Actual source code: bjacobi.c
1: /*
2: Defines a block Jacobi preconditioner.
3: */
5: #include <../src/ksp/pc/impls/bjacobi/bjacobi.h>
7: static PetscErrorCode PCSetUp_BJacobi_Singleblock(PC, Mat, Mat);
8: static PetscErrorCode PCSetUp_BJacobi_Multiblock(PC, Mat, Mat);
9: static PetscErrorCode PCSetUp_BJacobi_Multiproc(PC);
11: static PetscErrorCode PCSetUp_BJacobi(PC pc)
12: {
13: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
14: Mat mat = pc->mat, pmat = pc->pmat;
15: PetscBool hasop;
16: PetscInt N, M, start, i, sum, end;
17: PetscInt bs, i_start = -1, i_end = -1;
18: PetscMPIInt rank, size;
20: PetscFunctionBegin;
21: PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)pc), &rank));
22: PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size));
23: PetscCall(MatGetLocalSize(pc->pmat, &M, &N));
24: PetscCall(MatGetBlockSize(pc->pmat, &bs));
26: if (jac->n > 0 && jac->n < size) {
27: PetscCall(PCSetUp_BJacobi_Multiproc(pc));
28: PetscFunctionReturn(PETSC_SUCCESS);
29: }
31: /* Determines the number of blocks assigned to each processor */
32: /* local block count given */
33: if (jac->n_local > 0 && jac->n < 0) {
34: PetscCall(MPIU_Allreduce(&jac->n_local, &jac->n, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)pc)));
35: if (jac->l_lens) { /* check that user set these correctly */
36: sum = 0;
37: for (i = 0; i < jac->n_local; i++) {
38: PetscCheck(jac->l_lens[i] / bs * bs == jac->l_lens[i], PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat blocksize doesn't match block Jacobi layout");
39: sum += jac->l_lens[i];
40: }
41: PetscCheck(sum == M, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Local lens set incorrectly");
42: } else {
43: PetscCall(PetscMalloc1(jac->n_local, &jac->l_lens));
44: for (i = 0; i < jac->n_local; i++) jac->l_lens[i] = bs * ((M / bs) / jac->n_local + (((M / bs) % jac->n_local) > i));
45: }
46: } else if (jac->n > 0 && jac->n_local < 0) { /* global block count given */
47: /* global blocks given: determine which ones are local */
48: if (jac->g_lens) {
49: /* check if the g_lens is has valid entries */
50: for (i = 0; i < jac->n; i++) {
51: PetscCheck(jac->g_lens[i], PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Zero block not allowed");
52: PetscCheck(jac->g_lens[i] / bs * bs == jac->g_lens[i], PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat blocksize doesn't match block Jacobi layout");
53: }
54: if (size == 1) {
55: jac->n_local = jac->n;
56: PetscCall(PetscMalloc1(jac->n_local, &jac->l_lens));
57: PetscCall(PetscArraycpy(jac->l_lens, jac->g_lens, jac->n_local));
58: /* check that user set these correctly */
59: sum = 0;
60: for (i = 0; i < jac->n_local; i++) sum += jac->l_lens[i];
61: PetscCheck(sum == M, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Global lens set incorrectly");
62: } else {
63: PetscCall(MatGetOwnershipRange(pc->pmat, &start, &end));
64: /* loop over blocks determining first one owned by me */
65: sum = 0;
66: for (i = 0; i < jac->n + 1; i++) {
67: if (sum == start) {
68: i_start = i;
69: goto start_1;
70: }
71: if (i < jac->n) sum += jac->g_lens[i];
72: }
73: SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Block sizes used in PCBJacobiSetTotalBlocks()\nare not compatible with parallel matrix layout");
74: start_1:
75: for (i = i_start; i < jac->n + 1; i++) {
76: if (sum == end) {
77: i_end = i;
78: goto end_1;
79: }
80: if (i < jac->n) sum += jac->g_lens[i];
81: }
82: SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Block sizes used in PCBJacobiSetTotalBlocks()\nare not compatible with parallel matrix layout");
83: end_1:
84: jac->n_local = i_end - i_start;
85: PetscCall(PetscMalloc1(jac->n_local, &jac->l_lens));
86: PetscCall(PetscArraycpy(jac->l_lens, jac->g_lens + i_start, jac->n_local));
87: }
88: } else { /* no global blocks given, determine then using default layout */
89: jac->n_local = jac->n / size + ((jac->n % size) > rank);
90: PetscCall(PetscMalloc1(jac->n_local, &jac->l_lens));
91: for (i = 0; i < jac->n_local; i++) {
92: jac->l_lens[i] = ((M / bs) / jac->n_local + (((M / bs) % jac->n_local) > i)) * bs;
93: PetscCheck(jac->l_lens[i], PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Too many blocks given");
94: }
95: }
96: } else if (jac->n < 0 && jac->n_local < 0) { /* no blocks given */
97: jac->n = size;
98: jac->n_local = 1;
99: PetscCall(PetscMalloc1(1, &jac->l_lens));
100: jac->l_lens[0] = M;
101: } else { /* jac->n > 0 && jac->n_local > 0 */
102: if (!jac->l_lens) {
103: PetscCall(PetscMalloc1(jac->n_local, &jac->l_lens));
104: for (i = 0; i < jac->n_local; i++) jac->l_lens[i] = bs * ((M / bs) / jac->n_local + (((M / bs) % jac->n_local) > i));
105: }
106: }
107: PetscCheck(jac->n_local >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Number of blocks is less than number of processors");
109: /* Determines mat and pmat */
110: PetscCall(MatHasOperation(pc->mat, MATOP_GET_DIAGONAL_BLOCK, &hasop));
111: if (!hasop && size == 1) {
112: mat = pc->mat;
113: pmat = pc->pmat;
114: } else {
115: if (pc->useAmat) {
116: /* use block from Amat matrix, not Pmat for local MatMult() */
117: PetscCall(MatGetDiagonalBlock(pc->mat, &mat));
118: }
119: if (pc->pmat != pc->mat || !pc->useAmat) {
120: PetscCall(MatGetDiagonalBlock(pc->pmat, &pmat));
121: } else pmat = mat;
122: }
124: /*
125: Setup code depends on the number of blocks
126: */
127: if (jac->n_local == 1) {
128: PetscCall(PCSetUp_BJacobi_Singleblock(pc, mat, pmat));
129: } else {
130: PetscCall(PCSetUp_BJacobi_Multiblock(pc, mat, pmat));
131: }
132: PetscFunctionReturn(PETSC_SUCCESS);
133: }
135: /* Default destroy, if it has never been setup */
136: static PetscErrorCode PCDestroy_BJacobi(PC pc)
137: {
138: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
140: PetscFunctionBegin;
141: PetscCall(PetscFree(jac->g_lens));
142: PetscCall(PetscFree(jac->l_lens));
143: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJacobiGetSubKSP_C", NULL));
144: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJacobiSetTotalBlocks_C", NULL));
145: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJacobiGetTotalBlocks_C", NULL));
146: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJacobiSetLocalBlocks_C", NULL));
147: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJacobiGetLocalBlocks_C", NULL));
148: PetscCall(PetscFree(pc->data));
149: PetscFunctionReturn(PETSC_SUCCESS);
150: }
152: static PetscErrorCode PCSetFromOptions_BJacobi(PC pc, PetscOptionItems *PetscOptionsObject)
153: {
154: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
155: PetscInt blocks, i;
156: PetscBool flg;
158: PetscFunctionBegin;
159: PetscOptionsHeadBegin(PetscOptionsObject, "Block Jacobi options");
160: PetscCall(PetscOptionsInt("-pc_bjacobi_blocks", "Total number of blocks", "PCBJacobiSetTotalBlocks", jac->n, &blocks, &flg));
161: if (flg) PetscCall(PCBJacobiSetTotalBlocks(pc, blocks, NULL));
162: PetscCall(PetscOptionsInt("-pc_bjacobi_local_blocks", "Local number of blocks", "PCBJacobiSetLocalBlocks", jac->n_local, &blocks, &flg));
163: if (flg) PetscCall(PCBJacobiSetLocalBlocks(pc, blocks, NULL));
164: if (jac->ksp) {
165: /* The sub-KSP has already been set up (e.g., PCSetUp_BJacobi_Singleblock), but KSPSetFromOptions was not called
