetscErrorCode PetscCDIntNdSetID(PetscCDIntNd *a_this, PetscInt a_id)
102: {
104:   a_this->gid = a_id;
105:   return(0);
106: }

108: /* PetscCDIntNdGetID
109:  */
110: PetscErrorCode PetscCDIntNdGetID(const PetscCDIntNd *a_this, PetscInt *a_gid)
111: {
113:   *a_gid = a_this->gid;
114:   return(0);
115: }

117: /* PetscCDGetHeadPos
118:  */
119: PetscErrorCode PetscCDGetHeadPos(const PetscCoarsenData *ail, PetscInt a_idx, PetscCDIntNd **pos)
120: {
122:   if (a_idx>=ail->size) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"a_idx >= ail->size: a_idx=%D.",a_idx);
123:   *pos = ail->array[a_idx];
124:   return(0);
125: }

127: /* PetscCDGetNextPos
128:  */
129: PetscErrorCode PetscCDGetNextPos(const PetscCoarsenData *ail, PetscInt l_idx, PetscCDIntNd **pos)
130: {
132:   if (!(*pos)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"NULL input position.");
133:   *pos = (*pos)->next;
134:   return(0);
135: }

137: /* PetscCDAppendID
138:  */
139: PetscErrorCode PetscCDAppendID(PetscCoarsenData *ail, PetscInt a_idx, PetscInt a_id)
140: {
142:   PetscCDIntNd   *n,*n2;

145:   PetscCDGetNewNode(ail, &n, a_id);
146:   if (a_idx>=ail->size) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Index %D out of range.",a_idx);
147:   if (!(n2=ail->array[a_idx])) ail->array[a_idx] = n;
148:   else {
149:     do {
150:       if (!n2->next) {
151:         n2->next = n;
152:         if (n->next) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"n should not have a next");
153:         break;
154:       }
155:       n2 = n2->next;
156:     } while (n2);
157:     if (!n2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"n2 should be non-null");
158:   }
159:   return(0);
160: }

162: /* PetscCDAppendNode
163:  */
164: PetscErrorCode PetscCDAppendNode(PetscCoarsenData *ail, PetscInt a_idx,  PetscCDIntNd *a_n)
165: {
166:   PetscCDIntNd *n2;

169:   if (a_idx>=ail->size) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Index %D out of range.",a_idx);
170:   if (!(n2=ail->array[a_idx])) ail->array[a_idx] = a_n;
171:   else {
172:     do {
173:       if (!n2->next) {
174:         n2->next  = a_n;
175:         a_n->next = NULL;
176:         break;
177:       }
178:       n2 = n2->next;
179:     } while (n2);
180:     if (!n2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"n2 should be non-null");
181:   }
182:   return(0);
183: }

185: /* PetscCDRemoveNextNode: a_last->next, this exposes single linked list structure to API
186:  */
187: PetscErrorCode PetscCDRemoveNextNode(PetscCoarsenData *ail, PetscInt a_idx,  PetscCDIntNd *a_last)
188: {
189:   PetscCDIntNd *del;

192:   if (a_idx>=ail->size) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Index %D out of range.",a_idx);
193:   if (!a_last->next) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"a_last should have a next");
194:   del          = a_last->next;
195:   a_last->next = del->next;
196:   /* del->next = NULL; -- this still used in a iterator so keep it intact -- need to fix this with a double linked list */
197:   /* could reuse n2 but PetscCDAppendNode sometimes uses it */
198:   return(0);
199: }

201: /* PetscCDPrint
202:  */
203: PetscErrorCode PetscCDPrint(const PetscCoarsenData *ail, MPI_Comm comm)
204: {
206:   PetscCDIntNd   *n;
207:   PetscInt       ii,kk;
208:   PetscMPIInt    rank;

211:   MPI_Comm_rank(comm, &rank);
212:   for (ii=0; ii<ail->size; ii++) {
213:     kk = 0;
214:     n  = ail->array[ii];
215:     if (n) {PetscPrintf(comm,"[%d]%s list %d:\n",rank,PETSC_FUNCTION_NAME,ii);}
216:     while (n) {
217:       PetscPrintf(comm,"\t[%d] %D) id %D\n",rank,++kk,n->gid);
218:       n = n->next;
219:     }
220:   }
221:   return(0);
222: }

224: /* PetscCDAppendRemove
225:  */
226: PetscErrorCode PetscCDAppendRemove(PetscCoarsenData *ail, PetscInt a_destidx, PetscInt a_srcidx)
227: {
228:   PetscCDIntNd *n;

231:   if (a_srcidx>=ail->size) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Index %D out of range.",a_srcidx);
232:   if (a_destidx>=ail->size) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Index %D out of range.",a_destidx);
233:   if (a_destidx==a_srcidx) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"a_destidx==a_srcidx %D.",a_destidx);
234:   n = ail->array[a_destidx];
235:   if (!n) ail->array[a_destidx] = ail->array[a_srcidx];
236:   else {
237:     do {
238:       if (!n->next) {
239:         n->next = ail->array[a_srcidx];
240:         break;
241:       }
242:       n = n->next;
243:     } while (1);
244:   }
245:   ail->array[a_srcidx] = NULL;
246:   return(0);
247: }

249: /* PetscCDRemoveAll
250:  */
251: PetscErrorCode PetscCDRemoveAll(PetscCoarsenData *ail, PetscInt a_idx)
252: {
253:   PetscCDIntNd *rem,*n1;

256:   if (a_idx>=ail->size) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Index %D out of range.",a_idx);
257:   rem               = ail->array[a_idx];
258:   ail->array[a_idx] = NULL;
259:   if (!(n1=ail->extra_nodes)) ail->extra_nodes = rem;
260:   else {
261:     while (n1->next) n1 = n1->next;
262:     n1->next = rem;
263:   }
264:   return(0);
265: }

267: /* PetscCDSizeAt
268:  */
269: PetscErrorCode PetscCDSizeAt(const PetscCoarsenData *ail, PetscInt a_idx, PetscInt *a_sz)
270: {
271:   PetscCDIntNd *n1;
272:   PetscInt     sz = 0;

