Actual source code: mg.c
1: /*
2: Defines the multigrid preconditioner interface.
3: */
4: #include <petsc/private/pcmgimpl.h>
5: #include <petsc/private/kspimpl.h>
6: #include <petscdm.h>
7: PETSC_INTERN PetscErrorCode PCPreSolveChangeRHS(PC, PetscBool *);
9: /*
10: Contains the list of registered coarse space construction routines
11: */
12: PetscFunctionList PCMGCoarseList = NULL;
14: PetscErrorCode PCMGMCycle_Private(PC pc, PC_MG_Levels **mglevelsin, PetscBool transpose, PetscBool matapp, PCRichardsonConvergedReason *reason)
15: {
16: PC_MG *mg = (PC_MG *)pc->data;
17: PC_MG_Levels *mgc, *mglevels = *mglevelsin;
18: PetscInt cycles = (mglevels->level == 1) ? 1 : mglevels->cycles;
20: PetscFunctionBegin;
21: if (mglevels->eventsmoothsolve) PetscCall(PetscLogEventBegin(mglevels->eventsmoothsolve, 0, 0, 0, 0));
22: if (!transpose) {
23: if (matapp) {
24: PetscCall(KSPMatSolve(mglevels->smoothd, mglevels->B, mglevels->X)); /* pre-smooth */
25: PetscCall(KSPCheckSolve(mglevels->smoothd, pc, NULL));
26: } else {
27: PetscCall(KSPSolve(mglevels->smoothd, mglevels->b, mglevels->x)); /* pre-smooth */
28: PetscCall(KSPCheckSolve(mglevels->smoothd, pc, mglevels->x));
29: }
30: } else {
31: PetscCheck(!matapp, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Not supported");
32: PetscCall(KSPSolveTranspose(mglevels->smoothu, mglevels->b, mglevels->x)); /* transpose of post-smooth */
33: PetscCall(KSPCheckSolve(mglevels->smoothu, pc, mglevels->x));
34: }
35: if (mglevels->eventsmoothsolve) PetscCall(PetscLogEventEnd(mglevels->eventsmoothsolve, 0, 0, 0, 0));
36: if (mglevels->level) { /* not the coarsest grid */
37: if (mglevels->eventresidual) PetscCall(PetscLogEventBegin(mglevels->eventresidual, 0, 0, 0, 0));
38: if (matapp && !mglevels->R) PetscCall(MatDuplicate(mglevels->B, MAT_DO_NOT_COPY_VALUES, &mglevels->R));
39: if (!transpose) {
40: if (matapp) PetscCall((*mglevels->matresidual)(mglevels->A, mglevels->B, mglevels->X, mglevels->R));
41: else PetscCall((*mglevels->residual)(mglevels->A, mglevels->b, mglevels->x, mglevels->r));
42: } else {
43: if (matapp) PetscCall((*mglevels->matresidualtranspose)(mglevels->A, mglevels->B, mglevels->X, mglevels->R));
44: else PetscCall((*mglevels->residualtranspose)(mglevels->A, mglevels->b, mglevels->x, mglevels->r));
45: }
46: if (mglevels->eventresidual) PetscCall(PetscLogEventEnd(mglevels->eventresidual, 0, 0, 0, 0));
48: /* if on finest level and have convergence criteria set */
49: if (mglevels->level == mglevels->levels - 1 && mg->ttol && reason) {
50: PetscReal rnorm;
52: PetscCall(VecNorm(mglevels->r, NORM_2, &rnorm));
53: if (rnorm <= mg->ttol) {
54: if (rnorm < mg->abstol) {
55: *reason = PCRICHARDSON_CONVERGED_ATOL;
56: PetscCall(PetscInfo(pc, "Linear solver has converged. Residual norm %g is less than absolute tolerance %g\n", (double)rnorm, (double)mg->abstol));
57: } else {
58: *reason = PCRICHARDSON_CONVERGED_RTOL;
59: PetscCall(PetscInfo(pc, "Linear solver has converged. Residual norm %g is less than relative tolerance times initial residual norm %g\n", (double)rnorm, (double)mg->ttol));
60: }
61: PetscFunctionReturn(PETSC_SUCCESS);
62: }
63: }
65: mgc = *(mglevelsin - 1);
66: if (mglevels->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels->eventinterprestrict, 0, 0, 0, 0));
67: if (!transpose) {
68: if (matapp) PetscCall(MatMatRestrict(mglevels->restrct, mglevels->R, &mgc->B));
69: else PetscCall(MatRestrict(mglevels->restrct, mglevels->r, mgc->b));
70: } else {
71: if (matapp) PetscCall(MatMatRestrict(mglevels->interpolate, mglevels->R, &mgc->B));
72: else PetscCall(MatRestrict(mglevels->interpolate, mglevels->r, mgc->b));
73: }
74: if (mglevels->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels->eventinterprestrict, 0, 0, 0, 0));
75: if (matapp) {
76: if (!mgc->X) {
77: PetscCall(MatDuplicate(mgc->B, MAT_DO_NOT_COPY_VALUES, &mgc->X));
78: } else {
79: PetscCall(MatZeroEntries(mgc->X));
80: }
81: } else {
82: PetscCall(VecZeroEntries(mgc->x));
83: }
84: while (cycles--) PetscCall(PCMGMCycle_Private(pc, mglevelsin - 1, transpose, matapp, reason));
85: if (mglevels->eventinterprestrict) PetscCall(PetscLogEventBegin(mglevels->eventinterprestrict, 0, 0, 0, 0));
86: if (!transpose) {
87: if (matapp) PetscCall(MatMatInterpolateAdd(mglevels->interpolate, mgc->X, mglevels->X, &mglevels->X));
88: else PetscCall(MatInterpolateAdd(mglevels->interpolate, mgc->x, mglevels->x, mglevels->x));
89: } else {
90: PetscCall(MatInterpolateAdd(mglevels->restrct, mgc->x, mglevels->x, mglevels->x));
91: }
92: if (mglevels->eventinterprestrict) PetscCall(PetscLogEventEnd(mglevels->eventinterprestrict, 0, 0, 0, 0));
93: if (mglevels->eventsmoothsolve) PetscCall(PetscLogEventBegin(mglevels->eventsmoothsolve, 0, 0, 0, 0));
94: if (!transpose) {
95: if (matapp) {
96: PetscCall(KSPMatSolve(mglevels->smoothu, mglevels->B, mglevels->X)); /* post smooth */
97: PetscCall(KSPCheckSolve(mglevels->smoothu, pc, NULL));
98: } else {
99: PetscCall(KSPSolve(mglevels->smoothu, mglevels->b, mglevels->x)); /* post smooth */
100: PetscCall(KSPCheckSolve(mglevels->smoothu, pc, mglevels->x));
101: }
102: } else {
103: PetscCheck(!matapp, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Not supported");
104: PetscCall(KSPSolveTranspose(mglevels->smoothd, mglevels->b, mglevels->x)); /* post smooth */
105: PetscCall(KSPCheckSolve(mglevels->smoothd, pc, mglevels->x));
106: }
107: if (mglevels->cr) {
108: Mat crA;
110: PetscCheck(!matapp, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Not supported");
111: /* TODO Turn on copy and turn off noisy if we have an exact solution
112: PetscCall(VecCopy(mglevels->x, mglevels->crx));
113: PetscCall(VecCopy(mglevels->b, mglevels->crb)); */
114: PetscCall(KSPGetOperators(mglevels->cr, &crA, NULL));
115: PetscCall(KSPSetNoisy_Private(crA, mglevels->crx));
116: PetscCall(KSPSolve(mglevels->cr, mglevels->crb, mglevels->crx)); /* compatible relaxation */
117: PetscCall(KSPCheckSolve(mglevels->cr, pc, mglevels->crx));
118: }
119: if (mglevels->eventsmoothsolve) PetscCall(PetscLogEventEnd(mglevels->eventsmoothsolve, 0, 0, 0, 0));
120: }
121: PetscFunctionReturn(PETSC_SUCCESS);
122: }
124: static PetscErrorCode PCApplyRichardson_MG(PC pc, Vec b, Vec x, Vec w, PetscReal rtol, PetscReal abstol, PetscReal dtol, PetscInt its, PetscBool zeroguess, PetscInt *outits, PCRichardsonConvergedReason *reason)
125: {
126: PC_MG *mg = (PC_MG *)pc->data;
127: PC_MG_Levels **mglevels = mg->levels;
128: PC tpc;
129: PetscBool changeu, changed;
130: PetscInt levels = mglevels[0]->levels, i;
132: PetscFunctionBegin;
133: /* When the DM is supplying the matrix then it will not exist until here */
134: for (i = 0; i < levels; i++) {
135: if (!mglevels[i]->A) {
136: PetscCall(KSPGetOperators(mglevels[i]->smoothu, &mglevels[i]->A, NULL));
137: PetscCall(PetscObjectReference((PetscObject)mglevels[i]->A));
138: }
139: }
141: PetscCall(KSPGetPC(mglevels[levels - 1]->smoothd, &tpc));
142: PetscCall(PCPreSolveChangeRHS(tpc, &changed));
143: PetscCall(KSPGetPC(mglevels[levels - 1]->smoothu, &tpc));
144: PetscCall(PCPreSolveChangeRHS(tpc, &changeu));
145: if (!changed && !changeu) {
146: PetscCall(VecDestroy(&mglevels[levels - 1]->b));
147: mglevels[levels - 1]->b = b;
148: } else { /* if the smoother changes the rhs during PreSolve, we cannot use the input vector */
149: if (!mglevels[levels - 1]->b) {
150: Vec *vec;
152: PetscCall(KSPCreateVecs(mglevels[levels - 1]->smoothd, 1, &vec, 0, NULL));
153: mglevels[levels - 1]->b = *vec;
154: PetscCall(PetscFree(vec));
155: }
156: PetscCall(VecCopy(b, mglevels[levels - 1]->b));
157: }
158: mglevels[levels - 1]->x = x;
160: mg->rtol = rtol;
161: mg->abstol = abstol;
162: mg->dtol = dtol;
163: if (rtol) {
164: /* compute initial residual norm for relative convergence test */
165: PetscReal rnorm;
167: if (zeroguess) {
168: PetscCall(VecNorm(b, NORM_2, &rnorm));
169: } else {
170: PetscCall((*mglevels[levels - 1]->residual)(mglevels[levels - 1]->A, b, x, w));
171: PetscCall(VecNorm(w, NORM_2, &rnorm));
172: }
173: mg->ttol = PetscMax(rtol * rnorm, abstol);
174: } else if (abstol) mg->ttol = abstol;
175: else mg->ttol = 0.0;
177: /* since smoother is applied to full system, not just residual we need to make sure that smoothers don't
178: stop prematurely due to small residual */
179: for (i = 1; i < levels; i++) {
180: PetscCall(KSPSetTolerances(mglevels[i]->smoothu, 0, PETSC_CURRENT, PETSC_CURRENT, PETSC_CURRENT));
181: if (mglevels[i]->smoothu != mglevels[i]->smoothd) {
182: /* For Richardson the initial guess is nonzero since it is solving in each cycle the original system not just applying as a preconditioner */
183: PetscCall(KSPSetInitialGuessNonzero(mglevels[i]->smoothd, PETSC_TRUE));
184: PetscCall(KSPSetTolerances(mglevels[i]->smoothd, 0, PETSC_CURRENT, PETSC_CURRENT, PETSC_CURRENT));
185: }
186: }
188: *reason = PCRICHARDSON_NOT_SET;
189: for (i = 0; i < its; i++) {
190: PetscCall(PCMGMCycle_Private(pc, mglevels + levels - 1, PETSC_FALSE, PETSC_FALSE, reason));
191: if (*reason) break;
192: }
193: if (*reason == PCRICHARDSON_NOT_SET) *reason = PCRICHARDSON_CONVERGED_ITS;
194: *outits = i;
195: if (!changed && !changeu) mglevels[levels - 1]->b = NULL;
196: PetscFunctionReturn(PETSC_SUCCESS);
197: }
199: PetscErrorCode PCReset_MG(PC pc)
200: {
201: PC_MG *mg = (PC_MG *)pc->data;
202: PC_MG_Levels **mglevels = mg->levels;
203: PetscInt i, n;
205: PetscFunctionBegin;
206: if (mglevels) {
207: n = mglevels[0]->levels;
208: for (i = 0; i < n - 1; i++) {
209: PetscCall(VecDestroy(&mglevels[i + 1]->r));
210: PetscCall(VecDestroy(&mglevels[i]->b));
211: PetscCall(VecDestroy(&mglevels[i]->x));
212: PetscCall(MatDestroy(&mglevels[i + 1]->R));
213: PetscCall(MatDestroy(&mglevels[i]->B));
214: PetscCall(MatDestroy(&mglevels[i]->X));
215: PetscCall(VecDestroy(&mglevels[i]->crx));
216: PetscCall(VecDestroy(&mglevels[i]->crb));
217: PetscCall(MatDestroy(&mglevels[i + 1]->restrct));
218: PetscCall(MatDestroy(&mglevels[i + 1]->interpolate));
219: PetscCall(MatDestroy(&mglevels[i + 1]->inject));
220: PetscCall(VecDestroy(&mglevels[i + 1]->rscale));
221: }
222: PetscCall(VecDestroy(&mglevels[n - 1]->crx));
223: PetscCall(VecDestroy(&mglevels[n - 1]->crb));
224: /* this is not null only if the smoother on the finest level
225: changes the rhs during PreSolve */
226: PetscCall(VecDestroy(&mglevels[n - 1]->b));
227: PetscCall(MatDestroy(&mglevels[n - 1]->B));
229: for (i = 0; i < n; i++) {
230: PetscCall(MatDestroy(&mglevels[i]->coarseSpace));
231: PetscCall(MatDestroy(&mglevels[i]->A));
232: if (mglevels[i]->smoothd != mglevels[i]->smoothu) PetscCall(KSPReset(mglevels[i]->smoothd));
233: PetscCall(KSPReset(mglevels[i]->smoothu));
234: if (mglevels[i]->cr) PetscCall(KSPReset(mglevels[i]->cr));
235: }
236: mg->Nc = 0;
237: }
238: PetscFunctionReturn(PETSC_SUCCESS);
239: }
241: /* Implementing CR
243: We only want to make corrections that ``do not change'' the coarse solution. What we mean by not changing is that if I prolong my coarse solution to the fine grid and then inject that fine solution back to the coarse grid, I get the same answer. Injection is what Brannick calls R. We want the complementary projector to Inj, which we will call S, after Brannick, so that Inj S = 0. Now the orthogonal projector onto the range of Inj^T is
245: Inj^T (Inj Inj^T)^{-1} Inj
247: and if Inj is a VecScatter, as it is now in PETSc, we have
249: Inj^T Inj
251: and
253: S = I - Inj^T Inj
255: since
257: Inj S = Inj - (Inj Inj^T) Inj = 0.