166: * unless we had already been called. */
167: for (i = 0; i < jac->n_local; i++) PetscCall(KSPSetFromOptions(jac->ksp[i]));
168: }
169: PetscOptionsHeadEnd();
170: PetscFunctionReturn(PETSC_SUCCESS);
171: }
173: #include <petscdraw.h>
174: static PetscErrorCode PCView_BJacobi(PC pc, PetscViewer viewer)
175: {
176: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
177: PC_BJacobi_Multiproc *mpjac = (PC_BJacobi_Multiproc *)jac->data;
178: PetscMPIInt rank;
179: PetscInt i;
180: PetscBool iascii, isstring, isdraw;
181: PetscViewer sviewer;
182: PetscViewerFormat format;
183: const char *prefix;
185: PetscFunctionBegin;
186: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii));
187: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSTRING, &isstring));
188: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
189: if (iascii) {
190: if (pc->useAmat) PetscCall(PetscViewerASCIIPrintf(viewer, " using Amat local matrix, number of blocks = %" PetscInt_FMT "\n", jac->n));
191: PetscCall(PetscViewerASCIIPrintf(viewer, " number of blocks = %" PetscInt_FMT "\n", jac->n));
192: PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)pc), &rank));
193: PetscCall(PetscViewerGetFormat(viewer, &format));
194: if (format != PETSC_VIEWER_ASCII_INFO_DETAIL) {
195: PetscCall(PetscViewerASCIIPrintf(viewer, " Local solver information for first block is in the following KSP and PC objects on rank 0:\n"));
196: PetscCall(PCGetOptionsPrefix(pc, &prefix));
197: PetscCall(PetscViewerASCIIPrintf(viewer, " Use -%sksp_view ::ascii_info_detail to display information for all blocks\n", prefix ? prefix : ""));
198: if (jac->ksp && !jac->psubcomm) {
199: PetscCall(PetscViewerGetSubViewer(viewer, PETSC_COMM_SELF, &sviewer));
200: if (rank == 0) {
201: PetscCall(PetscViewerASCIIPushTab(sviewer));
202: PetscCall(KSPView(jac->ksp[0], sviewer));
203: PetscCall(PetscViewerASCIIPopTab(sviewer));
204: }
205: PetscCall(PetscViewerRestoreSubViewer(viewer, PETSC_COMM_SELF, &sviewer));
206: /* extra call needed because of the two calls to PetscViewerASCIIPushSynchronized() in PetscViewerGetSubViewer() */
207: PetscCall(PetscViewerASCIIPopSynchronized(viewer));
208: } else if (mpjac && jac->ksp && mpjac->psubcomm) {
209: PetscCall(PetscViewerGetSubViewer(viewer, mpjac->psubcomm->child, &sviewer));
210: if (!mpjac->psubcomm->color) {
211: PetscCall(PetscViewerASCIIPushTab(sviewer));
212: PetscCall(KSPView(*jac->ksp, sviewer));
213: PetscCall(PetscViewerASCIIPopTab(sviewer));
214: }
215: PetscCall(PetscViewerRestoreSubViewer(viewer, mpjac->psubcomm->child, &sviewer));
216: /* extra call needed because of the two calls to PetscViewerASCIIPushSynchronized() in PetscViewerGetSubViewer() */
217: PetscCall(PetscViewerASCIIPopSynchronized(viewer));
218: }
219: } else {
220: PetscInt n_global;
221: PetscCall(MPIU_Allreduce(&jac->n_local, &n_global, 1, MPIU_INT, MPI_MAX, PetscObjectComm((PetscObject)pc)));
222: PetscCall(PetscViewerASCIIPushSynchronized(viewer));
223: PetscCall(PetscViewerASCIIPrintf(viewer, " Local solver information for each block is in the following KSP and PC objects:\n"));
224: PetscCall(PetscViewerASCIIPushTab(viewer));
225: PetscCall(PetscViewerGetSubViewer(viewer, PETSC_COMM_SELF, &sviewer));
226: PetscCall(PetscViewerASCIIPrintf(sviewer, "[%d] number of local blocks = %" PetscInt_FMT ", first local block number = %" PetscInt_FMT "\n", rank, jac->n_local, jac->first_local));
227: for (i = 0; i < jac->n_local; i++) {
228: PetscCall(PetscViewerASCIIPrintf(sviewer, "[%d] local block number %" PetscInt_FMT "\n", rank, i));
229: PetscCall(KSPView(jac->ksp[i], sviewer));
230: PetscCall(PetscViewerASCIIPrintf(sviewer, "- - - - - - - - - - - - - - - - - -\n"));
231: }
232: PetscCall(PetscViewerRestoreSubViewer(viewer, PETSC_COMM_SELF, &sviewer));
233: PetscCall(PetscViewerASCIIPopTab(viewer));
234: PetscCall(PetscViewerASCIIPopSynchronized(viewer));
235: }
236: } else if (isstring) {
237: PetscCall(PetscViewerStringSPrintf(viewer, " blks=%" PetscInt_FMT, jac->n));
238: PetscCall(PetscViewerGetSubViewer(viewer, PETSC_COMM_SELF, &sviewer));
239: if (jac->ksp) PetscCall(KSPView(jac->ksp[0], sviewer));
240: PetscCall(PetscViewerRestoreSubViewer(viewer, PETSC_COMM_SELF, &sviewer));
241: } else if (isdraw) {
242: PetscDraw draw;
243: char str[25];
244: PetscReal x, y, bottom, h;
246: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
247: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
248: PetscCall(PetscSNPrintf(str, 25, "Number blocks %" PetscInt_FMT, jac->n));
249: PetscCall(PetscDrawStringBoxed(draw, x, y, PETSC_DRAW_RED, PETSC_DRAW_BLACK, str, NULL, &h));
250: bottom = y - h;
251: PetscCall(PetscDrawPushCurrentPoint(draw, x, bottom));
252: /* warning the communicator on viewer is different then on ksp in parallel */
253: if (jac->ksp) PetscCall(KSPView(jac->ksp[0], viewer));
254: PetscCall(PetscDrawPopCurrentPoint(draw));
255: }
256: PetscFunctionReturn(PETSC_SUCCESS);
257: }
259: static PetscErrorCode PCBJacobiGetSubKSP_BJacobi(PC pc, PetscInt *n_local, PetscInt *first_local, KSP **ksp)
260: {
261: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
263: PetscFunctionBegin;
264: PetscCheck(pc->setupcalled, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call KSPSetUp() or PCSetUp() first");
266: if (n_local) *n_local = jac->n_local;
267: if (first_local) *first_local = jac->first_local;
268: if (ksp) *ksp = jac->ksp;
269: PetscFunctionReturn(PETSC_SUCCESS);
270: }
272: static PetscErrorCode PCBJacobiSetTotalBlocks_BJacobi(PC pc, PetscInt blocks, const PetscInt *lens)
273: {
274: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
276: PetscFunctionBegin;
277: PetscCheck(pc->setupcalled <= 0 || jac->n == blocks, PetscObjectComm((PetscObject)pc), PETSC_ERR_ORDER, "Cannot alter number of blocks after PCSetUp()/KSPSetUp() has been called");
278: jac->n = blocks;
279: if (!lens) jac->g_lens = NULL;
280: else {
281: PetscCall(PetscMalloc1(blocks, &jac->g_lens));
282: PetscCall(PetscArraycpy(jac->g_lens, lens, blocks));
283: }
284: PetscFunctionReturn(PETSC_SUCCESS);
285: }
287: static PetscErrorCode PCBJacobiGetTotalBlocks_BJacobi(PC pc, PetscInt *blocks, const PetscInt *lens[])
288: {
289: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
291: PetscFunctionBegin;
292: *blocks = jac->n;
293: if (lens) *lens = jac->g_lens;
294: PetscFunctionReturn(PETSC_SUCCESS);
295: }
297: static PetscErrorCode PCBJacobiSetLocalBlocks_BJacobi(PC pc, PetscInt blocks, const PetscInt lens[])
298: {
299: PC_BJacobi *jac;
301: PetscFunctionBegin;
302: jac = (PC_BJacobi *)pc->data;
304: jac->n_local = blocks;
305: if (!lens) jac->l_lens = NULL;
306: else {
307: PetscCall(PetscMalloc1(blocks, &jac->l_lens));
308: PetscCall(PetscArraycpy(jac->l_lens, lens, blocks));
309: }
310: PetscFunctionReturn(PETSC_SUCCESS);
311: }
313: static PetscErrorCode PCBJacobiGetLocalBlocks_BJacobi(PC pc, PetscInt *blocks, const PetscInt *lens[])
314: {
315: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
317: PetscFunctionBegin;
318: *blocks = jac->n_local;
319: if (lens) *lens = jac->l_lens;
320: PetscFunctionReturn(PETSC_SUCCESS);
321: }
323: /*@C
324: PCBJacobiGetSubKSP - Gets the local `KSP` contexts for all blocks on
325: this processor.