275:   if (a_idx>=ail->size) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Index %D out of range.",a_idx);
276:   n1 = ail->array[a_idx];
277:   while (n1) {
278:     n1 = n1->next;
279:     sz++;
280:   }
281:   *a_sz = sz;
282:   return(0);
283: }

285: /* PetscCDEmptyAt
286:  */
287: PetscErrorCode PetscCDEmptyAt(const PetscCoarsenData *ail, PetscInt a_idx, PetscBool *a_e)
288: {
290:   if (a_idx>=ail->size) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Index %D out of range.",a_idx);
291:   *a_e = (PetscBool)(ail->array[a_idx]==NULL);
292:   return(0);
293: }

295: /* PetscCDGetMIS
296:  */
297: PetscErrorCode PetscCDGetMIS(PetscCoarsenData *ail, IS *a_mis)
298: {
300:   PetscCDIntNd   *n;
301:   PetscInt       ii,kk;
302:   PetscInt       *permute;

305:   for (ii=kk=0; ii<ail->size; ii++) {
306:     n = ail->array[ii];
307:     if (n) kk++;
308:   }
309:   PetscMalloc1(kk, &permute);
310:   for (ii=kk=0; ii<ail->size; ii++) {
311:     n = ail->array[ii];
312:     if (n) permute[kk++] = ii;
313:   }
314:   ISCreateGeneral(PETSC_COMM_SELF, kk, permute, PETSC_OWN_POINTER, a_mis);
315:   return(0);
316: }

318: /* PetscCDGetMat
319:  */
320: PetscErrorCode PetscCDGetMat(const PetscCoarsenData *ail, Mat *a_mat)
321: {
323:   *a_mat = ail->mat;
324:   return(0);
325: }

327: /* PetscCDSetMat
328:  */
329: PetscErrorCode PetscCDSetMat(PetscCoarsenData *ail, Mat a_mat)
330: {
332:   ail->mat = a_mat;
333:   return(0);
334: }

336: /* PetscCDGetASMBlocks
337:  */
338: PetscErrorCode PetscCDGetASMBlocks(const PetscCoarsenData *ail, const PetscInt a_bs, Mat mat, PetscInt *a_sz, IS **a_local_is)
339: {
341:   PetscCDIntNd   *n;
342:   PetscInt       lsz,ii,kk,*idxs,jj,s,e,gid;
343:   IS             *is_loc,is_bcs;

346:   for (ii=kk=0; ii<ail->size; ii++) {
347:     if (ail->array[ii]) kk++;
348:   }
349:   /* count BCs */
350:   MatGetOwnershipRange(mat, &s, &e);
351:   for (gid=s,lsz=0; gid<e; gid++) {
352:     MatGetRow(mat,gid,&jj,0,0);
353:     if (jj<2) lsz++;
354:     MatRestoreRow(mat,gid,&jj,0,0);
355:   }
356:   if (lsz) {
357:     PetscMalloc1(a_bs*lsz, &idxs);
358:     for (gid=s,lsz=0; gid<e; gid++) {
359:       MatGetRow(mat,gid,&jj,0,0);
360:       if (jj<2) {
361:         for (jj=0; jj<a_bs; lsz++,jj++) idxs[lsz] = a_bs*gid + jj;
362:       }
363:       MatRestoreRow(mat,gid,&jj,0,0);
364:     }
365:     ISCreateGeneral(PETSC_COMM_SELF, lsz, idxs, PETSC_OWN_POINTER, &is_bcs);
366:     *a_sz = kk + 1; /* out */
367:   } else {
368:     is_bcs=0;
369:     *a_sz = kk; /* out */
370:   }
371:   PetscMalloc1(*a_sz, &is_loc);

373:   for (ii=kk=0; ii<ail->size; ii++) {
374:     for (lsz=0, n=ail->array[ii]; n; lsz++, n=n->next) /* void */;
375:     if (lsz) {
376:       PetscMalloc1(a_bs*lsz, &idxs);
377:       for (lsz = 0, n=ail->array[ii]; n; n = n->next) {
378:         PetscCDIntNdGetID(n, &gid);
379:         for (jj=0; jj<a_bs; lsz++,jj++) idxs[lsz] = a_bs*gid + jj;
380:       }
381:       ISCreateGeneral(PETSC_COMM_SELF, lsz, idxs, PETSC_OWN_POINTER, &is_loc[kk++]);
382:     }
383:   }
384:   if (is_bcs) {
385:     is_loc[kk++] = is_bcs;
386:   }
387:   if (*a_sz != kk) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"*a_sz %D != kk %D",*a_sz,kk);
388:   *a_local_is = is_loc; /* out */

390:   return(0);
391: }

393: /* ********************************************************************** */
394: /* edge for priority queue */
395: typedef struct edge_tag {
396:   PetscReal weight;
397:   PetscInt  lid0,gid1,cpid1;
398: } Edge;

400: static int gamg_hem_compare(const void *a, const void *b)
401: {
402:   PetscReal va = ((Edge*)a)->weight, vb = ((Edge*)b)->weight;
403:   return (va < vb) ? 1 : (va == vb) ? 0 : -1; /* 0 for equal */
404: }

406: /* -------------------------------------------------------------------------- */
407: /*
408:    heavyEdgeMatchAgg - parallel heavy edge matching (HEM). MatAIJ specific!!!

410:    Input Parameter:
411:    . perm - permutation
412:    . a_Gmat - glabal matrix of graph (data not defined)

414:    Output Parameter:
415:    . a_locals_llist - array of list of local nodes rooted at local node
416: */
417: static PetscErrorCode heavyEdgeMatchAgg(IS perm,Mat a_Gmat,PetscCoarsenData **a_locals_llist)
418: {
419:   PetscErrorCode   ierr;
420:   PetscBool        isMPI;
421:   MPI_Comm         comm;
422:   PetscInt         sub_it,kk,n,ix,*idx,*ii,iter,Iend,my0;
423:   PetscMPIInt      rank,size;
424:   const PetscInt   nloc = a_Gmat->rmap->n,n_iter=6; /* need to figure out how to stop this */
425:   PetscInt         *lid_cprowID,*lid_gid;
426:   PetscBool        *lid_matched;
427:   Mat_SeqAIJ       *matA, *matB=0;
428:   Mat_MPIAIJ       *mpimat     =0;
429:   PetscScalar      one         =1.;
430:   PetscCoarsenData *agg_llists = NULL,*deleted_list = NULL;
431:   Mat              cMat,tMat,P;
432:   MatScalar        *ap;
433:   PetscMPIInt      tag1,tag2;

