Actual source code: gasm.c
petsc-3.13.6 2020-09-29
1: /*
2: This file defines an "generalized" additive Schwarz preconditioner for any Mat implementation.
3: In this version each processor may intersect multiple subdomains and any subdomain may
4: intersect multiple processors. Intersections of subdomains with processors are called *local
5: subdomains*.
7: N - total number of distinct global subdomains (set explicitly in PCGASMSetTotalSubdomains() or implicitly PCGASMSetSubdomains() and then calculated in PCSetUp_GASM())
8: n - actual number of local subdomains on this processor (set in PCGASMSetSubdomains() or calculated in PCGASMSetTotalSubdomains())
9: nmax - maximum number of local subdomains per processor (calculated in PCSetUp_GASM())
10: */
11: #include <petsc/private/pcimpl.h>
12: #include <petscdm.h>
14: typedef struct {
15: PetscInt N,n,nmax;
16: PetscInt overlap; /* overlap requested by user */
17: PCGASMType type; /* use reduced interpolation, restriction or both */
18: PetscBool type_set; /* if user set this value (so won't change it for symmetric problems) */
19: PetscBool same_subdomain_solvers; /* flag indicating whether all local solvers are same */
20: PetscBool sort_indices; /* flag to sort subdomain indices */
21: PetscBool user_subdomains; /* whether the user set explicit subdomain index sets -- keep them on PCReset() */
22: PetscBool dm_subdomains; /* whether DM is allowed to define subdomains */
23: PetscBool hierarchicalpartitioning;
24: IS *ois; /* index sets that define the outer (conceptually, overlapping) subdomains */
25: IS *iis; /* index sets that define the inner (conceptually, nonoverlapping) subdomains */
26: KSP *ksp; /* linear solvers for each subdomain */
27: Mat *pmat; /* subdomain block matrices */
28: Vec gx,gy; /* Merged work vectors */
29: Vec *x,*y; /* Split work vectors; storage aliases pieces of storage of the above merged vectors. */
30: VecScatter gorestriction; /* merged restriction to disjoint union of outer subdomains */
31: VecScatter girestriction; /* merged restriction to disjoint union of inner subdomains */
32: VecScatter pctoouter;
33: IS permutationIS;
34: Mat permutationP;
35: Mat pcmat;
36: Vec pcx,pcy;
37: } PC_GASM;
39: static PetscErrorCode PCGASMComputeGlobalSubdomainNumbering_Private(PC pc,PetscInt **numbering,PetscInt **permutation)
40: {
41: PC_GASM *osm = (PC_GASM*)pc->data;
42: PetscInt i;
46: /* Determine the number of globally-distinct subdomains and compute a global numbering for them. */
47: PetscMalloc2(osm->n,numbering,osm->n,permutation);
48: PetscObjectsListGetGlobalNumbering(PetscObjectComm((PetscObject)pc),osm->n,(PetscObject*)osm->iis,NULL,*numbering);
49: for (i = 0; i < osm->n; ++i) (*permutation)[i] = i;
50: PetscSortIntWithPermutation(osm->n,*numbering,*permutation);
51: return(0);
52: }
54: static PetscErrorCode PCGASMSubdomainView_Private(PC pc, PetscInt i, PetscViewer viewer)
55: {
56: PC_GASM *osm = (PC_GASM*)pc->data;
57: PetscInt j,nidx;
58: const PetscInt *idx;
59: PetscViewer sviewer;
60: char *cidx;
64: if (i < 0 || i > osm->n) SETERRQ2(PetscObjectComm((PetscObject)viewer), PETSC_ERR_ARG_WRONG, "Invalid subdomain %D: must nonnegative and less than %D", i, osm->n);
65: /* Inner subdomains. */
66: ISGetLocalSize(osm->iis[i], &nidx);
67: /*
68: No more than 15 characters per index plus a space.
69: PetscViewerStringSPrintf requires a string of size at least 2, so use (nidx+1) instead of nidx,
70: in case nidx == 0. That will take care of the space for the trailing '\0' as well.
71: For nidx == 0, the whole string 16 '\0'.
72: */
73: #define len 16*(nidx+1)+1
74: PetscMalloc1(len, &cidx);
75: PetscViewerStringOpen(PETSC_COMM_SELF, cidx, len, &sviewer);
76: #undef len
77: ISGetIndices(osm->iis[i], &idx);
78: for (j = 0; j < nidx; ++j) {
79: PetscViewerStringSPrintf(sviewer, "%D ", idx[j]);
80: }
81: ISRestoreIndices(osm->iis[i],&idx);
82: PetscViewerDestroy(&sviewer);
83: PetscViewerASCIIPrintf(viewer, "Inner subdomain:\n");
84: PetscViewerFlush(viewer);
85: PetscViewerASCIIPushSynchronized(viewer);
86: PetscViewerASCIISynchronizedPrintf(viewer, "%s", cidx);
87: PetscViewerFlush(viewer);
88: PetscViewerASCIIPopSynchronized(viewer);
89: PetscViewerASCIIPrintf(viewer, "\n");
90: PetscViewerFlush(viewer);
91: PetscFree(cidx);
92: /* Outer subdomains. */
93: ISGetLocalSize(osm->ois[i], &nidx);
94: /*
95: No more than 15 characters per index plus a space.
96: PetscViewerStringSPrintf requires a string of size at least 2, so use (nidx+1) instead of nidx,
97: in case nidx == 0. That will take care of the space for the trailing '\0' as well.
98: For nidx == 0, the whole string 16 '\0'.
99: */
100: #define len 16*(nidx+1)+1
101: PetscMalloc1(len, &cidx);
102: PetscViewerStringOpen(PETSC_COMM_SELF, cidx, len, &sviewer);
103: #undef len
104: ISGetIndices(osm->ois[i], &idx);
105: for (j = 0; j < nidx; ++j) {
106: PetscViewerStringSPrintf(sviewer,"%D ", idx[j]);
107: }
108: PetscViewerDestroy(&sviewer);
109: ISRestoreIndices(osm->ois[i],&idx);
110: PetscViewerASCIIPrintf(viewer, "Outer subdomain:\n");
111: PetscViewerFlush(viewer);
112: PetscViewerASCIIPushSynchronized(viewer);
113: PetscViewerASCIISynchronizedPrintf(viewer, "%s", cidx);
114: PetscViewerFlush(viewer);
115: PetscViewerASCIIPopSynchronized(viewer);
116: PetscViewerASCIIPrintf(viewer, "\n");
117: PetscViewerFlush(viewer);
118: PetscFree(cidx);
119: return(0);
120: }
122: static PetscErrorCode PCGASMPrintSubdomains(PC pc)
123: {
124: PC_GASM *osm = (PC_GASM*)pc->data;
125: const char *prefix;
126: char fname[PETSC_MAX_PATH_LEN+1];
127: PetscInt l, d, count;
128: PetscBool doprint,found;
129: PetscViewer viewer, sviewer = NULL;
130: PetscInt *numbering,*permutation;/* global numbering of locally-supported subdomains and the permutation from the local ordering */
134: PCGetOptionsPrefix(pc,&prefix);
135: doprint = PETSC_FALSE;
136: PetscOptionsGetBool(NULL,prefix,"-pc_gasm_print_subdomains",&doprint,NULL);
137: if (!doprint) return(0);
138: PetscOptionsGetString(NULL,prefix,"-pc_gasm_print_subdomains",fname,PETSC_MAX_PATH_LEN,&found);
139: if (!found) { PetscStrcpy(fname,"stdout"); };
140: PetscViewerASCIIOpen(PetscObjectComm((PetscObject)pc),fname,&viewer);
141: /*
142: Make sure the viewer has a name. Otherwise this may cause a deadlock or other weird errors when creating a subcomm viewer:
143: the subcomm viewer will attempt to inherit the viewer's name, which, if not set, will be constructed collectively on the comm.
144: */
145: PetscObjectName((PetscObject)viewer);
146: l = 0;
147: PCGASMComputeGlobalSubdomainNumbering_Private(pc,&numbering,&permutation);
148: for (count = 0; count < osm->N; ++count) {
149: /* Now let subdomains go one at a time in the global numbering order and print their subdomain/solver info. */
150: if (l<osm->n) {
151: d = permutation[l]; /* d is the local number of the l-th smallest (in the global ordering) among the locally supported subdomains */
152: if (numbering[d] == count) {
153: PetscViewerGetSubViewer(viewer,((PetscObject)osm->ois[d])->comm, &sviewer);
154: PCGASMSubdomainView_Private(pc,d,sviewer);
155: PetscViewerRestoreSubViewer(viewer,((PetscObject)osm->ois[d])->comm, &sviewer);
156: ++l;
157: }
158: }
159: MPI_Barrier(PetscObjectComm((PetscObject)pc));
160: }
161: PetscFree2(numbering,permutation);
162: PetscViewerDestroy(&viewer);
163: return(0);
164: }
167: static PetscErrorCode PCView_GASM(PC pc,PetscViewer viewer)
168: {
169: PC_GASM *osm = (PC_GASM*)pc->data;
170: const char *prefix;
172: PetscMPIInt rank, size;
173: PetscInt bsz;
174: PetscBool iascii,view_subdomains=PETSC_FALSE;
175: PetscViewer sviewer;
176: PetscInt count, l;
177: char overlap[256] = "user-defined overlap";
178: char gsubdomains[256] = "unknown total number of subdomains";
179: char msubdomains[256] = "unknown max number of local subdomains";
180: PetscInt *numbering,*permutation;/* global numbering of locally-supported subdomains and the permutation from the local ordering */
183: MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size);
184: MPI_Comm_rank(PetscObjectComm((PetscObject)pc), &rank);
186: if (osm->overlap >= 0) {
187: PetscSNPrintf(overlap,sizeof(overlap),"requested amount of overlap = %D",osm->overlap);
188: }
189: if (osm->N != PETSC_DETERMINE) {
190: PetscSNPrintf(gsubdomains, sizeof(gsubdomains), "total number of subdomains = %D",osm->N);
191: }
192: if (osm->nmax != PETSC_DETERMINE) {
193: PetscSNPrintf(msubdomains,sizeof(msubdomains),"max number of local subdomains = %D",osm->nmax);
194: }
196: PCGetOptionsPrefix(pc,&prefix);
197: PetscOptionsGetBool(NULL,prefix,"-pc_gasm_view_subdomains",&view_subdomains,NULL);
199: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
200: if (iascii) {
201: /*
202: Make sure the viewer has a name. Otherwise this may cause a deadlock when creating a subcomm viewer:
203: the subcomm viewer will attempt to inherit the viewer's name, which, if not set, will be constructed
204: collectively on the comm.