327: Not Collective
329: Input Parameter:
330: . pc - the preconditioner context
332: Output Parameters:
333: + n_local - the number of blocks on this processor, or NULL
334: . first_local - the global number of the first block on this processor, or NULL
335: - ksp - the array of KSP contexts
337: Notes:
338: After `PCBJacobiGetSubKSP()` the array of `KSP` contexts is not to be freed.
340: Currently for some matrix implementations only 1 block per processor
341: is supported.
343: You must call `KSPSetUp()` or `PCSetUp()` before calling `PCBJacobiGetSubKSP()`.
345: Fortran Notes:
346: You must pass in a `KSP` array that is large enough to contain all the local `KSP`s.
348: You can call `PCBJacobiGetSubKSP`(pc,nlocal,firstlocal,`PETSC_NULL_KSP`,ierr) to determine how large the
349: `KSP` array must be.
351: Level: advanced
353: .seealso: [](ch_ksp), `PCBJACOBI`, `PCASM`, `PCASMGetSubKSP()`
354: @*/
355: PetscErrorCode PCBJacobiGetSubKSP(PC pc, PetscInt *n_local, PetscInt *first_local, KSP *ksp[])
356: {
357: PetscFunctionBegin;
359: PetscUseMethod(pc, "PCBJacobiGetSubKSP_C", (PC, PetscInt *, PetscInt *, KSP **), (pc, n_local, first_local, ksp));
360: PetscFunctionReturn(PETSC_SUCCESS);
361: }
363: /*@
364: PCBJacobiSetTotalBlocks - Sets the global number of blocks for the block
365: Jacobi preconditioner.
367: Collective
369: Input Parameters:
370: + pc - the preconditioner context
371: . blocks - the number of blocks
372: - lens - [optional] integer array containing the size of each block
374: Options Database Key:
375: . -pc_bjacobi_blocks <blocks> - Sets the number of global blocks
377: Note:
378: Currently only a limited number of blocking configurations are supported.
379: All processors sharing the `PC` must call this routine with the same data.
381: Level: intermediate
383: .seealso: [](ch_ksp), `PCBJACOBI`, `PCSetUseAmat()`, `PCBJacobiSetLocalBlocks()`
384: @*/
385: PetscErrorCode PCBJacobiSetTotalBlocks(PC pc, PetscInt blocks, const PetscInt lens[])
386: {
387: PetscFunctionBegin;
389: PetscCheck(blocks > 0, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Must have positive blocks");
390: PetscTryMethod(pc, "PCBJacobiSetTotalBlocks_C", (PC, PetscInt, const PetscInt[]), (pc, blocks, lens));
391: PetscFunctionReturn(PETSC_SUCCESS);
392: }
394: /*@C
395: PCBJacobiGetTotalBlocks - Gets the global number of blocks for the block
396: Jacobi, `PCBJACOBI`, preconditioner.
398: Not Collective
400: Input Parameter:
401: . pc - the preconditioner context
403: Output Parameters:
404: + blocks - the number of blocks
405: - lens - integer array containing the size of each block
407: Level: intermediate
409: .seealso: [](ch_ksp), `PCBJACOBI`, `PCSetUseAmat()`, `PCBJacobiGetLocalBlocks()`
410: @*/
411: PetscErrorCode PCBJacobiGetTotalBlocks(PC pc, PetscInt *blocks, const PetscInt *lens[])
412: {
413: PetscFunctionBegin;
415: PetscAssertPointer(blocks, 2);
416: PetscUseMethod(pc, "PCBJacobiGetTotalBlocks_C", (PC, PetscInt *, const PetscInt *[]), (pc, blocks, lens));
417: PetscFunctionReturn(PETSC_SUCCESS);
418: }
420: /*@
421: PCBJacobiSetLocalBlocks - Sets the local number of blocks for the block
422: Jacobi, `PCBJACOBI`, preconditioner.
424: Not Collective
426: Input Parameters:
427: + pc - the preconditioner context
428: . blocks - the number of blocks
429: - lens - [optional] integer array containing size of each block
431: Options Database Key:
432: . -pc_bjacobi_local_blocks <blocks> - Sets the number of local blocks
434: Note:
435: Currently only a limited number of blocking configurations are supported.
437: Level: intermediate
439: .seealso: [](ch_ksp), `PCBJACOBI`, `PCSetUseAmat()`, `PCBJacobiSetTotalBlocks()`
440: @*/
441: PetscErrorCode PCBJacobiSetLocalBlocks(PC pc, PetscInt blocks, const PetscInt lens[])
442: {
443: PetscFunctionBegin;
445: PetscCheck(blocks >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Must have nonegative blocks");
446: PetscTryMethod(pc, "PCBJacobiSetLocalBlocks_C", (PC, PetscInt, const PetscInt[]), (pc, blocks, lens));
447: PetscFunctionReturn(PETSC_SUCCESS);
448: }
450: /*@C
451: PCBJacobiGetLocalBlocks - Gets the local number of blocks for the block
452: Jacobi, `PCBJACOBI`, preconditioner.
454: Not Collective
456: Input Parameters:
457: + pc - the preconditioner context
458: . blocks - the number of blocks
459: - lens - [optional] integer array containing size of each block
461: Note:
462: Currently only a limited number of blocking configurations are supported.
464: Level: intermediate
466: .seealso: [](ch_ksp), `PCBJACOBI`, `PCSetUseAmat()`, `PCBJacobiGetTotalBlocks()`
467: @*/
468: PetscErrorCode PCBJacobiGetLocalBlocks(PC pc, PetscInt *blocks, const PetscInt *lens[])
469: {
470: PetscFunctionBegin;
472: PetscAssertPointer(blocks, 2);
473: PetscUseMethod(pc, "PCBJacobiGetLocalBlocks_C", (PC, PetscInt *, const PetscInt *[]), (pc, blocks, lens));
474: PetscFunctionReturn(PETSC_SUCCESS);
475: }
477: /*MC
478: PCBJACOBI - Use block Jacobi preconditioning, each block is (approximately) solved with
479: its own `KSP` object.
481: Options Database Keys:
482: + -pc_use_amat - use Amat to apply block of operator in inner Krylov method
483: - -pc_bjacobi_blocks <n> - use n total blocks
485: Notes:
486: See `PCJACOBI` for diagonal Jacobi, `PCVPBJACOBI` for variable point block, and `PCPBJACOBI` for fixed size point block
488: Each processor can have one or more blocks, or a single block can be shared by several processes. Defaults to one block per processor.
490: To set options on the solvers for each block append -sub_ to all the `KSP` and `PC`
491: options database keys. For example, -sub_pc_type ilu -sub_pc_factor_levels 1 -sub_ksp_type preonly
493: To set the options on the solvers separate for each block call `PCBJacobiGetSubKSP()`
494: and set the options directly on the resulting `KSP` object (you can access its `PC`
495: `KSPGetPC()`)
497: For GPU-based vectors (`VECCUDA`, `VECViennaCL`) it is recommended to use exactly one block per MPI process for best
498: performance. Different block partitioning may lead to additional data transfers
499: between host and GPU that lead to degraded performance.
501: When multiple processes share a single block, each block encompasses exactly all the unknowns owned its set of processes.