436:   PetscObjectGetComm((PetscObject)a_Gmat,&comm);
437:   MPI_Comm_rank(comm, &rank);
438:   MPI_Comm_size(comm, &size);
439:   MatGetOwnershipRange(a_Gmat, &my0, &Iend);
440:   PetscCommGetNewTag(comm, &tag1);
441:   PetscCommGetNewTag(comm, &tag2);

443:   PetscMalloc1(nloc, &lid_gid); /* explicit array needed */
444:   PetscMalloc1(nloc, &lid_cprowID);
445:   PetscMalloc1(nloc, &lid_matched);

447:   PetscCDCreate(nloc, &agg_llists);
448:   /* PetscCDSetChuckSize(agg_llists, nloc+1); */
449:   *a_locals_llist = agg_llists;
450:   PetscCDCreate(size, &deleted_list);
451:   PetscCDSetChuckSize(deleted_list, 100);
452:   /* setup 'lid_gid' for scatters and add self to all lists */
453:   for (kk=0; kk<nloc; kk++) {
454:     lid_gid[kk] = kk + my0;
455:     PetscCDAppendID(agg_llists, kk, my0+kk);
456:   }

458:   /* make a copy of the graph, this gets destroyed in iterates */
459:   MatDuplicate(a_Gmat,MAT_COPY_VALUES,&cMat);
460:   PetscObjectTypeCompare((PetscObject)a_Gmat, MATMPIAIJ, &isMPI);
461:   iter = 0;
462:   while (iter++ < n_iter) {
463:     PetscScalar    *cpcol_gid,*cpcol_max_ew,*cpcol_max_pe,*lid_max_ew;
464:     PetscBool      *cpcol_matched;
465:     PetscMPIInt    *cpcol_pe,proc;
466:     Vec            locMaxEdge,locMaxPE,ghostMaxEdge,ghostMaxPE;
467:     PetscInt       nEdges,n_nz_row,jj;
468:     Edge           *Edges;
469:     PetscInt       gid;
470:     const PetscInt *perm_ix, n_sub_its = 120;

472:     /* get submatrices of cMat */
473:     if (isMPI) {
474:       mpimat = (Mat_MPIAIJ*)cMat->data;
475:       matA   = (Mat_SeqAIJ*)mpimat->A->data;
476:       matB   = (Mat_SeqAIJ*)mpimat->B->data;
477:       if (!matB->compressedrow.use) {
478:         /* force construction of compressed row data structure since code below requires it */
479:         MatCheckCompressedRow(mpimat->B,matB->nonzerorowcnt,&matB->compressedrow,matB->i,mpimat->B->rmap->n,-1.0);
480:       }
481:     } else {
482:       matA = (Mat_SeqAIJ*)cMat->data;
483:     }

485:     /* set max edge on nodes */
486:     MatCreateVecs(cMat, &locMaxEdge, 0);
487:     MatCreateVecs(cMat, &locMaxPE, 0);

489:     /* get 'cpcol_pe' & 'cpcol_gid' & init. 'cpcol_matched' using 'mpimat->lvec' */
490:     if (mpimat) {
491:       Vec         vec;
492:       PetscScalar vval;

494:       MatCreateVecs(cMat, &vec, 0);
495:       /* cpcol_pe */
496:       vval = (PetscScalar)(rank);
497:       for (kk=0,gid=my0; kk<nloc; kk++,gid++) {
498:         VecSetValues(vec, 1, &gid, &vval, INSERT_VALUES); /* set with GID */
499:       }
500:       VecAssemblyBegin(vec);
501:       VecAssemblyEnd(vec);
502:       VecScatterBegin(mpimat->Mvctx,vec,mpimat->lvec,INSERT_VALUES,SCATTER_FORWARD);
503:       VecScatterEnd(mpimat->Mvctx,vec,mpimat->lvec,INSERT_VALUES,SCATTER_FORWARD);
504:       VecGetArray(mpimat->lvec, &cpcol_gid); /* get proc ID in 'cpcol_gid' */
505:       VecGetLocalSize(mpimat->lvec, &n);
506:       PetscMalloc1(n, &cpcol_pe);
507:       for (kk=0; kk<n; kk++) cpcol_pe[kk] = (PetscMPIInt)PetscRealPart(cpcol_gid[kk]);
508:       VecRestoreArray(mpimat->lvec, &cpcol_gid);

510:       /* cpcol_gid */
511:       for (kk=0,gid=my0; kk<nloc; kk++,gid++) {
512:         vval = (PetscScalar)(gid);
513:         VecSetValues(vec, 1, &gid, &vval, INSERT_VALUES); /* set with GID */
514:       }
515:       VecAssemblyBegin(vec);
516:       VecAssemblyEnd(vec);
517:       VecScatterBegin(mpimat->Mvctx,vec,mpimat->lvec,INSERT_VALUES,SCATTER_FORWARD);
518:       VecScatterEnd(mpimat->Mvctx,vec,mpimat->lvec,INSERT_VALUES,SCATTER_FORWARD);
519:       VecDestroy(&vec);
520:       VecGetArray(mpimat->lvec, &cpcol_gid); /* get proc ID in 'cpcol_gid' */

522:       /* cpcol_matched */
523:       VecGetLocalSize(mpimat->lvec, &n);
524:       PetscMalloc1(n, &cpcol_matched);
525:       for (kk=0; kk<n; kk++) cpcol_matched[kk] = PETSC_FALSE;
526:     }

528:     /* need an inverse map - locals */
529:     for (kk=0; kk<nloc; kk++) lid_cprowID[kk] = -1;
530:     /* set index into compressed row 'lid_cprowID' */
531:     if (matB) {
532:       for (ix=0; ix<matB->compressedrow.nrows; ix++) {
533:         lid_cprowID[matB->compressedrow.rindex[ix]] = ix;
534:       }
535:     }