205: */
206: PetscObjectName((PetscObject)viewer);
207: PetscViewerASCIIPrintf(viewer," Restriction/interpolation type: %s\n",PCGASMTypes[osm->type]);
208: PetscViewerASCIIPrintf(viewer," %s\n",overlap);
209: PetscViewerASCIIPrintf(viewer," %s\n",gsubdomains);
210: PetscViewerASCIIPrintf(viewer," %s\n",msubdomains);
211: PetscViewerASCIIPushSynchronized(viewer);
212: PetscViewerASCIISynchronizedPrintf(viewer," [%d|%d] number of locally-supported subdomains = %D\n",rank,size,osm->n);
213: PetscViewerFlush(viewer);
214: PetscViewerASCIIPopSynchronized(viewer);
215: /* Cannot take advantage of osm->same_subdomain_solvers without a global numbering of subdomains. */
216: PetscViewerASCIIPrintf(viewer," Subdomain solver info is as follows:\n");
217: PetscViewerASCIIPushTab(viewer);
218: PetscViewerASCIIPrintf(viewer," - - - - - - - - - - - - - - - - - -\n");
219: /* Make sure that everybody waits for the banner to be printed. */
220: MPI_Barrier(PetscObjectComm((PetscObject)viewer));
221: /* Now let subdomains go one at a time in the global numbering order and print their subdomain/solver info. */
222: PCGASMComputeGlobalSubdomainNumbering_Private(pc,&numbering,&permutation);
223: l = 0;
224: for (count = 0; count < osm->N; ++count) {
225: PetscMPIInt srank, ssize;
226: if (l<osm->n) {
227: PetscInt d = permutation[l]; /* d is the local number of the l-th smallest (in the global ordering) among the locally supported subdomains */
228: if (numbering[d] == count) {
229: MPI_Comm_size(((PetscObject)osm->ois[d])->comm, &ssize);
230: MPI_Comm_rank(((PetscObject)osm->ois[d])->comm, &srank);
231: PetscViewerGetSubViewer(viewer,((PetscObject)osm->ois[d])->comm, &sviewer);
232: ISGetLocalSize(osm->ois[d],&bsz);
233: PetscViewerASCIISynchronizedPrintf(sviewer," [%d|%d] (subcomm [%d|%d]) local subdomain number %D, local size = %D\n",rank,size,srank,ssize,d,bsz);
234: PetscViewerFlush(sviewer);
235: if (view_subdomains) {
236: PCGASMSubdomainView_Private(pc,d,sviewer);
237: }
238: if (!pc->setupcalled) {
239: PetscViewerASCIIPrintf(sviewer, " Solver not set up yet: PCSetUp() not yet called\n");
240: } else {
241: KSPView(osm->ksp[d],sviewer);
242: }
243: PetscViewerASCIIPrintf(sviewer," - - - - - - - - - - - - - - - - - -\n");
244: PetscViewerFlush(sviewer);
245: PetscViewerRestoreSubViewer(viewer,((PetscObject)osm->ois[d])->comm, &sviewer);
246: ++l;
247: }
248: }
249: MPI_Barrier(PetscObjectComm((PetscObject)pc));
250: }
251: PetscFree2(numbering,permutation);
252: PetscViewerASCIIPopTab(viewer);
253: }
254: PetscViewerFlush(viewer);
255: PetscViewerASCIIPopSynchronized(viewer);
256: return(0);
257: }
259: PETSC_INTERN PetscErrorCode PCGASMCreateLocalSubdomains(Mat A, PetscInt nloc, IS *iis[]);
263: PetscErrorCode PCGASMSetHierarchicalPartitioning(PC pc)
264: {
265: PC_GASM *osm = (PC_GASM*)pc->data;
266: MatPartitioning part;
267: MPI_Comm comm;
268: PetscMPIInt size;
269: PetscInt nlocalsubdomains,fromrows_localsize;
270: IS partitioning,fromrows,isn;
271: Vec outervec;
272: PetscErrorCode ierr;
275: PetscObjectGetComm((PetscObject)pc,&comm);
276: MPI_Comm_size(comm,&size);
277: /* we do not need a hierarchical partitioning when
278: * the total number of subdomains is consistent with
279: * the number of MPI tasks.
280: * For the following cases, we do not need to use HP
281: * */
282: if(osm->N==PETSC_DETERMINE || osm->N>=size || osm->N==1) return(0);
283: if(size%osm->N != 0) SETERRQ2(PETSC_COMM_WORLD,PETSC_ERR_ARG_INCOMP,"have to specify the total number of subdomains %D to be a factor of the number of processors %d \n",osm->N,size);
284: nlocalsubdomains = size/osm->N;
285: osm->n = 1;
286: MatPartitioningCreate(comm,&part);
287: MatPartitioningSetAdjacency(part,pc->pmat);
288: MatPartitioningSetType(part,MATPARTITIONINGHIERARCH);
289: MatPartitioningHierarchicalSetNcoarseparts(part,osm->N);
290: MatPartitioningHierarchicalSetNfineparts(part,nlocalsubdomains);
291: MatPartitioningSetFromOptions(part);
292: /* get new processor owner number of each vertex */
293: MatPartitioningApply(part,&partitioning);
294: ISBuildTwoSided(partitioning,NULL,&fromrows);
295: ISPartitioningToNumbering(partitioning,&isn);
296: ISDestroy(&isn);
297: ISGetLocalSize(fromrows,&fromrows_localsize);
298: MatPartitioningDestroy(&part);
299: MatCreateVecs(pc->pmat,&outervec,NULL);
300: VecCreateMPI(comm,fromrows_localsize,PETSC_DETERMINE,&(osm->pcx));
301: VecDuplicate(osm->pcx,&(osm->pcy));
302: VecScatterCreate(osm->pcx,NULL,outervec,fromrows,&(osm->pctoouter));
303: MatCreateSubMatrix(pc->pmat,fromrows,fromrows,MAT_INITIAL_MATRIX,&(osm->permutationP));
304: PetscObjectReference((PetscObject)fromrows);
305: osm->permutationIS = fromrows;
306: osm->pcmat = pc->pmat;
307: PetscObjectReference((PetscObject)osm->permutationP);
308: pc->pmat = osm->permutationP;
309: VecDestroy(&outervec);
310: ISDestroy(&fromrows);
311: ISDestroy(&partitioning);
312: osm->n = PETSC_DETERMINE;
313: return(0);
314: }
318: static PetscErrorCode PCSetUp_GASM(PC pc)
319: {
320: PC_GASM *osm = (PC_GASM*)pc->data;
322: PetscInt i,nInnerIndices,nTotalInnerIndices;
323: PetscMPIInt rank, size;
324: MatReuse scall = MAT_REUSE_MATRIX;
325: KSP ksp;
326: PC subpc;
327: const char *prefix,*pprefix;
328: Vec x,y;
329: PetscInt oni; /* Number of indices in the i-th local outer subdomain. */
330: const PetscInt *oidxi; /* Indices from the i-th subdomain local outer subdomain. */
331: PetscInt on; /* Number of indices in the disjoint union of local outer subdomains. */
332: PetscInt *oidx; /* Indices in the disjoint union of local outer subdomains. */
333: IS gois; /* Disjoint union the global indices of outer subdomains. */
334: IS goid; /* Identity IS of the size of the disjoint union of outer subdomains. */
335: PetscScalar *gxarray, *gyarray;
336: PetscInt gostart; /* Start of locally-owned indices in the vectors -- osm->gx,osm->gy -- over the disjoint union of outer subdomains. */
337: PetscInt num_subdomains = 0;
338: DM *subdomain_dm = NULL;
339: char **subdomain_names = NULL;
340: PetscInt *numbering;
344: MPI_Comm_size(PetscObjectComm((PetscObject)pc),&size);
345: MPI_Comm_rank(PetscObjectComm((PetscObject)pc),&rank);
346: if (!pc->setupcalled) {
347: /* use a hierarchical partitioning */
348: if(osm->hierarchicalpartitioning){
349: PCGASMSetHierarchicalPartitioning(pc);
350: }
351: if (osm->n == PETSC_DETERMINE) {
352: if (osm->N != PETSC_DETERMINE) {
353: /* No local subdomains given, but the desired number of total subdomains is known, so construct them accordingly. */
354: PCGASMCreateSubdomains(pc->pmat,osm->N,&osm->n,&osm->iis);
355: } else if (osm->dm_subdomains && pc->dm) {
356: /* try pc->dm next, if allowed */
357: PetscInt d;
358: IS *inner_subdomain_is, *outer_subdomain_is;
359: DMCreateDomainDecomposition(pc->dm, &num_subdomains, &subdomain_names, &inner_subdomain_is, &outer_subdomain_is, &subdomain_dm);
360: if (num_subdomains) {
361: PCGASMSetSubdomains(pc, num_subdomains, inner_subdomain_is, outer_subdomain_is);
362: }
363: for (d = 0; d < num_subdomains; ++d) {
364: if (inner_subdomain_is) {ISDestroy(&inner_subdomain_is[d]);}
365: if (outer_subdomain_is) {ISDestroy(&outer_subdomain_is[d]);}
366: }
367: PetscFree(inner_subdomain_is);
368: PetscFree(outer_subdomain_is);
369: } else {
370: /* still no subdomains; use one per processor */
371: osm->nmax = osm->n = 1;
372: MPI_Comm_size(PetscObjectComm((PetscObject)pc),&size);
373: osm->N = size;
374: PCGASMCreateLocalSubdomains(pc->pmat,osm->n,&osm->iis);
375: }
376: }
377: if (!osm->iis) {
378: /*
379: osm->n was set in PCGASMSetSubdomains(), but the actual subdomains have not been supplied.
380: We create the requisite number of local inner subdomains and then expand them into
381: out subdomains, if necessary.
382: */
383: PCGASMCreateLocalSubdomains(pc->pmat,osm->n,&osm->iis);
384: }
385: if (!osm->ois) {
386: /*
387: Initially make outer subdomains the same as inner subdomains. If nonzero additional overlap
388: has been requested, copy the inner subdomains over so they can be modified.
389: */
390: PetscMalloc1(osm->n,&osm->ois);
391: for (i=0; i<osm->n; ++i) {
392: if (osm->overlap > 0 && osm->N>1) { /* With positive overlap, osm->iis[i] will be modified */
393: ISDuplicate(osm->iis[i],(osm->ois)+i);
394: ISCopy(osm->iis[i],osm->ois[i]);
395: } else {
396: PetscObjectReference((PetscObject)((osm->iis)[i]));
397: osm->ois[i] = osm->iis[i];
398: }
399: }
400: if (osm->overlap>0 && osm->N>1) {
401: /* Extend the "overlapping" regions by a number of steps */
402: MatIncreaseOverlapSplit(pc->pmat,osm->n,osm->ois,osm->overlap);
403: }
404: }
406: /* Now the subdomains are defined. Determine their global and max local numbers, if necessary. */
407: if (osm->nmax == PETSC_DETERMINE) {
408: PetscMPIInt inwork,outwork;
409: /* determine global number of subdomains and the max number of local subdomains */
410: inwork = osm->n;
411: MPIU_Allreduce(&inwork,&outwork,1,MPI_INT,MPI_MAX,PetscObjectComm((PetscObject)pc));
412: osm->nmax = outwork;
413: }
414: if (osm->N == PETSC_DETERMINE) {
415: /* Determine the number of globally-distinct subdomains and compute a global numbering for them. */
416: PetscObjectsListGetGlobalNumbering(PetscObjectComm((PetscObject)pc),osm->n,(PetscObject*)osm->ois,&osm->N,NULL);
417: }
420: if (osm->sort_indices) {
421: for (i=0; i<osm->n; i++) {
422: ISSort(osm->ois[i]);
423: ISSort(osm->iis[i]);
424: }
425: }
426: PCGetOptionsPrefix(pc,&prefix);
427: PCGASMPrintSubdomains(pc);
429: /*
430: Merge the ISs, create merged vectors and restrictions.