259: Brannick suggests
261: A \to S^T A S \qquad\mathrm{and}\qquad M \to S^T M S
263: but I do not think his :math:`S^T S = I` is correct. Our S is an orthogonal projector, so :math:`S^T S = S^2 = S`. We will use
265: M^{-1} A \to S M^{-1} A S
267: In fact, since it is somewhat hard in PETSc to do the symmetric application, we will just apply S on the left.
269: Check: || Inj P - I ||_F < tol
270: Check: In general, Inj Inj^T = I
271: */
273: typedef struct {
274: PC mg; /* The PCMG object */
275: PetscInt l; /* The multigrid level for this solver */
276: Mat Inj; /* The injection matrix */
277: Mat S; /* I - Inj^T Inj */
278: } CRContext;
280: static PetscErrorCode CRSetup_Private(PC pc)
281: {
282: CRContext *ctx;
283: Mat It;
285: PetscFunctionBeginUser;
286: PetscCall(PCShellGetContext(pc, &ctx));
287: PetscCall(PCMGGetInjection(ctx->mg, ctx->l, &It));
288: PetscCheck(It, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "CR requires that injection be defined for this PCMG");
289: PetscCall(MatCreateTranspose(It, &ctx->Inj));
290: PetscCall(MatCreateNormal(ctx->Inj, &ctx->S));
291: PetscCall(MatScale(ctx->S, -1.0));
292: PetscCall(MatShift(ctx->S, 1.0));
293: PetscFunctionReturn(PETSC_SUCCESS);
294: }
296: static PetscErrorCode CRApply_Private(PC pc, Vec x, Vec y)
297: {
298: CRContext *ctx;
300: PetscFunctionBeginUser;
301: PetscCall(PCShellGetContext(pc, &ctx));
302: PetscCall(MatMult(ctx->S, x, y));
303: PetscFunctionReturn(PETSC_SUCCESS);
304: }
306: static PetscErrorCode CRDestroy_Private(PC pc)
307: {
308: CRContext *ctx;
310: PetscFunctionBeginUser;
311: PetscCall(PCShellGetContext(pc, &ctx));
312: PetscCall(MatDestroy(&ctx->Inj));
313: PetscCall(MatDestroy(&ctx->S));
314: PetscCall(PetscFree(ctx));
315: PetscCall(PCShellSetContext(pc, NULL));
316: PetscFunctionReturn(PETSC_SUCCESS);
317: }
319: static PetscErrorCode CreateCR_Private(PC pc, PetscInt l, PC *cr)
320: {
321: CRContext *ctx;
323: PetscFunctionBeginUser;
324: PetscCall(PCCreate(PetscObjectComm((PetscObject)pc), cr));
325: PetscCall(PetscObjectSetName((PetscObject)*cr, "S (complementary projector to injection)"));
326: PetscCall(PetscCalloc1(1, &ctx));
327: ctx->mg = pc;
328: ctx->l = l;
329: PetscCall(PCSetType(*cr, PCSHELL));
330: PetscCall(PCShellSetContext(*cr, ctx));
331: PetscCall(PCShellSetApply(*cr, CRApply_Private));
332: PetscCall(PCShellSetSetUp(*cr, CRSetup_Private));
333: PetscCall(PCShellSetDestroy(*cr, CRDestroy_Private));
334: PetscFunctionReturn(PETSC_SUCCESS);
335: }
337: PETSC_EXTERN PetscErrorCode PetscOptionsFindPairPrefix_Private(PetscOptions, const char[], const char[], const char *[], const char *[], PetscBool *);
339: PetscErrorCode PCMGSetLevels_MG(PC pc, PetscInt levels, MPI_Comm *comms)
340: {
341: PC_MG *mg = (PC_MG *)pc->data;
342: MPI_Comm comm;
343: PC_MG_Levels **mglevels = mg->levels;
344: PCMGType mgtype = mg->am;
345: PetscInt mgctype = (PetscInt)PC_MG_CYCLE_V;
346: PetscInt i;
347: PetscMPIInt size;
348: const char *prefix;
349: PC ipc;
350: PetscInt n;
352: PetscFunctionBegin;
355: if (mg->nlevels == levels) PetscFunctionReturn(PETSC_SUCCESS);
356: PetscCall(PetscObjectGetComm((PetscObject)pc, &comm));
357: if (mglevels) {
358: mgctype = mglevels[0]->cycles;
359: /* changing the number of levels so free up the previous stuff */
360: PetscCall(PCReset_MG(pc));
361: n = mglevels[0]->levels;
362: for (i = 0; i < n; i++) {
363: if (mglevels[i]->smoothd != mglevels[i]->smoothu) PetscCall(KSPDestroy(&mglevels[i]->smoothd));
364: PetscCall(KSPDestroy(&mglevels[i]->smoothu));
365: PetscCall(KSPDestroy(&mglevels[i]->cr));
366: PetscCall(PetscFree(mglevels[i]));
367: }
368: PetscCall(PetscFree(mg->levels));
369: }
371: mg->nlevels = levels;
373: PetscCall(PetscMalloc1(levels, &mglevels));
375: PetscCall(PCGetOptionsPrefix(pc, &prefix));
377: mg->stageApply = 0;
378: for (i = 0; i < levels; i++) {
379: PetscCall(PetscNew(&mglevels[i]));
381: mglevels[i]->level = i;
382: mglevels[i]->levels = levels;
383: mglevels[i]->cycles = mgctype;
384: mg->default_smoothu = 2;
385: mg->default_smoothd = 2;
386: mglevels[i]->eventsmoothsetup = 0;
387: mglevels[i]->eventsmoothsolve = 0;
388: mglevels[i]->eventresidual = 0;
389: mglevels[i]->eventinterprestrict = 0;
391: if (comms) comm = comms[i];
392: if (comm != MPI_COMM_NULL) {
393: PetscCall(KSPCreate(comm, &mglevels[i]->smoothd));
394: PetscCall(KSPSetNestLevel(mglevels[i]->smoothd, pc->kspnestlevel));
395: PetscCall(KSPSetErrorIfNotConverged(mglevels[i]->smoothd, pc->erroriffailure));
396: PetscCall(PetscObjectIncrementTabLevel((PetscObject)mglevels[i]->smoothd, (PetscObject)pc, levels - i));
397: PetscCall(KSPSetOptionsPrefix(mglevels[i]->smoothd, prefix));
398: PetscCall(PetscObjectComposedDataSetInt((PetscObject)mglevels[i]->smoothd, PetscMGLevelId, mglevels[i]->level));
399: if (i == 0 && levels > 1) { // coarse grid
400: PetscCall(KSPAppendOptionsPrefix(mglevels[0]->smoothd, "mg_coarse_"));
402: /* coarse solve is (redundant) LU by default; set shifttype NONZERO to avoid annoying zero-pivot in LU preconditioner */
403: PetscCall(KSPSetType(mglevels[0]->smoothd, KSPPREONLY));
404: PetscCall(KSPGetPC(mglevels[0]->smoothd, &ipc));
405: PetscCallMPI(MPI_Comm_size(comm, &size));
406: if (size > 1) {
407: PetscCall(PCSetType(ipc, PCREDUNDANT));
408: } else {
409: PetscCall(PCSetType(ipc, PCLU));
410: }
411: PetscCall(PCFactorSetShiftType(ipc, MAT_SHIFT_INBLOCKS));
412: } else {
413: char tprefix[128];
415: PetscCall(KSPSetType(mglevels[i]->smoothd, KSPCHEBYSHEV));
416: PetscCall(KSPSetConvergenceTest(mglevels[i]->smoothd, KSPConvergedSkip, NULL, NULL));
417: PetscCall(KSPSetNormType(mglevels[i]->smoothd, KSP_NORM_NONE));
418: PetscCall(KSPGetPC(mglevels[i]->smoothd, &ipc));
419: PetscCall(PCSetType(ipc, PCSOR));
420: PetscCall(KSPSetTolerances(mglevels[i]->smoothd, PETSC_CURRENT, PETSC_CURRENT, PETSC_CURRENT, mg->default_smoothd));
422: if (i == levels - 1 && levels > 1) { // replace 'mg_finegrid_' with 'mg_levels_X_'
423: PetscBool set;
425: PetscCall(PetscOptionsFindPairPrefix_Private(((PetscObject)mglevels[i]->smoothd)->options, ((PetscObject)mglevels[i]->smoothd)->prefix, "-mg_fine_", NULL, NULL, &set));
426: if (set) {
427: if (prefix) PetscCall(PetscSNPrintf(tprefix, 128, "%smg_fine_", prefix));
428: else PetscCall(PetscSNPrintf(tprefix, 128, "mg_fine_"));
429: PetscCall(KSPSetOptionsPrefix(mglevels[i]->smoothd, tprefix));
430: } else {
431: PetscCall(PetscSNPrintf(tprefix, 128, "mg_levels_%" PetscInt_FMT "_", i));
432: PetscCall(KSPAppendOptionsPrefix(mglevels[i]->smoothd, tprefix));
433: }
434: } else {
435: PetscCall(PetscSNPrintf(tprefix, 128, "mg_levels_%" PetscInt_FMT "_", i));
436: PetscCall(KSPAppendOptionsPrefix(mglevels[i]->smoothd, tprefix));
437: }
438: }
439: }
440: mglevels[i]->smoothu = mglevels[i]->smoothd;
441: mg->rtol = 0.0;
442: mg->abstol = 0.0;
443: mg->dtol = 0.0;
444: mg->ttol = 0.0;
445: mg->cyclesperpcapply = 1;
446: }
447: mg->levels = mglevels;
448: PetscCall(PCMGSetType(pc, mgtype));
449: PetscFunctionReturn(PETSC_SUCCESS);
450: }
452: /*@C
453: PCMGSetLevels - Sets the number of levels to use with `PCMG`.
454: Must be called before any other `PCMG` routine.
456: Logically Collective
458: Input Parameters:
459: + pc - the preconditioner context
460: . levels - the number of levels
461: - comms - optional communicators for each level; this is to allow solving the coarser problems
462: on smaller sets of processes. For processes that are not included in the computation
463: you must pass `MPI_COMM_NULL`. Use comms = `NULL` to specify that all processes
464: should participate in each level of problem.
466: Options Database Key:
467: . -pc_mg_levels <levels> - set the number of levels to use
469: Level: intermediate
471: Notes:
472: If the number of levels is one then the multigrid uses the `-mg_levels` prefix
473: for setting the level options rather than the `-mg_coarse` or `-mg_fine` prefix.
475: You can free the information in comms after this routine is called.
477: The array of MPI communicators must contain `MPI_COMM_NULL` for those ranks that at each level
478: are not participating in the coarser solve. For example, with 2 levels and 1 and 2 ranks on
479: the two levels, rank 0 in the original communicator will pass in an array of 2 communicators
480: of size 2 and 1, while rank 1 in the original communicator will pass in array of 2 communicators
481: the first of size 2 and the second of value `MPI_COMM_NULL` since the rank 1 does not participate
482: in the coarse grid solve.
484: Since each coarser level may have a new `MPI_Comm` with fewer ranks than the previous, one
485: must take special care in providing the restriction and interpolation operation. We recommend
486: providing these as two step operations; first perform a standard restriction or interpolation on
487: the full number of ranks for that level and then use an MPI call to copy the resulting vector
488: array entries (after calls to VecGetArray()) to the smaller or larger number of ranks, note in both
489: cases the MPI calls must be made on the larger of the two communicators. Traditional MPI send and
490: receives or `MPI_AlltoAllv()` could be used to do the reshuffling of the vector entries.
492: Fortran Notes:
493: Use comms = `PETSC_NULL_MPI_COMM` as the equivalent of `NULL` in the C interface. Note `PETSC_NULL_MPI_COMM`
494: is not `MPI_COMM_NULL`. It is more like `PETSC_NULL_INTEGER`, `PETSC_NULL_REAL` etc.