537:     /* compute 'locMaxEdge' & 'locMaxPE', and create list of edges, count edges' */
538:     for (nEdges=0,kk=0,gid=my0; kk<nloc; kk++,gid++) {
539:       PetscReal   max_e = 0., tt;
540:       PetscScalar vval;
541:       PetscInt    lid   = kk;
542:       PetscMPIInt max_pe=rank,pe;

544:       ii = matA->i; n = ii[lid+1] - ii[lid]; idx = matA->j + ii[lid];
545:       ap = matA->a + ii[lid];
546:       for (jj=0; jj<n; jj++) {
547:         PetscInt lidj = idx[jj];
548:         if (lidj != lid && PetscRealPart(ap[jj]) > max_e) max_e = PetscRealPart(ap[jj]);
549:         if (lidj > lid) nEdges++;
550:       }
551:       if ((ix=lid_cprowID[lid]) != -1) { /* if I have any ghost neighbors */
552:         ii  = matB->compressedrow.i; n = ii[ix+1] - ii[ix];
553:         ap  = matB->a + ii[ix];
554:         idx = matB->j + ii[ix];
555:         for (jj=0; jj<n; jj++) {
556:           if ((tt=PetscRealPart(ap[jj])) > max_e) max_e = tt;
557:           nEdges++;
558:           if ((pe=cpcol_pe[idx[jj]]) > max_pe) max_pe = pe;
559:         }
560:       }
561:       vval = max_e;
562:       VecSetValues(locMaxEdge, 1, &gid, &vval, INSERT_VALUES);

564:       vval = (PetscScalar)max_pe;
565:       VecSetValues(locMaxPE, 1, &gid, &vval, INSERT_VALUES);
566:     }
567:     VecAssemblyBegin(locMaxEdge);
568:     VecAssemblyEnd(locMaxEdge);
569:     VecAssemblyBegin(locMaxPE);
570:     VecAssemblyEnd(locMaxPE);

572:     /* get 'cpcol_max_ew' & 'cpcol_max_pe' */
573:     if (mpimat) {
574:       VecDuplicate(mpimat->lvec, &ghostMaxEdge);
575:       VecScatterBegin(mpimat->Mvctx,locMaxEdge,ghostMaxEdge,INSERT_VALUES,SCATTER_FORWARD);
576:       VecScatterEnd(mpimat->Mvctx,locMaxEdge,ghostMaxEdge,INSERT_VALUES,SCATTER_FORWARD);
577:       VecGetArray(ghostMaxEdge, &cpcol_max_ew);

579:       VecDuplicate(mpimat->lvec, &ghostMaxPE);
580:       VecScatterBegin(mpimat->Mvctx,locMaxPE,ghostMaxPE,INSERT_VALUES,SCATTER_FORWARD);
581:       VecScatterEnd(mpimat->Mvctx,locMaxPE,ghostMaxPE,INSERT_VALUES,SCATTER_FORWARD);
582:       VecGetArray(ghostMaxPE, &cpcol_max_pe);
583:     }

585:     /* setup sorted list of edges */
586:     PetscMalloc1(nEdges, &Edges);
587:     ISGetIndices(perm, &perm_ix);
588:     for (nEdges=n_nz_row=kk=0; kk<nloc; kk++) {
589:       PetscInt nn, lid = perm_ix[kk];
590:       ii = matA->i; nn = n = ii[lid+1] - ii[lid]; idx = matA->j + ii[lid];
591:       ap = matA->a + ii[lid];
592:       for (jj=0; jj<n; jj++) {
593:         PetscInt lidj = idx[jj];
594:         if (lidj > lid) {
595:           Edges[nEdges].lid0   = lid;
596:           Edges[nEdges].gid1   = lidj + my0;
597:           Edges[nEdges].cpid1  = -1;
598:           Edges[nEdges].weight = PetscRealPart(ap[jj]);
599:           nEdges++;
600:         }
601:       }
602:       if ((ix=lid_cprowID[lid]) != -1) { /* if I have any ghost neighbors */
603:         ii  = matB->compressedrow.i; n = ii[ix+1] - ii[ix];
604:         ap  = matB->a + ii[ix];
605:         idx = matB->j + ii[ix];
606:         nn += n;
607:         for (jj=0; jj<n; jj++) {
608:           Edges[nEdges].lid0   = lid;
609:           Edges[nEdges].gid1   = (PetscInt)PetscRealPart(cpcol_gid[idx[jj]]);
610:           Edges[nEdges].cpid1  = idx[jj];
611:           Edges[nEdges].weight = PetscRealPart(ap[jj]);
612:           nEdges++;
613:         }
614:       }
615:       if (nn > 1) n_nz_row++;
616:       else if (iter == 1) {
617:         /* should select this because it is technically in the MIS but lets not */
618:         PetscCDRemoveAll(agg_llists, lid);
619:       }
620:     }
621:     ISRestoreIndices(perm,&perm_ix);

623:     qsort(Edges, nEdges, sizeof(Edge), gamg_hem_compare);

625:     /* projection matrix */
626:     MatCreateAIJ(comm, nloc, nloc, PETSC_DETERMINE, PETSC_DETERMINE, 1, 0, 1, 0, &P);

628:     /* clear matched flags */
629:     for (kk=0; kk<nloc; kk++) lid_matched[kk] = PETSC_FALSE;
630:     /* process - communicate - process */
631:     for (sub_it=0; sub_it<n_sub_its; sub_it++) {
632:       PetscInt nactive_edges;

634:       VecGetArray(locMaxEdge, &lid_max_ew);
635:       for (kk=nactive_edges=0; kk<nEdges; kk++) {
636:         /* HEM */
637:         const Edge     *e   = &Edges[kk];
638:         const PetscInt lid0 =e->lid0,gid1=e->gid1,cpid1=e->cpid1,gid0=lid0+my0,lid1=gid1-my0;
639:         PetscBool      isOK = PETSC_TRUE;

641:         /* skip if either (local) vertex is done already */
642:         if (lid_matched[lid0] || (gid1>=my0 && gid1<Iend && lid_matched[gid1-my0])) continue;

644:         /* skip if ghost vertex is done */
645:         if (cpid1 != -1 && cpcol_matched[cpid1]) continue;