503: Level: beginner
505: .seealso: [](ch_ksp), `PCCreate()`, `PCSetType()`, `PCType`, `PC`, `PCType`,
506: `PCASM`, `PCSetUseAmat()`, `PCGetUseAmat()`, `PCBJacobiGetSubKSP()`, `PCBJacobiSetTotalBlocks()`,
507: `PCBJacobiSetLocalBlocks()`, `PCSetModifySubMatrices()`, `PCJACOBI`, `PCVPBJACOBI`, `PCPBJACOBI`
508: M*/
510: PETSC_EXTERN PetscErrorCode PCCreate_BJacobi(PC pc)
511: {
512: PetscMPIInt rank;
513: PC_BJacobi *jac;
515: PetscFunctionBegin;
516: PetscCall(PetscNew(&jac));
517: PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)pc), &rank));
519: pc->ops->apply = NULL;
520: pc->ops->matapply = NULL;
521: pc->ops->applytranspose = NULL;
522: pc->ops->setup = PCSetUp_BJacobi;
523: pc->ops->destroy = PCDestroy_BJacobi;
524: pc->ops->setfromoptions = PCSetFromOptions_BJacobi;
525: pc->ops->view = PCView_BJacobi;
526: pc->ops->applyrichardson = NULL;
528: pc->data = (void *)jac;
529: jac->n = -1;
530: jac->n_local = -1;
531: jac->first_local = rank;
532: jac->ksp = NULL;
533: jac->g_lens = NULL;
534: jac->l_lens = NULL;
535: jac->psubcomm = NULL;
537: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJacobiGetSubKSP_C", PCBJacobiGetSubKSP_BJacobi));
538: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJacobiSetTotalBlocks_C", PCBJacobiSetTotalBlocks_BJacobi));
539: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJacobiGetTotalBlocks_C", PCBJacobiGetTotalBlocks_BJacobi));
540: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJacobiSetLocalBlocks_C", PCBJacobiSetLocalBlocks_BJacobi));
541: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJacobiGetLocalBlocks_C", PCBJacobiGetLocalBlocks_BJacobi));
542: PetscFunctionReturn(PETSC_SUCCESS);
543: }
545: /*
546: These are for a single block per processor; works for AIJ, BAIJ; Seq and MPI
547: */
548: static PetscErrorCode PCReset_BJacobi_Singleblock(PC pc)
549: {
550: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
551: PC_BJacobi_Singleblock *bjac = (PC_BJacobi_Singleblock *)jac->data;
553: PetscFunctionBegin;
554: PetscCall(KSPReset(jac->ksp[0]));
555: PetscCall(VecDestroy(&bjac->x));
556: PetscCall(VecDestroy(&bjac->y));
557: PetscFunctionReturn(PETSC_SUCCESS);
558: }
560: static PetscErrorCode PCDestroy_BJacobi_Singleblock(PC pc)
561: {
562: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
563: PC_BJacobi_Singleblock *bjac = (PC_BJacobi_Singleblock *)jac->data;
565: PetscFunctionBegin;
566: PetscCall(PCReset_BJacobi_Singleblock(pc));
567: PetscCall(KSPDestroy(&jac->ksp[0]));
568: PetscCall(PetscFree(jac->ksp));
569: PetscCall(PetscFree(bjac));
570: PetscCall(PCDestroy_BJacobi(pc));
571: PetscFunctionReturn(PETSC_SUCCESS);
572: }
574: static PetscErrorCode PCSetUpOnBlocks_BJacobi_Singleblock(PC pc)
575: {
576: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
577: KSP subksp = jac->ksp[0];
578: KSPConvergedReason reason;
580: PetscFunctionBegin;
581: PetscCall(KSPSetUp(subksp));
582: PetscCall(KSPGetConvergedReason(subksp, &reason));
583: if (reason == KSP_DIVERGED_PC_FAILED) pc->failedreason = PC_SUBPC_ERROR;
584: PetscFunctionReturn(PETSC_SUCCESS);
585: }
587: static PetscErrorCode PCApply_BJacobi_Singleblock(PC pc, Vec x, Vec y)
588: {
589: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
590: PC_BJacobi_Singleblock *bjac = (PC_BJacobi_Singleblock *)jac->data;
592: PetscFunctionBegin;
593: PetscCall(VecGetLocalVectorRead(x, bjac->x));
594: PetscCall(VecGetLocalVector(y, bjac->y));
595: /* Since the inner KSP matrix may point directly to the diagonal block of an MPI matrix the inner
596: matrix may change even if the outer KSP/PC has not updated the preconditioner, this will trigger a rebuild
597: of the inner preconditioner automatically unless we pass down the outer preconditioners reuse flag.*/
598: PetscCall(KSPSetReusePreconditioner(jac->ksp[0], pc->reusepreconditioner));
599: PetscCall(KSPSolve(jac->ksp[0], bjac->x, bjac->y));
600: PetscCall(KSPCheckSolve(jac->ksp[0], pc, bjac->y));
601: PetscCall(VecRestoreLocalVectorRead(x, bjac->x));
602: PetscCall(VecRestoreLocalVector(y, bjac->y));
603: PetscFunctionReturn(PETSC_SUCCESS);
604: }
606: static PetscErrorCode PCMatApply_BJacobi_Singleblock(PC pc, Mat X, Mat Y)
607: {
608: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
609: Mat sX, sY;
611: PetscFunctionBegin;
612: /* Since the inner KSP matrix may point directly to the diagonal block of an MPI matrix the inner
613: matrix may change even if the outer KSP/PC has not updated the preconditioner, this will trigger a rebuild
614: of the inner preconditioner automatically unless we pass down the outer preconditioners reuse flag.*/
615: PetscCall(KSPSetReusePreconditioner(jac->ksp[0], pc->reusepreconditioner));
616: PetscCall(MatDenseGetLocalMatrix(X, &sX));
617: PetscCall(MatDenseGetLocalMatrix(Y, &sY));
618: PetscCall(KSPMatSolve(jac->ksp[0], sX, sY));
619: PetscFunctionReturn(PETSC_SUCCESS);
620: }
622: static PetscErrorCode PCApplySymmetricLeft_BJacobi_Singleblock(PC pc, Vec x, Vec y)
623: {
624: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
625: PC_BJacobi_Singleblock *bjac = (PC_BJacobi_Singleblock *)jac->data;
626: PetscScalar *y_array;
627: const PetscScalar *x_array;
628: PC subpc;
630: PetscFunctionBegin;
631: /*
632: The VecPlaceArray() is to avoid having to copy the
633: y vector into the bjac->x vector. The reason for
634: the bjac->x vector is that we need a sequential vector
635: for the sequential solve.
636: */
637: PetscCall(VecGetArrayRead(x, &x_array));
638: PetscCall(VecGetArray(y, &y_array));
639: PetscCall(VecPlaceArray(bjac->x, x_array));
640: PetscCall(VecPlaceArray(bjac->y, y_array));
641: /* apply the symmetric left portion of the inner PC operator */
642: /* note this by-passes the inner KSP and its options completely */
643: PetscCall(KSPGetPC(jac->ksp[0], &subpc));
644: PetscCall(PCApplySymmetricLeft(subpc, bjac->x, bjac->y));
645: PetscCall(VecResetArray(bjac->x));
646: PetscCall(VecResetArray(bjac->y));
647: PetscCall(VecRestoreArrayRead(x, &x_array));
648: PetscCall(VecRestoreArray(y, &y_array));
649: PetscFunctionReturn(PETSC_SUCCESS);
650: }
652: static PetscErrorCode PCApplySymmetricRight_BJacobi_Singleblock(PC pc, Vec x, Vec y)
653: {
654: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
655: PC_BJacobi_Singleblock *bjac = (PC_BJacobi_Singleblock *)jac->data;
656: PetscScalar *y_array;
657: const PetscScalar *x_array;
658: PC subpc;
660: PetscFunctionBegin;
661: /*
662: The VecPlaceArray() is to avoid having to copy the
663: y vector into the bjac->x vector. The reason for
664: the bjac->x vector is that we need a sequential vector
665: for the sequential solve.
666: */
667: PetscCall(VecGetArrayRead(x, &x_array));
668: PetscCall(VecGetArray(y, &y_array));
669: PetscCall(VecPlaceArray(bjac->x, x_array));
670: PetscCall(VecPlaceArray(bjac->y, y_array));
672: /* apply the symmetric right portion of the inner PC operator */
673: /* note this by-passes the inner KSP and its options completely */
675: PetscCall(KSPGetPC(jac->ksp[0], &subpc));
676: PetscCall(PCApplySymmetricRight(subpc, bjac->x, bjac->y));
678: PetscCall(VecResetArray(bjac->x));
679: PetscCall(VecResetArray(bjac->y));
680: PetscCall(VecRestoreArrayRead(x, &x_array));
681: PetscCall(VecRestoreArray(y, &y_array));
682: PetscFunctionReturn(PETSC_SUCCESS);
683: }
685: static PetscErrorCode PCApplyTranspose_BJacobi_Singleblock(PC pc, Vec x, Vec y)
686: {
687: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
688: PC_BJacobi_Singleblock *bjac = (PC_BJacobi_Singleblock *)jac->data;
689: PetscScalar *y_array;
690: const PetscScalar *x_array;
692: PetscFunctionBegin;
693: /*
694: The VecPlaceArray() is to avoid having to copy the
695: y vector into the bjac->x vector. The reason for
696: the bjac->x vector is that we need a sequential vector
697: for the sequential solve.