496: .seealso: [](ch_ksp), `PCMGSetType()`, `PCMGGetLevels()`
497: @*/
498: PetscErrorCode PCMGSetLevels(PC pc, PetscInt levels, MPI_Comm *comms)
499: {
500: PetscFunctionBegin;
502: if (comms) PetscAssertPointer(comms, 3);
503: PetscTryMethod(pc, "PCMGSetLevels_C", (PC, PetscInt, MPI_Comm *), (pc, levels, comms));
504: PetscFunctionReturn(PETSC_SUCCESS);
505: }
507: PetscErrorCode PCDestroy_MG(PC pc)
508: {
509: PC_MG *mg = (PC_MG *)pc->data;
510: PC_MG_Levels **mglevels = mg->levels;
511: PetscInt i, n;
513: PetscFunctionBegin;
514: PetscCall(PCReset_MG(pc));
515: if (mglevels) {
516: n = mglevels[0]->levels;
517: for (i = 0; i < n; i++) {
518: if (mglevels[i]->smoothd != mglevels[i]->smoothu) PetscCall(KSPDestroy(&mglevels[i]->smoothd));
519: PetscCall(KSPDestroy(&mglevels[i]->smoothu));
520: PetscCall(KSPDestroy(&mglevels[i]->cr));
521: PetscCall(PetscFree(mglevels[i]));
522: }
523: PetscCall(PetscFree(mg->levels));
524: }
525: PetscCall(PetscFree(pc->data));
526: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGetInterpolations_C", NULL));
527: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGetCoarseOperators_C", NULL));
528: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGSetGalerkin_C", NULL));
529: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetReusePreconditioner_C", NULL));
530: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGGetLevels_C", NULL));
531: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGSetLevels_C", NULL));
532: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGetInterpolations_C", NULL));
533: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGetCoarseOperators_C", NULL));
534: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGSetAdaptInterpolation_C", NULL));
535: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGGetAdaptInterpolation_C", NULL));
536: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGSetAdaptCR_C", NULL));
537: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGGetAdaptCR_C", NULL));
538: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGSetAdaptCoarseSpaceType_C", NULL));
539: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGGetAdaptCoarseSpaceType_C", NULL));
540: PetscFunctionReturn(PETSC_SUCCESS);
541: }
543: /*
544: PCApply_MG - Runs either an additive, multiplicative, Kaskadic
545: or full cycle of multigrid.
547: Note:
548: A simple wrapper which calls PCMGMCycle(),PCMGACycle(), or PCMGFCycle().
549: */
550: static PetscErrorCode PCApply_MG_Internal(PC pc, Vec b, Vec x, Mat B, Mat X, PetscBool transpose)
551: {
552: PC_MG *mg = (PC_MG *)pc->data;
553: PC_MG_Levels **mglevels = mg->levels;
554: PC tpc;
555: PetscInt levels = mglevels[0]->levels, i;
556: PetscBool changeu, changed, matapp;
558: PetscFunctionBegin;
559: matapp = (PetscBool)(B && X);
560: if (mg->stageApply) PetscCall(PetscLogStagePush(mg->stageApply));
561: /* When the DM is supplying the matrix then it will not exist until here */
562: for (i = 0; i < levels; i++) {
563: if (!mglevels[i]->A) {
564: PetscCall(KSPGetOperators(mglevels[i]->smoothu, &mglevels[i]->A, NULL));
565: PetscCall(PetscObjectReference((PetscObject)mglevels[i]->A));
566: }
567: }
569: PetscCall(KSPGetPC(mglevels[levels - 1]->smoothd, &tpc));
570: PetscCall(PCPreSolveChangeRHS(tpc, &changed));
571: PetscCall(KSPGetPC(mglevels[levels - 1]->smoothu, &tpc));
572: PetscCall(PCPreSolveChangeRHS(tpc, &changeu));
573: if (!changeu && !changed) {
574: if (matapp) {
575: PetscCall(MatDestroy(&mglevels[levels - 1]->B));
576: mglevels[levels - 1]->B = B;
577: } else {
578: PetscCall(VecDestroy(&mglevels[levels - 1]->b));
579: mglevels[levels - 1]->b = b;
580: }
581: } else { /* if the smoother changes the rhs during PreSolve, we cannot use the input vector */
582: if (matapp) {
583: if (mglevels[levels - 1]->B) {
584: PetscInt N1, N2;
585: PetscBool flg;
587: PetscCall(MatGetSize(mglevels[levels - 1]->B, NULL, &N1));
588: PetscCall(MatGetSize(B, NULL, &N2));
589: PetscCall(PetscObjectTypeCompare((PetscObject)mglevels[levels - 1]->B, ((PetscObject)B)->type_name, &flg));
590: if (N1 != N2 || !flg) PetscCall(MatDestroy(&mglevels[levels - 1]->B));
591: }
592: if (!mglevels[levels - 1]->B) {
593: PetscCall(MatDuplicate(B, MAT_COPY_VALUES, &mglevels[levels - 1]->B));
594: } else {
595: PetscCall(MatCopy(B, mglevels[levels - 1]->B, SAME_NONZERO_PATTERN));
596: }
597: } else {
598: if (!mglevels[levels - 1]->b) {
599: Vec *vec;
601: PetscCall(KSPCreateVecs(mglevels[levels - 1]->smoothd, 1, &vec, 0, NULL));
602: mglevels[levels - 1]->b = *vec;
603: PetscCall(PetscFree(vec));
604: }
605: PetscCall(VecCopy(b, mglevels[levels - 1]->b));
606: }
607: }
608: if (matapp) {
609: mglevels[levels - 1]->X = X;
610: } else {
611: mglevels[levels - 1]->x = x;
612: }
614: /* If coarser Xs are present, it means we have already block applied the PC at least once
615: Reset operators if sizes/type do no match */
616: if (matapp && levels > 1 && mglevels[levels - 2]->X) {
617: PetscInt Xc, Bc;
618: PetscBool flg;
620: PetscCall(MatGetSize(mglevels[levels - 2]->X, NULL, &Xc));
621: PetscCall(MatGetSize(mglevels[levels - 1]->B, NULL, &Bc));
622: PetscCall(PetscObjectTypeCompare((PetscObject)mglevels[levels - 2]->X, ((PetscObject)mglevels[levels - 1]->X)->type_name, &flg));
623: if (Xc != Bc || !flg) {
624: PetscCall(MatDestroy(&mglevels[levels - 1]->R));
625: for (i = 0; i < levels - 1; i++) {
626: PetscCall(MatDestroy(&mglevels[i]->R));
627: PetscCall(MatDestroy(&mglevels[i]->B));
628: PetscCall(MatDestroy(&mglevels[i]->X));
629: }
630: }
631: }
633: if (mg->am == PC_MG_MULTIPLICATIVE) {
634: if (matapp) PetscCall(MatZeroEntries(X));
635: else PetscCall(VecZeroEntries(x));
636: for (i = 0; i < mg->cyclesperpcapply; i++) PetscCall(PCMGMCycle_Private(pc, mglevels + levels - 1, transpose, matapp, NULL));
637: } else if (mg->am == PC_MG_ADDITIVE) {
638: PetscCall(PCMGACycle_Private(pc, mglevels, transpose, matapp));
639: } else if (mg->am == PC_MG_KASKADE) {
640: PetscCall(PCMGKCycle_Private(pc, mglevels, transpose, matapp));
641: } else {
642: PetscCall(PCMGFCycle_Private(pc, mglevels, transpose, matapp));
643: }
644: if (mg->stageApply) PetscCall(PetscLogStagePop());
645: if (!changeu && !changed) {
646: if (matapp) {
647: mglevels[levels - 1]->B = NULL;
648: } else {
649: mglevels[levels - 1]->b = NULL;
650: }
651: }
652: PetscFunctionReturn(PETSC_SUCCESS);
653: }
655: static PetscErrorCode PCApply_MG(PC pc, Vec b, Vec x)
656: {
657: PetscFunctionBegin;
658: PetscCall(PCApply_MG_Internal(pc, b, x, NULL, NULL, PETSC_FALSE));
659: PetscFunctionReturn(PETSC_SUCCESS);
660: }
662: static PetscErrorCode PCApplyTranspose_MG(PC pc, Vec b, Vec x)
663: {
664: PetscFunctionBegin;
665: PetscCall(PCApply_MG_Internal(pc, b, x, NULL, NULL, PETSC_TRUE));
666: PetscFunctionReturn(PETSC_SUCCESS);
667: }
669: static PetscErrorCode PCMatApply_MG(PC pc, Mat b, Mat x)
670: {
671: PetscFunctionBegin;
672: PetscCall(PCApply_MG_Internal(pc, NULL, NULL, b, x, PETSC_FALSE));
673: PetscFunctionReturn(PETSC_SUCCESS);
674: }
676: static PetscErrorCode PCMatApplyTranspose_MG(PC pc, Mat b, Mat x)
677: {
678: PetscFunctionBegin;
679: PetscCall(PCApply_MG_Internal(pc, NULL, NULL, b, x, PETSC_TRUE));
680: PetscFunctionReturn(PETSC_SUCCESS);
681: }
683: PetscErrorCode PCSetFromOptions_MG(PC pc, PetscOptionItems PetscOptionsObject)
684: {
685: PetscInt levels, cycles;
686: PetscBool flg, flg2;
687: PC_MG *mg = (PC_MG *)pc->data;
688: PC_MG_Levels **mglevels;
689: PCMGType mgtype;
690: PCMGCycleType mgctype;
691: PCMGGalerkinType gtype;
692: PCMGCoarseSpaceType coarseSpaceType;
694: PetscFunctionBegin;
695: levels = PetscMax(mg->nlevels, 1);
696: PetscOptionsHeadBegin(PetscOptionsObject, "Multigrid options");
697: PetscCall(PetscOptionsInt("-pc_mg_levels", "Number of Levels", "PCMGSetLevels", levels, &levels, &flg));
698: if (!flg && !mg->levels && pc->dm) {
699: PetscCall(DMGetRefineLevel(pc->dm, &levels));
700: levels++;
701: mg->usedmfornumberoflevels = PETSC_TRUE;
702: }
703: PetscCall(PCMGSetLevels(pc, levels, NULL));
704: mglevels = mg->levels;
706: mgctype = (PCMGCycleType)mglevels[0]->cycles;
707: PetscCall(PetscOptionsEnum("-pc_mg_cycle_type", "V cycle or for W-cycle", "PCMGSetCycleType", PCMGCycleTypes, (PetscEnum)mgctype, (PetscEnum *)&mgctype, &flg));
708: if (flg) PetscCall(PCMGSetCycleType(pc, mgctype));
709: coarseSpaceType = mg->coarseSpaceType;
710: PetscCall(PetscOptionsEnum("-pc_mg_adapt_interp_coarse_space", "Type of adaptive coarse space: none, polynomial, harmonic, eigenvector, generalized_eigenvector, gdsw", "PCMGSetAdaptCoarseSpaceType", PCMGCoarseSpaceTypes, (PetscEnum)coarseSpaceType, (PetscEnum *)&coarseSpaceType, &flg));
711: if (flg) PetscCall(PCMGSetAdaptCoarseSpaceType(pc, coarseSpaceType));
712: PetscCall(PetscOptionsInt("-pc_mg_adapt_interp_n", "Size of the coarse space for adaptive interpolation", "PCMGSetCoarseSpace", mg->Nc, &mg->Nc, &flg));
713: PetscCall(PetscOptionsBool("-pc_mg_mesp_monitor", "Monitor the multilevel eigensolver", "PCMGSetAdaptInterpolation", PETSC_FALSE, &mg->mespMonitor, &flg));
714: flg2 = PETSC_FALSE;
715: PetscCall(PetscOptionsBool("-pc_mg_adapt_cr", "Monitor coarse space quality using Compatible Relaxation (CR)", "PCMGSetAdaptCR", PETSC_FALSE, &flg2, &flg));
716: if (flg) PetscCall(PCMGSetAdaptCR(pc, flg2));
717: flg = PETSC_FALSE;
718: PetscCall(PetscOptionsBool("-pc_mg_distinct_smoothup", "Create separate smoothup KSP and append the prefix _up", "PCMGSetDistinctSmoothUp", PETSC_FALSE, &flg, NULL));
719: if (flg) PetscCall(PCMGSetDistinctSmoothUp(pc));
720: PetscCall(PetscOptionsEnum("-pc_mg_galerkin", "Use Galerkin process to compute coarser operators", "PCMGSetGalerkin", PCMGGalerkinTypes, (PetscEnum)mg->galerkin, (PetscEnum *)>ype, &flg));
721: if (flg) PetscCall(PCMGSetGalerkin(pc, gtype));
722: mgtype = mg->am;
723: PetscCall(PetscOptionsEnum("-pc_mg_type", "Multigrid type", "PCMGSetType", PCMGTypes, (PetscEnum)mgtype, (PetscEnum *)&mgtype, &flg));
724: if (flg) PetscCall(PCMGSetType(pc, mgtype));
725: if (mg->am == PC_MG_MULTIPLICATIVE) {
726: PetscCall(PetscOptionsInt("-pc_mg_multiplicative_cycles", "Number of cycles for each preconditioner step", "PCMGMultiplicativeSetCycles", mg->cyclesperpcapply, &cycles, &flg));
727: if (flg) PetscCall(PCMGMultiplicativeSetCycles(pc, cycles));
728: }
729: flg = PETSC_FALSE;
730: PetscCall(PetscOptionsBool("-pc_mg_log", "Log times for each multigrid level", "None", flg, &flg, NULL));
731: if (flg) {
732: PetscInt i;
733: char eventname[128];
735: levels = mglevels[0]->levels;
736: for (i = 0; i < levels; i++) {
737: PetscCall(PetscSNPrintf(eventname, PETSC_STATIC_ARRAY_LENGTH(eventname), "MGSetup Level %" PetscInt_FMT, i));
738: PetscCall(PetscLogEventRegister(eventname, ((PetscObject)pc)->classid, &mglevels[i]->eventsmoothsetup));
739: PetscCall(PetscSNPrintf(eventname, PETSC_STATIC_ARRAY_LENGTH(eventname), "MGSmooth Level %" PetscInt_FMT, i));
740: PetscCall(PetscLogEventRegister(eventname, ((PetscObject)pc)->classid, &mglevels[i]->eventsmoothsolve));
741: if (i) {
742: PetscCall(PetscSNPrintf(eventname, PETSC_STATIC_ARRAY_LENGTH(eventname), "MGResid Level %" PetscInt_FMT, i));
743: PetscCall(PetscLogEventRegister(eventname, ((PetscObject)pc)->classid, &mglevels[i]->eventresidual));
744: PetscCall(PetscSNPrintf(eventname, PETSC_STATIC_ARRAY_LENGTH(eventname), "MGInterp Level %" PetscInt_FMT, i));
745: PetscCall(PetscLogEventRegister(eventname, ((PetscObject)pc)->classid, &mglevels[i]->eventinterprestrict));
