Actual source code: asm.c
petsc-3.14.0 2020-09-29
1: /*
2: This file defines an additive Schwarz preconditioner for any Mat implementation.
4: Note that each processor may have any number of subdomains. But in order to
5: deal easily with the VecScatter(), we treat each processor as if it has the
6: same number of subdomains.
8: n - total number of true subdomains on all processors
9: n_local_true - actual number of subdomains on this processor
10: n_local = maximum over all processors of n_local_true
11: */
13: #include <../src/ksp/pc/impls/asm/asm.h>
15: static PetscErrorCode PCView_ASM(PC pc,PetscViewer viewer)
16: {
17: PC_ASM *osm = (PC_ASM*)pc->data;
19: PetscMPIInt rank;
20: PetscInt i,bsz;
21: PetscBool iascii,isstring;
22: PetscViewer sviewer;
25: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
26: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);
27: if (iascii) {
28: char overlaps[256] = "user-defined overlap",blocks[256] = "total subdomain blocks not yet set";
29: if (osm->overlap >= 0) {PetscSNPrintf(overlaps,sizeof(overlaps),"amount of overlap = %D",osm->overlap);}
30: if (osm->n > 0) {PetscSNPrintf(blocks,sizeof(blocks),"total subdomain blocks = %D",osm->n);}
31: PetscViewerASCIIPrintf(viewer," %s, %s\n",blocks,overlaps);
32: PetscViewerASCIIPrintf(viewer," restriction/interpolation type - %s\n",PCASMTypes[osm->type]);
33: if (osm->dm_subdomains) {PetscViewerASCIIPrintf(viewer," Additive Schwarz: using DM to define subdomains\n");}
34: if (osm->loctype != PC_COMPOSITE_ADDITIVE) {PetscViewerASCIIPrintf(viewer," Additive Schwarz: local solve composition type - %s\n",PCCompositeTypes[osm->loctype]);}
35: MPI_Comm_rank(PetscObjectComm((PetscObject)pc),&rank);
36: if (osm->same_local_solves) {
37: if (osm->ksp) {
38: PetscViewerASCIIPrintf(viewer," Local solver is the same for all blocks, as in the following KSP and PC objects on rank 0:\n");
39: PetscViewerGetSubViewer(viewer,PETSC_COMM_SELF,&sviewer);
40: if (!rank) {
41: PetscViewerASCIIPushTab(viewer);
42: KSPView(osm->ksp[0],sviewer);
43: PetscViewerASCIIPopTab(viewer);
44: }
45: PetscViewerRestoreSubViewer(viewer,PETSC_COMM_SELF,&sviewer);
46: }
47: } else {
48: PetscViewerASCIIPushSynchronized(viewer);
49: PetscViewerASCIISynchronizedPrintf(viewer," [%d] number of local blocks = %D\n",(int)rank,osm->n_local_true);
50: PetscViewerFlush(viewer);
51: PetscViewerASCIIPrintf(viewer," Local solve info for each block is in the following KSP and PC objects:\n");
52: PetscViewerASCIIPushTab(viewer);
53: PetscViewerASCIIPrintf(viewer,"- - - - - - - - - - - - - - - - - -\n");
54: PetscViewerGetSubViewer(viewer,PETSC_COMM_SELF,&sviewer);
55: for (i=0; i<osm->n_local_true; i++) {
56: ISGetLocalSize(osm->is[i],&bsz);
57: PetscViewerASCIISynchronizedPrintf(sviewer,"[%d] local block number %D, size = %D\n",(int)rank,i,bsz);
58: KSPView(osm->ksp[i],sviewer);
59: PetscViewerASCIISynchronizedPrintf(sviewer,"- - - - - - - - - - - - - - - - - -\n");
60: }
61: PetscViewerRestoreSubViewer(viewer,PETSC_COMM_SELF,&sviewer);
62: PetscViewerASCIIPopTab(viewer);
63: PetscViewerFlush(viewer);
64: PetscViewerASCIIPopSynchronized(viewer);
65: }
66: } else if (isstring) {
67: PetscViewerStringSPrintf(viewer," blocks=%D, overlap=%D, type=%s",osm->n,osm->overlap,PCASMTypes[osm->type]);
68: PetscViewerGetSubViewer(viewer,PETSC_COMM_SELF,&sviewer);
69: if (osm->ksp) {KSPView(osm->ksp[0],sviewer);}
70: PetscViewerRestoreSubViewer(viewer,PETSC_COMM_SELF,&sviewer);
71: }
72: return(0);
73: }
75: static PetscErrorCode PCASMPrintSubdomains(PC pc)
76: {
77: PC_ASM *osm = (PC_ASM*)pc->data;
78: const char *prefix;
79: char fname[PETSC_MAX_PATH_LEN+1];
80: PetscViewer viewer, sviewer;
81: char *s;
82: PetscInt i,j,nidx;
83: const PetscInt *idx;
84: PetscMPIInt rank, size;
88: MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size);
89: MPI_Comm_rank(PetscObjectComm((PetscObject)pc), &rank);
90: PCGetOptionsPrefix(pc,&prefix);
91: PetscOptionsGetString(NULL,prefix,"-pc_asm_print_subdomains",fname,sizeof(fname),NULL);
92: if (fname[0] == 0) { PetscStrcpy(fname,"stdout"); };
93: PetscViewerASCIIOpen(PetscObjectComm((PetscObject)pc),fname,&viewer);
94: for (i=0; i<osm->n_local; i++) {
95: if (i < osm->n_local_true) {
96: ISGetLocalSize(osm->is[i],&nidx);
97: ISGetIndices(osm->is[i],&idx);
98: /* Print to a string viewer; no more than 15 characters per index plus 512 char for the header.*/
99: #define len 16*(nidx+1)+512
100: PetscMalloc1(len,&s);
101: PetscViewerStringOpen(PETSC_COMM_SELF, s, len, &sviewer);
102: #undef len
103: PetscViewerStringSPrintf(sviewer, "[%D:%D] Subdomain %D with overlap:\n", rank, size, i);
104: for (j=0; j<nidx; j++) {
105: PetscViewerStringSPrintf(sviewer,"%D ",idx[j]);
106: }
107: ISRestoreIndices(osm->is[i],&idx);
108: PetscViewerStringSPrintf(sviewer,"\n");
109: PetscViewerDestroy(&sviewer);
110: PetscViewerASCIIPushSynchronized(viewer);
111: PetscViewerASCIISynchronizedPrintf(viewer, s);
112: PetscViewerFlush(viewer);
113: PetscViewerASCIIPopSynchronized(viewer);
114: PetscFree(s);
115: if (osm->is_local) {
116: /* Print to a string viewer; no more than 15 characters per index plus 512 char for the header.*/
117: #define len 16*(nidx+1)+512
118: PetscMalloc1(len, &s);
119: PetscViewerStringOpen(PETSC_COMM_SELF, s, len, &sviewer);
120: #undef len
121: PetscViewerStringSPrintf(sviewer, "[%D:%D] Subdomain %D without overlap:\n", rank, size, i);
122: ISGetLocalSize(osm->is_local[i],&nidx);
123: ISGetIndices(osm->is_local[i],&idx);
124: for (j=0; j<nidx; j++) {
125: PetscViewerStringSPrintf(sviewer,"%D ",idx[j]);
126: }
127: ISRestoreIndices(osm->is_local[i],&idx);
128: PetscViewerStringSPrintf(sviewer,"\n");
129: PetscViewerDestroy(&sviewer);
130: PetscViewerASCIIPushSynchronized(viewer);
131: PetscViewerASCIISynchronizedPrintf(viewer, s);
132: PetscViewerFlush(viewer);
133: PetscViewerASCIIPopSynchronized(viewer);
134: PetscFree(s);
135: }
136: } else {
137: /* Participate in collective viewer calls. */
138: PetscViewerASCIIPushSynchronized(viewer);
139: PetscViewerFlush(viewer);
140: PetscViewerASCIIPopSynchronized(viewer);
141: /* Assume either all ranks have is_local or none do. */
142: if (osm->is_local) {
143: PetscViewerASCIIPushSynchronized(viewer);
144: PetscViewerFlush(viewer);
145: PetscViewerASCIIPopSynchronized(viewer);
146: }
147: }
148: }
149: PetscViewerFlush(viewer);
150: PetscViewerDestroy(&viewer);
151: return(0);
152: }
154: static PetscErrorCode PCSetUp_ASM(PC pc)
155: {
156: PC_ASM *osm = (PC_ASM*)pc->data;
158: PetscBool flg;
159: PetscInt i,m,m_local;
160: MatReuse scall = MAT_REUSE_MATRIX;
161: IS isl;
162: KSP ksp;
163: PC subpc;
164: const char *prefix,*pprefix;
165: Vec vec;
166: DM *domain_dm = NULL;
169: if (!pc->setupcalled) {
170: PetscInt m;
172: /* Note: if subdomains have been set either via PCASMSetTotalSubdomains() or via PCASMSetLocalSubdomains(), osm->n_local_true will not be PETSC_DECIDE */
173: if (osm->n_local_true == PETSC_DECIDE) {
174: /* no subdomains given */
175: /* try pc->dm first, if allowed */
176: if (osm->dm_subdomains && pc->dm) {
177: PetscInt num_domains, d;
178: char **domain_names;
179: IS *inner_domain_is, *outer_domain_is;
180: DMCreateDomainDecomposition(pc->dm, &num_domains, &domain_names, &inner_domain_is, &outer_domain_is, &domain_dm);
181: osm->overlap = -1; /* We do not want to increase the overlap of the IS.