647:         nactive_edges++;
648:         /* skip if I have a bigger edge someplace (lid_max_ew gets updated) */
649:         if (PetscRealPart(lid_max_ew[lid0]) > e->weight + PETSC_SMALL) continue;

651:         if (cpid1 == -1) {
652:           if (PetscRealPart(lid_max_ew[lid1]) > e->weight + PETSC_SMALL) continue;
653:         } else {
654:           /* see if edge might get matched on other proc */
655:           PetscReal g_max_e = PetscRealPart(cpcol_max_ew[cpid1]);
656:           if (g_max_e > e->weight + PETSC_SMALL) continue;
657:           else if (e->weight > g_max_e - PETSC_SMALL && (PetscMPIInt)PetscRealPart(cpcol_max_pe[cpid1]) > rank) {
658:             /* check for max_e == to this edge and larger processor that will deal with this */
659:             continue;
660:           }
661:         }

663:         /* check ghost for v0 */
664:         if (isOK) {
665:           PetscReal max_e,ew;
666:           if ((ix=lid_cprowID[lid0]) != -1) { /* if I have any ghost neighbors */
667:             ii  = matB->compressedrow.i; n = ii[ix+1] - ii[ix];
668:             ap  = matB->a + ii[ix];
669:             idx = matB->j + ii[ix];
670:             for (jj=0; jj<n && isOK; jj++) {
671:               PetscInt lidj = idx[jj];
672:               if (cpcol_matched[lidj]) continue;
673:               ew = PetscRealPart(ap[jj]); max_e = PetscRealPart(cpcol_max_ew[lidj]);
674:               /* check for max_e == to this edge and larger processor that will deal with this */
675:               if (ew > max_e - PETSC_SMALL && ew > PetscRealPart(lid_max_ew[lid0]) - PETSC_SMALL && (PetscMPIInt)PetscRealPart(cpcol_max_pe[lidj]) > rank) {
676:                 isOK = PETSC_FALSE;
677:               }
678:             }
679:           }

681:           /* for v1 */
682:           if (cpid1 == -1 && isOK) {
683:             if ((ix=lid_cprowID[lid1]) != -1) { /* if I have any ghost neighbors */
684:               ii  = matB->compressedrow.i; n = ii[ix+1] - ii[ix];
685:               ap  = matB->a + ii[ix];
686:               idx = matB->j + ii[ix];
687:               for (jj=0; jj<n && isOK; jj++) {
688:                 PetscInt lidj = idx[jj];
689:                 if (cpcol_matched[lidj]) continue;
690:                 ew = PetscRealPart(ap[jj]); max_e = PetscRealPart(cpcol_max_ew[lidj]);
691:                 /* check for max_e == to this edge and larger processor that will deal with this */
692:                 if (ew > max_e - PETSC_SMALL && ew > PetscRealPart(lid_max_ew[lid1]) - PETSC_SMALL && (PetscMPIInt)PetscRealPart(cpcol_max_pe[lidj]) > rank) {
693:                   isOK = PETSC_FALSE;
694:                 }
695:               }
696:             }
697:           }
698:         }

700:         /* do it */
701:         if (isOK) {
702:           if (cpid1 == -1) {
703:             lid_matched[lid1] = PETSC_TRUE;  /* keep track of what we've done this round */
704:             PetscCDAppendRemove(agg_llists, lid0, lid1);
705:           } else if (sub_it != n_sub_its-1) {
706:             /* add gid1 to list of ghost deleted by me -- I need their children */
707:             proc = cpcol_pe[cpid1];

709:             cpcol_matched[cpid1] = PETSC_TRUE; /* messing with VecGetArray array -- needed??? */

711:             PetscCDAppendID(deleted_list, proc, cpid1); /* cache to send messages */
712:             PetscCDAppendID(deleted_list, proc, lid0);
713:           } else continue;

715:           lid_matched[lid0] = PETSC_TRUE; /* keep track of what we've done this round */
716:           /* set projection */
717:           MatSetValues(P,1,&gid0,1,&gid0,&one,INSERT_VALUES);
718:           MatSetValues(P,1,&gid1,1,&gid0,&one,INSERT_VALUES);
719:         } /* matched */
720:       } /* edge loop */

722:       /* deal with deleted ghost on first pass */
723:       if (size>1 && sub_it != n_sub_its-1) {
724: #define REQ_BF_SIZE 100
725:         PetscCDIntNd *pos;
726:         PetscBool    ise = PETSC_FALSE;
727:         PetscInt     nSend1, **sbuffs1,nSend2;
728:         MPI_Request  *sreqs2[REQ_BF_SIZE],*rreqs2[REQ_BF_SIZE];
729:         MPI_Status   status;

731:         /* send request */
732:         for (proc=0,nSend1=0; proc<size; proc++) {
733:           PetscCDEmptyAt(deleted_list,proc,&ise);
734:           if (!ise) nSend1++;
735:         }
736:         PetscMalloc1(nSend1, &sbuffs1);
737:         for (proc=0,nSend1=0; proc<size; proc++) {
738:           /* count ghosts */
739:           PetscCDSizeAt(deleted_list,proc,&n);
740:           if (n>0) {
741: #define CHUNCK_SIZE 100
742:             PetscInt    *sbuff,*pt;
743:             MPI_Request *request;
744:             n   /= 2;
745:             PetscMalloc1(2 + 2*n + n*CHUNCK_SIZE + 2, &sbuff);
746:             /* save requests */
747:             sbuffs1[nSend1] = sbuff;
748:             request         = (MPI_Request*)sbuff;
749:             sbuff           = pt = (PetscInt*)(request+1);
750:             *pt++           = n; *pt++ = rank;