746: }
747: }
749: if (PetscDefined(USE_LOG)) {
750: const char sname[] = "MG Apply";
752: PetscCall(PetscLogStageGetId(sname, &mg->stageApply));
753: if (mg->stageApply < 0) PetscCall(PetscLogStageRegister(sname, &mg->stageApply));
754: }
755: }
756: PetscOptionsHeadEnd();
757: /* Check option consistency */
758: PetscCall(PCMGGetGalerkin(pc, >ype));
759: PetscCall(PCMGGetAdaptInterpolation(pc, &flg));
760: PetscCheck(!flg || !(gtype >= PC_MG_GALERKIN_NONE), PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_INCOMP, "Must use Galerkin coarse operators when adapting the interpolator");
761: PetscFunctionReturn(PETSC_SUCCESS);
762: }
764: const char *const PCMGTypes[] = {"MULTIPLICATIVE", "ADDITIVE", "FULL", "KASKADE", "PCMGType", "PC_MG", NULL};
765: const char *const PCMGCycleTypes[] = {"invalid", "v", "w", "PCMGCycleType", "PC_MG_CYCLE", NULL};
766: const char *const PCMGGalerkinTypes[] = {"both", "pmat", "mat", "none", "external", "PCMGGalerkinType", "PC_MG_GALERKIN", NULL};
767: const char *const PCMGCoarseSpaceTypes[] = {"none", "polynomial", "harmonic", "eigenvector", "generalized_eigenvector", "gdsw", "PCMGCoarseSpaceType", "PCMG_ADAPT_NONE", NULL};
769: #include <petscdraw.h>
770: PetscErrorCode PCView_MG(PC pc, PetscViewer viewer)
771: {
772: PC_MG *mg = (PC_MG *)pc->data;
773: PC_MG_Levels **mglevels = mg->levels;
774: PetscInt levels = mglevels ? mglevels[0]->levels : 0, i;
775: PetscBool isascii, isbinary, isdraw;
777: PetscFunctionBegin;
778: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
779: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
780: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
781: if (isascii) {
782: const char *cyclename = levels ? (mglevels[0]->cycles == PC_MG_CYCLE_V ? "v" : "w") : "unknown";
784: if (levels == 1) PetscCall(PetscViewerASCIIPrintf(viewer, " WARNING: Multigrid is being run with only a single level!\n"));
785: PetscCall(PetscViewerASCIIPrintf(viewer, " type is %s, levels=%" PetscInt_FMT " cycles=%s\n", PCMGTypes[mg->am], levels, cyclename));
786: if (mg->am == PC_MG_MULTIPLICATIVE) PetscCall(PetscViewerASCIIPrintf(viewer, " Cycles per PCApply=%" PetscInt_FMT "\n", mg->cyclesperpcapply));
787: if (mg->galerkin == PC_MG_GALERKIN_BOTH) {
788: PetscCall(PetscViewerASCIIPrintf(viewer, " Using Galerkin computed coarse grid matrices\n"));
789: } else if (mg->galerkin == PC_MG_GALERKIN_PMAT) {
790: PetscCall(PetscViewerASCIIPrintf(viewer, " Using Galerkin computed coarse grid matrices for pmat\n"));
791: } else if (mg->galerkin == PC_MG_GALERKIN_MAT) {
792: PetscCall(PetscViewerASCIIPrintf(viewer, " Using Galerkin computed coarse grid matrices for mat\n"));
793: } else if (mg->galerkin == PC_MG_GALERKIN_EXTERNAL) {
794: PetscCall(PetscViewerASCIIPrintf(viewer, " Using externally compute Galerkin coarse grid matrices\n"));
795: } else {
796: PetscCall(PetscViewerASCIIPrintf(viewer, " Not using Galerkin computed coarse grid matrices\n"));
797: }
798: if (mg->view) PetscCall((*mg->view)(pc, viewer));
799: for (i = 0; i < levels; i++) {
800: if (i) {
801: PetscCall(PetscViewerASCIIPrintf(viewer, "Down solver (pre-smoother) on level %" PetscInt_FMT " -------------------------------\n", i));
802: } else {
803: PetscCall(PetscViewerASCIIPrintf(viewer, "Coarse grid solver -- level %" PetscInt_FMT " -------------------------------\n", i));
804: }
805: PetscCall(PetscViewerASCIIPushTab(viewer));
806: PetscCall(KSPView(mglevels[i]->smoothd, viewer));
807: PetscCall(PetscViewerASCIIPopTab(viewer));
808: if (i && mglevels[i]->smoothd == mglevels[i]->smoothu) {
809: PetscCall(PetscViewerASCIIPrintf(viewer, "Up solver (post-smoother) same as down solver (pre-smoother)\n"));
810: } else if (i) {
811: PetscCall(PetscViewerASCIIPrintf(viewer, "Up solver (post-smoother) on level %" PetscInt_FMT " -------------------------------\n", i));
812: PetscCall(PetscViewerASCIIPushTab(viewer));
813: PetscCall(KSPView(mglevels[i]->smoothu, viewer));
814: PetscCall(PetscViewerASCIIPopTab(viewer));
815: }
816: if (i && mglevels[i]->cr) {
817: PetscCall(PetscViewerASCIIPrintf(viewer, "CR solver on level %" PetscInt_FMT " -------------------------------\n", i));
818: PetscCall(PetscViewerASCIIPushTab(viewer));
819: PetscCall(KSPView(mglevels[i]->cr, viewer));
820: PetscCall(PetscViewerASCIIPopTab(viewer));
821: }
822: }
823: } else if (isbinary) {
824: for (i = levels - 1; i >= 0; i--) {
825: PetscCall(KSPView(mglevels[i]->smoothd, viewer));
826: if (i && mglevels[i]->smoothd != mglevels[i]->smoothu) PetscCall(KSPView(mglevels[i]->smoothu, viewer));
827: }
828: } else if (isdraw) {
829: PetscDraw draw;
830: PetscReal x, w, y, bottom, th;
831: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
832: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
833: PetscCall(PetscDrawStringGetSize(draw, NULL, &th));
834: bottom = y - th;
835: for (i = levels - 1; i >= 0; i--) {
836: if (!mglevels[i]->smoothu || (mglevels[i]->smoothu == mglevels[i]->smoothd)) {
837: PetscCall(PetscDrawPushCurrentPoint(draw, x, bottom));
838: PetscCall(KSPView(mglevels[i]->smoothd, viewer));
839: PetscCall(PetscDrawPopCurrentPoint(draw));
840: } else {
841: w = 0.5 * PetscMin(1.0 - x, x);
842: PetscCall(PetscDrawPushCurrentPoint(draw, x + w, bottom));
843: PetscCall(KSPView(mglevels[i]->smoothd, viewer));
844: PetscCall(PetscDrawPopCurrentPoint(draw));
845: PetscCall(PetscDrawPushCurrentPoint(draw, x - w, bottom));
846: PetscCall(KSPView(mglevels[i]->smoothu, viewer));
847: PetscCall(PetscDrawPopCurrentPoint(draw));
848: }
849: PetscCall(PetscDrawGetBoundingBox(draw, NULL, &bottom, NULL, NULL));
850: bottom -= th;
851: }
852: }
853: PetscFunctionReturn(PETSC_SUCCESS);
854: }
856: #include <petsc/private/kspimpl.h>
858: /*
859: Calls setup for the KSP on each level
860: */
861: PetscErrorCode PCSetUp_MG(PC pc)
862: {
863: PC_MG *mg = (PC_MG *)pc->data;
864: PC_MG_Levels **mglevels = mg->levels;
865: PetscInt i, n;
866: PC cpc;
867: PetscBool dump = PETSC_FALSE, opsset, use_amat, missinginterpolate = PETSC_FALSE;
868: Mat dA, dB;
869: Vec tvec;
870: DM *dms;
871: PetscViewer viewer = NULL;
872: PetscBool dAeqdB = PETSC_FALSE, needRestricts = PETSC_FALSE, doCR = PETSC_FALSE;
873: PetscBool adaptInterpolation = mg->adaptInterpolation;
875: PetscFunctionBegin;
876: PetscCheck(mglevels, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must set MG levels with PCMGSetLevels() before setting up");
877: n = mglevels[0]->levels;
878: /* FIX: Move this to PCSetFromOptions_MG? */
879: if (mg->usedmfornumberoflevels) {
880: PetscInt levels;
882: PetscCall(DMGetRefineLevel(pc->dm, &levels));
883: levels++;
884: if (levels > n) { /* the problem is now being solved on a finer grid */
885: PetscCall(PCMGSetLevels(pc, levels, NULL));
886: n = levels;
887: PetscCall(PCSetFromOptions(pc)); /* it is bad to call this here, but otherwise will never be called for the new hierarchy */
888: mglevels = mg->levels;
889: }
890: }
892: /* If user did not provide fine grid operators OR operator was not updated since last global KSPSetOperators() */
893: /* so use those from global PC */
894: /* Is this what we always want? What if user wants to keep old one? */
895: PetscCall(KSPGetOperatorsSet(mglevels[n - 1]->smoothd, NULL, &opsset));
896: if (opsset) {
897: Mat mmat;
898: PetscCall(KSPGetOperators(mglevels[n - 1]->smoothd, NULL, &mmat));
899: if (mmat == pc->pmat) opsset = PETSC_FALSE;
900: }
901: /* fine grid smoother inherits the reuse-pc flag */
902: PetscCall(KSPGetPC(mglevels[n - 1]->smoothd, &cpc));
903: cpc->reusepreconditioner = pc->reusepreconditioner;
904: PetscCall(KSPGetPC(mglevels[n - 1]->smoothu, &cpc));
905: cpc->reusepreconditioner = pc->reusepreconditioner;
907: /* Create CR solvers */
908: PetscCall(PCMGGetAdaptCR(pc, &doCR));
909: if (doCR) {
910: const char *prefix;
912: PetscCall(PCGetOptionsPrefix(pc, &prefix));
913: for (i = 1; i < n; ++i) {
914: PC ipc, cr;
915: char crprefix[128];
917: PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &mglevels[i]->cr));
918: PetscCall(KSPSetNestLevel(mglevels[i]->cr, pc->kspnestlevel));
919: PetscCall(KSPSetErrorIfNotConverged(mglevels[i]->cr, PETSC_FALSE));
920: PetscCall(PetscObjectIncrementTabLevel((PetscObject)mglevels[i]->cr, (PetscObject)pc, n - i));
921: PetscCall(KSPSetOptionsPrefix(mglevels[i]->cr, prefix));
922: PetscCall(PetscObjectComposedDataSetInt((PetscObject)mglevels[i]->cr, PetscMGLevelId, mglevels[i]->level));
923: PetscCall(KSPSetType(mglevels[i]->cr, KSPCHEBYSHEV));
924: PetscCall(KSPSetConvergenceTest(mglevels[i]->cr, KSPConvergedSkip, NULL, NULL));
925: PetscCall(KSPSetNormType(mglevels[i]->cr, KSP_NORM_PRECONDITIONED));
926: PetscCall(KSPGetPC(mglevels[i]->cr, &ipc));
928: PetscCall(PCSetType(ipc, PCCOMPOSITE));
929: PetscCall(PCCompositeSetType(ipc, PC_COMPOSITE_MULTIPLICATIVE));
930: PetscCall(PCCompositeAddPCType(ipc, PCSOR));
931: PetscCall(CreateCR_Private(pc, i, &cr));
932: PetscCall(PCCompositeAddPC(ipc, cr));
933: PetscCall(PCDestroy(&cr));
935: PetscCall(KSPSetTolerances(mglevels[i]->cr, PETSC_CURRENT, PETSC_CURRENT, PETSC_CURRENT, mg->default_smoothd));
936: PetscCall(KSPSetInitialGuessNonzero(mglevels[i]->cr, PETSC_TRUE));
937: PetscCall(PetscSNPrintf(crprefix, 128, "mg_levels_%" PetscInt_FMT "_cr_", i));
938: PetscCall(KSPAppendOptionsPrefix(mglevels[i]->cr, crprefix));
939: }
940: }
942: if (!opsset) {
943: PetscCall(PCGetUseAmat(pc, &use_amat));
944: if (use_amat) {
945: PetscCall(PetscInfo(pc, "Using outer operators to define finest grid operator \n because PCMGGetSmoother(pc,nlevels-1,&ksp);KSPSetOperators(ksp,...); was not called.\n"));
946: PetscCall(KSPSetOperators(mglevels[n - 1]->smoothd, pc->mat, pc->pmat));
947: } else {
948: PetscCall(PetscInfo(pc, "Using matrix (pmat) operators to define finest grid operator \n because PCMGGetSmoother(pc,nlevels-1,&ksp);KSPSetOperators(ksp,...); was not called.\n"));
949: PetscCall(KSPSetOperators(mglevels[n - 1]->smoothd, pc->pmat, pc->pmat));
950: }
951: }
953: for (i = n - 1; i > 0; i--) {
954: if (!(mglevels[i]->interpolate || mglevels[i]->restrct)) {
955: missinginterpolate = PETSC_TRUE;
956: break;
957: }
958: }
960: PetscCall(KSPGetOperators(mglevels[n - 1]->smoothd, &dA, &dB));
961: if (dA == dB) dAeqdB = PETSC_TRUE;
962: if (mg->galerkin == PC_MG_GALERKIN_NONE || ((mg->galerkin == PC_MG_GALERKIN_PMAT || mg->galerkin == PC_MG_GALERKIN_MAT) && !dAeqdB)) needRestricts = PETSC_TRUE; /* user must compute either mat, pmat, or both so must restrict x to coarser levels */
964: if (pc->dm && !pc->setupcalled) {
965: /* finest smoother also gets DM but it is not active, independent of whether galerkin==PC_MG_GALERKIN_EXTERNAL */
966: PetscCall(KSPSetDM(mglevels[n - 1]->smoothd, pc->dm));
967: PetscCall(KSPSetDMActive(mglevels[n - 1]->smoothd, PETSC_FALSE));
968: if (mglevels[n - 1]->smoothd != mglevels[n - 1]->smoothu) {
969: PetscCall(KSPSetDM(mglevels[n - 1]->smoothu, pc->dm));
970: PetscCall(KSPSetDMActive(mglevels[n - 1]->smoothu, PETSC_FALSE));
971: }
972: if (mglevels[n - 1]->cr) {
973: PetscCall(KSPSetDM(mglevels[n - 1]->cr, pc->dm));
974: PetscCall(KSPSetDMActive(mglevels[n - 1]->cr, PETSC_FALSE));
975: }
976: }
978: /*
979: Skipping if user has provided all interpolation/restriction needed (since DM might not be able to produce them (when coming from SNES/TS)
980: Skipping for externally managed hierarchy (such as ML and GAMG). Cleaner logic here would be great. Wrap ML/GAMG as DMs?