182: A future improvement of this code might allow one to use
183: DM-defined subdomains and also increase the overlap,
184: but that is not currently supported */
185: if (num_domains) {
186: PCASMSetLocalSubdomains(pc, num_domains, outer_domain_is, inner_domain_is);
187: }
188: for (d = 0; d < num_domains; ++d) {
189: if (domain_names) {PetscFree(domain_names[d]);}
190: if (inner_domain_is) {ISDestroy(&inner_domain_is[d]);}
191: if (outer_domain_is) {ISDestroy(&outer_domain_is[d]);}
192: }
193: PetscFree(domain_names);
194: PetscFree(inner_domain_is);
195: PetscFree(outer_domain_is);
196: }
197: if (osm->n_local_true == PETSC_DECIDE) {
198: /* still no subdomains; use one subdomain per processor */
199: osm->n_local_true = 1;
200: }
201: }
202: { /* determine the global and max number of subdomains */
203: struct {PetscInt max,sum;} inwork,outwork;
204: PetscMPIInt size;
206: inwork.max = osm->n_local_true;
207: inwork.sum = osm->n_local_true;
208: MPIU_Allreduce(&inwork,&outwork,1,MPIU_2INT,MPIU_MAXSUM_OP,PetscObjectComm((PetscObject)pc));
209: osm->n_local = outwork.max;
210: osm->n = outwork.sum;
212: MPI_Comm_size(PetscObjectComm((PetscObject)pc),&size);
213: if (outwork.max == 1 && outwork.sum == size) {
214: /* osm->n_local_true = 1 on all processes, set this option may enable use of optimized MatCreateSubMatrices() implementation */
215: MatSetOption(pc->pmat,MAT_SUBMAT_SINGLEIS,PETSC_TRUE);
216: }
217: }
218: if (!osm->is) { /* create the index sets */
219: PCASMCreateSubdomains(pc->pmat,osm->n_local_true,&osm->is);
220: }
221: if (osm->n_local_true > 1 && !osm->is_local) {
222: PetscMalloc1(osm->n_local_true,&osm->is_local);
223: for (i=0; i<osm->n_local_true; i++) {
224: if (osm->overlap > 0) { /* With positive overlap, osm->is[i] will be modified */
225: ISDuplicate(osm->is[i],&osm->is_local[i]);
226: ISCopy(osm->is[i],osm->is_local[i]);
227: } else {
228: PetscObjectReference((PetscObject)osm->is[i]);
229: osm->is_local[i] = osm->is[i];
230: }
231: }
232: }
233: PCGetOptionsPrefix(pc,&prefix);
234: flg = PETSC_FALSE;
235: PetscOptionsGetBool(NULL,prefix,"-pc_asm_print_subdomains",&flg,NULL);
236: if (flg) { PCASMPrintSubdomains(pc); }
238: if (osm->overlap > 0) {
239: /* Extend the "overlapping" regions by a number of steps */
240: MatIncreaseOverlap(pc->pmat,osm->n_local_true,osm->is,osm->overlap);
241: }
242: if (osm->sort_indices) {
243: for (i=0; i<osm->n_local_true; i++) {
244: ISSort(osm->is[i]);
245: if (osm->is_local) {
246: ISSort(osm->is_local[i]);
247: }
248: }
249: }
251: if (!osm->ksp) {
252: /* Create the local solvers */
253: PetscMalloc1(osm->n_local_true,&osm->ksp);
254: if (domain_dm) {
255: PetscInfo(pc,"Setting up ASM subproblems using the embedded DM\n");
256: }
257: for (i=0; i<osm->n_local_true; i++) {
258: KSPCreate(PETSC_COMM_SELF,&ksp);
259: KSPSetErrorIfNotConverged(ksp,pc->erroriffailure);
260: PetscLogObjectParent((PetscObject)pc,(PetscObject)ksp);
261: PetscObjectIncrementTabLevel((PetscObject)ksp,(PetscObject)pc,1);
262: KSPSetType(ksp,KSPPREONLY);
263: KSPGetPC(ksp,&subpc);
264: PCGetOptionsPrefix(pc,&prefix);
265: KSPSetOptionsPrefix(ksp,prefix);
266: KSPAppendOptionsPrefix(ksp,"sub_");
267: if (domain_dm) {
268: KSPSetDM(ksp, domain_dm[i]);
269: KSPSetDMActive(ksp, PETSC_FALSE);
270: DMDestroy(&domain_dm[i]);
271: }
272: osm->ksp[i] = ksp;
273: }
274: if (domain_dm) {
275: PetscFree(domain_dm);
276: }
277: }
279: ISConcatenate(PETSC_COMM_SELF, osm->n_local_true, osm->is, &osm->lis);
280: ISSortRemoveDups(osm->lis);
281: ISGetLocalSize(osm->lis, &m);
282: VecCreateSeq(PETSC_COMM_SELF, m, &osm->lx);
283: VecDuplicate(osm->lx, &osm->ly);
285: scall = MAT_INITIAL_MATRIX;
286: } else {
287: /*
288: Destroy the blocks from the previous iteration
289: */
290: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
291: MatDestroyMatrices(osm->n_local_true,&osm->pmat);
292: scall = MAT_INITIAL_MATRIX;
293: }
294: }
296: /*
297: Extract out the submatrices
298: */
299: MatCreateSubMatrices(pc->pmat,osm->n_local_true,osm->is,osm->is,scall,&osm->pmat);
300: if (scall == MAT_INITIAL_MATRIX) {
301: PetscObjectGetOptionsPrefix((PetscObject)pc->pmat,&pprefix);
302: for (i=0; i<osm->n_local_true; i++) {
303: PetscLogObjectParent((PetscObject)pc,(PetscObject)osm->pmat[i]);
304: PetscObjectSetOptionsPrefix((PetscObject)osm->pmat[i],pprefix);
305: }
306: }
308: /* Convert the types of the submatrices (if needbe) */
309: if (osm->sub_mat_type) {
310: for (i=0; i<osm->n_local_true; i++) {
311: MatConvert(osm->pmat[i],osm->sub_mat_type,MAT_INPLACE_MATRIX,&(osm->pmat[i]));
312: }
313: }
315: if (!pc->setupcalled) {
316: /* Create the local work vectors (from the local matrices) and scatter contexts */
317: MatCreateVecs(pc->pmat,&vec,NULL);
319: if (osm->is_local && (osm->type == PC_ASM_INTERPOLATE || osm->type == PC_ASM_NONE)) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cannot use interpolate or none PCASMType if is_local was provided to PCASMSetLocalSubdomains()");
320: if (osm->is_local && osm->type == PC_ASM_RESTRICT && osm->loctype == PC_COMPOSITE_ADDITIVE) {
321: PetscMalloc1(osm->n_local_true,&osm->lprolongation);
322: }
323: PetscMalloc1(osm->n_local_true,&osm->lrestriction);
324: PetscMalloc1(osm->n_local_true,&osm->x);
325: PetscMalloc1(osm->n_local_true,&osm->y);
327: ISGetLocalSize(osm->lis,&m);
328: ISCreateStride(PETSC_COMM_SELF,m,0,1,&isl);
329: VecScatterCreate(vec,osm->lis,osm->lx,isl,&osm->restriction);
330: ISDestroy(&isl);
333: for (i=0; i<osm->n_local_true; ++i) {
334: ISLocalToGlobalMapping ltog;
335: IS isll;
336: const PetscInt *idx_is;
337: PetscInt *idx_lis,nout;
339: ISGetLocalSize(osm->is[i],&m);
340: MatCreateVecs(osm->pmat[i],&osm->x[i],NULL);
341: VecDuplicate(osm->x[i],&osm->y[i]);
343: /* generate a scatter from ly to y[i] picking all the overlapping is[i] entries */
344: ISLocalToGlobalMappingCreateIS(osm->lis,<og);
345: ISGetLocalSize(osm->is[i],&m);
346: ISGetIndices(osm->is[i], &idx_is);
347: PetscMalloc1(m,&idx_lis);
348: ISGlobalToLocalMappingApply(ltog,IS_GTOLM_DROP,m,idx_is,&nout,idx_lis);
349: if (nout != m) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"is not a subset of lis");
350: ISRestoreIndices(osm->is[i], &idx_is);
351: ISCreateGeneral(PETSC_COMM_SELF,m,idx_lis,PETSC_OWN_POINTER,&isll);
352: ISLocalToGlobalMappingDestroy(<og);
353: ISCreateStride(PETSC_COMM_SELF,m,0,1,&isl);
354: VecScatterCreate(osm->ly,isll,osm->y[i],isl,&osm->lrestriction[i]);
355: ISDestroy(&isll);
356: ISDestroy(&isl);
357: if (osm->lprolongation) { /* generate a scatter from y[i] to ly picking only the the non-overlapping is_local[i] entries */
358: ISLocalToGlobalMapping ltog;
359: IS isll,isll_local;
360: const PetscInt *idx_local;
361: PetscInt *idx1, *idx2, nout;
363: ISGetLocalSize(osm->is_local[i],&m_local);
364: ISGetIndices(osm->is_local[i], &idx_local);
366: ISLocalToGlobalMappingCreateIS(osm->is[i],<og);
367: PetscMalloc1(m_local,&idx1);
368: ISGlobalToLocalMappingApply(ltog,IS_GTOLM_DROP,m_local,idx_local,&nout,idx1);
369: ISLocalToGlobalMappingDestroy(<og);
370: if (nout != m_local) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"is_local not a subset of is");
371: ISCreateGeneral(PETSC_COMM_SELF,m_local,idx1,PETSC_OWN_POINTER,&isll);
373: ISLocalToGlobalMappingCreateIS(osm->lis,<og);
374: PetscMalloc1(m_local,&idx2);
375: ISGlobalToLocalMappingApply(ltog,IS_GTOLM_DROP,m_local,idx_local,&nout,idx2);
376: ISLocalToGlobalMappingDestroy(<og);
377: if (nout != m_local) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"is_local not a subset of lis");
378: ISCreateGeneral(PETSC_COMM_SELF,m_local,idx2,PETSC_OWN_POINTER,&isll_local);
380: ISRestoreIndices(osm->is_local[i], &idx_local);
381: VecScatterCreate(osm->y[i],isll,osm->ly,isll_local,&osm->lprolongation[i]);
383: ISDestroy(&isll);
384: ISDestroy(&isll_local);
385: }
386: }
387: VecDestroy(&vec);
388: }
390: if (osm->loctype == PC_COMPOSITE_MULTIPLICATIVE) {
391: IS *cis;
392: PetscInt c;
394: PetscMalloc1(osm->n_local_true, &cis);
395: for (c = 0; c < osm->n_local_true; ++c) cis[c] = osm->lis;
396: MatCreateSubMatrices(pc->pmat, osm->n_local_true, osm->is, cis, scall, &osm->lmats);
397: PetscFree(cis);
398: }
400: /* Return control to the user so that the submatrices can be modified (e.g., to apply
401: different boundary conditions for the submatrices than for the global problem) */
402: PCModifySubMatrices(pc,osm->n_local_true,osm->is,osm->is,osm->pmat,pc->modifysubmatricesP);
404: /*
405: Loop over subdomains putting them into local ksp
406: */
407: for (i=0; i<osm->n_local_true; i++) {
408: KSPSetOperators(osm->ksp[i],osm->pmat[i],osm->pmat[i]);
409: if (!pc->setupcalled) {
410: KSPSetFromOptions(osm->ksp[i]);
411: }
412: }
413: return(0);
414: }
416: static PetscErrorCode PCSetUpOnBlocks_ASM(PC pc)
417: {
418: PC_ASM *osm = (PC_ASM*)pc->data;
419: PetscErrorCode ierr;
420: PetscInt i;
421: KSPConvergedReason reason;
424: for (i=0; i<osm->n_local_true; i++) {
425: KSPSetUp(osm->ksp[i]);
426: KSPGetConvergedReason(osm->ksp[i],&reason);
427: if (reason == KSP_DIVERGED_PC_FAILED) {
428: pc->failedreason = PC_SUBPC_ERROR;
429: }
430: }
431: return(0);
432: }
434: static PetscErrorCode PCApply_ASM(PC pc,Vec x,Vec y)
435: {
436: PC_ASM *osm = (PC_ASM*)pc->data;
438: PetscInt i,n_local_true = osm->n_local_true;
439: ScatterMode forward = SCATTER_FORWARD,reverse = SCATTER_REVERSE;
442: /*
443: support for limiting the restriction or interpolation to only local
444: subdomain values (leaving the other values 0).