698: */
699: PetscCall(VecGetArrayRead(x, &x_array));
700: PetscCall(VecGetArray(y, &y_array));
701: PetscCall(VecPlaceArray(bjac->x, x_array));
702: PetscCall(VecPlaceArray(bjac->y, y_array));
703: PetscCall(KSPSolveTranspose(jac->ksp[0], bjac->x, bjac->y));
704: PetscCall(KSPCheckSolve(jac->ksp[0], pc, bjac->y));
705: PetscCall(VecResetArray(bjac->x));
706: PetscCall(VecResetArray(bjac->y));
707: PetscCall(VecRestoreArrayRead(x, &x_array));
708: PetscCall(VecRestoreArray(y, &y_array));
709: PetscFunctionReturn(PETSC_SUCCESS);
710: }
712: static PetscErrorCode PCSetUp_BJacobi_Singleblock(PC pc, Mat mat, Mat pmat)
713: {
714: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
715: PetscInt m;
716: KSP ksp;
717: PC_BJacobi_Singleblock *bjac;
718: PetscBool wasSetup = PETSC_TRUE;
719: VecType vectype;
720: const char *prefix;
722: PetscFunctionBegin;
723: if (!pc->setupcalled) {
724: if (!jac->ksp) {
725: PetscInt nestlevel;
727: wasSetup = PETSC_FALSE;
729: PetscCall(KSPCreate(PETSC_COMM_SELF, &ksp));
730: PetscCall(PCGetKSPNestLevel(pc, &nestlevel));
731: PetscCall(KSPSetNestLevel(ksp, nestlevel + 1));
732: PetscCall(KSPSetErrorIfNotConverged(ksp, pc->erroriffailure));
733: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ksp, (PetscObject)pc, 1));
734: PetscCall(KSPSetType(ksp, KSPPREONLY));
735: PetscCall(PCGetOptionsPrefix(pc, &prefix));
736: PetscCall(KSPSetOptionsPrefix(ksp, prefix));
737: PetscCall(KSPAppendOptionsPrefix(ksp, "sub_"));
739: pc->ops->reset = PCReset_BJacobi_Singleblock;
740: pc->ops->destroy = PCDestroy_BJacobi_Singleblock;
741: pc->ops->apply = PCApply_BJacobi_Singleblock;
742: pc->ops->matapply = PCMatApply_BJacobi_Singleblock;
743: pc->ops->applysymmetricleft = PCApplySymmetricLeft_BJacobi_Singleblock;
744: pc->ops->applysymmetricright = PCApplySymmetricRight_BJacobi_Singleblock;
745: pc->ops->applytranspose = PCApplyTranspose_BJacobi_Singleblock;
746: pc->ops->setuponblocks = PCSetUpOnBlocks_BJacobi_Singleblock;
748: PetscCall(PetscMalloc1(1, &jac->ksp));
749: jac->ksp[0] = ksp;
751: PetscCall(PetscNew(&bjac));
752: jac->data = (void *)bjac;
753: } else {
754: ksp = jac->ksp[0];
755: bjac = (PC_BJacobi_Singleblock *)jac->data;
756: }
758: /*
759: The reason we need to generate these vectors is to serve
760: as the right-hand side and solution vector for the solve on the
761: block. We do not need to allocate space for the vectors since
762: that is provided via VecPlaceArray() just before the call to
763: KSPSolve() on the block.
764: */
765: PetscCall(MatGetSize(pmat, &m, &m));
766: PetscCall(VecCreateSeqWithArray(PETSC_COMM_SELF, 1, m, NULL, &bjac->x));
767: PetscCall(VecCreateSeqWithArray(PETSC_COMM_SELF, 1, m, NULL, &bjac->y));
768: PetscCall(MatGetVecType(pmat, &vectype));
769: PetscCall(VecSetType(bjac->x, vectype));
770: PetscCall(VecSetType(bjac->y, vectype));
771: } else {
772: ksp = jac->ksp[0];
773: bjac = (PC_BJacobi_Singleblock *)jac->data;
774: }
775: PetscCall(KSPGetOptionsPrefix(ksp, &prefix));
776: if (pc->useAmat) {
777: PetscCall(KSPSetOperators(ksp, mat, pmat));
778: PetscCall(MatSetOptionsPrefix(mat, prefix));
779: } else {
780: PetscCall(KSPSetOperators(ksp, pmat, pmat));
781: }
782: PetscCall(MatSetOptionsPrefix(pmat, prefix));
783: if (!wasSetup && pc->setfromoptionscalled) {
784: /* If PCSetFromOptions_BJacobi is called later, KSPSetFromOptions will be called at that time. */
785: PetscCall(KSPSetFromOptions(ksp));
786: }
787: PetscFunctionReturn(PETSC_SUCCESS);
788: }
790: static PetscErrorCode PCReset_BJacobi_Multiblock(PC pc)
791: {
792: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
793: PC_BJacobi_Multiblock *bjac = (PC_BJacobi_Multiblock *)jac->data;
794: PetscInt i;
796: PetscFunctionBegin;
797: if (bjac && bjac->pmat) {
798: PetscCall(MatDestroyMatrices(jac->n_local, &bjac->pmat));
799: if (pc->useAmat) PetscCall(MatDestroyMatrices(jac->n_local, &bjac->mat));
800: }
802: for (i = 0; i < jac->n_local; i++) {
803: PetscCall(KSPReset(jac->ksp[i]));
804: if (bjac && bjac->x) {
805: PetscCall(VecDestroy(&bjac->x[i]));
806: PetscCall(VecDestroy(&bjac->y[i]));
807: PetscCall(ISDestroy(&bjac->is[i]));
808: }
809: }
810: PetscCall(PetscFree(jac->l_lens));
811: PetscCall(PetscFree(jac->g_lens));
812: PetscFunctionReturn(PETSC_SUCCESS);
813: }
815: static PetscErrorCode PCDestroy_BJacobi_Multiblock(PC pc)
816: {
817: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
818: PC_BJacobi_Multiblock *bjac = (PC_BJacobi_Multiblock *)jac->data;
819: PetscInt i;
821: PetscFunctionBegin;
822: PetscCall(PCReset_BJacobi_Multiblock(pc));
823: if (bjac) {
824: PetscCall(PetscFree2(bjac->x, bjac->y));
825: PetscCall(PetscFree(bjac->starts));
826: PetscCall(PetscFree(bjac->is));
827: }
828: PetscCall(PetscFree(jac->data));
829: for (i = 0; i < jac->n_local; i++) PetscCall(KSPDestroy(&jac->ksp[i]));
830: PetscCall(PetscFree(jac->ksp));
831: PetscCall(PCDestroy_BJacobi(pc));
832: PetscFunctionReturn(PETSC_SUCCESS);
833: }
835: static PetscErrorCode PCSetUpOnBlocks_BJacobi_Multiblock(PC pc)
836: {
837: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
838: PetscInt i, n_local = jac->n_local;
839: KSPConvergedReason reason;
841: PetscFunctionBegin;
842: for (i = 0; i < n_local; i++) {
843: PetscCall(KSPSetUp(jac->ksp[i]));
844: PetscCall(KSPGetConvergedReason(jac->ksp[i], &reason));
845: if (reason == KSP_DIVERGED_PC_FAILED) pc->failedreason = PC_SUBPC_ERROR;
846: }
847: PetscFunctionReturn(PETSC_SUCCESS);
848: }
850: static PetscErrorCode PCApply_BJacobi_Multiblock(PC pc, Vec x, Vec y)
851: {
852: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
853: PetscInt i, n_local = jac->n_local;
854: PC_BJacobi_Multiblock *bjac = (PC_BJacobi_Multiblock *)jac->data;
855: PetscScalar *yin;
856: const PetscScalar *xin;
858: PetscFunctionBegin;
859: PetscCall(VecGetArrayRead(x, &xin));
860: PetscCall(VecGetArray(y, &yin));
861: for (i = 0; i < n_local; i++) {
862: /*
863: To avoid copying the subvector from x into a workspace we instead
864: make the workspace vector array point to the subpart of the array of
865: the global vector.