752:             PetscCDGetHeadPos(deleted_list,proc,&pos);
753:             while (pos) {
754:               PetscInt lid0, cpid, gid;
755:               PetscCDIntNdGetID(pos, &cpid);
756:               gid   = (PetscInt)PetscRealPart(cpcol_gid[cpid]);
757:               PetscCDGetNextPos(deleted_list,proc,&pos);
758:               PetscCDIntNdGetID(pos, &lid0);
759:               PetscCDGetNextPos(deleted_list,proc,&pos);
760:               *pt++ = gid; *pt++ = lid0;
761:             }
762:             /* send request tag1 [n, proc, n*[gid1,lid0] ] */
763:             MPI_Isend(sbuff, 2*n+2, MPIU_INT, proc, tag1, comm, request);
764:             /* post recieve */
765:             request        = (MPI_Request*)pt;
766:             rreqs2[nSend1] = request; /* cache recv request */
767:             pt             = (PetscInt*)(request+1);
768:             MPI_Irecv(pt, n*CHUNCK_SIZE, MPIU_INT, proc, tag2, comm, request);
769:             /* clear list */
770:             PetscCDRemoveAll(deleted_list, proc);
771:             nSend1++;
772:           }
773:         }
774:         /* recieve requests, send response, clear lists */
775:         kk     = nactive_edges;
776:         MPIU_Allreduce(&kk,&nactive_edges,1,MPIU_INT,MPI_SUM,comm); /* not correct syncronization and global */
777:         nSend2 = 0;
778:         while (1) {
779: #define BF_SZ 10000
780:           PetscMPIInt flag,count;
781:           PetscInt    rbuff[BF_SZ],*pt,*pt2,*pt3,count2,*sbuff,count3;
782:           MPI_Request *request;

784:           MPI_Iprobe(MPI_ANY_SOURCE, tag1, comm, &flag, &status);
785:           if (!flag) break;
786:           MPI_Get_count(&status, MPIU_INT, &count);
787:           if (count > BF_SZ) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"buffer too small for recieve: %d",count);
788:           proc = status.MPI_SOURCE;
789:           /* recieve request tag1 [n, proc, n*[gid1,lid0] ] */
790:           MPI_Recv(rbuff, count, MPIU_INT, proc, tag1, comm, &status);
791:           /* count sends */
792:           pt = rbuff; count3 = count2 = 0;
793:           n  = *pt++; kk = *pt++;
794:           while (n--) {
795:             PetscInt gid1=*pt++, lid1=gid1-my0; kk=*pt++;
796:             if (lid_matched[lid1]) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Recieved deleted gid %D, deleted by (lid) %D from proc %D\n",sub_it,gid1,kk);
797:             lid_matched[lid1] = PETSC_TRUE; /* keep track of what we've done this round */
798:             PetscCDSizeAt(agg_llists, lid1, &kk);
799:             count2           += kk + 2;
800:             count3++; /* number of verts requested (n) */
801:           }
802:           if (count2 > count3*CHUNCK_SIZE) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"Irecv will be too small: %D",count2);
803:           /* send tag2 *[lid0, n, n*[gid] ] */
804:           PetscMalloc(count2*sizeof(PetscInt) + sizeof(MPI_Request), &sbuff);
805:           request          = (MPI_Request*)sbuff;
806:           sreqs2[nSend2++] = request; /* cache request */
807:           if (nSend2==REQ_BF_SIZE) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"buffer too small for requests: %D",nSend2);
808:           pt2 = sbuff = (PetscInt*)(request+1);
809:           pt  = rbuff;
810:           n   = *pt++; kk = *pt++;
811:           while (n--) {
812:             /* read [n, proc, n*[gid1,lid0] */
813:             PetscInt gid1=*pt++, lid1=gid1-my0, lid0=*pt++;
814:             /* write [lid0, n, n*[gid] ] */
815:             *pt2++ = lid0;
816:             pt3    = pt2++; /* save pointer for later */
817:             PetscCDGetHeadPos(agg_llists,lid1,&pos);
818:             while (pos) {
819:               PetscInt gid;
820:               PetscCDIntNdGetID(pos, &gid);
821:               PetscCDGetNextPos(agg_llists,lid1,&pos);
822:               *pt2++ = gid;
823:             }
824:             *pt3 = (pt2-pt3)-1;
825:             /* clear list */
826:             PetscCDRemoveAll(agg_llists, lid1);
827:           }
828:           /* send requested data tag2 *[lid0, n, n*[gid1] ] */
829:           MPI_Isend(sbuff, count2, MPIU_INT, proc, tag2, comm, request);
830:         }

832:         /* recieve tag2 *[lid0, n, n*[gid] ] */
833:         for (kk=0; kk<nSend1; kk++) {
834:           PetscMPIInt count;
835:           MPI_Request *request;
836:           PetscInt    *pt, *pt2;

838:           request = rreqs2[kk]; /* no need to free -- buffer is in 'sbuffs1' */
839:           MPI_Wait(request, &status);
840:           MPI_Get_count(&status, MPIU_INT, &count);
841:           pt      = pt2 = (PetscInt*)(request+1);
842:           while (pt-pt2 < count) {
843:             PetscInt lid0 = *pt++, n = *pt++;
844:             while (n--) {
845:               PetscInt gid1 = *pt++;
846:               PetscCDAppendID(agg_llists, lid0, gid1);
847:             }
848:           }
849:         }

851:         /* wait for tag1 isends */
852:         while (nSend1--) {
853:           MPI_Request *request;
854:           request = (MPI_Request*)sbuffs1[nSend1];
855:           MPI_Wait(request, &status);
856:           PetscFree(request);
857:         }
858:         PetscFree(sbuffs1);

860:         /* wait for tag2 isends */
861:         while (nSend2--) {
862:           MPI_Request *request = sreqs2[nSend2];
863:           MPI_Wait(request, &status);
864:           PetscFree(request);
865:         }

867:         VecRestoreArray(ghostMaxEdge, &cpcol_max_ew);
868:         VecRestoreArray(ghostMaxPE, &cpcol_max_pe);

870:         /* get 'cpcol_matched' - use locMaxPE, ghostMaxEdge, cpcol_max_ew */
871:         for (kk=0,gid=my0; kk<nloc; kk++,gid++) {
872:           PetscScalar vval = lid_matched[kk] ? 1.0 : 0.0;
873:           VecSetValues(locMaxPE, 1, &gid, &vval, INSERT_VALUES); /* set with GID */
874:         }
875:         VecAssemblyBegin(locMaxPE);
876:         VecAssemblyEnd(locMaxPE);
877:         VecScatterBegin(mpimat->Mvctx,locMaxPE,ghostMaxEdge,INSERT_VALUES,SCATTER_FORWARD);
878:         VecScatterEnd(mpimat->Mvctx,locMaxPE,ghostMaxEdge,INSERT_VALUES,SCATTER_FORWARD);
879:         VecGetArray(ghostMaxEdge, &cpcol_max_ew);
880:         VecGetLocalSize(mpimat->lvec, &n);
881:         for (kk=0; kk<n; kk++) {
882:           cpcol_matched[kk] = (PetscBool)(PetscRealPart(cpcol_max_ew[kk]) != 0.0);
883:         }
884:         VecRestoreArray(ghostMaxEdge, &cpcol_max_ew);
885:       } /* size > 1 */