445: */
446: if (!(osm->type & PC_ASM_RESTRICT)) {
447: forward = SCATTER_FORWARD_LOCAL;
448: /* have to zero the work RHS since scatter may leave some slots empty */
449: VecSet(osm->lx, 0.0);
450: }
451: if (!(osm->type & PC_ASM_INTERPOLATE)) {
452: reverse = SCATTER_REVERSE_LOCAL;
453: }
455: if (osm->loctype == PC_COMPOSITE_MULTIPLICATIVE || osm->loctype == PC_COMPOSITE_ADDITIVE) {
456: /* zero the global and the local solutions */
457: VecSet(y, 0.0);
458: VecSet(osm->ly, 0.0);
460: /* copy the global RHS to local RHS including the ghost nodes */
461: VecScatterBegin(osm->restriction, x, osm->lx, INSERT_VALUES, forward);
462: VecScatterEnd(osm->restriction, x, osm->lx, INSERT_VALUES, forward);
464: /* restrict local RHS to the overlapping 0-block RHS */
465: VecScatterBegin(osm->lrestriction[0], osm->lx, osm->x[0], INSERT_VALUES, forward);
466: VecScatterEnd(osm->lrestriction[0], osm->lx, osm->x[0], INSERT_VALUES, forward);
468: /* do the local solves */
469: for (i = 0; i < n_local_true; ++i) {
471: /* solve the overlapping i-block */
472: PetscLogEventBegin(PC_ApplyOnBlocks, osm->ksp[i], osm->x[i], osm->y[i],0);
473: KSPSolve(osm->ksp[i], osm->x[i], osm->y[i]);
474: KSPCheckSolve(osm->ksp[i], pc, osm->y[i]);
475: PetscLogEventEnd(PC_ApplyOnBlocks, osm->ksp[i], osm->x[i], osm->y[i], 0);
477: if (osm->lprolongation) { /* interpolate the non-overlapping i-block solution to the local solution (only for restrictive additive) */
478: VecScatterBegin(osm->lprolongation[i], osm->y[i], osm->ly, ADD_VALUES, forward);
479: VecScatterEnd(osm->lprolongation[i], osm->y[i], osm->ly, ADD_VALUES, forward);
480: } else { /* interpolate the overlapping i-block solution to the local solution */
481: VecScatterBegin(osm->lrestriction[i], osm->y[i], osm->ly, ADD_VALUES, reverse);
482: VecScatterEnd(osm->lrestriction[i], osm->y[i], osm->ly, ADD_VALUES, reverse);
483: }
485: if (i < n_local_true-1) {
486: /* restrict local RHS to the overlapping (i+1)-block RHS */
487: VecScatterBegin(osm->lrestriction[i+1], osm->lx, osm->x[i+1], INSERT_VALUES, forward);
488: VecScatterEnd(osm->lrestriction[i+1], osm->lx, osm->x[i+1], INSERT_VALUES, forward);
490: if (osm->loctype == PC_COMPOSITE_MULTIPLICATIVE) {
491: /* update the overlapping (i+1)-block RHS using the current local solution */
492: MatMult(osm->lmats[i+1], osm->ly, osm->y[i+1]);
493: VecAXPBY(osm->x[i+1],-1.,1., osm->y[i+1]);
494: }
495: }
496: }
497: /* add the local solution to the global solution including the ghost nodes */
498: VecScatterBegin(osm->restriction, osm->ly, y, ADD_VALUES, reverse);
499: VecScatterEnd(osm->restriction, osm->ly, y, ADD_VALUES, reverse);
500: } else SETERRQ1(PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Invalid local composition type: %s", PCCompositeTypes[osm->loctype]);
501: return(0);
502: }
504: static PetscErrorCode PCMatApply_ASM(PC pc,Mat X,Mat Y)
505: {
506: PC_ASM *osm = (PC_ASM*)pc->data;
507: Mat Z,W;
508: Vec x;
509: PetscInt i,m,N;
510: ScatterMode forward = SCATTER_FORWARD,reverse = SCATTER_REVERSE;
514: if (osm->n_local_true > 1) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Not yet implemented");
515: /*
516: support for limiting the restriction or interpolation to only local
517: subdomain values (leaving the other values 0).
518: */
519: if (!(osm->type & PC_ASM_RESTRICT)) {
520: forward = SCATTER_FORWARD_LOCAL;
521: /* have to zero the work RHS since scatter may leave some slots empty */
522: VecSet(osm->lx, 0.0);
523: }
524: if (!(osm->type & PC_ASM_INTERPOLATE)) {
525: reverse = SCATTER_REVERSE_LOCAL;
526: }
527: VecGetLocalSize(osm->x[0], &m);
528: MatGetSize(X, NULL, &N);
529: MatCreateSeqDense(PETSC_COMM_SELF, m, N, NULL, &Z);
530: if (osm->loctype == PC_COMPOSITE_MULTIPLICATIVE || osm->loctype == PC_COMPOSITE_ADDITIVE) {
531: /* zero the global and the local solutions */
532: MatZeroEntries(Y);
533: VecSet(osm->ly, 0.0);
535: for (i = 0; i < N; ++i) {
536: MatDenseGetColumnVecRead(X, i, &x);
537: /* copy the global RHS to local RHS including the ghost nodes */
538: VecScatterBegin(osm->restriction, x, osm->lx, INSERT_VALUES, forward);
539: VecScatterEnd(osm->restriction, x, osm->lx, INSERT_VALUES, forward);
540: MatDenseRestoreColumnVecRead(X, i, &x);
542: MatDenseGetColumnVecWrite(Z, i, &x);
543: /* restrict local RHS to the overlapping 0-block RHS */
544: VecScatterBegin(osm->lrestriction[0], osm->lx, x, INSERT_VALUES, forward);
545: VecScatterEnd(osm->lrestriction[0], osm->lx, x, INSERT_VALUES, forward);
546: MatDenseRestoreColumnVecWrite(Z, i, &x);
547: }
548: MatCreateSeqDense(PETSC_COMM_SELF, m, N, NULL, &W);
549: /* solve the overlapping 0-block */
550: PetscLogEventBegin(PC_ApplyOnBlocks, osm->ksp[0], Z, W, 0);
551: KSPMatSolve(osm->ksp[0], Z, W);
552: KSPCheckSolve(osm->ksp[0], pc, NULL);
553: PetscLogEventEnd(PC_ApplyOnBlocks, osm->ksp[0], Z, W,0);
554: MatDestroy(&Z);
556: for (i = 0; i < N; ++i) {
557: VecSet(osm->ly, 0.0);
558: MatDenseGetColumnVecRead(W, i, &x);
559: if (osm->lprolongation) { /* interpolate the non-overlapping 0-block solution to the local solution (only for restrictive additive) */
560: VecScatterBegin(osm->lprolongation[0], x, osm->ly, ADD_VALUES, forward);
561: VecScatterEnd(osm->lprolongation[0], x, osm->ly, ADD_VALUES, forward);
562: } else { /* interpolate the overlapping 0-block solution to the local solution */
563: VecScatterBegin(osm->lrestriction[0], x, osm->ly, ADD_VALUES, reverse);
564: VecScatterEnd(osm->lrestriction[0], x, osm->ly, ADD_VALUES, reverse);
565: }
566: MatDenseRestoreColumnVecRead(W, i, &x);
568: MatDenseGetColumnVecWrite(Y, i, &x);
569: /* add the local solution to the global solution including the ghost nodes */
570: VecScatterBegin(osm->restriction, osm->ly, x, ADD_VALUES, reverse);
571: VecScatterEnd(osm->restriction, osm->ly, x, ADD_VALUES, reverse);
572: MatDenseRestoreColumnVecWrite(Y, i, &x);
573: }
574: MatDestroy(&W);
575: } else SETERRQ1(PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Invalid local composition type: %s", PCCompositeTypes[osm->loctype]);
576: return(0);
577: }
579: static PetscErrorCode PCApplyTranspose_ASM(PC pc,Vec x,Vec y)
580: {
581: PC_ASM *osm = (PC_ASM*)pc->data;
583: PetscInt i,n_local_true = osm->n_local_true;
584: ScatterMode forward = SCATTER_FORWARD,reverse = SCATTER_REVERSE;
587: /*
588: Support for limiting the restriction or interpolation to only local
589: subdomain values (leaving the other values 0).