431: */
432: /* Merge outer subdomain ISs and construct a restriction onto the disjoint union of local outer subdomains. */
433: on = 0;
434: for (i=0; i<osm->n; i++) {
435: ISGetLocalSize(osm->ois[i],&oni);
436: on += oni;
437: }
438: PetscMalloc1(on, &oidx);
439: on = 0;
440: /* Merge local indices together */
441: for (i=0; i<osm->n; i++) {
442: ISGetLocalSize(osm->ois[i],&oni);
443: ISGetIndices(osm->ois[i],&oidxi);
444: PetscArraycpy(oidx+on,oidxi,oni);
445: ISRestoreIndices(osm->ois[i],&oidxi);
446: on += oni;
447: }
448: ISCreateGeneral(((PetscObject)(pc))->comm,on,oidx,PETSC_OWN_POINTER,&gois);
449: nTotalInnerIndices = 0;
450: for(i=0; i<osm->n; i++){
451: ISGetLocalSize(osm->iis[i],&nInnerIndices);
452: nTotalInnerIndices += nInnerIndices;
453: }
454: VecCreateMPI(((PetscObject)(pc))->comm,nTotalInnerIndices,PETSC_DETERMINE,&x);
455: VecDuplicate(x,&y);
457: VecCreateMPI(PetscObjectComm((PetscObject)pc),on,PETSC_DECIDE,&osm->gx);
458: VecDuplicate(osm->gx,&osm->gy);
459: VecGetOwnershipRange(osm->gx, &gostart, NULL);
460: ISCreateStride(PetscObjectComm((PetscObject)pc),on,gostart,1, &goid);
461: /* gois might indices not on local */
462: VecScatterCreate(x,gois,osm->gx,goid, &(osm->gorestriction));
463: PetscMalloc1(osm->n,&numbering);
464: PetscObjectsListGetGlobalNumbering(PetscObjectComm((PetscObject)pc),osm->n,(PetscObject*)osm->ois,NULL,numbering);
465: VecDestroy(&x);
466: ISDestroy(&gois);
468: /* Merge inner subdomain ISs and construct a restriction onto the disjoint union of local inner subdomains. */
469: {
470: PetscInt ini; /* Number of indices the i-th a local inner subdomain. */
471: PetscInt in; /* Number of indices in the disjoint union of local inner subdomains. */
472: PetscInt *iidx; /* Global indices in the merged local inner subdomain. */
473: PetscInt *ioidx; /* Global indices of the disjoint union of inner subdomains within the disjoint union of outer subdomains. */
474: IS giis; /* IS for the disjoint union of inner subdomains. */
475: IS giois; /* IS for the disjoint union of inner subdomains within the disjoint union of outer subdomains. */
476: PetscScalar *array;
477: const PetscInt *indices;
478: PetscInt k;
479: on = 0;
480: for (i=0; i<osm->n; i++) {
481: ISGetLocalSize(osm->ois[i],&oni);
482: on += oni;
483: }
484: PetscMalloc1(on, &iidx);
485: PetscMalloc1(on, &ioidx);
486: VecGetArray(y,&array);
487: /* set communicator id to determine where overlap is */
488: in = 0;
489: for (i=0; i<osm->n; i++) {
490: ISGetLocalSize(osm->iis[i],&ini);
491: for (k = 0; k < ini; ++k){
492: array[in+k] = numbering[i];
493: }
494: in += ini;
495: }
496: VecRestoreArray(y,&array);
497: VecScatterBegin(osm->gorestriction,y,osm->gy,INSERT_VALUES,SCATTER_FORWARD);
498: VecScatterEnd(osm->gorestriction,y,osm->gy,INSERT_VALUES,SCATTER_FORWARD);
499: VecGetOwnershipRange(osm->gy,&gostart, NULL);
500: VecGetArray(osm->gy,&array);
501: on = 0;
502: in = 0;
503: for (i=0; i<osm->n; i++) {
504: ISGetLocalSize(osm->ois[i],&oni);
505: ISGetIndices(osm->ois[i],&indices);
506: for (k=0; k<oni; k++) {
507: /* skip overlapping indices to get inner domain */
508: if(PetscRealPart(array[on+k]) != numbering[i]) continue;
509: iidx[in] = indices[k];
510: ioidx[in++] = gostart+on+k;
511: }
512: ISRestoreIndices(osm->ois[i], &indices);
513: on += oni;
514: }
515: VecRestoreArray(osm->gy,&array);
516: ISCreateGeneral(PetscObjectComm((PetscObject)pc),in,iidx,PETSC_OWN_POINTER,&giis);
517: ISCreateGeneral(PetscObjectComm((PetscObject)pc),in,ioidx,PETSC_OWN_POINTER,&giois);
518: VecScatterCreate(y,giis,osm->gy,giois,&osm->girestriction);
519: VecDestroy(&y);
520: ISDestroy(&giis);
521: ISDestroy(&giois);
522: }
523: ISDestroy(&goid);
524: PetscFree(numbering);
526: /* Create the subdomain work vectors. */
527: PetscMalloc1(osm->n,&osm->x);
528: PetscMalloc1(osm->n,&osm->y);
529: VecGetArray(osm->gx, &gxarray);
530: VecGetArray(osm->gy, &gyarray);
531: for (i=0, on=0; i<osm->n; ++i, on += oni) {
532: PetscInt oNi;
533: ISGetLocalSize(osm->ois[i],&oni);
534: /* on a sub communicator */
535: ISGetSize(osm->ois[i],&oNi);
536: VecCreateMPIWithArray(((PetscObject)(osm->ois[i]))->comm,1,oni,oNi,gxarray+on,&osm->x[i]);
537: VecCreateMPIWithArray(((PetscObject)(osm->ois[i]))->comm,1,oni,oNi,gyarray+on,&osm->y[i]);
538: }
539: VecRestoreArray(osm->gx, &gxarray);
540: VecRestoreArray(osm->gy, &gyarray);
541: /* Create the subdomain solvers */
542: PetscMalloc1(osm->n,&osm->ksp);
543: for (i=0; i<osm->n; i++) {
544: char subprefix[PETSC_MAX_PATH_LEN+1];
545: KSPCreate(((PetscObject)(osm->ois[i]))->comm,&ksp);
546: KSPSetErrorIfNotConverged(ksp,pc->erroriffailure);
547: PetscLogObjectParent((PetscObject)pc,(PetscObject)ksp);
548: PetscObjectIncrementTabLevel((PetscObject)ksp,(PetscObject)pc,1);
549: KSPSetType(ksp,KSPPREONLY);
550: KSPGetPC(ksp,&subpc); /* Why do we need this here? */
551: if (subdomain_dm) {
552: KSPSetDM(ksp,subdomain_dm[i]);
553: DMDestroy(subdomain_dm+i);
554: }
555: PCGetOptionsPrefix(pc,&prefix);
556: KSPSetOptionsPrefix(ksp,prefix);
557: if (subdomain_names && subdomain_names[i]) {
558: PetscSNPrintf(subprefix,PETSC_MAX_PATH_LEN,"sub_%s_",subdomain_names[i]);
559: KSPAppendOptionsPrefix(ksp,subprefix);
560: PetscFree(subdomain_names[i]);
561: }
562: KSPAppendOptionsPrefix(ksp,"sub_");
563: osm->ksp[i] = ksp;
564: }
565: PetscFree(subdomain_dm);
566: PetscFree(subdomain_names);
567: scall = MAT_INITIAL_MATRIX;
569: } else { /* if (pc->setupcalled) */
570: /*
571: Destroy the submatrices from the previous iteration
572: */
573: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
574: MatDestroyMatrices(osm->n,&osm->pmat);
575: scall = MAT_INITIAL_MATRIX;
576: }
577: if(osm->permutationIS){
578: MatCreateSubMatrix(pc->pmat,osm->permutationIS,osm->permutationIS,scall,&osm->permutationP);
579: PetscObjectReference((PetscObject)osm->permutationP);
580: osm->pcmat = pc->pmat;
581: pc->pmat = osm->permutationP;
582: }
584: }
587: /*
588: Extract out the submatrices.
589: */
590: if (size > 1) {
591: MatCreateSubMatricesMPI(pc->pmat,osm->n,osm->ois,osm->ois,scall,&osm->pmat);
592: } else {
593: MatCreateSubMatrices(pc->pmat,osm->n,osm->ois,osm->ois,scall,&osm->pmat);
594: }
595: if (scall == MAT_INITIAL_MATRIX) {
596: PetscObjectGetOptionsPrefix((PetscObject)pc->pmat,&pprefix);
597: for (i=0; i<osm->n; i++) {
598: PetscLogObjectParent((PetscObject)pc,(PetscObject)osm->pmat[i]);
599: PetscObjectSetOptionsPrefix((PetscObject)osm->pmat[i],pprefix);
600: }
601: }
603: /* Return control to the user so that the submatrices can be modified (e.g., to apply
604: different boundary conditions for the submatrices than for the global problem) */
605: PCModifySubMatrices(pc,osm->n,osm->ois,osm->ois,osm->pmat,pc->modifysubmatricesP);
607: /*
608: Loop over submatrices putting them into local ksps
609: */
610: for (i=0; i<osm->n; i++) {
611: KSPSetOperators(osm->ksp[i],osm->pmat[i],osm->pmat[i]);
612: if (!pc->setupcalled) {
613: KSPSetFromOptions(osm->ksp[i]);
614: }
615: }
616: if(osm->pcmat){
617: MatDestroy(&pc->pmat);
618: pc->pmat = osm->pcmat;
619: osm->pcmat = 0;
620: }
621: return(0);
622: }
624: static PetscErrorCode PCSetUpOnBlocks_GASM(PC pc)
625: {
626: PC_GASM *osm = (PC_GASM*)pc->data;
628: PetscInt i;
631: for (i=0; i<osm->n; i++) {
632: KSPSetUp(osm->ksp[i]);
633: }
634: return(0);
635: }
637: static PetscErrorCode PCApply_GASM(PC pc,Vec xin,Vec yout)
638: {
639: PC_GASM *osm = (PC_GASM*)pc->data;
641: PetscInt i;
642: Vec x,y;
643: ScatterMode forward = SCATTER_FORWARD,reverse = SCATTER_REVERSE;
646: if(osm->pctoouter){
647: VecScatterBegin(osm->pctoouter,xin,osm->pcx,INSERT_VALUES,SCATTER_REVERSE);
648: VecScatterEnd(osm->pctoouter,xin,osm->pcx,INSERT_VALUES,SCATTER_REVERSE);
649: x = osm->pcx;
650: y = osm->pcy;
651: }else{
652: x = xin;
653: y = yout;
654: }
655: /*
656: Support for limiting the restriction or interpolation only to the inner
657: subdomain values (leaving the other values 0).