866: */
867: PetscCall(VecPlaceArray(bjac->x[i], xin + bjac->starts[i]));
868: PetscCall(VecPlaceArray(bjac->y[i], yin + bjac->starts[i]));
870: PetscCall(PetscLogEventBegin(PC_ApplyOnBlocks, jac->ksp[i], bjac->x[i], bjac->y[i], 0));
871: PetscCall(KSPSolve(jac->ksp[i], bjac->x[i], bjac->y[i]));
872: PetscCall(KSPCheckSolve(jac->ksp[i], pc, bjac->y[i]));
873: PetscCall(PetscLogEventEnd(PC_ApplyOnBlocks, jac->ksp[i], bjac->x[i], bjac->y[i], 0));
875: PetscCall(VecResetArray(bjac->x[i]));
876: PetscCall(VecResetArray(bjac->y[i]));
877: }
878: PetscCall(VecRestoreArrayRead(x, &xin));
879: PetscCall(VecRestoreArray(y, &yin));
880: PetscFunctionReturn(PETSC_SUCCESS);
881: }
883: static PetscErrorCode PCApplySymmetricLeft_BJacobi_Multiblock(PC pc, Vec x, Vec y)
884: {
885: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
886: PetscInt i, n_local = jac->n_local;
887: PC_BJacobi_Multiblock *bjac = (PC_BJacobi_Multiblock *)jac->data;
888: PetscScalar *yin;
889: const PetscScalar *xin;
890: PC subpc;
892: PetscFunctionBegin;
893: PetscCall(VecGetArrayRead(x, &xin));
894: PetscCall(VecGetArray(y, &yin));
895: for (i = 0; i < n_local; i++) {
896: /*
897: To avoid copying the subvector from x into a workspace we instead
898: make the workspace vector array point to the subpart of the array of
899: the global vector.
900: */
901: PetscCall(VecPlaceArray(bjac->x[i], xin + bjac->starts[i]));
902: PetscCall(VecPlaceArray(bjac->y[i], yin + bjac->starts[i]));
904: PetscCall(PetscLogEventBegin(PC_ApplyOnBlocks, jac->ksp[i], bjac->x[i], bjac->y[i], 0));
905: /* apply the symmetric left portion of the inner PC operator */
906: /* note this by-passes the inner KSP and its options completely */
907: PetscCall(KSPGetPC(jac->ksp[i], &subpc));
908: PetscCall(PCApplySymmetricLeft(subpc, bjac->x[i], bjac->y[i]));
909: PetscCall(PetscLogEventEnd(PC_ApplyOnBlocks, jac->ksp[i], bjac->x[i], bjac->y[i], 0));
911: PetscCall(VecResetArray(bjac->x[i]));
912: PetscCall(VecResetArray(bjac->y[i]));
913: }
914: PetscCall(VecRestoreArrayRead(x, &xin));
915: PetscCall(VecRestoreArray(y, &yin));
916: PetscFunctionReturn(PETSC_SUCCESS);
917: }
919: static PetscErrorCode PCApplySymmetricRight_BJacobi_Multiblock(PC pc, Vec x, Vec y)
920: {
921: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
922: PetscInt i, n_local = jac->n_local;
923: PC_BJacobi_Multiblock *bjac = (PC_BJacobi_Multiblock *)jac->data;
924: PetscScalar *yin;
925: const PetscScalar *xin;
926: PC subpc;
928: PetscFunctionBegin;
929: PetscCall(VecGetArrayRead(x, &xin));
930: PetscCall(VecGetArray(y, &yin));
931: for (i = 0; i < n_local; i++) {
932: /*
933: To avoid copying the subvector from x into a workspace we instead
934: make the workspace vector array point to the subpart of the array of
935: the global vector.
936: */
937: PetscCall(VecPlaceArray(bjac->x[i], xin + bjac->starts[i]));
938: PetscCall(VecPlaceArray(bjac->y[i], yin + bjac->starts[i]));
940: PetscCall(PetscLogEventBegin(PC_ApplyOnBlocks, jac->ksp[i], bjac->x[i], bjac->y[i], 0));
941: /* apply the symmetric left portion of the inner PC operator */
942: /* note this by-passes the inner KSP and its options completely */
943: PetscCall(KSPGetPC(jac->ksp[i], &subpc));
944: PetscCall(PCApplySymmetricRight(subpc, bjac->x[i], bjac->y[i]));
945: PetscCall(PetscLogEventEnd(PC_ApplyOnBlocks, jac->ksp[i], bjac->x[i], bjac->y[i], 0));
947: PetscCall(VecResetArray(bjac->x[i]));
948: PetscCall(VecResetArray(bjac->y[i]));
949: }
950: PetscCall(VecRestoreArrayRead(x, &xin));
951: PetscCall(VecRestoreArray(y, &yin));
952: PetscFunctionReturn(PETSC_SUCCESS);
953: }
955: static PetscErrorCode PCApplyTranspose_BJacobi_Multiblock(PC pc, Vec x, Vec y)
956: {
957: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
958: PetscInt i, n_local = jac->n_local;
959: PC_BJacobi_Multiblock *bjac = (PC_BJacobi_Multiblock *)jac->data;
960: PetscScalar *yin;
961: const PetscScalar *xin;
963: PetscFunctionBegin;
964: PetscCall(VecGetArrayRead(x, &xin));
965: PetscCall(VecGetArray(y, &yin));
966: for (i = 0; i < n_local; i++) {
967: /*
968: To avoid copying the subvector from x into a workspace we instead
969: make the workspace vector array point to the subpart of the array of
970: the global vector.
971: */
972: PetscCall(VecPlaceArray(bjac->x[i], xin + bjac->starts[i]));
973: PetscCall(VecPlaceArray(bjac->y[i], yin + bjac->starts[i]));
975: PetscCall(PetscLogEventBegin(PC_ApplyTransposeOnBlocks, jac->ksp[i], bjac->x[i], bjac->y[i], 0));
976: PetscCall(KSPSolveTranspose(jac->ksp[i], bjac->x[i], bjac->y[i]));
977: PetscCall(KSPCheckSolve(jac->ksp[i], pc, bjac->y[i]));
978: PetscCall(PetscLogEventEnd(PC_ApplyTransposeOnBlocks, jac->ksp[i], bjac->x[i], bjac->y[i], 0));
980: PetscCall(VecResetArray(bjac->x[i]));
981: PetscCall(VecResetArray(bjac->y[i]));
982: }
983: PetscCall(VecRestoreArrayRead(x, &xin));
984: PetscCall(VecRestoreArray(y, &yin));
985: PetscFunctionReturn(PETSC_SUCCESS);
986: }
988: static PetscErrorCode PCSetUp_BJacobi_Multiblock(PC pc, Mat mat, Mat pmat)
989: {
990: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
991: PetscInt m, n_local, N, M, start, i;
992: const char *prefix;
993: KSP ksp;
994: Vec x, y;
995: PC_BJacobi_Multiblock *bjac = (PC_BJacobi_Multiblock *)jac->data;
996: PC subpc;
997: IS is;
998: MatReuse scall;
999: VecType vectype;
1000: MatNullSpace *nullsp_mat = NULL, *nullsp_pmat = NULL;
1002: PetscFunctionBegin;
1003: PetscCall(MatGetLocalSize(pc->pmat, &M, &N));
1005: n_local = jac->n_local;
1007: if (pc->useAmat) {
1008: PetscBool same;
1009: PetscCall(PetscObjectTypeCompare((PetscObject)mat, ((PetscObject)pmat)->type_name, &same));
1010: PetscCheck(same, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_INCOMP, "Matrices not of same type");
1011: }
1013: if (!pc->setupcalled) {
1014: PetscInt nestlevel;
1016: scall = MAT_INITIAL_MATRIX;
1018: if (!jac->ksp) {
1019: pc->ops->reset = PCReset_BJacobi_Multiblock;
1020: pc->ops->destroy = PCDestroy_BJacobi_Multiblock;
1021: pc->ops->apply = PCApply_BJacobi_Multiblock;
1022: pc->ops->matapply = NULL;
1023: pc->ops->applysymmetricleft = PCApplySymmetricLeft_BJacobi_Multiblock;
1024: pc->ops->applysymmetricright = PCApplySymmetricRight_BJacobi_Multiblock;
1025: pc->ops->applytranspose = PCApplyTranspose_BJacobi_Multiblock;
1026: pc->ops->setuponblocks = PCSetUpOnBlocks_BJacobi_Multiblock;
1028: PetscCall(PetscNew(&bjac));
1029: PetscCall(PetscMalloc1(n_local, &jac->ksp));
1030: PetscCall(PetscMalloc2(n_local, &bjac->x, n_local, &bjac->y));
1031: PetscCall(PetscMalloc1(n_local, &bjac->starts));
1033: jac->data = (void *)bjac;
1034: PetscCall(PetscMalloc1(n_local, &bjac->is));
1036: for (i = 0; i < n_local; i++) {
1037: PetscCall(KSPCreate(PETSC_COMM_SELF, &ksp));
1038: PetscCall(PCGetKSPNestLevel(pc, &nestlevel));
1039: PetscCall(KSPSetNestLevel(ksp, nestlevel + 1));
1040: PetscCall(KSPSetErrorIfNotConverged(ksp, pc->erroriffailure));
1041: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ksp, (PetscObject)pc, 1));
1042: PetscCall(KSPSetType(ksp, KSPPREONLY));
1043: PetscCall(KSPGetPC(ksp, &subpc));
1044: PetscCall(PCGetOptionsPrefix(pc, &prefix));
1045: PetscCall(KSPSetOptionsPrefix(ksp, prefix));
1046: PetscCall(KSPAppendOptionsPrefix(ksp, "sub_"));
1048: jac->ksp[i] = ksp;
1049: }
1050: } else {
1051: bjac = (PC_BJacobi_Multiblock *)jac->data;
1052: }
1054: start = 0;
1055: PetscCall(MatGetVecType(pmat, &vectype));
1056: for (i = 0; i < n_local; i++) {
1057: m = jac->l_lens[i];
1058: /*
1059: The reason we need to generate these vectors is to serve
1060: as the right-hand side and solution vector for the solve on the
1061: block. We do not need to allocate space for the vectors since
1062: that is provided via VecPlaceArray() just before the call to
1063: KSPSolve() on the block.