981: */
982: if (missinginterpolate && mg->galerkin != PC_MG_GALERKIN_EXTERNAL && !pc->setupcalled) {
983: /* first see if we can compute a coarse space */
984: if (mg->coarseSpaceType == PCMG_ADAPT_GDSW) {
985: for (i = n - 2; i > -1; i--) {
986: if (!mglevels[i + 1]->restrct && !mglevels[i + 1]->interpolate) {
987: PetscCall(PCMGComputeCoarseSpace_Internal(pc, i + 1, mg->coarseSpaceType, mg->Nc, NULL, &mglevels[i + 1]->coarseSpace));
988: PetscCall(PCMGSetInterpolation(pc, i + 1, mglevels[i + 1]->coarseSpace));
989: }
990: }
991: } else { /* construct the interpolation from the DMs */
992: Mat p;
993: Vec rscale;
995: PetscCheck(n == 1 || pc->dm, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "PC lacks a DM so cannot automatically construct a multigrid hierarchy. Number of levels requested %" PetscInt_FMT, n);
996: PetscCall(PetscMalloc1(n, &dms));
997: dms[n - 1] = pc->dm;
998: /* Separately create them so we do not get DMKSP interference between levels */
999: for (i = n - 2; i > -1; i--) PetscCall(DMCoarsen(dms[i + 1], MPI_COMM_NULL, &dms[i]));
1000: for (i = n - 2; i > -1; i--) {
1001: DMKSP kdm;
1002: PetscBool dmhasrestrict, dmhasinject;
1004: PetscCall(KSPSetDM(mglevels[i]->smoothd, dms[i]));
1005: if (!needRestricts) PetscCall(KSPSetDMActive(mglevels[i]->smoothd, PETSC_FALSE));
1006: if (mglevels[i]->smoothd != mglevels[i]->smoothu) {
1007: PetscCall(KSPSetDM(mglevels[i]->smoothu, dms[i]));
1008: if (!needRestricts) PetscCall(KSPSetDMActive(mglevels[i]->smoothu, PETSC_FALSE));
1009: }
1010: if (mglevels[i]->cr) {
1011: PetscCall(KSPSetDM(mglevels[i]->cr, dms[i]));
1012: if (!needRestricts) PetscCall(KSPSetDMActive(mglevels[i]->cr, PETSC_FALSE));
1013: }
1014: PetscCall(DMGetDMKSPWrite(dms[i], &kdm));
1015: /* Ugly hack so that the next KSPSetUp() will use the RHS that we set. A better fix is to change dmActive to take
1016: * a bitwise OR of computing the matrix, RHS, and initial iterate. */
1017: kdm->ops->computerhs = NULL;
1018: kdm->rhsctx = NULL;
1019: if (!mglevels[i + 1]->interpolate) {
1020: PetscCall(DMCreateInterpolation(dms[i], dms[i + 1], &p, &rscale));
1021: PetscCall(PCMGSetInterpolation(pc, i + 1, p));
1022: if (rscale) PetscCall(PCMGSetRScale(pc, i + 1, rscale));
1023: PetscCall(VecDestroy(&rscale));
1024: PetscCall(MatDestroy(&p));
1025: }
1026: PetscCall(DMHasCreateRestriction(dms[i], &dmhasrestrict));
1027: if (dmhasrestrict && !mglevels[i + 1]->restrct) {
1028: PetscCall(DMCreateRestriction(dms[i], dms[i + 1], &p));
1029: PetscCall(PCMGSetRestriction(pc, i + 1, p));
1030: PetscCall(MatDestroy(&p));
1031: }
1032: PetscCall(DMHasCreateInjection(dms[i], &dmhasinject));
1033: if (dmhasinject && !mglevels[i + 1]->inject) {
1034: PetscCall(DMCreateInjection(dms[i], dms[i + 1], &p));
1035: PetscCall(PCMGSetInjection(pc, i + 1, p));
1036: PetscCall(MatDestroy(&p));
1037: }
1038: }
1040: for (i = n - 2; i > -1; i--) PetscCall(DMDestroy(&dms[i]));
1041: PetscCall(PetscFree(dms));
1042: }
1043: }
1045: if (mg->galerkin < PC_MG_GALERKIN_NONE) {
1046: Mat A, B;
1047: PetscBool doA = PETSC_FALSE, doB = PETSC_FALSE;
1048: MatReuse reuse = MAT_INITIAL_MATRIX;
1050: if (mg->galerkin == PC_MG_GALERKIN_PMAT || mg->galerkin == PC_MG_GALERKIN_BOTH) doB = PETSC_TRUE;
1051: if (mg->galerkin == PC_MG_GALERKIN_MAT || (mg->galerkin == PC_MG_GALERKIN_BOTH && dA != dB)) doA = PETSC_TRUE;
1052: if (pc->setupcalled) reuse = MAT_REUSE_MATRIX;
1053: for (i = n - 2; i > -1; i--) {
1054: PetscCheck(mglevels[i + 1]->restrct || mglevels[i + 1]->interpolate, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must provide interpolation or restriction for each MG level except level 0");
1055: if (!mglevels[i + 1]->interpolate) PetscCall(PCMGSetInterpolation(pc, i + 1, mglevels[i + 1]->restrct));
1056: if (!mglevels[i + 1]->restrct) PetscCall(PCMGSetRestriction(pc, i + 1, mglevels[i + 1]->interpolate));
1057: if (reuse == MAT_REUSE_MATRIX) PetscCall(KSPGetOperators(mglevels[i]->smoothd, &A, &B));
1058: if (doA) PetscCall(MatGalerkin(mglevels[i + 1]->restrct, dA, mglevels[i + 1]->interpolate, reuse, 1.0, &A));
1059: if (doB) PetscCall(MatGalerkin(mglevels[i + 1]->restrct, dB, mglevels[i + 1]->interpolate, reuse, 1.0, &B));
1060: /* the management of the PetscObjectReference() and PetscObjecDereference() below is rather delicate */
1061: if (!doA && dAeqdB) {
1062: if (reuse == MAT_INITIAL_MATRIX) PetscCall(PetscObjectReference((PetscObject)B));
1063: A = B;
1064: } else if (!doA && reuse == MAT_INITIAL_MATRIX) {
1065: PetscCall(KSPGetOperators(mglevels[i]->smoothd, &A, NULL));
1066: PetscCall(PetscObjectReference((PetscObject)A));
1067: }
1068: if (!doB && dAeqdB) {
1069: if (reuse == MAT_INITIAL_MATRIX) PetscCall(PetscObjectReference((PetscObject)A));
1070: B = A;
1071: } else if (!doB && reuse == MAT_INITIAL_MATRIX) {
1072: PetscCall(KSPGetOperators(mglevels[i]->smoothd, NULL, &B));
1073: PetscCall(PetscObjectReference((PetscObject)B));
1074: }
1075: if (reuse == MAT_INITIAL_MATRIX) {
1076: PetscCall(KSPSetOperators(mglevels[i]->smoothd, A, B));
1077: PetscCall(PetscObjectDereference((PetscObject)A));
1078: PetscCall(PetscObjectDereference((PetscObject)B));
1079: }
1080: dA = A;
1081: dB = B;
1082: }
1083: }
1085: /* Adapt interpolation matrices */
1086: if (adaptInterpolation) {
1087: for (i = 0; i < n; ++i) {
1088: if (!mglevels[i]->coarseSpace) PetscCall(PCMGComputeCoarseSpace_Internal(pc, i, mg->coarseSpaceType, mg->Nc, !i ? NULL : mglevels[i - 1]->coarseSpace, &mglevels[i]->coarseSpace));
1089: if (i) PetscCall(PCMGAdaptInterpolator_Internal(pc, i, mglevels[i - 1]->smoothu, mglevels[i]->smoothu, mglevels[i - 1]->coarseSpace, mglevels[i]->coarseSpace));
1090: }
1091: for (i = n - 2; i > -1; --i) PetscCall(PCMGRecomputeLevelOperators_Internal(pc, i));
1092: }
1094: if (needRestricts && pc->dm) {
1095: for (i = n - 2; i >= 0; i--) {
1096: DM dmfine, dmcoarse;
1097: Mat Restrict, Inject;
1098: Vec rscale;
1100: PetscCall(KSPGetDM(mglevels[i + 1]->smoothd, &dmfine));
1101: PetscCall(KSPGetDM(mglevels[i]->smoothd, &dmcoarse));
1102: PetscCall(PCMGGetRestriction(pc, i + 1, &Restrict));
1103: PetscCall(PCMGGetRScale(pc, i + 1, &rscale));
1104: PetscCall(PCMGGetInjection(pc, i + 1, &Inject));
1105: PetscCall(DMRestrict(dmfine, Restrict, rscale, Inject, dmcoarse));
1106: }
1107: }
1109: if (!pc->setupcalled) {
1110: for (i = 0; i < n; i++) PetscCall(KSPSetFromOptions(mglevels[i]->smoothd));
1111: for (i = 1; i < n; i++) {
1112: if (mglevels[i]->smoothu && (mglevels[i]->smoothu != mglevels[i]->smoothd)) PetscCall(KSPSetFromOptions(mglevels[i]->smoothu));
1113: if (mglevels[i]->cr) PetscCall(KSPSetFromOptions(mglevels[i]->cr));
1114: }
1115: /* insure that if either interpolation or restriction is set the other one is set */
1116: for (i = 1; i < n; i++) {
1117: PetscCall(PCMGGetInterpolation(pc, i, NULL));
1118: PetscCall(PCMGGetRestriction(pc, i, NULL));
1119: }
1120: for (i = 0; i < n - 1; i++) {
1121: if (!mglevels[i]->b) {
1122: Vec *vec;
1123: PetscCall(KSPCreateVecs(mglevels[i]->smoothd, 1, &vec, 0, NULL));
1124: PetscCall(PCMGSetRhs(pc, i, *vec));
1125: PetscCall(VecDestroy(vec));
1126: PetscCall(PetscFree(vec));
1127: }
1128: if (!mglevels[i]->r && i) {
1129: PetscCall(VecDuplicate(mglevels[i]->b, &tvec));
1130: PetscCall(PCMGSetR(pc, i, tvec));
1131: PetscCall(VecDestroy(&tvec));
1132: }
1133: if (!mglevels[i]->x) {
1134: PetscCall(VecDuplicate(mglevels[i]->b, &tvec));
1135: PetscCall(PCMGSetX(pc, i, tvec));
1136: PetscCall(VecDestroy(&tvec));
1137: }
1138: if (doCR) {
1139: PetscCall(VecDuplicate(mglevels[i]->b, &mglevels[i]->crx));
1140: PetscCall(VecDuplicate(mglevels[i]->b, &mglevels[i]->crb));
1141: PetscCall(VecZeroEntries(mglevels[i]->crb));
1142: }
1143: }
1144: if (n != 1 && !mglevels[n - 1]->r) {
1145: /* PCMGSetR() on the finest level if user did not supply it */
1146: Vec *vec;
1148: PetscCall(KSPCreateVecs(mglevels[n - 1]->smoothd, 1, &vec, 0, NULL));
1149: PetscCall(PCMGSetR(pc, n - 1, *vec));
1150: PetscCall(VecDestroy(vec));
1151: PetscCall(PetscFree(vec));
1152: }
1153: if (doCR) {
1154: PetscCall(VecDuplicate(mglevels[n - 1]->r, &mglevels[n - 1]->crx));
1155: PetscCall(VecDuplicate(mglevels[n - 1]->r, &mglevels[n - 1]->crb));
1156: PetscCall(VecZeroEntries(mglevels[n - 1]->crb));
1157: }
1158: }
1160: if (pc->dm) {
1161: /* need to tell all the coarser levels to rebuild the matrix using the DM for that level */
1162: for (i = 0; i < n - 1; i++) {
1163: if (mglevels[i]->smoothd->setupstage != KSP_SETUP_NEW) mglevels[i]->smoothd->setupstage = KSP_SETUP_NEWMATRIX;
1164: }
1165: }
1166: // We got here (PCSetUp_MG) because the matrix has changed, which means the smoother needs to be set up again (e.g.,
1167: // new diagonal for Jacobi). Setting it here allows it to be logged under PCSetUp rather than deep inside a PCApply.