658: */
659: if (!(osm->type & PC_GASM_RESTRICT)) {
660: /* have to zero the work RHS since scatter may leave some slots empty */
661: VecZeroEntries(osm->gx);
662: VecScatterBegin(osm->girestriction,x,osm->gx,INSERT_VALUES,forward);
663: } else {
664: VecScatterBegin(osm->gorestriction,x,osm->gx,INSERT_VALUES,forward);
665: }
666: VecZeroEntries(osm->gy);
667: if (!(osm->type & PC_GASM_RESTRICT)) {
668: VecScatterEnd(osm->girestriction,x,osm->gx,INSERT_VALUES,forward);
669: } else {
670: VecScatterEnd(osm->gorestriction,x,osm->gx,INSERT_VALUES,forward);
671: }
672: /* do the subdomain solves */
673: for (i=0; i<osm->n; ++i) {
674: KSPSolve(osm->ksp[i],osm->x[i],osm->y[i]);
675: KSPCheckSolve(osm->ksp[i],pc,osm->y[i]);
676: }
677: /* Do we need to zero y ?? */
678: VecZeroEntries(y);
679: if (!(osm->type & PC_GASM_INTERPOLATE)) {
680: VecScatterBegin(osm->girestriction,osm->gy,y,ADD_VALUES,reverse);
681: VecScatterEnd(osm->girestriction,osm->gy,y,ADD_VALUES,reverse);
682: } else {
683: VecScatterBegin(osm->gorestriction,osm->gy,y,ADD_VALUES,reverse);
684: VecScatterEnd(osm->gorestriction,osm->gy,y,ADD_VALUES,reverse);
685: }
686: if(osm->pctoouter){
687: VecScatterBegin(osm->pctoouter,y,yout,INSERT_VALUES,SCATTER_FORWARD);
688: VecScatterEnd(osm->pctoouter,y,yout,INSERT_VALUES,SCATTER_FORWARD);
689: }
690: return(0);
691: }
693: static PetscErrorCode PCApplyTranspose_GASM(PC pc,Vec xin,Vec yout)
694: {
695: PC_GASM *osm = (PC_GASM*)pc->data;
697: PetscInt i;
698: Vec x,y;
699: ScatterMode forward = SCATTER_FORWARD,reverse = SCATTER_REVERSE;
702: if(osm->pctoouter){
703: VecScatterBegin(osm->pctoouter,xin,osm->pcx,INSERT_VALUES,SCATTER_REVERSE);
704: VecScatterEnd(osm->pctoouter,xin,osm->pcx,INSERT_VALUES,SCATTER_REVERSE);
705: x = osm->pcx;
706: y = osm->pcy;
707: }else{
708: x = xin;
709: y = yout;
710: }
711: /*
712: Support for limiting the restriction or interpolation to only local
713: subdomain values (leaving the other values 0).
715: Note: these are reversed from the PCApply_GASM() because we are applying the
716: transpose of the three terms
717: */
718: if (!(osm->type & PC_GASM_INTERPOLATE)) {
719: /* have to zero the work RHS since scatter may leave some slots empty */
720: VecZeroEntries(osm->gx);
721: VecScatterBegin(osm->girestriction,x,osm->gx,INSERT_VALUES,forward);
722: } else {
723: VecScatterBegin(osm->gorestriction,x,osm->gx,INSERT_VALUES,forward);
724: }
725: VecZeroEntries(osm->gy);
726: if (!(osm->type & PC_GASM_INTERPOLATE)) {
727: VecScatterEnd(osm->girestriction,x,osm->gx,INSERT_VALUES,forward);
728: } else {
729: VecScatterEnd(osm->gorestriction,x,osm->gx,INSERT_VALUES,forward);
730: }
731: /* do the local solves */
732: for (i=0; i<osm->n; ++i) { /* Note that the solves are local, so we can go to osm->n, rather than osm->nmax. */
733: KSPSolveTranspose(osm->ksp[i],osm->x[i],osm->y[i]);
734: KSPCheckSolve(osm->ksp[i],pc,osm->y[i]);
735: }
736: VecZeroEntries(y);
737: if (!(osm->type & PC_GASM_RESTRICT)) {
738: VecScatterBegin(osm->girestriction,osm->gy,y,ADD_VALUES,reverse);
739: VecScatterEnd(osm->girestriction,osm->gy,y,ADD_VALUES,reverse);
740: } else {
741: VecScatterBegin(osm->gorestriction,osm->gy,y,ADD_VALUES,reverse);
742: VecScatterEnd(osm->gorestriction,osm->gy,y,ADD_VALUES,reverse);
743: }
744: if(osm->pctoouter){
745: VecScatterBegin(osm->pctoouter,y,yout,INSERT_VALUES,SCATTER_FORWARD);
746: VecScatterEnd(osm->pctoouter,y,yout,INSERT_VALUES,SCATTER_FORWARD);
747: }
748: return(0);
749: }
751: static PetscErrorCode PCReset_GASM(PC pc)
752: {
753: PC_GASM *osm = (PC_GASM*)pc->data;
755: PetscInt i;
758: if (osm->ksp) {
759: for (i=0; i<osm->n; i++) {
760: KSPReset(osm->ksp[i]);
761: }
762: }
763: if (osm->pmat) {
764: if (osm->n > 0) {
765: PetscMPIInt size;
766: MPI_Comm_size(PetscObjectComm((PetscObject)pc),&size);
767: if (size > 1) {
768: /* osm->pmat is created by MatCreateSubMatricesMPI(), cannot use MatDestroySubMatrices() */
769: MatDestroyMatrices(osm->n,&osm->pmat);
770: } else {
771: MatDestroySubMatrices(osm->n,&osm->pmat);
772: }
773: }
774: }
775: if (osm->x) {
776: for (i=0; i<osm->n; i++) {
777: VecDestroy(&osm->x[i]);
778: VecDestroy(&osm->y[i]);
779: }
780: }
781: VecDestroy(&osm->gx);
782: VecDestroy(&osm->gy);
784: VecScatterDestroy(&osm->gorestriction);
785: VecScatterDestroy(&osm->girestriction);
786: if (!osm->user_subdomains) {
787: PCGASMDestroySubdomains(osm->n,&osm->ois,&osm->iis);
788: osm->N = PETSC_DETERMINE;
789: osm->nmax = PETSC_DETERMINE;
790: }
791: if(osm->pctoouter){
792: VecScatterDestroy(&(osm->pctoouter));
793: }
794: if(osm->permutationIS){
795: ISDestroy(&(osm->permutationIS));
796: }
797: if(osm->pcx){
798: VecDestroy(&(osm->pcx));
799: }
800: if(osm->pcy){
801: VecDestroy(&(osm->pcy));
802: }
803: if(osm->permutationP){
804: MatDestroy(&(osm->permutationP));
805: }
806: if(osm->pcmat){
807: MatDestroy(&osm->pcmat);
808: }
809: return(0);
810: }
812: static PetscErrorCode PCDestroy_GASM(PC pc)
813: {
814: PC_GASM *osm = (PC_GASM*)pc->data;
816: PetscInt i;
819: PCReset_GASM(pc);
820: /* PCReset will not destroy subdomains, if user_subdomains is true. */
821: PCGASMDestroySubdomains(osm->n,&osm->ois,&osm->iis);
822: if (osm->ksp) {
823: for (i=0; i<osm->n; i++) {
824: KSPDestroy(&osm->ksp[i]);
825: }
826: PetscFree(osm->ksp);
827: }
828: PetscFree(osm->x);
829: PetscFree(osm->y);
830: PetscFree(pc->data);
831: return(0);
832: }
834: static PetscErrorCode PCSetFromOptions_GASM(PetscOptionItems *PetscOptionsObject,PC pc)
835: {
836: PC_GASM *osm = (PC_GASM*)pc->data;
838: PetscInt blocks,ovl;
839: PetscBool flg;
840: PCGASMType gasmtype;
843: PetscOptionsHead(PetscOptionsObject,"Generalized additive Schwarz options");
844: PetscOptionsBool("-pc_gasm_use_dm_subdomains","If subdomains aren't set, use DMCreateDomainDecomposition() to define subdomains.","PCGASMSetUseDMSubdomains",osm->dm_subdomains,&osm->dm_subdomains,&flg);
845: PetscOptionsInt("-pc_gasm_total_subdomains","Total number of subdomains across communicator","PCGASMSetTotalSubdomains",osm->N,&blocks,&flg);
846: if (flg) {
847: PCGASMSetTotalSubdomains(pc,blocks);
848: }
849: PetscOptionsInt("-pc_gasm_overlap","Number of overlapping degrees of freedom","PCGASMSetOverlap",osm->overlap,&ovl,&flg);
850: if (flg) {
851: PCGASMSetOverlap(pc,ovl);
852: osm->dm_subdomains = PETSC_FALSE;
853: }
854: flg = PETSC_FALSE;
855: PetscOptionsEnum("-pc_gasm_type","Type of restriction/extension","PCGASMSetType",PCGASMTypes,(PetscEnum)osm->type,(PetscEnum*)&gasmtype,&flg);
856: if (flg) {PCGASMSetType(pc,gasmtype);}
857: PetscOptionsBool("-pc_gasm_use_hierachical_partitioning","use hierarchical partitioning",NULL,osm->hierarchicalpartitioning,&osm->hierarchicalpartitioning,&flg);
858: PetscOptionsTail();
859: return(0);
860: }
862: /*------------------------------------------------------------------------------------*/
864: /*@
865: PCGASMSetTotalSubdomains - sets the total number of subdomains to use across the
866: communicator.