591: Note: these are reversed from the PCApply_ASM() because we are applying the
592: transpose of the three terms
593: */
595: if (!(osm->type & PC_ASM_INTERPOLATE)) {
596: forward = SCATTER_FORWARD_LOCAL;
597: /* have to zero the work RHS since scatter may leave some slots empty */
598: VecSet(osm->lx, 0.0);
599: }
600: if (!(osm->type & PC_ASM_RESTRICT)) reverse = SCATTER_REVERSE_LOCAL;
602: /* zero the global and the local solutions */
603: VecSet(y, 0.0);
604: VecSet(osm->ly, 0.0);
606: /* Copy the global RHS to local RHS including the ghost nodes */
607: VecScatterBegin(osm->restriction, x, osm->lx, INSERT_VALUES, forward);
608: VecScatterEnd(osm->restriction, x, osm->lx, INSERT_VALUES, forward);
610: /* Restrict local RHS to the overlapping 0-block RHS */
611: VecScatterBegin(osm->lrestriction[0], osm->lx, osm->x[0], INSERT_VALUES, forward);
612: VecScatterEnd(osm->lrestriction[0], osm->lx, osm->x[0], INSERT_VALUES, forward);
614: /* do the local solves */
615: for (i = 0; i < n_local_true; ++i) {
617: /* solve the overlapping i-block */
618: PetscLogEventBegin(PC_ApplyOnBlocks,osm->ksp[i],osm->x[i],osm->y[i],0);
619: KSPSolveTranspose(osm->ksp[i], osm->x[i], osm->y[i]);
620: KSPCheckSolve(osm->ksp[i],pc,osm->y[i]);
621: PetscLogEventEnd(PC_ApplyOnBlocks,osm->ksp[i],osm->x[i],osm->y[i],0);
623: if (osm->lprolongation) { /* interpolate the non-overlapping i-block solution to the local solution */
624: VecScatterBegin(osm->lprolongation[i], osm->y[i], osm->ly, ADD_VALUES, forward);
625: VecScatterEnd(osm->lprolongation[i], osm->y[i], osm->ly, ADD_VALUES, forward);
626: } else { /* interpolate the overlapping i-block solution to the local solution */
627: VecScatterBegin(osm->lrestriction[i], osm->y[i], osm->ly, ADD_VALUES, reverse);
628: VecScatterEnd(osm->lrestriction[i], osm->y[i], osm->ly, ADD_VALUES, reverse);
629: }
631: if (i < n_local_true-1) {
632: /* Restrict local RHS to the overlapping (i+1)-block RHS */
633: VecScatterBegin(osm->lrestriction[i+1], osm->lx, osm->x[i+1], INSERT_VALUES, forward);
634: VecScatterEnd(osm->lrestriction[i+1], osm->lx, osm->x[i+1], INSERT_VALUES, forward);
635: }
636: }
637: /* Add the local solution to the global solution including the ghost nodes */
638: VecScatterBegin(osm->restriction, osm->ly, y, ADD_VALUES, reverse);
639: VecScatterEnd(osm->restriction, osm->ly, y, ADD_VALUES, reverse);
641: return(0);
643: }
645: static PetscErrorCode PCReset_ASM(PC pc)
646: {
647: PC_ASM *osm = (PC_ASM*)pc->data;
649: PetscInt i;
652: if (osm->ksp) {
653: for (i=0; i<osm->n_local_true; i++) {
654: KSPReset(osm->ksp[i]);
655: }
656: }
657: if (osm->pmat) {
658: if (osm->n_local_true > 0) {
659: MatDestroySubMatrices(osm->n_local_true,&osm->pmat);
660: }
661: }
662: if (osm->lrestriction) {
663: VecScatterDestroy(&osm->restriction);
664: for (i=0; i<osm->n_local_true; i++) {
665: VecScatterDestroy(&osm->lrestriction[i]);
666: if (osm->lprolongation) {VecScatterDestroy(&osm->lprolongation[i]);}
667: VecDestroy(&osm->x[i]);
668: VecDestroy(&osm->y[i]);
669: }
670: PetscFree(osm->lrestriction);
671: if (osm->lprolongation) {PetscFree(osm->lprolongation);}
672: PetscFree(osm->x);
673: PetscFree(osm->y);
675: }
676: PCASMDestroySubdomains(osm->n_local_true,osm->is,osm->is_local);
677: ISDestroy(&osm->lis);
678: VecDestroy(&osm->lx);
679: VecDestroy(&osm->ly);
680: if (osm->loctype == PC_COMPOSITE_MULTIPLICATIVE) {
681: MatDestroyMatrices(osm->n_local_true, &osm->lmats);
682: }
684: PetscFree(osm->sub_mat_type);
686: osm->is = NULL;
687: osm->is_local = NULL;
688: return(0);
689: }
691: static PetscErrorCode PCDestroy_ASM(PC pc)
692: {
693: PC_ASM *osm = (PC_ASM*)pc->data;
695: PetscInt i;
698: PCReset_ASM(pc);
699: if (osm->ksp) {
700: for (i=0; i<osm->n_local_true; i++) {
701: KSPDestroy(&osm->ksp[i]);
702: }
703: PetscFree(osm->ksp);
704: }
705: PetscFree(pc->data);
706: return(0);
707: }
709: static PetscErrorCode PCSetFromOptions_ASM(PetscOptionItems *PetscOptionsObject,PC pc)
710: {
711: PC_ASM *osm = (PC_ASM*)pc->data;
713: PetscInt blocks,ovl;
714: PetscBool flg;
715: PCASMType asmtype;
716: PCCompositeType loctype;
717: char sub_mat_type[256];
720: PetscOptionsHead(PetscOptionsObject,"Additive Schwarz options");
721: PetscOptionsBool("-pc_asm_dm_subdomains","Use DMCreateDomainDecomposition() to define subdomains","PCASMSetDMSubdomains",osm->dm_subdomains,&osm->dm_subdomains,&flg);
722: PetscOptionsInt("-pc_asm_blocks","Number of subdomains","PCASMSetTotalSubdomains",osm->n,&blocks,&flg);
723: if (flg) {
724: PCASMSetTotalSubdomains(pc,blocks,NULL,NULL);
725: osm->dm_subdomains = PETSC_FALSE;
726: }
727: PetscOptionsInt("-pc_asm_local_blocks","Number of local subdomains","PCASMSetLocalSubdomains",osm->n_local_true,&blocks,&flg);
728: if (flg) {
729: PCASMSetLocalSubdomains(pc,blocks,NULL,NULL);
730: osm->dm_subdomains = PETSC_FALSE;
731: }
732: PetscOptionsInt("-pc_asm_overlap","Number of grid points overlap","PCASMSetOverlap",osm->overlap,&ovl,&flg);
733: if (flg) {
734: PCASMSetOverlap(pc,ovl);
735: osm->dm_subdomains = PETSC_FALSE;
736: }
737: flg = PETSC_FALSE;
738: PetscOptionsEnum("-pc_asm_type","Type of restriction/extension","PCASMSetType",PCASMTypes,(PetscEnum)osm->type,(PetscEnum*)&asmtype,&flg);
739: if (flg) {PCASMSetType(pc,asmtype); }
740: flg = PETSC_FALSE;
741: PetscOptionsEnum("-pc_asm_local_type","Type of local solver composition","PCASMSetLocalType",PCCompositeTypes,(PetscEnum)osm->loctype,(PetscEnum*)&loctype,&flg);
742: if (flg) {PCASMSetLocalType(pc,loctype); }
743: PetscOptionsFList("-pc_asm_sub_mat_type","Subsolve Matrix Type","PCASMSetSubMatType",MatList,NULL,sub_mat_type,256,&flg);
744: if (flg) {
745: PCASMSetSubMatType(pc,sub_mat_type);
746: }
747: PetscOptionsTail();
748: return(0);
749: }
751: /*------------------------------------------------------------------------------------*/
753: static PetscErrorCode PCASMSetLocalSubdomains_ASM(PC pc,PetscInt n,IS is[],IS is_local[])
754: {
755: PC_ASM *osm = (PC_ASM*)pc->data;
757: PetscInt i;
760: if (n < 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Each process must have 1 or more blocks, n = %D",n);
761: if (pc->setupcalled && (n != osm->n_local_true || is)) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"PCASMSetLocalSubdomains() should be called before calling PCSetUp().");
763: if (!pc->setupcalled) {
764: if (is) {
765: for (i=0; i<n; i++) {PetscObjectReference((PetscObject)is[i]);}
766: }
767: if (is_local) {
768: for (i=0; i<n; i++) {PetscObjectReference((PetscObject)is_local[i]);}
769: }
770: PCASMDestroySubdomains(osm->n_local_true,osm->is,osm->is_local);
772: osm->n_local_true = n;
773: osm->is = NULL;
774: osm->is_local = NULL;
775: if (is) {
776: PetscMalloc1(n,&osm->is);
777: for (i=0; i<n; i++) osm->is[i] = is[i];
778: /* Flag indicating that the user has set overlapping subdomains so PCASM should not increase their size. */
779: osm->overlap = -1;
780: }
781: if (is_local) {
782: PetscMalloc1(n,&osm->is_local);
783: for (i=0; i<n; i++) osm->is_local[i] = is_local[i];
784: if (!is) {
785: PetscMalloc1(osm->n_local_true,&osm->is);
786: for (i=0; i<osm->n_local_true; i++) {
787: if (osm->overlap > 0) { /* With positive overlap, osm->is[i] will be modified */
788: ISDuplicate(osm->is_local[i],&osm->is[i]);
789: ISCopy(osm->is_local[i],osm->is[i]);
790: } else {
791: PetscObjectReference((PetscObject)osm->is_local[i]);
792: osm->is[i] = osm->is_local[i];
793: }
794: }
795: }
796: }
797: }
798: return(0);
799: }
801: static PetscErrorCode PCASMSetTotalSubdomains_ASM(PC pc,PetscInt N,IS *is,IS *is_local)
802: {
803: PC_ASM *osm = (PC_ASM*)pc->data;
805: PetscMPIInt rank,size;
806: PetscInt n;
809: if (N < 1) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Number of total blocks must be > 0, N = %D",N);
810: if (is || is_local) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Use PCASMSetLocalSubdomains() to set specific index sets\n\they cannot be set globally yet.");
812: /*
813: Split the subdomains equally among all processors
814: */
815: MPI_Comm_rank(PetscObjectComm((PetscObject)pc),&rank);
816: MPI_Comm_size(PetscObjectComm((PetscObject)pc),&size);
817: n = N/size + ((N % size) > rank);
818: if (!n) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Process %d must have at least one block: total processors %d total blocks %D",(int)rank,(int)size,N);
819: if (pc->setupcalled && n != osm->n_local_true) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"PCASMSetTotalSubdomains() should be called before PCSetUp().");
820: if (!pc->setupcalled) {
821: PCASMDestroySubdomains(osm->n_local_true,osm->is,osm->is_local);
823: osm->n_local_true = n;
824: osm->is = NULL;
825: osm->is_local = NULL;
826: }
827: return(0);
828: }
830: static PetscErrorCode PCASMSetOverlap_ASM(PC pc,PetscInt ovl)
831: {
832: PC_ASM *osm = (PC_ASM*)pc->data;
835: if (ovl < 0) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Negative overlap value requested");
836: if (pc->setupcalled && ovl != osm->overlap) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"PCASMSetOverlap() should be called before PCSetUp().");
837: if (!pc->setupcalled) osm->overlap = ovl;