887:       /* compute 'locMaxEdge' */
888:       VecRestoreArray(locMaxEdge, &lid_max_ew);
889:       for (kk=0,gid=my0; kk<nloc; kk++,gid++) {
890:         PetscReal max_e = 0.,tt;
891:         PetscScalar vval;
892:         PetscInt lid = kk;

894:         if (lid_matched[lid]) vval = 0.;
895:         else {
896:           ii = matA->i; n = ii[lid+1] - ii[lid]; idx = matA->j + ii[lid];
897:           ap = matA->a + ii[lid];
898:           for (jj=0; jj<n; jj++) {
899:             PetscInt lidj = idx[jj];
900:             if (lid_matched[lidj]) continue; /* this is new - can change local max */
901:             if (lidj != lid && PetscRealPart(ap[jj]) > max_e) max_e = PetscRealPart(ap[jj]);
902:           }
903:           if (lid_cprowID && (ix=lid_cprowID[lid]) != -1) { /* if I have any ghost neighbors */
904:             ii  = matB->compressedrow.i; n = ii[ix+1] - ii[ix];
905:             ap  = matB->a + ii[ix];
906:             idx = matB->j + ii[ix];
907:             for (jj=0; jj<n; jj++) {
908:               PetscInt lidj = idx[jj];
909:               if (cpcol_matched[lidj]) continue;
910:               if ((tt=PetscRealPart(ap[jj])) > max_e) max_e = tt;
911:             }
912:           }
913:         }
914:         vval = (PetscScalar)max_e;
915:         VecSetValues(locMaxEdge, 1, &gid, &vval, INSERT_VALUES); /* set with GID */
916:       }
917:       VecAssemblyBegin(locMaxEdge);
918:       VecAssemblyEnd(locMaxEdge);

920:       if (size>1 && sub_it != n_sub_its-1) {
921:         /* compute 'cpcol_max_ew' */
922:         VecScatterBegin(mpimat->Mvctx,locMaxEdge,ghostMaxEdge,INSERT_VALUES,SCATTER_FORWARD);
923:         VecScatterEnd(mpimat->Mvctx,locMaxEdge,ghostMaxEdge,INSERT_VALUES,SCATTER_FORWARD);
924:         VecGetArray(ghostMaxEdge, &cpcol_max_ew);
925:         VecGetArray(locMaxEdge, &lid_max_ew);

927:         /* compute 'cpcol_max_pe' */
928:         for (kk=0,gid=my0; kk<nloc; kk++,gid++) {
929:           PetscInt lid = kk;
930:           PetscReal ew,v1_max_e,v0_max_e=PetscRealPart(lid_max_ew[lid]);
931:           PetscScalar vval;
932:           PetscMPIInt max_pe=rank,pe;

934:           if (lid_matched[lid]) vval = (PetscScalar)rank;
935:           else if ((ix=lid_cprowID[lid]) != -1) { /* if I have any ghost neighbors */
936:             ii  = matB->compressedrow.i; n = ii[ix+1] - ii[ix];
937:             ap  = matB->a + ii[ix];
938:             idx = matB->j + ii[ix];
939:             for (jj=0; jj<n; jj++) {
940:               PetscInt lidj = idx[jj];
941:               if (cpcol_matched[lidj]) continue;
942:               ew = PetscRealPart(ap[jj]); v1_max_e = PetscRealPart(cpcol_max_ew[lidj]);
943:               /* get max pe that has a max_e == to this edge w */
944:               if ((pe=cpcol_pe[idx[jj]]) > max_pe && ew > v1_max_e - PETSC_SMALL && ew > v0_max_e - PETSC_SMALL) max_pe = pe;
945:             }
946:             vval = (PetscScalar)max_pe;
947:           }
948:           VecSetValues(locMaxPE, 1, &gid, &vval, INSERT_VALUES);
949:         }
950:         VecAssemblyBegin(locMaxPE);
951:         VecAssemblyEnd(locMaxPE);

953:         VecScatterBegin(mpimat->Mvctx,locMaxPE,ghostMaxPE,INSERT_VALUES,SCATTER_FORWARD);
954:         VecScatterEnd(mpimat->Mvctx,locMaxPE,ghostMaxPE,INSERT_VALUES,SCATTER_FORWARD);
955:         VecGetArray(ghostMaxPE, &cpcol_max_pe);
956:         VecRestoreArray(locMaxEdge, &lid_max_ew);
957:       } /* deal with deleted ghost */
958:       PetscInfo3(a_Gmat,"\t %D.%D: %D active edges.\n",iter,sub_it,nactive_edges);
959:       if (!nactive_edges) break;
960:     } /* sub_it loop */

962:     /* clean up iteration */
963:     PetscFree(Edges);
964:     if (mpimat) {
965:       VecRestoreArray(ghostMaxEdge, &cpcol_max_ew);
966:       VecDestroy(&ghostMaxEdge);
967:       VecRestoreArray(ghostMaxPE, &cpcol_max_pe);
968:       VecDestroy(&ghostMaxPE);
969:       PetscFree(cpcol_pe);
970:       PetscFree(cpcol_matched);
971:     }

973:     VecDestroy(&locMaxEdge);
974:     VecDestroy(&locMaxPE);

976:     if (mpimat) {
977:       VecRestoreArray(mpimat->lvec, &cpcol_gid);
978:     }