867: Logically collective on pc
869: Input Parameters:
870: + pc - the preconditioner
871: - N - total number of subdomains
874: Level: beginner
876: .seealso: PCGASMSetSubdomains(), PCGASMSetOverlap()
877: PCGASMCreateSubdomains2D()
878: @*/
879: PetscErrorCode PCGASMSetTotalSubdomains(PC pc,PetscInt N)
880: {
881: PC_GASM *osm = (PC_GASM*)pc->data;
882: PetscMPIInt size,rank;
886: if (N < 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Total number of subdomains must be 1 or more, got N = %D",N);
887: if (pc->setupcalled) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"PCGASMSetTotalSubdomains() should be called before calling PCSetUp().");
889: PCGASMDestroySubdomains(osm->n,&osm->iis,&osm->ois);
890: osm->ois = osm->iis = NULL;
892: MPI_Comm_size(PetscObjectComm((PetscObject)pc),&size);
893: MPI_Comm_rank(PetscObjectComm((PetscObject)pc),&rank);
894: osm->N = N;
895: osm->n = PETSC_DETERMINE;
896: osm->nmax = PETSC_DETERMINE;
897: osm->dm_subdomains = PETSC_FALSE;
898: return(0);
899: }
902: static PetscErrorCode PCGASMSetSubdomains_GASM(PC pc,PetscInt n,IS iis[],IS ois[])
903: {
904: PC_GASM *osm = (PC_GASM*)pc->data;
905: PetscErrorCode ierr;
906: PetscInt i;
909: if (n < 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Each process must have 1 or more subdomains, got n = %D",n);
910: if (pc->setupcalled) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"PCGASMSetSubdomains() should be called before calling PCSetUp().");
912: PCGASMDestroySubdomains(osm->n,&osm->iis,&osm->ois);
913: osm->iis = osm->ois = NULL;
914: osm->n = n;
915: osm->N = PETSC_DETERMINE;
916: osm->nmax = PETSC_DETERMINE;
917: if (ois) {
918: PetscMalloc1(n,&osm->ois);
919: for (i=0; i<n; i++) {
920: PetscObjectReference((PetscObject)ois[i]);
921: osm->ois[i] = ois[i];
922: }
923: /*
924: Since the user set the outer subdomains, even if nontrivial overlap was requested via PCGASMSetOverlap(),
925: it will be ignored. To avoid confusion later on (e.g., when viewing the PC), the overlap size is set to -1.
926: */
927: osm->overlap = -1;
928: /* inner subdomains must be provided */
929: if (!iis) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NULL,"inner indices have to be provided \n");
930: }/* end if */
931: if (iis) {
932: PetscMalloc1(n,&osm->iis);
933: for (i=0; i<n; i++) {
934: PetscObjectReference((PetscObject)iis[i]);
935: osm->iis[i] = iis[i];
936: }
937: if (!ois) {
938: osm->ois = NULL;
939: /* if user does not provide outer indices, we will create the corresponding outer indices using osm->overlap =1 in PCSetUp_GASM */
940: }
941: }
942: #if defined(PETSC_USE_DEBUG)
943: {
944: PetscInt j,rstart,rend,*covered,lsize;
945: const PetscInt *indices;
946: /* check if the inner indices cover and only cover the local portion of the preconditioning matrix */
947: MatGetOwnershipRange(pc->pmat,&rstart,&rend);
948: PetscCalloc1(rend-rstart,&covered);
949: /* check if the current processor owns indices from others */
950: for (i=0; i<n; i++) {
951: ISGetIndices(osm->iis[i],&indices);
952: ISGetLocalSize(osm->iis[i],&lsize);
953: for (j=0; j<lsize; j++) {
954: if (indices[j]<rstart || indices[j]>=rend) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"inner subdomains can not own an index %d from other processors", indices[j]);
955: else if (covered[indices[j]-rstart]==1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"inner subdomains can not have an overlapping index %d ",indices[j]);
956: else covered[indices[j]-rstart] = 1;
957: }
958: ISRestoreIndices(osm->iis[i],&indices);
959: }
960: /* check if we miss any indices */
961: for (i=rstart; i<rend; i++) {
962: if (!covered[i-rstart]) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_NULL,"local entity %d was not covered by inner subdomains",i);
963: }
964: PetscFree(covered);
965: }
966: #endif
967: if (iis) osm->user_subdomains = PETSC_TRUE;
968: return(0);
969: }
972: static PetscErrorCode PCGASMSetOverlap_GASM(PC pc,PetscInt ovl)
973: {
974: PC_GASM *osm = (PC_GASM*)pc->data;
977: if (ovl < 0) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Negative overlap value requested");
978: if (pc->setupcalled && ovl != osm->overlap) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"PCGASMSetOverlap() should be called before PCSetUp().");
979: if (!pc->setupcalled) osm->overlap = ovl;
980: return(0);
981: }
983: static PetscErrorCode PCGASMSetType_GASM(PC pc,PCGASMType type)
984: {
985: PC_GASM *osm = (PC_GASM*)pc->data;
988: osm->type = type;
989: osm->type_set = PETSC_TRUE;
990: return(0);
991: }
993: static PetscErrorCode PCGASMSetSortIndices_GASM(PC pc,PetscBool doSort)
994: {
995: PC_GASM *osm = (PC_GASM*)pc->data;
998: osm->sort_indices = doSort;
999: return(0);
1000: }
1002: /*
1003: FIXME: This routine might need to be modified now that multiple ranks per subdomain are allowed.
1004: In particular, it would upset the global subdomain number calculation.
1005: */
1006: static PetscErrorCode PCGASMGetSubKSP_GASM(PC pc,PetscInt *n,PetscInt *first,KSP **ksp)
1007: {
1008: PC_GASM *osm = (PC_GASM*)pc->data;
1012: if (osm->n < 1) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ORDER,"Need to call PCSetUp() on PC (or KSPSetUp() on the outer KSP object) before calling here");
1014: if (n) *n = osm->n;
1015: if (first) {
1016: MPI_Scan(&osm->n,first,1,MPIU_INT,MPI_SUM,PetscObjectComm((PetscObject)pc));
1017: *first -= osm->n;
1018: }
1019: if (ksp) {
1020: /* Assume that local solves are now different; not necessarily
1021: true, though! This flag is used only for PCView_GASM() */
1022: *ksp = osm->ksp;
1023: osm->same_subdomain_solvers = PETSC_FALSE;
1024: }
1025: return(0);
1026: } /* PCGASMGetSubKSP_GASM() */
1028: /*@C
1029: PCGASMSetSubdomains - Sets the subdomains for this processor
1030: for the additive Schwarz preconditioner.
1032: Collective on pc
1034: Input Parameters:
1035: + pc - the preconditioner object
1036: . n - the number of subdomains for this processor
1037: . iis - the index sets that define the inner subdomains (or NULL for PETSc to determine subdomains)
1038: - ois - the index sets that define the outer subdomains (or NULL to use the same as iis, or to construct by expanding iis by the requested overlap)
1040: Notes:
1041: The IS indices use the parallel, global numbering of the vector entries.
1042: Inner subdomains are those where the correction is applied.
1043: Outer subdomains are those where the residual necessary to obtain the
1044: corrections is obtained (see PCGASMType for the use of inner/outer subdomains).
1045: Both inner and outer subdomains can extend over several processors.
1046: This processor's portion of a subdomain is known as a local subdomain.
1048: Inner subdomains can not overlap with each other, do not have any entities from remote processors,
1049: and have to cover the entire local subdomain owned by the current processor. The index sets on each
1050: process should be ordered such that the ith local subdomain is connected to the ith remote subdomain
1051: on another MPI process.
1053: By default the GASM preconditioner uses 1 (local) subdomain per processor.
1056: Level: advanced
1058: .seealso: PCGASMSetNumSubdomains(), PCGASMSetOverlap(), PCGASMGetSubKSP(),
1059: PCGASMCreateSubdomains2D(), PCGASMGetSubdomains()
1060: @*/
1061: PetscErrorCode PCGASMSetSubdomains(PC pc,PetscInt n,IS iis[],IS ois[])
1062: {
1063: PC_GASM *osm = (PC_GASM*)pc->data;
1068: PetscTryMethod(pc,"PCGASMSetSubdomains_C",(PC,PetscInt,IS[],IS[]),(pc,n,iis,ois));
1069: osm->dm_subdomains = PETSC_FALSE;
1070: return(0);
1071: }
1074: /*@
1075: PCGASMSetOverlap - Sets the overlap between a pair of subdomains for the
1076: additive Schwarz preconditioner. Either all or no processors in the
1077: pc communicator must call this routine.
1079: Logically Collective on pc
1081: Input Parameters:
1082: + pc - the preconditioner context
1083: - ovl - the amount of overlap between subdomains (ovl >= 0, default value = 0)
1085: Options Database Key:
1086: . -pc_gasm_overlap <overlap> - Sets overlap
1088: Notes:
1089: By default the GASM preconditioner uses 1 subdomain per processor. To use
1090: multiple subdomain per perocessor or "straddling" subdomains that intersect
1091: multiple processors use PCGASMSetSubdomains() (or option -pc_gasm_total_subdomains <n>).
1093: The overlap defaults to 0, so if one desires that no additional
1094: overlap be computed beyond what may have been set with a call to
1095: PCGASMSetSubdomains(), then ovl must be set to be 0. In particular, if one does
1096: not explicitly set the subdomains in Section 1.5 Writing Application Codes with PETSc code, then all overlap would be computed
1097: internally by PETSc, and using an overlap of 0 would result in an GASM
1098: variant that is equivalent to the block Jacobi preconditioner.
1100: Note that one can define initial index sets with any overlap via
1101: PCGASMSetSubdomains(); the routine PCGASMSetOverlap() merely allows
1102: PETSc to extend that overlap further, if desired.
1104: Level: intermediate
1106: .seealso: PCGASMSetSubdomains(), PCGASMGetSubKSP(),
1107: PCGASMCreateSubdomains2D(), PCGASMGetSubdomains()
1108: @*/
1109: PetscErrorCode PCGASMSetOverlap(PC pc,PetscInt ovl)
1110: {
1112: PC_GASM *osm = (PC_GASM*)pc->data;
1117: PetscTryMethod(pc,"PCGASMSetOverlap_C",(PC,PetscInt),(pc,ovl));
1118: osm->dm_subdomains = PETSC_FALSE;
1119: return(0);
1120: }
1122: /*@
1123: PCGASMSetType - Sets the type of restriction and interpolation used
1124: for local problems in the additive Schwarz method.
1126: Logically Collective on PC
1128: Input Parameters:
1129: + pc - the preconditioner context
1130: - type - variant of GASM, one of
1131: .vb
1132: PC_GASM_BASIC - full interpolation and restriction
1133: PC_GASM_RESTRICT - full restriction, local processor interpolation
1134: PC_GASM_INTERPOLATE - full interpolation, local processor restriction
1135: PC_GASM_NONE - local processor restriction and interpolation
1136: .ve
1138: Options Database Key:
1139: . -pc_gasm_type [basic,restrict,interpolate,none] - Sets GASM type
1141: Level: intermediate
1143: .seealso: PCGASMSetSubdomains(), PCGASMGetSubKSP(),
1144: PCGASMCreateSubdomains2D()
1145: @*/
1146: PetscErrorCode PCGASMSetType(PC pc,PCGASMType type)
1147: {
1153: PetscTryMethod(pc,"PCGASMSetType_C",(PC,PCGASMType),(pc,type));
1154: return(0);
1155: }
1157: /*@
1158: PCGASMSetSortIndices - Determines whether subdomain indices are sorted.
1160: Logically Collective on PC
1162: Input Parameters:
1163: + pc - the preconditioner context
1164: - doSort - sort the subdomain indices
1166: Level: intermediate
1168: .seealso: PCGASMSetSubdomains(), PCGASMGetSubKSP(),
1169: PCGASMCreateSubdomains2D()
1170: @*/
1171: PetscErrorCode PCGASMSetSortIndices(PC pc,PetscBool doSort)
1172: {
1178: PetscTryMethod(pc,"PCGASMSetSortIndices_C",(PC,PetscBool),(pc,doSort));
1179: return(0);
1180: }
1182: /*@C
1183: PCGASMGetSubKSP - Gets the local KSP contexts for all blocks on
1184: this processor.