1065: */
1066: PetscCall(VecCreateSeq(PETSC_COMM_SELF, m, &x));
1067: PetscCall(VecCreateSeqWithArray(PETSC_COMM_SELF, 1, m, NULL, &y));
1068: PetscCall(VecSetType(x, vectype));
1069: PetscCall(VecSetType(y, vectype));
1071: bjac->x[i] = x;
1072: bjac->y[i] = y;
1073: bjac->starts[i] = start;
1075: PetscCall(ISCreateStride(PETSC_COMM_SELF, m, start, 1, &is));
1076: bjac->is[i] = is;
1078: start += m;
1079: }
1080: } else {
1081: bjac = (PC_BJacobi_Multiblock *)jac->data;
1082: /*
1083: Destroy the blocks from the previous iteration
1084: */
1085: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
1086: PetscCall(MatGetNullSpaces(n_local, bjac->pmat, &nullsp_pmat));
1087: PetscCall(MatDestroyMatrices(n_local, &bjac->pmat));
1088: if (pc->useAmat) {
1089: PetscCall(MatGetNullSpaces(n_local, bjac->mat, &nullsp_mat));
1090: PetscCall(MatDestroyMatrices(n_local, &bjac->mat));
1091: }
1092: scall = MAT_INITIAL_MATRIX;
1093: } else scall = MAT_REUSE_MATRIX;
1094: }
1096: PetscCall(MatCreateSubMatrices(pmat, n_local, bjac->is, bjac->is, scall, &bjac->pmat));
1097: if (nullsp_pmat) PetscCall(MatRestoreNullSpaces(n_local, bjac->pmat, &nullsp_pmat));
1098: if (pc->useAmat) {
1099: PetscCall(MatCreateSubMatrices(mat, n_local, bjac->is, bjac->is, scall, &bjac->mat));
1100: if (nullsp_mat) PetscCall(MatRestoreNullSpaces(n_local, bjac->mat, &nullsp_mat));
1101: }
1102: /* Return control to the user so that the submatrices can be modified (e.g., to apply
1103: different boundary conditions for the submatrices than for the global problem) */
1104: PetscCall(PCModifySubMatrices(pc, n_local, bjac->is, bjac->is, bjac->pmat, pc->modifysubmatricesP));
1106: for (i = 0; i < n_local; i++) {
1107: PetscCall(KSPGetOptionsPrefix(jac->ksp[i], &prefix));
1108: if (pc->useAmat) {
1109: PetscCall(KSPSetOperators(jac->ksp[i], bjac->mat[i], bjac->pmat[i]));
1110: PetscCall(MatSetOptionsPrefix(bjac->mat[i], prefix));
1111: } else {
1112: PetscCall(KSPSetOperators(jac->ksp[i], bjac->pmat[i], bjac->pmat[i]));
1113: }
1114: PetscCall(MatSetOptionsPrefix(bjac->pmat[i], prefix));
1115: if (pc->setfromoptionscalled) PetscCall(KSPSetFromOptions(jac->ksp[i]));
1116: }
1117: PetscFunctionReturn(PETSC_SUCCESS);
1118: }
1120: /*
1121: These are for a single block with multiple processes
1122: */
1123: static PetscErrorCode PCSetUpOnBlocks_BJacobi_Multiproc(PC pc)
1124: {
1125: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
1126: KSP subksp = jac->ksp[0];
1127: KSPConvergedReason reason;
1129: PetscFunctionBegin;
1130: PetscCall(KSPSetUp(subksp));
1131: PetscCall(KSPGetConvergedReason(subksp, &reason));
1132: if (reason == KSP_DIVERGED_PC_FAILED) pc->failedreason = PC_SUBPC_ERROR;
1133: PetscFunctionReturn(PETSC_SUCCESS);
1134: }
1136: static PetscErrorCode PCReset_BJacobi_Multiproc(PC pc)
1137: {
1138: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
1139: PC_BJacobi_Multiproc *mpjac = (PC_BJacobi_Multiproc *)jac->data;
1141: PetscFunctionBegin;
1142: PetscCall(VecDestroy(&mpjac->ysub));
1143: PetscCall(VecDestroy(&mpjac->xsub));
1144: PetscCall(MatDestroy(&mpjac->submats));
1145: if (jac->ksp) PetscCall(KSPReset(jac->ksp[0]));
1146: PetscFunctionReturn(PETSC_SUCCESS);
1147: }
1149: static PetscErrorCode PCDestroy_BJacobi_Multiproc(PC pc)
1150: {
1151: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
1152: PC_BJacobi_Multiproc *mpjac = (PC_BJacobi_Multiproc *)jac->data;
1154: PetscFunctionBegin;
1155: PetscCall(PCReset_BJacobi_Multiproc(pc));
1156: PetscCall(KSPDestroy(&jac->ksp[0]));
1157: PetscCall(PetscFree(jac->ksp));
1158: PetscCall(PetscSubcommDestroy(&mpjac->psubcomm));
1160: PetscCall(PetscFree(mpjac));
1161: PetscCall(PCDestroy_BJacobi(pc));
1162: PetscFunctionReturn(PETSC_SUCCESS);
1163: }
1165: static PetscErrorCode PCApply_BJacobi_Multiproc(PC pc, Vec x, Vec y)
1166: {
1167: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
1168: PC_BJacobi_Multiproc *mpjac = (PC_BJacobi_Multiproc *)jac->data;
1169: PetscScalar *yarray;
1170: const PetscScalar *xarray;
1171: KSPConvergedReason reason;
1173: PetscFunctionBegin;
1174: /* place x's and y's local arrays into xsub and ysub */
1175: PetscCall(VecGetArrayRead(x, &xarray));
1176: PetscCall(VecGetArray(y, &yarray));
1177: PetscCall(VecPlaceArray(mpjac->xsub, xarray));
1178: PetscCall(VecPlaceArray(mpjac->ysub, yarray));
1180: /* apply preconditioner on each matrix block */
1181: PetscCall(PetscLogEventBegin(PC_ApplyOnBlocks, jac->ksp[0], mpjac->xsub, mpjac->ysub, 0));
1182: PetscCall(KSPSolve(jac->ksp[0], mpjac->xsub, mpjac->ysub));
1183: PetscCall(KSPCheckSolve(jac->ksp[0], pc, mpjac->ysub));
1184: PetscCall(PetscLogEventEnd(PC_ApplyOnBlocks, jac->ksp[0], mpjac->xsub, mpjac->ysub, 0));
1185: PetscCall(KSPGetConvergedReason(jac->ksp[0], &reason));
1186: if (reason == KSP_DIVERGED_PC_FAILED) pc->failedreason = PC_SUBPC_ERROR;
1188: PetscCall(VecResetArray(mpjac->xsub));
1189: PetscCall(VecResetArray(mpjac->ysub));
1190: PetscCall(VecRestoreArrayRead(x, &xarray));
1191: PetscCall(VecRestoreArray(y, &yarray));
1192: PetscFunctionReturn(PETSC_SUCCESS);
1193: }
1195: static PetscErrorCode PCMatApply_BJacobi_Multiproc(PC pc, Mat X, Mat Y)
1196: {