838: return(0);
839: }
841: static PetscErrorCode PCASMSetType_ASM(PC pc,PCASMType type)
842: {
843: PC_ASM *osm = (PC_ASM*)pc->data;
846: osm->type = type;
847: osm->type_set = PETSC_TRUE;
848: return(0);
849: }
851: static PetscErrorCode PCASMGetType_ASM(PC pc,PCASMType *type)
852: {
853: PC_ASM *osm = (PC_ASM*)pc->data;
856: *type = osm->type;
857: return(0);
858: }
860: static PetscErrorCode PCASMSetLocalType_ASM(PC pc, PCCompositeType type)
861: {
862: PC_ASM *osm = (PC_ASM *) pc->data;
865: if (type != PC_COMPOSITE_ADDITIVE && type != PC_COMPOSITE_MULTIPLICATIVE) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Only supports additive or multiplicative as the local type");
866: osm->loctype = type;
867: return(0);
868: }
870: static PetscErrorCode PCASMGetLocalType_ASM(PC pc, PCCompositeType *type)
871: {
872: PC_ASM *osm = (PC_ASM *) pc->data;
875: *type = osm->loctype;
876: return(0);
877: }
879: static PetscErrorCode PCASMSetSortIndices_ASM(PC pc,PetscBool doSort)
880: {
881: PC_ASM *osm = (PC_ASM*)pc->data;
884: osm->sort_indices = doSort;
885: return(0);
886: }
888: static PetscErrorCode PCASMGetSubKSP_ASM(PC pc,PetscInt *n_local,PetscInt *first_local,KSP **ksp)
889: {
890: PC_ASM *osm = (PC_ASM*)pc->data;
894: if (osm->n_local_true < 1) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ORDER,"Need to call PCSetUp() on PC (or KSPSetUp() on the outer KSP object) before calling here");
896: if (n_local) *n_local = osm->n_local_true;
897: if (first_local) {
898: MPI_Scan(&osm->n_local_true,first_local,1,MPIU_INT,MPI_SUM,PetscObjectComm((PetscObject)pc));
899: *first_local -= osm->n_local_true;
900: }
901: if (ksp) {
902: /* Assume that local solves are now different; not necessarily
903: true though! This flag is used only for PCView_ASM() */
904: *ksp = osm->ksp;
905: osm->same_local_solves = PETSC_FALSE;
906: }
907: return(0);
908: }
910: static PetscErrorCode PCASMGetSubMatType_ASM(PC pc,MatType *sub_mat_type)
911: {
912: PC_ASM *osm = (PC_ASM*)pc->data;
917: *sub_mat_type = osm->sub_mat_type;
918: return(0);
919: }
921: static PetscErrorCode PCASMSetSubMatType_ASM(PC pc,MatType sub_mat_type)
922: {
923: PetscErrorCode ierr;
924: PC_ASM *osm = (PC_ASM*)pc->data;
928: PetscFree(osm->sub_mat_type);
929: PetscStrallocpy(sub_mat_type,(char**)&osm->sub_mat_type);
930: return(0);
931: }
933: /*@C
934: PCASMSetLocalSubdomains - Sets the local subdomains (for this processor only) for the additive Schwarz preconditioner.
936: Collective on pc
938: Input Parameters:
939: + pc - the preconditioner context
940: . n - the number of subdomains for this processor (default value = 1)
941: . is - the index set that defines the subdomains for this processor
942: (or NULL for PETSc to determine subdomains)
943: - is_local - the index sets that define the local part of the subdomains for this processor, not used unless PCASMType is PC_ASM_RESTRICT
944: (or NULL to not provide these)
946: Options Database Key:
947: To set the total number of subdomain blocks rather than specify the
948: index sets, use the option
949: . -pc_asm_local_blocks <blks> - Sets local blocks
951: Notes:
952: The IS numbering is in the parallel, global numbering of the vector for both is and is_local
954: By default the ASM preconditioner uses 1 block per processor.
956: Use PCASMSetTotalSubdomains() to set the subdomains for all processors.
958: If is_local is provided and PCASMType is PC_ASM_RESTRICT then the solution only over the is_local region is interpolated
959: back to form the global solution (this is the standard restricted additive Schwarz method)
961: If the is_local is provided and PCASMType is PC_ASM_INTERPOLATE or PC_ASM_NONE then an error is generated since there is
962: no code to handle that case.
964: Level: advanced
966: .seealso: PCASMSetTotalSubdomains(), PCASMSetOverlap(), PCASMGetSubKSP(),
967: PCASMCreateSubdomains2D(), PCASMGetLocalSubdomains(), PCASMType, PCASMSetType()
968: @*/
969: PetscErrorCode PCASMSetLocalSubdomains(PC pc,PetscInt n,IS is[],IS is_local[])
970: {
975: PetscTryMethod(pc,"PCASMSetLocalSubdomains_C",(PC,PetscInt,IS[],IS[]),(pc,n,is,is_local));
976: return(0);
977: }
979: /*@C
980: PCASMSetTotalSubdomains - Sets the subdomains for all processors for the
981: additive Schwarz preconditioner. Either all or no processors in the
982: PC communicator must call this routine, with the same index sets.
984: Collective on pc
986: Input Parameters:
987: + pc - the preconditioner context
988: . N - the number of subdomains for all processors
989: . is - the index sets that define the subdomains for all processors
990: (or NULL to ask PETSc to determine the subdomains)
991: - is_local - the index sets that define the local part of the subdomains for this processor
992: (or NULL to not provide this information)
994: Options Database Key:
995: To set the total number of subdomain blocks rather than specify the
996: index sets, use the option
997: . -pc_asm_blocks <blks> - Sets total blocks
999: Notes:
1000: Currently you cannot use this to set the actual subdomains with the argument is or is_local.
1002: By default the ASM preconditioner uses 1 block per processor.
1004: These index sets cannot be destroyed until after completion of the
1005: linear solves for which the ASM preconditioner is being used.
1007: Use PCASMSetLocalSubdomains() to set local subdomains.
1009: The IS numbering is in the parallel, global numbering of the vector for both is and is_local
1011: Level: advanced
1013: .seealso: PCASMSetLocalSubdomains(), PCASMSetOverlap(), PCASMGetSubKSP(),
1014: PCASMCreateSubdomains2D()
1015: @*/
1016: PetscErrorCode PCASMSetTotalSubdomains(PC pc,PetscInt N,IS is[],IS is_local[])
1017: {
1022: PetscTryMethod(pc,"PCASMSetTotalSubdomains_C",(PC,PetscInt,IS[],IS[]),(pc,N,is,is_local));
1023: return(0);
1024: }
1026: /*@
1027: PCASMSetOverlap - Sets the overlap between a pair of subdomains for the
1028: additive Schwarz preconditioner. Either all or no processors in the
1029: PC communicator must call this routine.
1031: Logically Collective on pc
1033: Input Parameters:
1034: + pc - the preconditioner context
1035: - ovl - the amount of overlap between subdomains (ovl >= 0, default value = 1)
1037: Options Database Key:
1038: . -pc_asm_overlap <ovl> - Sets overlap
1040: Notes:
1041: By default the ASM preconditioner uses 1 block per processor. To use
1042: multiple blocks per perocessor, see PCASMSetTotalSubdomains() and
1043: PCASMSetLocalSubdomains() (and the option -pc_asm_blocks <blks>).
1045: The overlap defaults to 1, so if one desires that no additional
1046: overlap be computed beyond what may have been set with a call to
1047: PCASMSetTotalSubdomains() or PCASMSetLocalSubdomains(), then ovl
1048: must be set to be 0. In particular, if one does not explicitly set
1049: the subdomains an application code, then all overlap would be computed
1050: internally by PETSc, and using an overlap of 0 would result in an ASM
1051: variant that is equivalent to the block Jacobi preconditioner.
1053: The default algorithm used by PETSc to increase overlap is fast, but not scalable,
1054: use the option -mat_increase_overlap_scalable when the problem and number of processes is large.
1056: Note that one can define initial index sets with any overlap via
1057: PCASMSetLocalSubdomains(); the routine
1058: PCASMSetOverlap() merely allows PETSc to extend that overlap further
1059: if desired.
1061: Level: intermediate
1063: .seealso: PCASMSetTotalSubdomains(), PCASMSetLocalSubdomains(), PCASMGetSubKSP(),
1064: PCASMCreateSubdomains2D(), PCASMGetLocalSubdomains(), MatIncreaseOverlap()
1065: @*/
1066: PetscErrorCode PCASMSetOverlap(PC pc,PetscInt ovl)
1067: {
1073: PetscTryMethod(pc,"PCASMSetOverlap_C",(PC,PetscInt),(pc,ovl));
1074: return(0);
1075: }
1077: /*@
1078: PCASMSetType - Sets the type of restriction and interpolation used
1079: for local problems in the additive Schwarz method.
1081: Logically Collective on pc
1083: Input Parameters:
1084: + pc - the preconditioner context
1085: - type - variant of ASM, one of
1086: .vb
1087: PC_ASM_BASIC - full interpolation and restriction
1088: PC_ASM_RESTRICT - full restriction, local processor interpolation
1089: PC_ASM_INTERPOLATE - full interpolation, local processor restriction
1090: PC_ASM_NONE - local processor restriction and interpolation
1091: .ve
1093: Options Database Key:
1094: . -pc_asm_type [basic,restrict,interpolate,none] - Sets ASM type
1096: Notes:
1097: if the is_local arguments are passed to PCASMSetLocalSubdomains() then they are used when PC_ASM_RESTRICT has been selected
1098: to limit the local processor interpolation
1100: Level: intermediate
1102: .seealso: PCASMSetTotalSubdomains(), PCASMSetTotalSubdomains(), PCASMGetSubKSP(),
1103: PCASMCreateSubdomains2D(), PCASMType, PCASMSetLocalType(), PCASMGetLocalType()
1104: @*/
1105: PetscErrorCode PCASMSetType(PC pc,PCASMType type)
1106: {
1112: PetscTryMethod(pc,"PCASMSetType_C",(PC,PCASMType),(pc,type));
1113: return(0);
1114: }
1116: /*@
1117: PCASMGetType - Gets the type of restriction and interpolation used
1118: for local problems in the additive Schwarz method.