1186: Collective on PC iff first_local is requested
1188: Input Parameter:
1189: . pc - the preconditioner context
1191: Output Parameters:
1192: + n_local - the number of blocks on this processor or NULL
1193: . first_local - the global number of the first block on this processor or NULL,
1194: all processors must request or all must pass NULL
1195: - ksp - the array of KSP contexts
1197: Note:
1198: After PCGASMGetSubKSP() the array of KSPes is not to be freed
1200: Currently for some matrix implementations only 1 block per processor
1201: is supported.
1203: You must call KSPSetUp() before calling PCGASMGetSubKSP().
1205: Level: advanced
1207: .seealso: PCGASMSetSubdomains(), PCGASMSetOverlap(),
1208: PCGASMCreateSubdomains2D(),
1209: @*/
1210: PetscErrorCode PCGASMGetSubKSP(PC pc,PetscInt *n_local,PetscInt *first_local,KSP *ksp[])
1211: {
1216: PetscUseMethod(pc,"PCGASMGetSubKSP_C",(PC,PetscInt*,PetscInt*,KSP **),(pc,n_local,first_local,ksp));
1217: return(0);
1218: }
1220: /* -------------------------------------------------------------------------------------*/
1221: /*MC
1222: PCGASM - Use the (restricted) additive Schwarz method, each block is (approximately) solved with
1223: its own KSP object.
1225: Options Database Keys:
1226: + -pc_gasm_total_subdomains <n> - Sets total number of local subdomains to be distributed among processors
1227: . -pc_gasm_view_subdomains - activates the printing of subdomain indices in PCView(), -ksp_view or -snes_view
1228: . -pc_gasm_print_subdomains - activates the printing of subdomain indices in PCSetUp()
1229: . -pc_gasm_overlap <ovl> - Sets overlap by which to (automatically) extend local subdomains
1230: - -pc_gasm_type [basic,restrict,interpolate,none] - Sets GASM type
1232: IMPORTANT: If you run with, for example, 3 blocks on 1 processor or 3 blocks on 3 processors you
1233: will get a different convergence rate due to the default option of -pc_gasm_type restrict. Use
1234: -pc_gasm_type basic to use the standard GASM.
1236: Notes:
1237: Blocks can be shared by multiple processes.
1239: To set options on the solvers for each block append -sub_ to all the KSP, and PC
1240: options database keys. For example, -sub_pc_type ilu -sub_pc_factor_levels 1 -sub_ksp_type preonly
1242: To set the options on the solvers separate for each block call PCGASMGetSubKSP()
1243: and set the options directly on the resulting KSP object (you can access its PC
1244: with KSPGetPC())
1247: Level: beginner
1249: References:
1250: + 1. - M Dryja, OB Widlund, An additive variant of the Schwarz alternating method for the case of many subregions
1251: Courant Institute, New York University Technical report
1252: - 2. - Barry Smith, Petter Bjorstad, and William Gropp, Domain Decompositions: Parallel Multilevel Methods for Elliptic Partial Differential Equations,
1253: Cambridge University Press.
1255: .seealso: PCCreate(), PCSetType(), PCType (for list of available types), PC,
1256: PCBJACOBI, PCGASMGetSubKSP(), PCGASMSetSubdomains(),
1257: PCSetModifySubMatrices(), PCGASMSetOverlap(), PCGASMSetType()
1259: M*/
1261: PETSC_EXTERN PetscErrorCode PCCreate_GASM(PC pc)
1262: {
1264: PC_GASM *osm;
1267: PetscNewLog(pc,&osm);
1269: osm->N = PETSC_DETERMINE;
1270: osm->n = PETSC_DECIDE;
1271: osm->nmax = PETSC_DETERMINE;
1272: osm->overlap = 0;
1273: osm->ksp = 0;
1274: osm->gorestriction = 0;
1275: osm->girestriction = 0;
1276: osm->pctoouter = 0;
1277: osm->gx = 0;
1278: osm->gy = 0;
1279: osm->x = 0;
1280: osm->y = 0;
1281: osm->pcx = 0;
1282: osm->pcy = 0;
1283: osm->permutationIS = 0;
1284: osm->permutationP = 0;
1285: osm->pcmat = 0;
1286: osm->ois = 0;
1287: osm->iis = 0;
1288: osm->pmat = 0;
1289: osm->type = PC_GASM_RESTRICT;
1290: osm->same_subdomain_solvers = PETSC_TRUE;
1291: osm->sort_indices = PETSC_TRUE;
1292: osm->dm_subdomains = PETSC_FALSE;
1293: osm->hierarchicalpartitioning = PETSC_FALSE;
1295: pc->data = (void*)osm;
1296: pc->ops->apply = PCApply_GASM;
1297: pc->ops->applytranspose = PCApplyTranspose_GASM;
1298: pc->ops->setup = PCSetUp_GASM;
1299: pc->ops->reset = PCReset_GASM;
1300: pc->ops->destroy = PCDestroy_GASM;
1301: pc->ops->setfromoptions = PCSetFromOptions_GASM;
1302: pc->ops->setuponblocks = PCSetUpOnBlocks_GASM;
1303: pc->ops->view = PCView_GASM;
1304: pc->ops->applyrichardson = 0;
1306: PetscObjectComposeFunction((PetscObject)pc,"PCGASMSetSubdomains_C",PCGASMSetSubdomains_GASM);
1307: PetscObjectComposeFunction((PetscObject)pc,"PCGASMSetOverlap_C",PCGASMSetOverlap_GASM);
1308: PetscObjectComposeFunction((PetscObject)pc,"PCGASMSetType_C",PCGASMSetType_GASM);
1309: PetscObjectComposeFunction((PetscObject)pc,"PCGASMSetSortIndices_C",PCGASMSetSortIndices_GASM);
1310: PetscObjectComposeFunction((PetscObject)pc,"PCGASMGetSubKSP_C",PCGASMGetSubKSP_GASM);
1311: return(0);
1312: }
1315: PetscErrorCode PCGASMCreateLocalSubdomains(Mat A, PetscInt nloc, IS *iis[])
1316: {
1317: MatPartitioning mpart;
1318: const char *prefix;
1319: PetscInt i,j,rstart,rend,bs;
1320: PetscBool hasop, isbaij = PETSC_FALSE,foundpart = PETSC_FALSE;
1321: Mat Ad = NULL, adj;
1322: IS ispart,isnumb,*is;
1323: PetscErrorCode ierr;
1326: if (nloc < 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"number of local subdomains must > 0, got nloc = %D",nloc);
1328: /* Get prefix, row distribution, and block size */
1329: MatGetOptionsPrefix(A,&prefix);
1330: MatGetOwnershipRange(A,&rstart,&rend);
1331: MatGetBlockSize(A,&bs);
1332: if (rstart/bs*bs != rstart || rend/bs*bs != rend) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"bad row distribution [%D,%D) for matrix block size %D",rstart,rend,bs);
1334: /* Get diagonal block from matrix if possible */
1335: MatHasOperation(A,MATOP_GET_DIAGONAL_BLOCK,&hasop);
1336: if (hasop) {
1337: MatGetDiagonalBlock(A,&Ad);
1338: }
1339: if (Ad) {
1340: PetscObjectBaseTypeCompare((PetscObject)Ad,MATSEQBAIJ,&isbaij);
1341: if (!isbaij) {PetscObjectBaseTypeCompare((PetscObject)Ad,MATSEQSBAIJ,&isbaij);}
1342: }
1343: if (Ad && nloc > 1) {
1344: PetscBool match,done;
1345: /* Try to setup a good matrix partitioning if available */
1346: MatPartitioningCreate(PETSC_COMM_SELF,&mpart);
1347: PetscObjectSetOptionsPrefix((PetscObject)mpart,prefix);
1348: MatPartitioningSetFromOptions(mpart);
1349: PetscObjectTypeCompare((PetscObject)mpart,MATPARTITIONINGCURRENT,&match);
1350: if (!match) {
1351: PetscObjectTypeCompare((PetscObject)mpart,MATPARTITIONINGSQUARE,&match);
1352: }
1353: if (!match) { /* assume a "good" partitioner is available */
1354: PetscInt na;
1355: const PetscInt *ia,*ja;
1356: MatGetRowIJ(Ad,0,PETSC_TRUE,isbaij,&na,&ia,&ja,&done);
1357: if (done) {
1358: /* Build adjacency matrix by hand. Unfortunately a call to
1359: MatConvert(Ad,MATMPIADJ,MAT_INITIAL_MATRIX,&adj) will
1360: remove the block-aij structure and we cannot expect
1361: MatPartitioning to split vertices as we need */
1362: PetscInt i,j,len,nnz,cnt,*iia=0,*jja=0;
1363: const PetscInt *row;
1364: nnz = 0;
1365: for (i=0; i<na; i++) { /* count number of nonzeros */
1366: len = ia[i+1] - ia[i];
1367: row = ja + ia[i];
1368: for (j=0; j<len; j++) {
1369: if (row[j] == i) { /* don't count diagonal */
1370: len--; break;
1371: }
1372: }
1373: nnz += len;
1374: }
1375: PetscMalloc1(na+1,&iia);
1376: PetscMalloc1(nnz,&jja);
1377: nnz = 0;
1378: iia[0] = 0;
1379: for (i=0; i<na; i++) { /* fill adjacency */
1380: cnt = 0;
1381: len = ia[i+1] - ia[i];
1382: row = ja + ia[i];
1383: for (j=0; j<len; j++) {
1384: if (row[j] != i) jja[nnz+cnt++] = row[j]; /* if not diagonal */
1385: }
1386: nnz += cnt;
1387: iia[i+1] = nnz;
1388: }
1389: /* Partitioning of the adjacency matrix */
1390: MatCreateMPIAdj(PETSC_COMM_SELF,na,na,iia,jja,NULL,&adj);
1391: MatPartitioningSetAdjacency(mpart,adj);
1392: MatPartitioningSetNParts(mpart,nloc);
1393: MatPartitioningApply(mpart,&ispart);
1394: ISPartitioningToNumbering(ispart,&isnumb);
1395: MatDestroy(&adj);
1396: foundpart = PETSC_TRUE;
1397: }
1398: MatRestoreRowIJ(Ad,0,PETSC_TRUE,isbaij,&na,&ia,&ja,&done);
1399: }
1400: MatPartitioningDestroy(&mpart);
1401: }
1402: PetscMalloc1(nloc,&is);
1403: if (!foundpart) {
1405: /* Partitioning by contiguous chunks of rows */
1407: PetscInt mbs = (rend-rstart)/bs;
1408: PetscInt start = rstart;
1409: for (i=0; i<nloc; i++) {
1410: PetscInt count = (mbs/nloc + ((mbs % nloc) > i)) * bs;
1411: ISCreateStride(PETSC_COMM_SELF,count,start,1,&is[i]);
1412: start += count;
1413: }
1415: } else {
1417: /* Partitioning by adjacency of diagonal block */
1419: const PetscInt *numbering;
1420: PetscInt *count,nidx,*indices,*newidx,start=0;
1421: /* Get node count in each partition */
1422: PetscMalloc1(nloc,&count);
1423: ISPartitioningCount(ispart,nloc,count);
1424: if (isbaij && bs > 1) { /* adjust for the block-aij case */
1425: for (i=0; i<nloc; i++) count[i] *= bs;
1426: }
1427: /* Build indices from node numbering */
1428: ISGetLocalSize(isnumb,&nidx);
1429: PetscMalloc1(nidx,&indices);
1430: for (i=0; i<nidx; i++) indices[i] = i; /* needs to be initialized */
1431: ISGetIndices(isnumb,&numbering);
1432: PetscSortIntWithPermutation(nidx,numbering,indices);
1433: ISRestoreIndices(isnumb,&numbering);
1434: if (isbaij && bs > 1) { /* adjust for the block-aij case */
1435: PetscMalloc1(nidx*bs,&newidx);
1436: for (i=0; i<nidx; i++) {
1437: for (j=0; j<bs; j++) newidx[i*bs+j] = indices[i]*bs + j;
1438: }
1439: PetscFree(indices);
1440: nidx *= bs;
1441: indices = newidx;
1442: }
1443: /* Shift to get global indices */
1444: for (i=0; i<nidx; i++) indices[i] += rstart;
1446: /* Build the index sets for each block */
1447: for (i=0; i<nloc; i++) {
1448: ISCreateGeneral(PETSC_COMM_SELF,count[i],&indices[start],PETSC_COPY_VALUES,&is[i]);
1449: ISSort(is[i]);
1450: start += count[i];
1451: }
1453: PetscFree(count);
1454: PetscFree(indices);
1455: ISDestroy(&isnumb);
1456: ISDestroy(&ispart);
1457: }
1458: *iis = is;
1459: return(0);
1460: }
1462: PETSC_INTERN PetscErrorCode PCGASMCreateStraddlingSubdomains(Mat A,PetscInt N,PetscInt *n,IS *iis[])
1463: {
1464: PetscErrorCode ierr;
1467: MatSubdomainsCreateCoalesce(A,N,n,iis);
1468: return(0);
1469: }
1473: /*@C
1474: PCGASMCreateSubdomains - Creates n index sets defining n nonoverlapping subdomains for the additive
1475: Schwarz preconditioner for a any problem based on its matrix.