1168: if (mglevels[n - 1]->smoothd->setupstage != KSP_SETUP_NEW) mglevels[n - 1]->smoothd->setupstage = KSP_SETUP_NEWMATRIX;
1170: for (i = 1; i < n; i++) {
1171: if (mglevels[i]->smoothu == mglevels[i]->smoothd || mg->am == PC_MG_FULL || mg->am == PC_MG_KASKADE || mg->cyclesperpcapply > 1) {
1172: /* if doing only down then initial guess is zero */
1173: PetscCall(KSPSetInitialGuessNonzero(mglevels[i]->smoothd, PETSC_TRUE));
1174: }
1175: if (mglevels[i]->cr) PetscCall(KSPSetInitialGuessNonzero(mglevels[i]->cr, PETSC_TRUE));
1176: if (mglevels[i]->eventsmoothsetup) PetscCall(PetscLogEventBegin(mglevels[i]->eventsmoothsetup, 0, 0, 0, 0));
1177: PetscCall(KSPSetUp(mglevels[i]->smoothd));
1178: if (mglevels[i]->smoothd->reason) pc->failedreason = PC_SUBPC_ERROR;
1179: if (mglevels[i]->eventsmoothsetup) PetscCall(PetscLogEventEnd(mglevels[i]->eventsmoothsetup, 0, 0, 0, 0));
1180: if (!mglevels[i]->residual) {
1181: Mat mat;
1183: PetscCall(KSPGetOperators(mglevels[i]->smoothd, &mat, NULL));
1184: PetscCall(PCMGSetResidual(pc, i, PCMGResidualDefault, mat));
1185: }
1186: if (!mglevels[i]->residualtranspose) {
1187: Mat mat;
1189: PetscCall(KSPGetOperators(mglevels[i]->smoothd, &mat, NULL));
1190: PetscCall(PCMGSetResidualTranspose(pc, i, PCMGResidualTransposeDefault, mat));
1191: }
1192: }
1193: for (i = 1; i < n; i++) {
1194: if (mglevels[i]->smoothu && mglevels[i]->smoothu != mglevels[i]->smoothd) {
1195: Mat downmat, downpmat;
1197: /* check if operators have been set for up, if not use down operators to set them */
1198: PetscCall(KSPGetOperatorsSet(mglevels[i]->smoothu, &opsset, NULL));
1199: if (!opsset) {
1200: PetscCall(KSPGetOperators(mglevels[i]->smoothd, &downmat, &downpmat));
1201: PetscCall(KSPSetOperators(mglevels[i]->smoothu, downmat, downpmat));
1202: }
1204: PetscCall(KSPSetInitialGuessNonzero(mglevels[i]->smoothu, PETSC_TRUE));
1205: if (mglevels[i]->eventsmoothsetup) PetscCall(PetscLogEventBegin(mglevels[i]->eventsmoothsetup, 0, 0, 0, 0));
1206: PetscCall(KSPSetUp(mglevels[i]->smoothu));
1207: if (mglevels[i]->smoothu->reason) pc->failedreason = PC_SUBPC_ERROR;
1208: if (mglevels[i]->eventsmoothsetup) PetscCall(PetscLogEventEnd(mglevels[i]->eventsmoothsetup, 0, 0, 0, 0));
1209: }
1210: if (mglevels[i]->cr) {
1211: Mat downmat, downpmat;
1213: /* check if operators have been set for up, if not use down operators to set them */
1214: PetscCall(KSPGetOperatorsSet(mglevels[i]->cr, &opsset, NULL));
1215: if (!opsset) {
1216: PetscCall(KSPGetOperators(mglevels[i]->smoothd, &downmat, &downpmat));
1217: PetscCall(KSPSetOperators(mglevels[i]->cr, downmat, downpmat));
1218: }
1220: PetscCall(KSPSetInitialGuessNonzero(mglevels[i]->cr, PETSC_TRUE));
1221: if (mglevels[i]->eventsmoothsetup) PetscCall(PetscLogEventBegin(mglevels[i]->eventsmoothsetup, 0, 0, 0, 0));
1222: PetscCall(KSPSetUp(mglevels[i]->cr));
1223: if (mglevels[i]->cr->reason) pc->failedreason = PC_SUBPC_ERROR;
1224: if (mglevels[i]->eventsmoothsetup) PetscCall(PetscLogEventEnd(mglevels[i]->eventsmoothsetup, 0, 0, 0, 0));
1225: }
1226: }
1228: if (mglevels[0]->eventsmoothsetup) PetscCall(PetscLogEventBegin(mglevels[0]->eventsmoothsetup, 0, 0, 0, 0));
1229: PetscCall(KSPSetUp(mglevels[0]->smoothd));
1230: if (mglevels[0]->smoothd->reason) pc->failedreason = PC_SUBPC_ERROR;
1231: if (mglevels[0]->eventsmoothsetup) PetscCall(PetscLogEventEnd(mglevels[0]->eventsmoothsetup, 0, 0, 0, 0));
1233: /*
1234: Dump the interpolation/restriction matrices plus the
1235: Jacobian/stiffness on each level. This allows MATLAB users to
1236: easily check if the Galerkin condition A_c = R A_f R^T is satisfied.
1238: Only support one or the other at the same time.
1239: */
1240: #if defined(PETSC_USE_SOCKET_VIEWER)
1241: PetscCall(PetscOptionsGetBool(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, "-pc_mg_dump_matlab", &dump, NULL));
1242: if (dump) viewer = PETSC_VIEWER_SOCKET_(PetscObjectComm((PetscObject)pc));
1243: dump = PETSC_FALSE;
1244: #endif
1245: PetscCall(PetscOptionsGetBool(((PetscObject)pc)->options, ((PetscObject)pc)->prefix, "-pc_mg_dump_binary", &dump, NULL));
1246: if (dump) viewer = PETSC_VIEWER_BINARY_(PetscObjectComm((PetscObject)pc));
1248: if (viewer) {
1249: for (i = 1; i < n; i++) PetscCall(MatView(mglevels[i]->restrct, viewer));
1250: for (i = 0; i < n; i++) {
1251: PetscCall(KSPGetPC(mglevels[i]->smoothd, &pc));
1252: PetscCall(MatView(pc->mat, viewer));
1253: }
1254: }
1255: PetscFunctionReturn(PETSC_SUCCESS);
1256: }
1258: PetscErrorCode PCMGGetLevels_MG(PC pc, PetscInt *levels)
1259: {
1260: PC_MG *mg = (PC_MG *)pc->data;
1262: PetscFunctionBegin;
1263: *levels = mg->nlevels;
1264: PetscFunctionReturn(PETSC_SUCCESS);
1265: }
1267: /*@
1268: PCMGGetLevels - Gets the number of levels to use with `PCMG`.
1270: Not Collective
1272: Input Parameter:
1273: . pc - the preconditioner context
1275: Output Parameter:
1276: . levels - the number of levels
1278: Level: advanced
1280: .seealso: [](ch_ksp), `PCMG`, `PCMGSetLevels()`
1281: @*/
1282: PetscErrorCode PCMGGetLevels(PC pc, PetscInt *levels)
1283: {
1284: PetscFunctionBegin;
1286: PetscAssertPointer(levels, 2);
1287: *levels = 0;
1288: PetscTryMethod(pc, "PCMGGetLevels_C", (PC, PetscInt *), (pc, levels));
1289: PetscFunctionReturn(PETSC_SUCCESS);
1290: }
1292: /*@
1293: PCMGGetGridComplexity - compute operator and grid complexity of the `PCMG` hierarchy
1295: Input Parameter:
1296: . pc - the preconditioner context
1298: Output Parameters:
1299: + gc - grid complexity = sum_i(n_i) / n_0
1300: - oc - operator complexity = sum_i(nnz_i) / nnz_0
1302: Level: advanced
1304: Note:
1305: This is often call the operator complexity in multigrid literature
1307: .seealso: [](ch_ksp), `PCMG`, `PCMGGetLevels()`, `PCMGSetLevels()`
1308: @*/
1309: PetscErrorCode PCMGGetGridComplexity(PC pc, PetscReal *gc, PetscReal *oc)
1310: {
1311: PC_MG *mg = (PC_MG *)pc->data;
1312: PC_MG_Levels **mglevels = mg->levels;
1313: PetscInt lev, N;
1314: PetscLogDouble nnz0 = 0, sgc = 0, soc = 0, n0 = 0;
1315: MatInfo info;
1317: PetscFunctionBegin;
1319: if (gc) PetscAssertPointer(gc, 2);
1320: if (oc) PetscAssertPointer(oc, 3);
1321: if (!pc->setupcalled) {
1322: if (gc) *gc = 0;
1323: if (oc) *oc = 0;
1324: PetscFunctionReturn(PETSC_SUCCESS);
1325: }
1326: PetscCheck(mg->nlevels > 0, PETSC_COMM_SELF, PETSC_ERR_PLIB, "MG has no levels");
1327: for (lev = 0; lev < mg->nlevels; lev++) {
1328: Mat dB;
1329: PetscCall(KSPGetOperators(mglevels[lev]->smoothd, NULL, &dB));
1330: PetscCall(MatGetInfo(dB, MAT_GLOBAL_SUM, &info)); /* global reduction */
1331: PetscCall(MatGetSize(dB, &N, NULL));
1332: sgc += N;
1333: soc += info.nz_used;
1334: if (lev == mg->nlevels - 1) {
1335: nnz0 = info.nz_used;
1336: n0 = N;
1337: }
1338: }
1339: PetscCheck(n0 > 0 && gc, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Number for grid points on finest level is not available");
1340: *gc = (PetscReal)(sgc / n0);
1341: if (nnz0 > 0 && oc) *oc = (PetscReal)(soc / nnz0);
1342: PetscFunctionReturn(PETSC_SUCCESS);
1343: }
1345: /*@
1346: PCMGSetType - Determines the form of multigrid to use, either
1347: multiplicative, additive, full, or the Kaskade algorithm.
1349: Logically Collective
1351: Input Parameters:
1352: + pc - the preconditioner context
1353: - form - multigrid form, one of `PC_MG_MULTIPLICATIVE`, `PC_MG_ADDITIVE`, `PC_MG_FULL`, `PC_MG_KASKADE`
1355: Options Database Key:
1356: . -pc_mg_type <form> - Sets <form>, one of multiplicative, additive, full, kaskade
1358: Level: advanced
1360: .seealso: [](ch_ksp), `PCMGType`, `PCMG`, `PCMGGetLevels()`, `PCMGSetLevels()`, `PCMGGetType()`, `PCMGCycleType`
1361: @*/
1362: PetscErrorCode PCMGSetType(PC pc, PCMGType form)
1363: {
1364: PC_MG *mg = (PC_MG *)pc->data;
1366: PetscFunctionBegin;
1369: mg->am = form;
1370: if (form == PC_MG_MULTIPLICATIVE) pc->ops->applyrichardson = PCApplyRichardson_MG;
1371: else pc->ops->applyrichardson = NULL;
1372: PetscFunctionReturn(PETSC_SUCCESS);
1373: }
1375: /*@
1376: PCMGGetType - Finds the form of multigrid the `PCMG` is using multiplicative, additive, full, or the Kaskade algorithm.
1378: Logically Collective
1380: Input Parameter:
1381: . pc - the preconditioner context
1383: Output Parameter:
1384: . type - one of `PC_MG_MULTIPLICATIVE`, `PC_MG_ADDITIVE`, `PC_MG_FULL`, `PC_MG_KASKADE`, `PCMGCycleType`
1386: Level: advanced
1388: .seealso: [](ch_ksp), `PCMGType`, `PCMG`, `PCMGGetLevels()`, `PCMGSetLevels()`, `PCMGSetType()`
1389: @*/
1390: PetscErrorCode PCMGGetType(PC pc, PCMGType *type)
1391: {
1392: PC_MG *mg = (PC_MG *)pc->data;
1394: PetscFunctionBegin;
1396: *type = mg->am;
1397: PetscFunctionReturn(PETSC_SUCCESS);
1398: }
1400: /*@
1401: PCMGSetCycleType - Sets the type cycles to use. Use `PCMGSetCycleTypeOnLevel()` for more
1402: complicated cycling.
1404: Logically Collective
1406: Input Parameters:
1407: + pc - the multigrid context
1408: - n - either `PC_MG_CYCLE_V` or `PC_MG_CYCLE_W`
1410: Options Database Key:
1411: . -pc_mg_cycle_type <v,w> - provide the cycle desired
1413: Level: advanced
1415: .seealso: [](ch_ksp), `PCMG`, `PCMGSetCycleTypeOnLevel()`, `PCMGType`, `PCMGCycleType`
1416: @*/
1417: PetscErrorCode PCMGSetCycleType(PC pc, PCMGCycleType n)
1418: {
1419: PC_MG *mg = (PC_MG *)pc->data;
1420: PC_MG_Levels **mglevels = mg->levels;
1421: PetscInt i, levels;
1423: PetscFunctionBegin;
1426: PetscCheck(mglevels, PetscObjectComm((PetscObject)pc), PETSC_ERR_ORDER, "Must set MG levels with PCMGSetLevels() before calling");
1427: levels = mglevels[0]->levels;
1428: for (i = 0; i < levels; i++) mglevels[i]->cycles = n;
1429: PetscFunctionReturn(PETSC_SUCCESS);
1430: }
1432: /*@
1433: PCMGMultiplicativeSetCycles - Sets the number of cycles to use for each preconditioner step
1434: of multigrid when `PCMGType` is `PC_MG_MULTIPLICATIVE`
1436: Logically Collective
1438: Input Parameters:
1439: + pc - the multigrid context
1440: - n - number of cycles (default is 1)
1442: Options Database Key:
1443: . -pc_mg_multiplicative_cycles n - set the number of cycles
1445: Level: advanced
1447: Note:
1448: This is not associated with setting a v or w cycle, that is set with `PCMGSetCycleType()`
1450: .seealso: [](ch_ksp), `PCMGSetCycleTypeOnLevel()`, `PCMGSetCycleType()`, `PCMGCycleType`, `PCMGType`
1451: @*/
1452: PetscErrorCode PCMGMultiplicativeSetCycles(PC pc, PetscInt n)
1453: {
1454: PC_MG *mg = (PC_MG *)pc->data;
1456: PetscFunctionBegin;
1459: mg->cyclesperpcapply = n;
1460: PetscFunctionReturn(PETSC_SUCCESS);
1461: }
1463: /*
1464: Since the finest level KSP shares the original matrix (of the entire system), it's preconditioner
1465: should not be updated if the whole PC is supposed to reuse the preconditioner
1466: */
1467: static PetscErrorCode PCSetReusePreconditioner_MG(PC pc, PetscBool flag)
1468: {
1469: PC_MG *mg = (PC_MG *)pc->data;
1470: PC_MG_Levels **mglevels = mg->levels;
1471: PetscInt levels;
1472: PC tpc;
1474: PetscFunctionBegin;
1477: if (mglevels) {
1478: levels = mglevels[0]->levels;
1479: PetscCall(KSPGetPC(mglevels[levels - 1]->smoothd, &tpc));
1480: tpc->reusepreconditioner = flag;
1481: PetscCall(KSPGetPC(mglevels[levels - 1]->smoothu, &tpc));
1482: tpc->reusepreconditioner = flag;
1483: }
1484: PetscFunctionReturn(PETSC_SUCCESS);
1485: }
1487: static PetscErrorCode PCMGSetGalerkin_MG(PC pc, PCMGGalerkinType use)
1488: {
1489: PC_MG *mg = (PC_MG *)pc->data;
1491: PetscFunctionBegin;
1492: mg->galerkin = use;
1493: PetscFunctionReturn(PETSC_SUCCESS);
1494: }
1496: /*@
1497: PCMGSetGalerkin - Causes the coarser grid matrices to be computed from the
1498: finest grid via the Galerkin process: A_i-1 = r_i * A_i * p_i
1500: Logically Collective
1502: Input Parameters:
1503: + pc - the multigrid context
1504: - use - one of `PC_MG_GALERKIN_BOTH`, `PC_MG_GALERKIN_PMAT`, `PC_MG_GALERKIN_MAT`, or `PC_MG_GALERKIN_NONE`
1506: Options Database Key:
1507: . -pc_mg_galerkin <both,pmat,mat,none> - set the matrices to form via the Galerkin process
1509: Level: intermediate
1511: Note:
1512: Some codes that use `PCMG` such as `PCGAMG` use Galerkin internally while constructing the hierarchy and thus do not
1513: use the `PCMG` construction of the coarser grids.