1120: Logically Collective on pc
1122: Input Parameter:
1123: . pc - the preconditioner context
1125: Output Parameter:
1126: . type - variant of ASM, one of
1128: .vb
1129: PC_ASM_BASIC - full interpolation and restriction
1130: PC_ASM_RESTRICT - full restriction, local processor interpolation
1131: PC_ASM_INTERPOLATE - full interpolation, local processor restriction
1132: PC_ASM_NONE - local processor restriction and interpolation
1133: .ve
1135: Options Database Key:
1136: . -pc_asm_type [basic,restrict,interpolate,none] - Sets ASM type
1138: Level: intermediate
1140: .seealso: PCASMSetTotalSubdomains(), PCASMSetTotalSubdomains(), PCASMGetSubKSP(),
1141: PCASMCreateSubdomains2D(), PCASMType, PCASMSetType(), PCASMSetLocalType(), PCASMGetLocalType()
1142: @*/
1143: PetscErrorCode PCASMGetType(PC pc,PCASMType *type)
1144: {
1149: PetscUseMethod(pc,"PCASMGetType_C",(PC,PCASMType*),(pc,type));
1150: return(0);
1151: }
1153: /*@
1154: PCASMSetLocalType - Sets the type of composition used for local problems in the additive Schwarz method.
1156: Logically Collective on pc
1158: Input Parameters:
1159: + pc - the preconditioner context
1160: - type - type of composition, one of
1161: .vb
1162: PC_COMPOSITE_ADDITIVE - local additive combination
1163: PC_COMPOSITE_MULTIPLICATIVE - local multiplicative combination
1164: .ve
1166: Options Database Key:
1167: . -pc_asm_local_type [additive,multiplicative] - Sets local solver composition type
1169: Level: intermediate
1171: .seealso: PCASMSetType(), PCASMGetType(), PCASMGetLocalType(), PCASM, PCASMType, PCASMSetType(), PCASMGetType(), PCCompositeType
1172: @*/
1173: PetscErrorCode PCASMSetLocalType(PC pc, PCCompositeType type)
1174: {
1180: PetscTryMethod(pc, "PCASMSetLocalType_C", (PC, PCCompositeType), (pc, type));
1181: return(0);
1182: }
1184: /*@
1185: PCASMGetLocalType - Gets the type of composition used for local problems in the additive Schwarz method.
1187: Logically Collective on pc
1189: Input Parameter:
1190: . pc - the preconditioner context
1192: Output Parameter:
1193: . type - type of composition, one of
1194: .vb
1195: PC_COMPOSITE_ADDITIVE - local additive combination
1196: PC_COMPOSITE_MULTIPLICATIVE - local multiplicative combination
1197: .ve
1199: Options Database Key:
1200: . -pc_asm_local_type [additive,multiplicative] - Sets local solver composition type
1202: Level: intermediate
1204: .seealso: PCASMSetType(), PCASMGetType(), PCASMSetLocalType(), PCASMCreate(), PCASMType, PCASMSetType(), PCASMGetType(), PCCompositeType
1205: @*/
1206: PetscErrorCode PCASMGetLocalType(PC pc, PCCompositeType *type)
1207: {
1213: PetscUseMethod(pc, "PCASMGetLocalType_C", (PC, PCCompositeType *), (pc, type));
1214: return(0);
1215: }
1217: /*@
1218: PCASMSetSortIndices - Determines whether subdomain indices are sorted.
1220: Logically Collective on pc
1222: Input Parameters:
1223: + pc - the preconditioner context
1224: - doSort - sort the subdomain indices
1226: Level: intermediate
1228: .seealso: PCASMSetLocalSubdomains(), PCASMSetTotalSubdomains(), PCASMGetSubKSP(),
1229: PCASMCreateSubdomains2D()
1230: @*/
1231: PetscErrorCode PCASMSetSortIndices(PC pc,PetscBool doSort)
1232: {
1238: PetscTryMethod(pc,"PCASMSetSortIndices_C",(PC,PetscBool),(pc,doSort));
1239: return(0);
1240: }
1242: /*@C
1243: PCASMGetSubKSP - Gets the local KSP contexts for all blocks on
1244: this processor.
1246: Collective on pc iff first_local is requested
1248: Input Parameter:
1249: . pc - the preconditioner context
1251: Output Parameters:
1252: + n_local - the number of blocks on this processor or NULL
1253: . first_local - the global number of the first block on this processor or NULL,
1254: all processors must request or all must pass NULL
1255: - ksp - the array of KSP contexts
1257: Note:
1258: After PCASMGetSubKSP() the array of KSPes is not to be freed.
1260: You must call KSPSetUp() before calling PCASMGetSubKSP().
1262: Fortran note:
1263: The output argument 'ksp' must be an array of sufficient length or PETSC_NULL_KSP. The latter can be used to learn the necessary length.
1265: Level: advanced
1267: .seealso: PCASMSetTotalSubdomains(), PCASMSetTotalSubdomains(), PCASMSetOverlap(),
1268: PCASMCreateSubdomains2D(),
1269: @*/
1270: PetscErrorCode PCASMGetSubKSP(PC pc,PetscInt *n_local,PetscInt *first_local,KSP *ksp[])
1271: {
1276: PetscUseMethod(pc,"PCASMGetSubKSP_C",(PC,PetscInt*,PetscInt*,KSP **),(pc,n_local,first_local,ksp));
1277: return(0);
1278: }
1280: /* -------------------------------------------------------------------------------------*/
1281: /*MC
1282: PCASM - Use the (restricted) additive Schwarz method, each block is (approximately) solved with
1283: its own KSP object.
1285: Options Database Keys:
1286: + -pc_asm_blocks <blks> - Sets total blocks
1287: . -pc_asm_overlap <ovl> - Sets overlap
1288: . -pc_asm_type [basic,restrict,interpolate,none] - Sets ASM type, default is restrict
1289: - -pc_asm_local_type [additive, multiplicative] - Sets ASM type, default is additive
1291: IMPORTANT: If you run with, for example, 3 blocks on 1 processor or 3 blocks on 3 processors you
1292: will get a different convergence rate due to the default option of -pc_asm_type restrict. Use
1293: -pc_asm_type basic to use the standard ASM.
1295: Notes:
1296: Each processor can have one or more blocks, but a block cannot be shared by more
1297: than one processor. Use PCGASM for subdomains shared by multiple processes. Defaults to one block per processor.
1299: To set options on the solvers for each block append -sub_ to all the KSP, and PC
1300: options database keys. For example, -sub_pc_type ilu -sub_pc_factor_levels 1 -sub_ksp_type preonly
1302: To set the options on the solvers separate for each block call PCASMGetSubKSP()
1303: and set the options directly on the resulting KSP object (you can access its PC
1304: with KSPGetPC())
1306: Level: beginner
1308: References:
1309: + 1. - M Dryja, OB Widlund, An additive variant of the Schwarz alternating method for the case of many subregions
1310: Courant Institute, New York University Technical report
1311: - 2. - Barry Smith, Petter Bjorstad, and William Gropp, Domain Decompositions: Parallel Multilevel Methods for Elliptic Partial Differential Equations,
1312: Cambridge University Press.
1314: .seealso: PCCreate(), PCSetType(), PCType (for list of available types), PC,
1315: PCBJACOBI, PCASMGetSubKSP(), PCASMSetLocalSubdomains(), PCASMType, PCASMGetType(), PCASMSetLocalType(), PCASMGetLocalType()
1316: PCASMSetTotalSubdomains(), PCSetModifySubMatrices(), PCASMSetOverlap(), PCASMSetType(), PCCompositeType
1318: M*/
1320: PETSC_EXTERN PetscErrorCode PCCreate_ASM(PC pc)
1321: {
1323: PC_ASM *osm;
1326: PetscNewLog(pc,&osm);
1328: osm->n = PETSC_DECIDE;
1329: osm->n_local = 0;
1330: osm->n_local_true = PETSC_DECIDE;
1331: osm->overlap = 1;
1332: osm->ksp = NULL;
1333: osm->restriction = NULL;
1334: osm->lprolongation = NULL;
1335: osm->lrestriction = NULL;
1336: osm->x = NULL;
1337: osm->y = NULL;
1338: osm->is = NULL;
1339: osm->is_local = NULL;
1340: osm->mat = NULL;
1341: osm->pmat = NULL;
1342: osm->type = PC_ASM_RESTRICT;
1343: osm->loctype = PC_COMPOSITE_ADDITIVE;
1344: osm->same_local_solves = PETSC_TRUE;
1345: osm->sort_indices = PETSC_TRUE;
1346: osm->dm_subdomains = PETSC_FALSE;
1347: osm->sub_mat_type = NULL;
1349: pc->data = (void*)osm;
1350: pc->ops->apply = PCApply_ASM;
1351: pc->ops->matapply = PCMatApply_ASM;
1352: pc->ops->applytranspose = PCApplyTranspose_ASM;
1353: pc->ops->setup = PCSetUp_ASM;
1354: pc->ops->reset = PCReset_ASM;
1355: pc->ops->destroy = PCDestroy_ASM;
1356: pc->ops->setfromoptions = PCSetFromOptions_ASM;
1357: pc->ops->setuponblocks = PCSetUpOnBlocks_ASM;
1358: pc->ops->view = PCView_ASM;
1359: pc->ops->applyrichardson = NULL;
1361: PetscObjectComposeFunction((PetscObject)pc,"PCASMSetLocalSubdomains_C",PCASMSetLocalSubdomains_ASM);
1362: PetscObjectComposeFunction((PetscObject)pc,"PCASMSetTotalSubdomains_C",PCASMSetTotalSubdomains_ASM);
1363: PetscObjectComposeFunction((PetscObject)pc,"PCASMSetOverlap_C",PCASMSetOverlap_ASM);
1364: PetscObjectComposeFunction((PetscObject)pc,"PCASMSetType_C",PCASMSetType_ASM);
1365: PetscObjectComposeFunction((PetscObject)pc,"PCASMGetType_C",PCASMGetType_ASM);
1366: PetscObjectComposeFunction((PetscObject)pc,"PCASMSetLocalType_C",PCASMSetLocalType_ASM);
1367: PetscObjectComposeFunction((PetscObject)pc,"PCASMGetLocalType_C",PCASMGetLocalType_ASM);
1368: PetscObjectComposeFunction((PetscObject)pc,"PCASMSetSortIndices_C",PCASMSetSortIndices_ASM);
1369: PetscObjectComposeFunction((PetscObject)pc,"PCASMGetSubKSP_C",PCASMGetSubKSP_ASM);
1370: PetscObjectComposeFunction((PetscObject)pc,"PCASMGetSubMatType_C",PCASMGetSubMatType_ASM);
1371: PetscObjectComposeFunction((PetscObject)pc,"PCASMSetSubMatType_C",PCASMSetSubMatType_ASM);
1372: return(0);
1373: }
1375: /*@C
1376: PCASMCreateSubdomains - Creates the index sets for the overlapping Schwarz
1377: preconditioner for a any problem on a general grid.