1477: Collective
1479: Input Parameters:
1480: + A - The global matrix operator
1481: - N - the number of global subdomains requested
1483: Output Parameters:
1484: + n - the number of subdomains created on this processor
1485: - iis - the array of index sets defining the local inner subdomains (on which the correction is applied)
1487: Level: advanced
1489: Note: When N >= A's communicator size, each subdomain is local -- contained within a single processor.
1490: When N < size, the subdomains are 'straddling' (processor boundaries) and are no longer local.
1491: The resulting subdomains can be use in PCGASMSetSubdomains(pc,n,iss,NULL). The overlapping
1492: outer subdomains will be automatically generated from these according to the requested amount of
1493: overlap; this is currently supported only with local subdomains.
1496: .seealso: PCGASMSetSubdomains(), PCGASMDestroySubdomains()
1497: @*/
1498: PetscErrorCode PCGASMCreateSubdomains(Mat A,PetscInt N,PetscInt *n,IS *iis[])
1499: {
1500: PetscMPIInt size;
1501: PetscErrorCode ierr;
1507: if (N < 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Number of subdomains must be > 0, N = %D",N);
1508: MPI_Comm_size(PetscObjectComm((PetscObject)A),&size);
1509: if (N >= size) {
1510: *n = N/size + (N%size);
1511: PCGASMCreateLocalSubdomains(A,*n,iis);
1512: } else {
1513: PCGASMCreateStraddlingSubdomains(A,N,n,iis);
1514: }
1515: return(0);
1516: }
1518: /*@C
1519: PCGASMDestroySubdomains - Destroys the index sets created with
1520: PCGASMCreateSubdomains() or PCGASMCreateSubdomains2D. Should be
1521: called after setting subdomains with PCGASMSetSubdomains().
1523: Collective
1525: Input Parameters:
1526: + n - the number of index sets
1527: . iis - the array of inner subdomains,
1528: - ois - the array of outer subdomains, can be NULL
1530: Level: intermediate
1532: Notes:
1533: this is merely a convenience subroutine that walks each list,
1534: destroys each IS on the list, and then frees the list. At the end the
1535: list pointers are set to NULL.
1537: .seealso: PCGASMCreateSubdomains(), PCGASMSetSubdomains()
1538: @*/
1539: PetscErrorCode PCGASMDestroySubdomains(PetscInt n,IS **iis,IS **ois)
1540: {
1541: PetscInt i;
1545: if (n <= 0) return(0);
1546: if (ois) {
1548: if (*ois) {
1550: for (i=0; i<n; i++) {
1551: ISDestroy(&(*ois)[i]);
1552: }
1553: PetscFree((*ois));
1554: }
1555: }
1556: if (iis) {
1558: if (*iis) {
1560: for (i=0; i<n; i++) {
1561: ISDestroy(&(*iis)[i]);
1562: }
1563: PetscFree((*iis));
1564: }
1565: }
1566: return(0);
1567: }
1570: #define PCGASMLocalSubdomainBounds2D(M,N,xleft,ylow,xright,yhigh,first,last,xleft_loc,ylow_loc,xright_loc,yhigh_loc,n) \
1571: { \
1572: PetscInt first_row = first/M, last_row = last/M+1; \
1573: /* \
1574: Compute ylow_loc and yhigh_loc so that (ylow_loc,xleft) and (yhigh_loc,xright) are the corners \
1575: of the bounding box of the intersection of the subdomain with the local ownership range (local \
1576: subdomain). \
1577: Also compute xleft_loc and xright_loc as the lower and upper bounds on the first and last rows \
1578: of the intersection. \
1579: */ \
1580: /* ylow_loc is the grid row containing the first element of the local sumbdomain */ \
1581: *ylow_loc = PetscMax(first_row,ylow); \
1582: /* xleft_loc is the offset of first element of the local subdomain within its grid row (might actually be outside the local subdomain) */ \
1583: *xleft_loc = *ylow_loc==first_row ? PetscMax(first%M,xleft) : xleft; \
1584: /* yhigh_loc is the grid row above the last local subdomain element */ \
1585: *yhigh_loc = PetscMin(last_row,yhigh); \
1586: /* xright is the offset of the end of the local subdomain within its grid row (might actually be outside the local subdomain) */ \
1587: *xright_loc = *yhigh_loc==last_row ? PetscMin(xright,last%M) : xright; \
1588: /* Now compute the size of the local subdomain n. */ \
1589: *n = 0; \
1590: if (*ylow_loc < *yhigh_loc) { \
1591: PetscInt width = xright-xleft; \
1592: *n += width*(*yhigh_loc-*ylow_loc-1); \
1593: *n += PetscMin(PetscMax(*xright_loc-xleft,0),width); \
1594: *n -= PetscMin(PetscMax(*xleft_loc-xleft,0), width); \
1595: } \
1596: }
1600: /*@
1601: PCGASMCreateSubdomains2D - Creates the index sets for the overlapping Schwarz
1602: preconditioner for a two-dimensional problem on a regular grid.
1604: Collective
1606: Input Parameters:
1607: + M, N - the global number of grid points in the x and y directions
1608: . Mdomains, Ndomains - the global number of subdomains in the x and y directions
1609: . dof - degrees of freedom per node
1610: - overlap - overlap in mesh lines
1612: Output Parameters:
1613: + Nsub - the number of local subdomains created
1614: . iis - array of index sets defining inner (nonoverlapping) subdomains
1615: - ois - array of index sets defining outer (overlapping, if overlap > 0) subdomains
1618: Level: advanced
1620: .seealso: PCGASMSetSubdomains(), PCGASMGetSubKSP(), PCGASMSetOverlap()
1621: @*/
1622: PetscErrorCode PCGASMCreateSubdomains2D(PC pc,PetscInt M,PetscInt N,PetscInt Mdomains,PetscInt Ndomains,PetscInt dof,PetscInt overlap,PetscInt *nsub,IS **iis,IS **ois)
1623: {
1625: PetscMPIInt size, rank;
1626: PetscInt i, j;
1627: PetscInt maxheight, maxwidth;
1628: PetscInt xstart, xleft, xright, xleft_loc, xright_loc;
1629: PetscInt ystart, ylow, yhigh, ylow_loc, yhigh_loc;
1630: PetscInt x[2][2], y[2][2], n[2];
1631: PetscInt first, last;
1632: PetscInt nidx, *idx;
1633: PetscInt ii,jj,s,q,d;
1634: PetscInt k,kk;
1635: PetscMPIInt color;
1636: MPI_Comm comm, subcomm;
1637: IS **xis = 0, **is = ois, **is_local = iis;
1640: PetscObjectGetComm((PetscObject)pc, &comm);
1641: MPI_Comm_size(comm, &size);
1642: MPI_Comm_rank(comm, &rank);
1643: MatGetOwnershipRange(pc->pmat, &first, &last);
1644: if (first%dof || last%dof) SETERRQ3(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Matrix row partitioning unsuitable for domain decomposition: local row range (%D,%D) "
1645: "does not respect the number of degrees of freedom per grid point %D", first, last, dof);
1647: /* Determine the number of domains with nonzero intersections with the local ownership range. */
1648: s = 0;
1649: ystart = 0;
1650: for (j=0; j<Ndomains; ++j) {
1651: maxheight = N/Ndomains + ((N % Ndomains) > j); /* Maximal height of subdomain */
1652: if (maxheight < 2) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many %D subdomains in the vertical directon for mesh height %D", Ndomains, N);
1653: /* Vertical domain limits with an overlap. */
1654: ylow = PetscMax(ystart - overlap,0);
1655: yhigh = PetscMin(ystart + maxheight + overlap,N);
1656: xstart = 0;
1657: for (i=0; i<Mdomains; ++i) {
1658: maxwidth = M/Mdomains + ((M % Mdomains) > i); /* Maximal width of subdomain */
1659: if (maxwidth < 2) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many %D subdomains in the horizontal direction for mesh width %D", Mdomains, M);
1660: /* Horizontal domain limits with an overlap. */
1661: xleft = PetscMax(xstart - overlap,0);
1662: xright = PetscMin(xstart + maxwidth + overlap,M);
1663: /*
1664: Determine whether this subdomain intersects this processor's ownership range of pc->pmat.