1197: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
1198: KSPConvergedReason reason;
1199: Mat sX, sY;
1200: const PetscScalar *x;
1201: PetscScalar *y;
1202: PetscInt m, N, lda, ldb;
1204: PetscFunctionBegin;
1205: /* apply preconditioner on each matrix block */
1206: PetscCall(MatGetLocalSize(X, &m, NULL));
1207: PetscCall(MatGetSize(X, NULL, &N));
1208: PetscCall(MatDenseGetLDA(X, &lda));
1209: PetscCall(MatDenseGetLDA(Y, &ldb));
1210: PetscCall(MatDenseGetArrayRead(X, &x));
1211: PetscCall(MatDenseGetArrayWrite(Y, &y));
1212: PetscCall(MatCreateDense(PetscObjectComm((PetscObject)jac->ksp[0]), m, PETSC_DECIDE, PETSC_DECIDE, N, (PetscScalar *)x, &sX));
1213: PetscCall(MatCreateDense(PetscObjectComm((PetscObject)jac->ksp[0]), m, PETSC_DECIDE, PETSC_DECIDE, N, y, &sY));
1214: PetscCall(MatDenseSetLDA(sX, lda));
1215: PetscCall(MatDenseSetLDA(sY, ldb));
1216: PetscCall(PetscLogEventBegin(PC_ApplyOnBlocks, jac->ksp[0], X, Y, 0));
1217: PetscCall(KSPMatSolve(jac->ksp[0], sX, sY));
1218: PetscCall(KSPCheckSolve(jac->ksp[0], pc, NULL));
1219: PetscCall(PetscLogEventEnd(PC_ApplyOnBlocks, jac->ksp[0], X, Y, 0));
1220: PetscCall(MatDestroy(&sY));
1221: PetscCall(MatDestroy(&sX));
1222: PetscCall(MatDenseRestoreArrayWrite(Y, &y));
1223: PetscCall(MatDenseRestoreArrayRead(X, &x));
1224: PetscCall(KSPGetConvergedReason(jac->ksp[0], &reason));
1225: if (reason == KSP_DIVERGED_PC_FAILED) pc->failedreason = PC_SUBPC_ERROR;
1226: PetscFunctionReturn(PETSC_SUCCESS);
1227: }
1229: static PetscErrorCode PCSetUp_BJacobi_Multiproc(PC pc)
1230: {
1231: PC_BJacobi *jac = (PC_BJacobi *)pc->data;
1232: PC_BJacobi_Multiproc *mpjac = (PC_BJacobi_Multiproc *)jac->data;
1233: PetscInt m, n;
1234: MPI_Comm comm, subcomm = 0;
1235: const char *prefix;
1236: PetscBool wasSetup = PETSC_TRUE;
1237: VecType vectype;
1239: PetscFunctionBegin;
1240: PetscCall(PetscObjectGetComm((PetscObject)pc, &comm));
1241: PetscCheck(jac->n_local <= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Only a single block in a subcommunicator is supported");
1242: jac->n_local = 1; /* currently only a single block is supported for a subcommunicator */
1243: if (!pc->setupcalled) {
1244: PetscInt nestlevel;
1246: wasSetup = PETSC_FALSE;
1247: PetscCall(PetscNew(&mpjac));
1248: jac->data = (void *)mpjac;
1250: /* initialize datastructure mpjac */
1251: if (!jac->psubcomm) {
1252: /* Create default contiguous subcommunicatiors if user does not provide them */
1253: PetscCall(PetscSubcommCreate(comm, &jac->psubcomm));
1254: PetscCall(PetscSubcommSetNumber(jac->psubcomm, jac->n));
1255: PetscCall(PetscSubcommSetType(jac->psubcomm, PETSC_SUBCOMM_CONTIGUOUS));
1256: }
1257: mpjac->psubcomm = jac->psubcomm;
1258: subcomm = PetscSubcommChild(mpjac->psubcomm);
1260: /* Get matrix blocks of pmat */
1261: PetscCall(MatGetMultiProcBlock(pc->pmat, subcomm, MAT_INITIAL_MATRIX, &mpjac->submats));
1263: /* create a new PC that processors in each subcomm have copy of */
1264: PetscCall(PetscMalloc1(1, &jac->ksp));
1265: PetscCall(KSPCreate(subcomm, &jac->ksp[0]));
1266: PetscCall(PCGetKSPNestLevel(pc, &nestlevel));
1267: PetscCall(KSPSetNestLevel(jac->ksp[0], nestlevel + 1));
1268: PetscCall(KSPSetErrorIfNotConverged(jac->ksp[0], pc->erroriffailure));
1269: PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->ksp[0], (PetscObject)pc, 1));
1270: PetscCall(KSPSetOperators(jac->ksp[0], mpjac->submats, mpjac->submats));
1271: PetscCall(KSPGetPC(jac->ksp[0], &mpjac->pc));
1273: PetscCall(PCGetOptionsPrefix(pc, &prefix));
1274: PetscCall(KSPSetOptionsPrefix(jac->ksp[0], prefix));
1275: PetscCall(KSPAppendOptionsPrefix(jac->ksp[0], "sub_"));
1276: PetscCall(KSPGetOptionsPrefix(jac->ksp[0], &prefix));
1277: PetscCall(MatSetOptionsPrefix(mpjac->submats, prefix));
1279: /* create dummy vectors xsub and ysub */
1280: PetscCall(MatGetLocalSize(mpjac->submats, &m, &n));
1281: PetscCall(VecCreateMPIWithArray(subcomm, 1, n, PETSC_DECIDE, NULL, &mpjac->xsub));
1282: PetscCall(VecCreateMPIWithArray(subcomm, 1, m, PETSC_DECIDE, NULL, &mpjac->ysub));
1283: PetscCall(MatGetVecType(mpjac->submats, &vectype));
1284: PetscCall(VecSetType(mpjac->xsub, vectype));
1285: PetscCall(VecSetType(mpjac->ysub, vectype));
1287: pc->ops->setuponblocks = PCSetUpOnBlocks_BJacobi_Multiproc;
1288: pc->ops->reset = PCReset_BJacobi_Multiproc;
1289: pc->ops->destroy = PCDestroy_BJacobi_Multiproc;
1290: pc->ops->apply = PCApply_BJacobi_Multiproc;
1291: pc->ops->matapply = PCMatApply_BJacobi_Multiproc;
1292: } else { /* pc->setupcalled */
1293: subcomm = PetscSubcommChild(mpjac->psubcomm);
1294: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
1295: /* destroy old matrix blocks, then get new matrix blocks */
1296: if (mpjac->submats) PetscCall(MatDestroy(&mpjac->submats));
1297: PetscCall(MatGetMultiProcBlock(pc->pmat, subcomm, MAT_INITIAL_MATRIX, &mpjac->submats));
1298: } else {
1299: PetscCall(MatGetMultiProcBlock(pc->pmat, subcomm, MAT_REUSE_MATRIX, &mpjac->submats));
1300: }
1301: PetscCall(KSPSetOperators(jac->ksp[0], mpjac->submats, mpjac->submats));
1302: }
1304: if (!wasSetup && pc->setfromoptionscalled) PetscCall(KSPSetFromOptions(jac->ksp[0]));
1305: PetscFunctionReturn(PETSC_SUCCESS);
1306: }