980:     /* create next G if needed */
981:     if (iter == n_iter) { /* hard wired test - need to look at full surrounded nodes or something */
982:       MatDestroy(&P);
983:       MatDestroy(&cMat);
984:       break;
985:     } else {
986:       Vec diag;
987:       /* add identity for unmatched vertices so they stay alive */
988:       for (kk=0,gid=my0; kk<nloc; kk++,gid++) {
989:         if (!lid_matched[kk]) {
990:           gid  = kk+my0;
991:           MatGetRow(cMat,gid,&n,0,0);
992:           if (n>1) {
993:             MatSetValues(P,1,&gid,1,&gid,&one,INSERT_VALUES);
994:           }
995:           MatRestoreRow(cMat,gid,&n,0,0);
996:         }
997:       }
998:       MatAssemblyBegin(P,MAT_FINAL_ASSEMBLY);
999:       MatAssemblyEnd(P,MAT_FINAL_ASSEMBLY);

1001:       /* project to make new graph with colapsed edges */
1002:       MatPtAP(cMat,P,MAT_INITIAL_MATRIX,1.0,&tMat);
1003:       MatDestroy(&P);
1004:       MatDestroy(&cMat);
1005:       cMat = tMat;
1006:       MatCreateVecs(cMat, &diag, 0);
1007:       MatGetDiagonal(cMat, diag); /* effectively PCJACOBI */
1008:       VecReciprocal(diag);
1009:       VecSqrtAbs(diag);
1010:       MatDiagonalScale(cMat, diag, diag);
1011:       VecDestroy(&diag);
1012:     }
1013:   } /* coarsen iterator */

1015:   /* make fake matrix */
1016:   if (size>1) {
1017:     Mat          mat;
1018:     PetscCDIntNd *pos;
1019:     PetscInt     gid, NN, MM, jj = 0, mxsz = 0;

1021:     for (kk=0; kk<nloc; kk++) {
1022:       PetscCDSizeAt(agg_llists, kk, &jj);
1023:       if (jj > mxsz) mxsz = jj;
1024:     }
1025:     MatGetSize(a_Gmat, &MM, &NN);
1026:     if (mxsz > MM-nloc) mxsz = MM-nloc;

1028:     MatCreateAIJ(comm, nloc, nloc,PETSC_DETERMINE, PETSC_DETERMINE,0, 0, mxsz, 0, &mat);

1030:     for (kk=0,gid=my0; kk<nloc; kk++,gid++) {
1031:       /* for (pos=PetscCDGetHeadPos(agg_llists,kk) ; pos ; pos=PetscCDGetNextPos(agg_llists,kk,pos)) { */
1032:       PetscCDGetHeadPos(agg_llists,kk,&pos);
1033:       while (pos) {
1034:         PetscInt gid1;
1035:         PetscCDIntNdGetID(pos, &gid1);
1036:         PetscCDGetNextPos(agg_llists,kk,&pos);

1038:         if (gid1 < my0 || gid1 >= my0+nloc) {
1039:           MatSetValues(mat,1,&gid,1,&gid1,&one,ADD_VALUES);
1040:         }
1041:       }
1042:     }
1043:     MatAssemblyBegin(mat,MAT_FINAL_ASSEMBLY);
1044:     MatAssemblyEnd(mat,MAT_FINAL_ASSEMBLY);
1045:     PetscCDSetMat(agg_llists, mat);
1046:   }

1048:   PetscFree(lid_cprowID);
1049:   PetscFree(lid_gid);
1050:   PetscFree(lid_matched);
1051:   PetscCDDestroy(deleted_list);
1052:   return(0);
1053: }

1055: typedef struct {
1056:   int dummy;
1057: } MatCoarsen_HEM;
1058: /*
1059:    HEM coarsen, simple greedy.
1060: */
1061: static PetscErrorCode MatCoarsenApply_HEM(MatCoarsen coarse)
1062: {
1063:   /* MatCoarsen_HEM *HEM = (MatCoarsen_HEM*)coarse->subctx; */
1065:   Mat            mat = coarse->graph;

1069:   if (!coarse->perm) {
1070:     IS       perm;
1071:     PetscInt n,m;

1073:     MatGetLocalSize(mat, &m, &n);
1074:     ISCreateStride(PetscObjectComm((PetscObject)mat), m, 0, 1, &perm);
1075:     heavyEdgeMatchAgg(perm, mat, &coarse->agg_lists);
1076:     ISDestroy(&perm);
1077:   } else {
1078:     heavyEdgeMatchAgg(coarse->perm, mat, &coarse->agg_lists);
1079:   }
1080:   return(0);
1081: }

1083: static PetscErrorCode MatCoarsenView_HEM(MatCoarsen coarse,PetscViewer viewer)
1084: {
1085:   /* MatCoarsen_HEM *HEM = (MatCoarsen_HEM*)coarse->subctx; */
1087:   PetscMPIInt    rank;
1088:   PetscBool      iascii;

1092:   MPI_Comm_rank(PetscObjectComm((PetscObject)coarse),&rank);
1093:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
1094:   if (iascii) {
1095:     PetscViewerASCIIPushSynchronized(viewer);
1096:     PetscViewerASCIISynchronizedPrintf(viewer,"  [%d] HEM aggregator\n",rank);
1097:     PetscViewerFlush(viewer);
1098:     PetscViewerASCIIPopSynchronized(viewer);
1099:   }
1100:   return(0);
1101: }

1103: static PetscErrorCode MatCoarsenDestroy_HEM(MatCoarsen coarse)
1104: {
1105:   MatCoarsen_HEM *HEM = (MatCoarsen_HEM*)coarse->subctx;

1110:   PetscFree(HEM);
1111:   return(0);
1112: }

1114: /*MC
1115:    MATCOARSENHEM - A coarsener that uses HEM a simple greedy coarsener

1117:    Level: beginner

1119: .keywords: Coarsen, create, context

1121: .seealso: MatCoarsenSetType(), MatCoarsenType, MatCoarsenCreate()

1123: M*/

1125: PETSC_EXTERN PetscErrorCode MatCoarsenCreate_HEM(MatCoarsen coarse)
1126: {
1128:   MatCoarsen_HEM *HEM;

1131:   PetscNewLog(coarse,&HEM);
1132:   coarse->subctx       = (void*)HEM;
1133:   coarse->ops->apply   = MatCoarsenApply_HEM;
1134:   coarse->ops->view    = MatCoarsenView_HEM;
1135:   coarse->ops->destroy = MatCoarsenDestroy_HEM;
1136:   return(0);
1137: }