1379: Collective
1381: Input Parameters:
1382: + A - The global matrix operator
1383: - n - the number of local blocks
1385: Output Parameters:
1386: . outis - the array of index sets defining the subdomains
1388: Level: advanced
1390: Note: this generates nonoverlapping subdomains; the PCASM will generate the overlap
1391: from these if you use PCASMSetLocalSubdomains()
1393: In the Fortran version you must provide the array outis[] already allocated of length n.
1395: .seealso: PCASMSetLocalSubdomains(), PCASMDestroySubdomains()
1396: @*/
1397: PetscErrorCode PCASMCreateSubdomains(Mat A, PetscInt n, IS* outis[])
1398: {
1399: MatPartitioning mpart;
1400: const char *prefix;
1401: PetscInt i,j,rstart,rend,bs;
1402: PetscBool hasop, isbaij = PETSC_FALSE,foundpart = PETSC_FALSE;
1403: Mat Ad = NULL, adj;
1404: IS ispart,isnumb,*is;
1405: PetscErrorCode ierr;
1410: if (n < 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"number of local blocks must be > 0, n = %D",n);
1412: /* Get prefix, row distribution, and block size */
1413: MatGetOptionsPrefix(A,&prefix);
1414: MatGetOwnershipRange(A,&rstart,&rend);
1415: MatGetBlockSize(A,&bs);
1416: 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);
1418: /* Get diagonal block from matrix if possible */
1419: MatHasOperation(A,MATOP_GET_DIAGONAL_BLOCK,&hasop);
1420: if (hasop) {
1421: MatGetDiagonalBlock(A,&Ad);
1422: }
1423: if (Ad) {
1424: PetscObjectBaseTypeCompare((PetscObject)Ad,MATSEQBAIJ,&isbaij);
1425: if (!isbaij) {PetscObjectBaseTypeCompare((PetscObject)Ad,MATSEQSBAIJ,&isbaij);}
1426: }
1427: if (Ad && n > 1) {
1428: PetscBool match,done;
1429: /* Try to setup a good matrix partitioning if available */
1430: MatPartitioningCreate(PETSC_COMM_SELF,&mpart);
1431: PetscObjectSetOptionsPrefix((PetscObject)mpart,prefix);
1432: MatPartitioningSetFromOptions(mpart);
1433: PetscObjectTypeCompare((PetscObject)mpart,MATPARTITIONINGCURRENT,&match);
1434: if (!match) {
1435: PetscObjectTypeCompare((PetscObject)mpart,MATPARTITIONINGSQUARE,&match);
1436: }
1437: if (!match) { /* assume a "good" partitioner is available */
1438: PetscInt na;
1439: const PetscInt *ia,*ja;
1440: MatGetRowIJ(Ad,0,PETSC_TRUE,isbaij,&na,&ia,&ja,&done);
1441: if (done) {
1442: /* Build adjacency matrix by hand. Unfortunately a call to
1443: MatConvert(Ad,MATMPIADJ,MAT_INITIAL_MATRIX,&adj) will
1444: remove the block-aij structure and we cannot expect
1445: MatPartitioning to split vertices as we need */
1446: PetscInt i,j,len,nnz,cnt,*iia=NULL,*jja=NULL;
1447: const PetscInt *row;
1448: nnz = 0;
1449: for (i=0; i<na; i++) { /* count number of nonzeros */
1450: len = ia[i+1] - ia[i];
1451: row = ja + ia[i];
1452: for (j=0; j<len; j++) {
1453: if (row[j] == i) { /* don't count diagonal */
1454: len--; break;
1455: }
1456: }
1457: nnz += len;
1458: }
1459: PetscMalloc1(na+1,&iia);
1460: PetscMalloc1(nnz,&jja);
1461: nnz = 0;
1462: iia[0] = 0;
1463: for (i=0; i<na; i++) { /* fill adjacency */
1464: cnt = 0;
1465: len = ia[i+1] - ia[i];
1466: row = ja + ia[i];
1467: for (j=0; j<len; j++) {
1468: if (row[j] != i) { /* if not diagonal */
1469: jja[nnz+cnt++] = row[j];
1470: }
1471: }
1472: nnz += cnt;
1473: iia[i+1] = nnz;
1474: }
1475: /* Partitioning of the adjacency matrix */
1476: MatCreateMPIAdj(PETSC_COMM_SELF,na,na,iia,jja,NULL,&adj);
1477: MatPartitioningSetAdjacency(mpart,adj);
1478: MatPartitioningSetNParts(mpart,n);
1479: MatPartitioningApply(mpart,&ispart);
1480: ISPartitioningToNumbering(ispart,&isnumb);
1481: MatDestroy(&adj);
1482: foundpart = PETSC_TRUE;
1483: }
1484: MatRestoreRowIJ(Ad,0,PETSC_TRUE,isbaij,&na,&ia,&ja,&done);
1485: }
1486: MatPartitioningDestroy(&mpart);
1487: }
1489: PetscMalloc1(n,&is);
1490: *outis = is;
1492: if (!foundpart) {
1494: /* Partitioning by contiguous chunks of rows */
1496: PetscInt mbs = (rend-rstart)/bs;
1497: PetscInt start = rstart;
1498: for (i=0; i<n; i++) {
1499: PetscInt count = (mbs/n + ((mbs % n) > i)) * bs;
1500: ISCreateStride(PETSC_COMM_SELF,count,start,1,&is[i]);
1501: start += count;
1502: }
1504: } else {
1506: /* Partitioning by adjacency of diagonal block */
1508: const PetscInt *numbering;
1509: PetscInt *count,nidx,*indices,*newidx,start=0;
1510: /* Get node count in each partition */
1511: PetscMalloc1(n,&count);
1512: ISPartitioningCount(ispart,n,count);
1513: if (isbaij && bs > 1) { /* adjust for the block-aij case */
1514: for (i=0; i<n; i++) count[i] *= bs;
1515: }
1516: /* Build indices from node numbering */
1517: ISGetLocalSize(isnumb,&nidx);
1518: PetscMalloc1(nidx,&indices);
1519: for (i=0; i<nidx; i++) indices[i] = i; /* needs to be initialized */
1520: ISGetIndices(isnumb,&numbering);
1521: PetscSortIntWithPermutation(nidx,numbering,indices);
1522: ISRestoreIndices(isnumb,&numbering);
1523: if (isbaij && bs > 1) { /* adjust for the block-aij case */
1524: PetscMalloc1(nidx*bs,&newidx);
1525: for (i=0; i<nidx; i++) {
1526: for (j=0; j<bs; j++) newidx[i*bs+j] = indices[i]*bs + j;
1527: }
1528: PetscFree(indices);
1529: nidx *= bs;
1530: indices = newidx;
1531: }
1532: /* Shift to get global indices */
1533: for (i=0; i<nidx; i++) indices[i] += rstart;
1535: /* Build the index sets for each block */
1536: for (i=0; i<n; i++) {
1537: ISCreateGeneral(PETSC_COMM_SELF,count[i],&indices[start],PETSC_COPY_VALUES,&is[i]);
1538: ISSort(is[i]);
1539: start += count[i];
1540: }
1542: PetscFree(count);
1543: PetscFree(indices);
1544: ISDestroy(&isnumb);
1545: ISDestroy(&ispart);
1547: }
1548: return(0);
1549: }
1551: /*@C
1552: PCASMDestroySubdomains - Destroys the index sets created with
1553: PCASMCreateSubdomains(). Should be called after setting subdomains
1554: with PCASMSetLocalSubdomains().
1556: Collective
1558: Input Parameters:
1559: + n - the number of index sets
1560: . is - the array of index sets
1561: - is_local - the array of local index sets, can be NULL
1563: Level: advanced
1565: .seealso: PCASMCreateSubdomains(), PCASMSetLocalSubdomains()
1566: @*/
1567: PetscErrorCode PCASMDestroySubdomains(PetscInt n, IS is[], IS is_local[])
1568: {
1569: PetscInt i;
1573: if (n <= 0) return(0);
1574: if (is) {
1576: for (i=0; i<n; i++) { ISDestroy(&is[i]); }
1577: PetscFree(is);
1578: }
1579: if (is_local) {
1581: for (i=0; i<n; i++) { ISDestroy(&is_local[i]); }
1582: PetscFree(is_local);
1583: }
1584: return(0);
1585: }
1587: /*@
1588: PCASMCreateSubdomains2D - Creates the index sets for the overlapping Schwarz
1589: preconditioner for a two-dimensional problem on a regular grid.
1591: Not Collective
1593: Input Parameters:
1594: + m, n - the number of mesh points in the x and y directions
1595: . M, N - the number of subdomains in the x and y directions
1596: . dof - degrees of freedom per node
1597: - overlap - overlap in mesh lines
1599: Output Parameters:
1600: + Nsub - the number of subdomains created
1601: . is - array of index sets defining overlapping (if overlap > 0) subdomains
1602: - is_local - array of index sets defining non-overlapping subdomains
1604: Note:
1605: Presently PCAMSCreateSubdomains2d() is valid only for sequential
1606: preconditioners. More general related routines are
1607: PCASMSetTotalSubdomains() and PCASMSetLocalSubdomains().