1665: */
1666: PCGASMLocalSubdomainBounds2D(M,N,xleft,ylow,xright,yhigh,first,last,(&xleft_loc),(&ylow_loc),(&xright_loc),(&yhigh_loc),(&nidx));
1667: if (nidx) ++s;
1668: xstart += maxwidth;
1669: } /* for (i = 0; i < Mdomains; ++i) */
1670: ystart += maxheight;
1671: } /* for (j = 0; j < Ndomains; ++j) */
1673: /* Now we can allocate the necessary number of ISs. */
1674: *nsub = s;
1675: PetscMalloc1(*nsub,is);
1676: PetscMalloc1(*nsub,is_local);
1677: s = 0;
1678: ystart = 0;
1679: for (j=0; j<Ndomains; ++j) {
1680: maxheight = N/Ndomains + ((N % Ndomains) > j); /* Maximal height of subdomain */
1681: if (maxheight < 2) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many %D subdomains in the vertical directon for mesh height %D", Ndomains, N);
1682: /* Vertical domain limits with an overlap. */
1683: y[0][0] = PetscMax(ystart - overlap,0);
1684: y[0][1] = PetscMin(ystart + maxheight + overlap,N);
1685: /* Vertical domain limits without an overlap. */
1686: y[1][0] = ystart;
1687: y[1][1] = PetscMin(ystart + maxheight,N);
1688: xstart = 0;
1689: for (i=0; i<Mdomains; ++i) {
1690: maxwidth = M/Mdomains + ((M % Mdomains) > i); /* Maximal width of subdomain */
1691: if (maxwidth < 2) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many %D subdomains in the horizontal direction for mesh width %D", Mdomains, M);
1692: /* Horizontal domain limits with an overlap. */
1693: x[0][0] = PetscMax(xstart - overlap,0);
1694: x[0][1] = PetscMin(xstart + maxwidth + overlap,M);
1695: /* Horizontal domain limits without an overlap. */
1696: x[1][0] = xstart;
1697: x[1][1] = PetscMin(xstart+maxwidth,M);
1698: /*
1699: Determine whether this domain intersects this processor's ownership range of pc->pmat.
1700: Do this twice: first for the domains with overlaps, and once without.
1701: During the first pass create the subcommunicators, and use them on the second pass as well.
1702: */
1703: for (q = 0; q < 2; ++q) {
1704: PetscBool split = PETSC_FALSE;
1705: /*
1706: domain limits, (xleft, xright) and (ylow, yheigh) are adjusted
1707: according to whether the domain with an overlap or without is considered.
1708: */
1709: xleft = x[q][0]; xright = x[q][1];
1710: ylow = y[q][0]; yhigh = y[q][1];
1711: PCGASMLocalSubdomainBounds2D(M,N,xleft,ylow,xright,yhigh,first,last,(&xleft_loc),(&ylow_loc),(&xright_loc),(&yhigh_loc),(&nidx));
1712: nidx *= dof;
1713: n[q] = nidx;
1714: /*
1715: Based on the counted number of indices in the local domain *with an overlap*,
1716: construct a subcommunicator of all the processors supporting this domain.
1717: Observe that a domain with an overlap might have nontrivial local support,
1718: while the domain without an overlap might not. Hence, the decision to participate
1719: in the subcommunicator must be based on the domain with an overlap.
1720: */
1721: if (q == 0) {
1722: if (nidx) color = 1;
1723: else color = MPI_UNDEFINED;
1724: MPI_Comm_split(comm, color, rank, &subcomm);
1725: split = PETSC_TRUE;
1726: }
1727: /*
1728: Proceed only if the number of local indices *with an overlap* is nonzero.
1729: */
1730: if (n[0]) {
1731: if (q == 0) xis = is;
1732: if (q == 1) {
1733: /*
1734: The IS for the no-overlap subdomain shares a communicator with the overlapping domain.
1735: Moreover, if the overlap is zero, the two ISs are identical.
1736: */
1737: if (overlap == 0) {
1738: (*is_local)[s] = (*is)[s];
1739: PetscObjectReference((PetscObject)(*is)[s]);
1740: continue;
1741: } else {
1742: xis = is_local;
1743: subcomm = ((PetscObject)(*is)[s])->comm;
1744: }
1745: } /* if (q == 1) */
1746: idx = NULL;
1747: PetscMalloc1(nidx,&idx);
1748: if (nidx) {
1749: k = 0;
1750: for (jj=ylow_loc; jj<yhigh_loc; ++jj) {
1751: PetscInt x0 = (jj==ylow_loc) ? xleft_loc : xleft;
1752: PetscInt x1 = (jj==yhigh_loc-1) ? xright_loc : xright;
1753: kk = dof*(M*jj + x0);
1754: for (ii=x0; ii<x1; ++ii) {
1755: for (d = 0; d < dof; ++d) {
1756: idx[k++] = kk++;
1757: }
1758: }
1759: }
1760: }
1761: ISCreateGeneral(subcomm,nidx,idx,PETSC_OWN_POINTER,(*xis)+s);
1762: if (split) {
1763: MPI_Comm_free(&subcomm);
1764: }
1765: }/* if (n[0]) */
1766: }/* for (q = 0; q < 2; ++q) */
1767: if (n[0]) ++s;
1768: xstart += maxwidth;
1769: } /* for (i = 0; i < Mdomains; ++i) */
1770: ystart += maxheight;
1771: } /* for (j = 0; j < Ndomains; ++j) */
1772: return(0);
1773: }
1775: /*@C
1776: PCGASMGetSubdomains - Gets the subdomains supported on this processor
1777: for the additive Schwarz preconditioner.
1779: Not Collective
1781: Input Parameter:
1782: . pc - the preconditioner context
1784: Output Parameters:
1785: + n - the number of subdomains for this processor (default value = 1)
1786: . iis - the index sets that define the inner subdomains (without overlap) supported on this processor (can be NULL)
1787: - ois - the index sets that define the outer subdomains (with overlap) supported on this processor (can be NULL)
1790: Notes:
1791: The user is responsible for destroying the ISs and freeing the returned arrays.
1792: The IS numbering is in the parallel, global numbering of the vector.
1794: Level: advanced
1796: .seealso: PCGASMSetOverlap(), PCGASMGetSubKSP(), PCGASMCreateSubdomains2D(),
1797: PCGASMSetSubdomains(), PCGASMGetSubmatrices()
1798: @*/
1799: PetscErrorCode PCGASMGetSubdomains(PC pc,PetscInt *n,IS *iis[],IS *ois[])
1800: {
1801: PC_GASM *osm;
1803: PetscBool match;
1804: PetscInt i;
1808: PetscObjectTypeCompare((PetscObject)pc,PCGASM,&match);
1809: if (!match) SETERRQ2(PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Incorrect object type: expected %s, got %s instead", PCGASM, ((PetscObject)pc)->type_name);
1810: osm = (PC_GASM*)pc->data;
1811: if (n) *n = osm->n;
1812: if (iis) {
1813: PetscMalloc1(osm->n, iis);
1814: }
1815: if (ois) {
1816: PetscMalloc1(osm->n, ois);
1817: }
1818: if (iis || ois) {
1819: for (i = 0; i < osm->n; ++i) {
1820: if (iis) (*iis)[i] = osm->iis[i];
1821: if (ois) (*ois)[i] = osm->ois[i];
1822: }
1823: }
1824: return(0);
1825: }
1827: /*@C
1828: PCGASMGetSubmatrices - Gets the local submatrices (for this processor
1829: only) for the additive Schwarz preconditioner.
1831: Not Collective
1833: Input Parameter:
1834: . pc - the preconditioner context
1836: Output Parameters:
1837: + n - the number of matrices for this processor (default value = 1)
1838: - mat - the matrices
1840: Notes:
1841: matrices returned by this routine have the same communicators as the index sets (IS)
1842: used to define subdomains in PCGASMSetSubdomains()
1843: Level: advanced
1845: .seealso: PCGASMSetOverlap(), PCGASMGetSubKSP(),
1846: PCGASMCreateSubdomains2D(), PCGASMSetSubdomains(), PCGASMGetSubdomains()
1847: @*/
1848: PetscErrorCode PCGASMGetSubmatrices(PC pc,PetscInt *n,Mat *mat[])
1849: {
1850: PC_GASM *osm;
1852: PetscBool match;
1858: if (!pc->setupcalled) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Must call after KSPSetUp() or PCSetUp().");
1859: PetscObjectTypeCompare((PetscObject)pc,PCGASM,&match);
1860: if (!match) SETERRQ2(PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Expected %s, got %s instead", PCGASM, ((PetscObject)pc)->type_name);
1861: osm = (PC_GASM*)pc->data;
1862: if (n) *n = osm->n;
1863: if (mat) *mat = osm->pmat;
1864: return(0);
1865: }
1867: /*@
1868: PCGASMSetUseDMSubdomains - Indicates whether to use DMCreateDomainDecomposition() to define the subdomains, whenever possible.
1869: Logically Collective
1871: Input Parameter:
1872: + pc - the preconditioner
1873: - flg - boolean indicating whether to use subdomains defined by the DM
1875: Options Database Key:
1876: . -pc_gasm_dm_subdomains -pc_gasm_overlap -pc_gasm_total_subdomains
1878: Level: intermediate
1880: Notes:
1881: PCGASMSetSubdomains(), PCGASMSetTotalSubdomains() or PCGASMSetOverlap() take precedence over PCGASMSetUseDMSubdomains(),
1882: so setting PCGASMSetSubdomains() with nontrivial subdomain ISs or any of PCGASMSetTotalSubdomains() and PCGASMSetOverlap()
1883: automatically turns the latter off.
1885: .seealso: PCGASMGetUseDMSubdomains(), PCGASMSetSubdomains(), PCGASMSetOverlap()
1886: PCGASMCreateSubdomains2D()
1887: @*/
1888: PetscErrorCode PCGASMSetUseDMSubdomains(PC pc,PetscBool flg)
1889: {
1890: PC_GASM *osm = (PC_GASM*)pc->data;
1892: PetscBool match;
1897: if (pc->setupcalled) SETERRQ(((PetscObject)pc)->comm,PETSC_ERR_ARG_WRONGSTATE,"Not for a setup PC.");
1898: PetscObjectTypeCompare((PetscObject)pc,PCGASM,&match);
1899: if (match) {
1900: if (!osm->user_subdomains && osm->N == PETSC_DETERMINE && osm->overlap < 0) {
1901: osm->dm_subdomains = flg;
1902: }
1903: }
1904: return(0);
1905: }
1907: /*@
1908: PCGASMGetUseDMSubdomains - Returns flag indicating whether to use DMCreateDomainDecomposition() to define the subdomains, whenever possible.
1909: Not Collective
1911: Input Parameter:
1912: . pc - the preconditioner
1914: Output Parameter:
1915: . flg - boolean indicating whether to use subdomains defined by the DM
1917: Level: intermediate
1919: .seealso: PCGASMSetUseDMSubdomains(), PCGASMSetOverlap()
1920: PCGASMCreateSubdomains2D()
1921: @*/
1922: PetscErrorCode PCGASMGetUseDMSubdomains(PC pc,PetscBool* flg)
1923: {
1924: PC_GASM *osm = (PC_GASM*)pc->data;
1926: PetscBool match;
1931: PetscObjectTypeCompare((PetscObject)pc,PCGASM,&match);
1932: if (match) {
1933: if (flg) *flg = osm->dm_subdomains;
1934: }
1935: return(0);
1936: }