1515: .seealso: [](ch_ksp), `PCMG`, `PCMGGetGalerkin()`, `PCMGGalerkinType`
1516: @*/
1517: PetscErrorCode PCMGSetGalerkin(PC pc, PCMGGalerkinType use)
1518: {
1519: PetscFunctionBegin;
1521: PetscTryMethod(pc, "PCMGSetGalerkin_C", (PC, PCMGGalerkinType), (pc, use));
1522: PetscFunctionReturn(PETSC_SUCCESS);
1523: }
1525: /*@
1526: PCMGGetGalerkin - Checks if Galerkin multigrid is being used, i.e. A_i-1 = r_i * A_i * p_i
1528: Not Collective
1530: Input Parameter:
1531: . pc - the multigrid context
1533: Output Parameter:
1534: . galerkin - one of `PC_MG_GALERKIN_BOTH`,`PC_MG_GALERKIN_PMAT`,`PC_MG_GALERKIN_MAT`, `PC_MG_GALERKIN_NONE`, or `PC_MG_GALERKIN_EXTERNAL`
1536: Level: intermediate
1538: .seealso: [](ch_ksp), `PCMG`, `PCMGSetGalerkin()`, `PCMGGalerkinType`
1539: @*/
1540: PetscErrorCode PCMGGetGalerkin(PC pc, PCMGGalerkinType *galerkin)
1541: {
1542: PC_MG *mg = (PC_MG *)pc->data;
1544: PetscFunctionBegin;
1546: *galerkin = mg->galerkin;
1547: PetscFunctionReturn(PETSC_SUCCESS);
1548: }
1550: static PetscErrorCode PCMGSetAdaptInterpolation_MG(PC pc, PetscBool adapt)
1551: {
1552: PC_MG *mg = (PC_MG *)pc->data;
1554: PetscFunctionBegin;
1555: mg->adaptInterpolation = adapt;
1556: PetscFunctionReturn(PETSC_SUCCESS);
1557: }
1559: static PetscErrorCode PCMGGetAdaptInterpolation_MG(PC pc, PetscBool *adapt)
1560: {
1561: PC_MG *mg = (PC_MG *)pc->data;
1563: PetscFunctionBegin;
1564: *adapt = mg->adaptInterpolation;
1565: PetscFunctionReturn(PETSC_SUCCESS);
1566: }
1568: static PetscErrorCode PCMGSetAdaptCoarseSpaceType_MG(PC pc, PCMGCoarseSpaceType ctype)
1569: {
1570: PC_MG *mg = (PC_MG *)pc->data;
1572: PetscFunctionBegin;
1573: mg->adaptInterpolation = ctype != PCMG_ADAPT_NONE ? PETSC_TRUE : PETSC_FALSE;
1574: mg->coarseSpaceType = ctype;
1575: PetscCall(PCMGSetGalerkin(pc, PC_MG_GALERKIN_BOTH));
1576: PetscFunctionReturn(PETSC_SUCCESS);
1577: }
1579: static PetscErrorCode PCMGGetAdaptCoarseSpaceType_MG(PC pc, PCMGCoarseSpaceType *ctype)
1580: {
1581: PC_MG *mg = (PC_MG *)pc->data;
1583: PetscFunctionBegin;
1584: *ctype = mg->coarseSpaceType;
1585: PetscFunctionReturn(PETSC_SUCCESS);
1586: }
1588: static PetscErrorCode PCMGSetAdaptCR_MG(PC pc, PetscBool cr)
1589: {
1590: PC_MG *mg = (PC_MG *)pc->data;
1592: PetscFunctionBegin;
1593: mg->compatibleRelaxation = cr;
1594: PetscFunctionReturn(PETSC_SUCCESS);
1595: }
1597: static PetscErrorCode PCMGGetAdaptCR_MG(PC pc, PetscBool *cr)
1598: {
1599: PC_MG *mg = (PC_MG *)pc->data;
1601: PetscFunctionBegin;
1602: *cr = mg->compatibleRelaxation;
1603: PetscFunctionReturn(PETSC_SUCCESS);
1604: }
1606: /*@
1607: PCMGSetAdaptCoarseSpaceType - Set the type of adaptive coarse space.
1609: Adapts or creates the interpolator based upon a vector space which should be accurately captured by the next coarser mesh, and thus accurately interpolated.
1611: Logically Collective
1613: Input Parameters:
1614: + pc - the multigrid context
1615: - ctype - the type of coarse space
1617: Options Database Keys:
1618: + -pc_mg_adapt_interp_n <int> - The number of modes to use
1619: - -pc_mg_adapt_interp_coarse_space <type> - The type of coarse space: none, `polynomial`, `harmonic`, `eigenvector`, `generalized_eigenvector`, `gdsw`
1621: Level: intermediate
1623: Note:
1624: Requires a `DM` with specific functionality be attached to the `PC`.
1626: .seealso: [](ch_ksp), `PCMG`, `PCMGCoarseSpaceType`, `PCMGGetAdaptCoarseSpaceType()`, `PCMGSetGalerkin()`, `PCMGSetAdaptInterpolation()`, `DM`
1627: @*/
1628: PetscErrorCode PCMGSetAdaptCoarseSpaceType(PC pc, PCMGCoarseSpaceType ctype)
1629: {
1630: PetscFunctionBegin;
1633: PetscTryMethod(pc, "PCMGSetAdaptCoarseSpaceType_C", (PC, PCMGCoarseSpaceType), (pc, ctype));
1634: PetscFunctionReturn(PETSC_SUCCESS);
1635: }
1637: /*@
1638: PCMGGetAdaptCoarseSpaceType - Get the type of adaptive coarse space.
1640: Not Collective
1642: Input Parameter:
1643: . pc - the multigrid context
1645: Output Parameter:
1646: . ctype - the type of coarse space
1648: Level: intermediate
1650: .seealso: [](ch_ksp), `PCMG`, `PCMGCoarseSpaceType`, `PCMGSetAdaptCoarseSpaceType()`, `PCMGSetGalerkin()`, `PCMGSetAdaptInterpolation()`
1651: @*/
1652: PetscErrorCode PCMGGetAdaptCoarseSpaceType(PC pc, PCMGCoarseSpaceType *ctype)
1653: {
1654: PetscFunctionBegin;
1656: PetscAssertPointer(ctype, 2);
1657: PetscUseMethod(pc, "PCMGGetAdaptCoarseSpaceType_C", (PC, PCMGCoarseSpaceType *), (pc, ctype));
1658: PetscFunctionReturn(PETSC_SUCCESS);
1659: }
1661: /* MATT: REMOVE? */
1662: /*@
1663: PCMGSetAdaptInterpolation - Adapt the interpolator based upon a vector space which should be accurately captured by the next coarser mesh, and thus accurately interpolated.
1665: Logically Collective
1667: Input Parameters:
1668: + pc - the multigrid context
1669: - adapt - flag for adaptation of the interpolator
1671: Options Database Keys:
1672: + -pc_mg_adapt_interp - Turn on adaptation
1673: . -pc_mg_adapt_interp_n <int> - The number of modes to use, should be divisible by dimension
1674: - -pc_mg_adapt_interp_coarse_space <type> - The type of coarse space: polynomial, harmonic, eigenvector, generalized_eigenvector
1676: Level: intermediate
1678: .seealso: [](ch_ksp), `PCMG`, `PCMGGetAdaptInterpolation()`, `PCMGSetGalerkin()`, `PCMGGetAdaptCoarseSpaceType()`, `PCMGSetAdaptCoarseSpaceType()`
1679: @*/
1680: PetscErrorCode PCMGSetAdaptInterpolation(PC pc, PetscBool adapt)
1681: {
1682: PetscFunctionBegin;
1684: PetscTryMethod(pc, "PCMGSetAdaptInterpolation_C", (PC, PetscBool), (pc, adapt));
1685: PetscFunctionReturn(PETSC_SUCCESS);
1686: }
1688: /*@
1689: PCMGGetAdaptInterpolation - Get the flag to adapt the interpolator based upon a vector space which should be accurately captured by the next coarser mesh,
1690: and thus accurately interpolated.
1692: Not Collective
1694: Input Parameter:
1695: . pc - the multigrid context
1697: Output Parameter:
1698: . adapt - flag for adaptation of the interpolator
1700: Level: intermediate
1702: .seealso: [](ch_ksp), `PCMG`, `PCMGSetAdaptInterpolation()`, `PCMGSetGalerkin()`, `PCMGGetAdaptCoarseSpaceType()`, `PCMGSetAdaptCoarseSpaceType()`
1703: @*/
1704: PetscErrorCode PCMGGetAdaptInterpolation(PC pc, PetscBool *adapt)
1705: {
1706: PetscFunctionBegin;
1708: PetscAssertPointer(adapt, 2);
1709: PetscUseMethod(pc, "PCMGGetAdaptInterpolation_C", (PC, PetscBool *), (pc, adapt));
1710: PetscFunctionReturn(PETSC_SUCCESS);
1711: }
1713: /*@
1714: PCMGSetAdaptCR - Monitor the coarse space quality using an auxiliary solve with compatible relaxation.
1716: Logically Collective
1718: Input Parameters:
1719: + pc - the multigrid context
1720: - cr - flag for compatible relaxation
1722: Options Database Key:
1723: . -pc_mg_adapt_cr - Turn on compatible relaxation
1725: Level: intermediate
1727: .seealso: [](ch_ksp), `PCMG`, `PCMGGetAdaptCR()`, `PCMGSetAdaptInterpolation()`, `PCMGSetGalerkin()`, `PCMGGetAdaptCoarseSpaceType()`, `PCMGSetAdaptCoarseSpaceType()`
1728: @*/
1729: PetscErrorCode PCMGSetAdaptCR(PC pc, PetscBool cr)
1730: {
1731: PetscFunctionBegin;
1733: PetscTryMethod(pc, "PCMGSetAdaptCR_C", (PC, PetscBool), (pc, cr));
1734: PetscFunctionReturn(PETSC_SUCCESS);
1735: }
1737: /*@
1738: PCMGGetAdaptCR - Get the flag to monitor coarse space quality using an auxiliary solve with compatible relaxation.
1740: Not Collective
1742: Input Parameter:
1743: . pc - the multigrid context
1745: Output Parameter:
1746: . cr - flag for compatible relaxaion
1748: Level: intermediate
1750: .seealso: [](ch_ksp), `PCMGSetAdaptCR()`, `PCMGGetAdaptInterpolation()`, `PCMGSetGalerkin()`, `PCMGGetAdaptCoarseSpaceType()`, `PCMGSetAdaptCoarseSpaceType()`
1751: @*/
1752: PetscErrorCode PCMGGetAdaptCR(PC pc, PetscBool *cr)
1753: {
1754: PetscFunctionBegin;
1756: PetscAssertPointer(cr, 2);
1757: PetscUseMethod(pc, "PCMGGetAdaptCR_C", (PC, PetscBool *), (pc, cr));
1758: PetscFunctionReturn(PETSC_SUCCESS);
1759: }
1761: /*@
1762: PCMGSetNumberSmooth - Sets the number of pre and post-smoothing steps to use
1763: on all levels. Use `PCMGDistinctSmoothUp()` to create separate up and down smoothers if you want different numbers of
1764: pre- and post-smoothing steps.
1766: Logically Collective
1768: Input Parameters:
1769: + pc - the multigrid context
1770: - n - the number of smoothing steps
1772: Options Database Key:
1773: . -mg_levels_ksp_max_it <n> - Sets number of pre and post-smoothing steps
1775: Level: advanced
1777: Note:
1778: This does not set a value on the coarsest grid, since we assume that there is no separate smooth up on the coarsest grid.