1609: Level: advanced
1611: .seealso: PCASMSetTotalSubdomains(), PCASMSetLocalSubdomains(), PCASMGetSubKSP(),
1612: PCASMSetOverlap()
1613: @*/
1614: PetscErrorCode PCASMCreateSubdomains2D(PetscInt m,PetscInt n,PetscInt M,PetscInt N,PetscInt dof,PetscInt overlap,PetscInt *Nsub,IS **is,IS **is_local)
1615: {
1616: PetscInt i,j,height,width,ystart,xstart,yleft,yright,xleft,xright,loc_outer;
1618: PetscInt nidx,*idx,loc,ii,jj,count;
1621: if (dof != 1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP," ");
1623: *Nsub = N*M;
1624: PetscMalloc1(*Nsub,is);
1625: PetscMalloc1(*Nsub,is_local);
1626: ystart = 0;
1627: loc_outer = 0;
1628: for (i=0; i<N; i++) {
1629: height = n/N + ((n % N) > i); /* height of subdomain */
1630: if (height < 2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many N subdomains for mesh dimension n");
1631: yleft = ystart - overlap; if (yleft < 0) yleft = 0;
1632: yright = ystart + height + overlap; if (yright > n) yright = n;
1633: xstart = 0;
1634: for (j=0; j<M; j++) {
1635: width = m/M + ((m % M) > j); /* width of subdomain */
1636: if (width < 2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many M subdomains for mesh dimension m");
1637: xleft = xstart - overlap; if (xleft < 0) xleft = 0;
1638: xright = xstart + width + overlap; if (xright > m) xright = m;
1639: nidx = (xright - xleft)*(yright - yleft);
1640: PetscMalloc1(nidx,&idx);
1641: loc = 0;
1642: for (ii=yleft; ii<yright; ii++) {
1643: count = m*ii + xleft;
1644: for (jj=xleft; jj<xright; jj++) idx[loc++] = count++;
1645: }
1646: ISCreateGeneral(PETSC_COMM_SELF,nidx,idx,PETSC_COPY_VALUES,(*is)+loc_outer);
1647: if (overlap == 0) {
1648: PetscObjectReference((PetscObject)(*is)[loc_outer]);
1650: (*is_local)[loc_outer] = (*is)[loc_outer];
1651: } else {
1652: for (loc=0,ii=ystart; ii<ystart+height; ii++) {
1653: for (jj=xstart; jj<xstart+width; jj++) {
1654: idx[loc++] = m*ii + jj;
1655: }
1656: }
1657: ISCreateGeneral(PETSC_COMM_SELF,loc,idx,PETSC_COPY_VALUES,*is_local+loc_outer);
1658: }
1659: PetscFree(idx);
1660: xstart += width;
1661: loc_outer++;
1662: }
1663: ystart += height;
1664: }
1665: for (i=0; i<*Nsub; i++) { ISSort((*is)[i]); }
1666: return(0);
1667: }
1669: /*@C
1670: PCASMGetLocalSubdomains - Gets the local subdomains (for this processor
1671: only) for the additive Schwarz preconditioner.
1673: Not Collective
1675: Input Parameter:
1676: . pc - the preconditioner context
1678: Output Parameters:
1679: + n - the number of subdomains for this processor (default value = 1)
1680: . is - the index sets that define the subdomains for this processor
1681: - is_local - the index sets that define the local part of the subdomains for this processor (can be NULL)
1684: Notes:
1685: The IS numbering is in the parallel, global numbering of the vector.
1687: Level: advanced
1689: .seealso: PCASMSetTotalSubdomains(), PCASMSetOverlap(), PCASMGetSubKSP(),
1690: PCASMCreateSubdomains2D(), PCASMSetLocalSubdomains(), PCASMGetLocalSubmatrices()
1691: @*/
1692: PetscErrorCode PCASMGetLocalSubdomains(PC pc,PetscInt *n,IS *is[],IS *is_local[])
1693: {
1694: PC_ASM *osm = (PC_ASM*)pc->data;
1696: PetscBool match;
1702: PetscObjectTypeCompare((PetscObject)pc,PCASM,&match);
1703: if (!match) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONG,"PC is not a PCASM");
1704: if (n) *n = osm->n_local_true;
1705: if (is) *is = osm->is;
1706: if (is_local) *is_local = osm->is_local;
1707: return(0);
1708: }
1710: /*@C
1711: PCASMGetLocalSubmatrices - Gets the local submatrices (for this processor
1712: only) for the additive Schwarz preconditioner.
1714: Not Collective
1716: Input Parameter:
1717: . pc - the preconditioner context
1719: Output Parameters:
1720: + n - the number of matrices for this processor (default value = 1)
1721: - mat - the matrices
1723: Level: advanced
1725: Notes:
1726: Call after PCSetUp() (or KSPSetUp()) but before PCApply() and before PCSetUpOnBlocks())
1728: Usually one would use PCSetModifySubMatrices() to change the submatrices in building the preconditioner.
1730: .seealso: PCASMSetTotalSubdomains(), PCASMSetOverlap(), PCASMGetSubKSP(),
1731: PCASMCreateSubdomains2D(), PCASMSetLocalSubdomains(), PCASMGetLocalSubdomains(), PCSetModifySubMatrices()
1732: @*/
1733: PetscErrorCode PCASMGetLocalSubmatrices(PC pc,PetscInt *n,Mat *mat[])
1734: {
1735: PC_ASM *osm;
1737: PetscBool match;
1743: if (!pc->setupcalled) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Must call after KSPSetUp() or PCSetUp().");
1744: PetscObjectTypeCompare((PetscObject)pc,PCASM,&match);
1745: if (!match) {
1746: if (n) *n = 0;
1747: if (mat) *mat = NULL;
1748: } else {
1749: osm = (PC_ASM*)pc->data;
1750: if (n) *n = osm->n_local_true;
1751: if (mat) *mat = osm->pmat;
1752: }
1753: return(0);
1754: }
1756: /*@
1757: PCASMSetDMSubdomains - Indicates whether to use DMCreateDomainDecomposition() to define the subdomains, whenever possible.
1759: Logically Collective
1761: Input Parameter:
1762: + pc - the preconditioner
1763: - flg - boolean indicating whether to use subdomains defined by the DM
1765: Options Database Key:
1766: . -pc_asm_dm_subdomains
1768: Level: intermediate
1770: Notes:
1771: PCASMSetTotalSubdomains() and PCASMSetOverlap() take precedence over PCASMSetDMSubdomains(),
1772: so setting either of the first two effectively turns the latter off.
1774: .seealso: PCASMGetDMSubdomains(), PCASMSetTotalSubdomains(), PCASMSetOverlap()
1775: PCASMCreateSubdomains2D(), PCASMSetLocalSubdomains(), PCASMGetLocalSubdomains()
1776: @*/
1777: PetscErrorCode PCASMSetDMSubdomains(PC pc,PetscBool flg)
1778: {
1779: PC_ASM *osm = (PC_ASM*)pc->data;
1781: PetscBool match;
1786: if (pc->setupcalled) SETERRQ(((PetscObject)pc)->comm,PETSC_ERR_ARG_WRONGSTATE,"Not for a setup PC.");
1787: PetscObjectTypeCompare((PetscObject)pc,PCASM,&match);
1788: if (match) {
1789: osm->dm_subdomains = flg;
1790: }
1791: return(0);
1792: }
1794: /*@
1795: PCASMGetDMSubdomains - Returns flag indicating whether to use DMCreateDomainDecomposition() to define the subdomains, whenever possible.
1796: Not Collective
1798: Input Parameter:
1799: . pc - the preconditioner
1801: Output Parameter:
1802: . flg - boolean indicating whether to use subdomains defined by the DM
1804: Level: intermediate
1806: .seealso: PCASMSetDMSubdomains(), PCASMSetTotalSubdomains(), PCASMSetOverlap()
1807: PCASMCreateSubdomains2D(), PCASMSetLocalSubdomains(), PCASMGetLocalSubdomains()
1808: @*/
1809: PetscErrorCode PCASMGetDMSubdomains(PC pc,PetscBool* flg)
1810: {
1811: PC_ASM *osm = (PC_ASM*)pc->data;
1813: PetscBool match;
1818: PetscObjectTypeCompare((PetscObject)pc,PCASM,&match);
1819: if (match) {
1820: if (flg) *flg = osm->dm_subdomains;
1821: }
1822: return(0);
1823: }
1825: /*@
1826: PCASMGetSubMatType - Gets the matrix type used for ASM subsolves, as a string.
1828: Not Collective
1830: Input Parameter:
1831: . pc - the PC
1833: Output Parameter:
1834: . -pc_asm_sub_mat_type - name of matrix type
1836: Level: advanced
1838: .seealso: PCASMSetSubMatType(), PCASM, PCSetType(), VecSetType(), MatType, Mat
1839: @*/
1840: PetscErrorCode PCASMGetSubMatType(PC pc,MatType *sub_mat_type) {
1843: PetscTryMethod(pc,"PCASMGetSubMatType_C",(PC,MatType*),(pc,sub_mat_type));
1844: return(0);
1845: }
1847: /*@
1848: PCASMSetSubMatType - Set the type of matrix used for ASM subsolves
1850: Collective on Mat
1852: Input Parameters:
1853: + pc - the PC object
1854: - sub_mat_type - matrix type
1856: Options Database Key:
1857: . -pc_asm_sub_mat_type <sub_mat_type> - Sets the matrix type used for subsolves, for example, seqaijviennacl. If you specify a base name like aijviennacl, the corresponding sequential type is assumed.
1859: Notes:
1860: See "${PETSC_DIR}/include/petscmat.h" for available types
1862: Level: advanced
1864: .seealso: PCASMGetSubMatType(), PCASM, PCSetType(), VecSetType(), MatType, Mat
1865: @*/
1866: PetscErrorCode PCASMSetSubMatType(PC pc,MatType sub_mat_type)
1867: {
1870: PetscTryMethod(pc,"PCASMSetSubMatType_C",(PC,MatType),(pc,sub_mat_type));
1871: return(0);
1872: }