1780: .seealso: [](ch_ksp), `PCMG`, `PCMGSetDistinctSmoothUp()`
1781: @*/
1782: PetscErrorCode PCMGSetNumberSmooth(PC pc, PetscInt n)
1783: {
1784: PC_MG *mg = (PC_MG *)pc->data;
1785: PC_MG_Levels **mglevels = mg->levels;
1786: PetscInt i, levels;
1788: PetscFunctionBegin;
1791: PetscCheck(mglevels, PetscObjectComm((PetscObject)pc), PETSC_ERR_ORDER, "Must set MG levels with PCMGSetLevels() before calling");
1792: levels = mglevels[0]->levels;
1794: for (i = 1; i < levels; i++) {
1795: PetscCall(KSPSetTolerances(mglevels[i]->smoothu, PETSC_CURRENT, PETSC_CURRENT, PETSC_CURRENT, n));
1796: PetscCall(KSPSetTolerances(mglevels[i]->smoothd, PETSC_CURRENT, PETSC_CURRENT, PETSC_CURRENT, n));
1797: mg->default_smoothu = n;
1798: mg->default_smoothd = n;
1799: }
1800: PetscFunctionReturn(PETSC_SUCCESS);
1801: }
1803: /*@
1804: PCMGSetDistinctSmoothUp - sets the up (post) smoother to be a separate `KSP` from the down (pre) smoother on all levels
1805: and adds the suffix _up to the options name
1807: Logically Collective
1809: Input Parameter:
1810: . pc - the preconditioner context
1812: Options Database Key:
1813: . -pc_mg_distinct_smoothup <bool> - use distinct smoothing objects
1815: Level: advanced
1817: Note:
1818: This does not set a value on the coarsest grid, since we assume that there is no separate smooth up on the coarsest grid.
1820: .seealso: [](ch_ksp), `PCMG`, `PCMGSetNumberSmooth()`
1821: @*/
1822: PetscErrorCode PCMGSetDistinctSmoothUp(PC pc)
1823: {
1824: PC_MG *mg = (PC_MG *)pc->data;
1825: PC_MG_Levels **mglevels = mg->levels;
1826: PetscInt i, levels;
1827: KSP subksp;
1829: PetscFunctionBegin;
1831: PetscCheck(mglevels, PetscObjectComm((PetscObject)pc), PETSC_ERR_ORDER, "Must set MG levels with PCMGSetLevels() before calling");
1832: levels = mglevels[0]->levels;
1834: for (i = 1; i < levels; i++) {
1835: const char *prefix = NULL;
1836: /* make sure smoother up and down are different */
1837: PetscCall(PCMGGetSmootherUp(pc, i, &subksp));
1838: PetscCall(KSPGetOptionsPrefix(mglevels[i]->smoothd, &prefix));
1839: PetscCall(KSPSetOptionsPrefix(subksp, prefix));
1840: PetscCall(KSPAppendOptionsPrefix(subksp, "up_"));
1841: }
1842: PetscFunctionReturn(PETSC_SUCCESS);
1843: }
1845: /* No new matrices are created, and the coarse operator matrices are the references to the original ones */
1846: static PetscErrorCode PCGetInterpolations_MG(PC pc, PetscInt *num_levels, Mat *interpolations[])
1847: {
1848: PC_MG *mg = (PC_MG *)pc->data;
1849: PC_MG_Levels **mglevels = mg->levels;
1850: Mat *mat;
1851: PetscInt l;
1853: PetscFunctionBegin;
1854: PetscCheck(mglevels, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must set MG levels before calling");
1855: PetscCall(PetscMalloc1(mg->nlevels, &mat));
1856: for (l = 1; l < mg->nlevels; l++) {
1857: mat[l - 1] = mglevels[l]->interpolate;
1858: PetscCall(PetscObjectReference((PetscObject)mat[l - 1]));
1859: }
1860: *num_levels = mg->nlevels;
1861: *interpolations = mat;
1862: PetscFunctionReturn(PETSC_SUCCESS);
1863: }
1865: /* No new matrices are created, and the coarse operator matrices are the references to the original ones */
1866: static PetscErrorCode PCGetCoarseOperators_MG(PC pc, PetscInt *num_levels, Mat *coarseOperators[])
1867: {
1868: PC_MG *mg = (PC_MG *)pc->data;
1869: PC_MG_Levels **mglevels = mg->levels;
1870: PetscInt l;
1871: Mat *mat;
1873: PetscFunctionBegin;
1874: PetscCheck(mglevels, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must set MG levels before calling");
1875: PetscCall(PetscMalloc1(mg->nlevels, &mat));
1876: for (l = 0; l < mg->nlevels - 1; l++) {
1877: PetscCall(KSPGetOperators(mglevels[l]->smoothd, NULL, &mat[l]));
1878: PetscCall(PetscObjectReference((PetscObject)mat[l]));
1879: }
1880: *num_levels = mg->nlevels;
1881: *coarseOperators = mat;
1882: PetscFunctionReturn(PETSC_SUCCESS);
1883: }
1885: /*@C
1886: PCMGRegisterCoarseSpaceConstructor - Adds a method to the `PCMG` package for coarse space construction.
1888: Not Collective, No Fortran Support
1890: Input Parameters:
1891: + name - name of the constructor
1892: - function - constructor routine, see `PCMGCoarseSpaceConstructorFn`
1894: Level: advanced
1896: Developer Notes:
1897: This does not appear to be used anywhere
1899: .seealso: [](ch_ksp), `PCMGCoarseSpaceConstructorFn`, `PCMG`, `PCMGGetCoarseSpaceConstructor()`, `PCRegister()`
1900: @*/
1901: PetscErrorCode PCMGRegisterCoarseSpaceConstructor(const char name[], PCMGCoarseSpaceConstructorFn *function)
1902: {
1903: PetscFunctionBegin;
1904: PetscCall(PCInitializePackage());
1905: PetscCall(PetscFunctionListAdd(&PCMGCoarseList, name, function));
1906: PetscFunctionReturn(PETSC_SUCCESS);
1907: }
1909: /*@C
1910: PCMGGetCoarseSpaceConstructor - Returns the given coarse space construction method.
1912: Not Collective, No Fortran Support
1914: Input Parameter:
1915: . name - name of the constructor
1917: Output Parameter:
1918: . function - constructor routine
1920: Level: advanced
1922: .seealso: [](ch_ksp), `PCMGCoarseSpaceConstructorFn`, `PCMG`, `PCMGRegisterCoarseSpaceConstructor()`, `PCRegister()`
1923: @*/
1924: PetscErrorCode PCMGGetCoarseSpaceConstructor(const char name[], PCMGCoarseSpaceConstructorFn **function)
1925: {
1926: PetscFunctionBegin;
1927: PetscCall(PetscFunctionListFind(PCMGCoarseList, name, function));
1928: PetscFunctionReturn(PETSC_SUCCESS);
1929: }
1931: /*MC
1932: PCMG - Use multigrid preconditioning. This preconditioner requires you provide additional information about the restriction/interpolation
1933: operators using `PCMGSetInterpolation()` and/or `PCMGSetRestriction()`(and possibly the coarser grid matrices) or a `DM` that can provide such information.
1935: Options Database Keys:
1936: + -pc_mg_levels <nlevels> - number of levels including finest
1937: . -pc_mg_cycle_type <v,w> - provide the cycle desired
1938: . -pc_mg_type <additive,multiplicative,full,kaskade> - multiplicative is the default
1939: . -pc_mg_log - log information about time spent on each level of the solver
1940: . -pc_mg_distinct_smoothup - configure up (after interpolation) and down (before restriction) smoothers separately (with different options prefixes)
1941: . -pc_mg_galerkin <both,pmat,mat,none> - use the Galerkin process to compute coarser operators, i.e., $A_{coarse} = R A_{fine} R^T$
1942: . -pc_mg_multiplicative_cycles - number of cycles to use as the preconditioner (defaults to 1)
1943: . -pc_mg_dump_matlab - dumps the matrices for each level and the restriction/interpolation matrices
1944: to a `PETSCVIEWERSOCKET` for reading from MATLAB.
1945: - -pc_mg_dump_binary -dumps the matrices for each level and the restriction/interpolation matrices
1946: to the binary output file called binaryoutput
1948: Level: intermediate
1950: Notes:
1951: `PCMG` provides a general framework for implementing multigrid methods. Use `PCGAMG` for PETSc's algebraic multigrid preconditioner, `PCHYPRE` for hypre's
1952: BoomerAMG algebraic multigrid, and `PCML` for Trilinos's ML preconditioner. `PCAMGX` provides access to NVIDIA's AmgX algebraic multigrid.
1954: If you use `KSPSetDM()` (or `SNESSetDM()` or `TSSetDM()`) with an appropriate `DM`, such as `DMDA`, then `PCMG` will use the geometric information
1955: from the `DM` to generate appropriate restriction and interpolation information and construct a geometric multigrid.
1957: If you do not provide an appropriate `DM` and do not provide restriction or interpolation operators with `PCMGSetInterpolation()` and/or `PCMGSetRestriction()`,
1958: then `PCMG` will run multigrid with only a single level (so not really multigrid).
1960: The Krylov solver (if any) and preconditioner (smoother) and their parameters are controlled from the options database with the standard
1961: options database keywords prefixed with `-mg_levels_` to affect all the levels but the coarsest, which is controlled with `-mg_coarse_`,
1962: and the finest where `-mg_fine_` can override `-mg_levels_`. One can set different preconditioners etc on specific levels with the prefix
1963: `-mg_levels_n_` where `n` is the level number (zero being the coarse level. For example
1964: .vb
1965: -mg_levels_ksp_type gmres -mg_levels_pc_type bjacobi -mg_coarse_pc_type svd -mg_levels_2_pc_type sor
1966: .ve
1967: These options also work for controlling the smoothers etc inside `PCGAMG`
1969: If one uses a Krylov method such `KSPGMRES` or `KSPCG` as the smoother than one must use `KSPFGMRES`, `KSPGCR`, or `KSPRICHARDSON` as the outer Krylov method
1971: When run with a single level the smoother options are used on that level NOT the coarse grid solver options
1973: When run with `KSPRICHARDSON` the convergence test changes slightly if monitor is turned on. The iteration count may change slightly. This
1974: is because without monitoring the residual norm is computed WITHIN each multigrid cycle on the finest level after the pre-smoothing
1975: (because the residual has just been computed for the multigrid algorithm and is hence available for free) while with monitoring the
1976: residual is computed at the end of each cycle.
1978: .seealso: [](sec_mg), `PCCreate()`, `PCSetType()`, `PCType`, `PC`, `PCMGType`, `PCEXOTIC`, `PCGAMG`, `PCML`, `PCHYPRE`
1979: `PCMGSetLevels()`, `PCMGGetLevels()`, `PCMGSetType()`, `PCMGSetCycleType()`,
1980: `PCMGSetDistinctSmoothUp()`, `PCMGGetCoarseSolve()`, `PCMGSetResidual()`, `PCMGSetInterpolation()`,
1981: `PCMGSetRestriction()`, `PCMGGetSmoother()`, `PCMGGetSmootherUp()`, `PCMGGetSmootherDown()`,
1982: `PCMGSetCycleTypeOnLevel()`, `PCMGSetRhs()`, `PCMGSetX()`, `PCMGSetR()`,
1983: `PCMGSetAdaptCR()`, `PCMGGetAdaptInterpolation()`, `PCMGSetGalerkin()`, `PCMGGetAdaptCoarseSpaceType()`, `PCMGSetAdaptCoarseSpaceType()`
1984: M*/
1986: PETSC_EXTERN PetscErrorCode PCCreate_MG(PC pc)
1987: {
1988: PC_MG *mg;
1990: PetscFunctionBegin;
1991: PetscCall(PetscNew(&mg));
1992: pc->data = mg;
1993: mg->nlevels = -1;
1994: mg->am = PC_MG_MULTIPLICATIVE;
1995: mg->galerkin = PC_MG_GALERKIN_NONE;
1996: mg->adaptInterpolation = PETSC_FALSE;
1997: mg->Nc = -1;
1998: mg->eigenvalue = -1;
2000: pc->useAmat = PETSC_TRUE;
2002: pc->ops->apply = PCApply_MG;
2003: pc->ops->applytranspose = PCApplyTranspose_MG;
2004: pc->ops->matapply = PCMatApply_MG;
2005: pc->ops->matapplytranspose = PCMatApplyTranspose_MG;
2006: pc->ops->setup = PCSetUp_MG;
2007: pc->ops->reset = PCReset_MG;
2008: pc->ops->destroy = PCDestroy_MG;
2009: pc->ops->setfromoptions = PCSetFromOptions_MG;
2010: pc->ops->view = PCView_MG;
2012: PetscCall(PetscObjectComposedDataRegister(&mg->eigenvalue));
2013: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGSetGalerkin_C", PCMGSetGalerkin_MG));
2014: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetReusePreconditioner_C", PCSetReusePreconditioner_MG));
2015: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGGetLevels_C", PCMGGetLevels_MG));
2016: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGSetLevels_C", PCMGSetLevels_MG));
2017: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGetInterpolations_C", PCGetInterpolations_MG));
2018: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGetCoarseOperators_C", PCGetCoarseOperators_MG));
2019: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGSetAdaptInterpolation_C", PCMGSetAdaptInterpolation_MG));
2020: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGGetAdaptInterpolation_C", PCMGGetAdaptInterpolation_MG));
2021: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGSetAdaptCR_C", PCMGSetAdaptCR_MG));
2022: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGGetAdaptCR_C", PCMGGetAdaptCR_MG));
2023: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGSetAdaptCoarseSpaceType_C", PCMGSetAdaptCoarseSpaceType_MG));
2024: PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCMGGetAdaptCoarseSpaceType_C", PCMGGetAdaptCoarseSpaceType_MG));
2025: PetscFunctionReturn(PETSC_SUCCESS);
2026: }