Actual source code: snescomposite.c

  1: /*
  2:       Defines a SNES that can consist of a collection of SNESes
  3: */
  4: #include <petsc/private/snesimpl.h>
  5: #include <petscblaslapack.h>

  7: const char *const SNESCompositeTypes[] = {"ADDITIVE", "MULTIPLICATIVE", "ADDITIVEOPTIMAL", "SNESCompositeType", "SNES_COMPOSITE", NULL};

  9: typedef struct _SNES_CompositeLink *SNES_CompositeLink;
 10: struct _SNES_CompositeLink {
 11:   SNES               snes;
 12:   PetscReal          dmp;
 13:   Vec                X;
 14:   SNES_CompositeLink next;
 15:   SNES_CompositeLink previous;
 16: };

 18: typedef struct {
 19:   SNES_CompositeLink head;
 20:   PetscInt           nsnes;
 21:   SNESCompositeType  type;
 22:   Vec                Xorig;
 23:   PetscInt           innerFailures; /* the number of inner failures we've seen */

 25:   /* context for ADDITIVEOPTIMAL */
 26:   Vec         *Xes, *Fes; /* solution and residual vectors for the subsolvers */
 27:   PetscReal   *fnorms;    /* norms of the solutions */
 28:   PetscScalar *h;         /* the matrix formed as q_ij = (rdot_i, rdot_j) */
 29:   PetscScalar *g;         /* the dotproducts of the previous function with the candidate functions */
 30:   PetscBLASInt n;         /* matrix dimension -- nsnes */
 31:   PetscBLASInt nrhs;      /* the number of right-hand sides */
 32:   PetscBLASInt lda;       /* the padded matrix dimension */
 33:   PetscBLASInt ldb;       /* the padded vector dimension */
 34:   PetscReal   *s;         /* the singular values */
 35:   PetscScalar *beta;      /* the RHS and combination */
 36:   PetscReal    rcond;     /* the exit condition */
 37:   PetscBLASInt rank;      /* the effective rank */
 38:   PetscScalar *work;      /* the work vector */
 39:   PetscReal   *rwork;     /* the real work vector used for complex */
 40:   PetscBLASInt lwork;     /* the size of the work vector */
 41:   PetscBLASInt info;      /* the output condition */

 43:   PetscReal rtol; /* restart tolerance for accepting the combination */
 44:   PetscReal stol; /* restart tolerance for the combination */
 45: } SNES_Composite;

 47: static PetscErrorCode SNESCompositeApply_Multiplicative(SNES snes, Vec X, Vec B, Vec F, PetscReal *fnorm)
 48: {
 49:   SNES_Composite     *jac  = (SNES_Composite *)snes->data;
 50:   SNES_CompositeLink  next = jac->head;
 51:   Vec                 FSub;
 52:   SNESConvergedReason reason;

 54:   PetscFunctionBegin;
 55:   PetscCheck(next, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONGSTATE, "No composite SNESes supplied via SNESCompositeAddSNES() or -snes_composite_sneses");
 56:   if (snes->normschedule == SNES_NORM_ALWAYS) PetscCall(SNESSetInitialFunction(next->snes, F));
 57:   PetscCall(SNESSolve(next->snes, B, X));
 58:   PetscCall(SNESGetConvergedReason(next->snes, &reason));
 59:   if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
 60:     jac->innerFailures++;
 61:     if (jac->innerFailures >= snes->maxFailures) {
 62:       snes->reason = SNES_DIVERGED_INNER;
 63:       PetscFunctionReturn(PETSC_SUCCESS);
 64:     }
 65:   }

 67:   while (next->next) {
 68:     /* only copy the function over in the case where the functions correspond */
 69:     if (next->snes->npcside == PC_RIGHT && next->snes->normschedule != SNES_NORM_NONE) {
 70:       PetscCall(SNESGetFunction(next->snes, &FSub, NULL, NULL));
 71:       next = next->next;
 72:       PetscCall(SNESSetInitialFunction(next->snes, FSub));
 73:     } else {
 74:       next = next->next;
 75:     }
 76:     PetscCall(SNESSolve(next->snes, B, X));
 77:     PetscCall(SNESGetConvergedReason(next->snes, &reason));
 78:     if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
 79:       jac->innerFailures++;
 80:       if (jac->innerFailures >= snes->maxFailures) {
 81:         snes->reason = SNES_DIVERGED_INNER;
 82:         PetscFunctionReturn(PETSC_SUCCESS);
 83:       }
 84:     }
 85:   }
 86:   if (next->snes->npcside == PC_RIGHT) {
 87:     PetscCall(SNESGetFunction(next->snes, &FSub, NULL, NULL));
 88:     PetscCall(VecCopy(FSub, F));
 89:     if (fnorm) {
 90:       if (snes->xl && snes->xu) {
 91:         PetscCall(SNESVIComputeInactiveSetFnorm(snes, F, X, fnorm));
 92:       } else {
 93:         PetscCall(VecNorm(F, NORM_2, fnorm));
 94:       }
 95:       SNESCheckFunctionNorm(snes, *fnorm);
 96:     }
 97:   } else if (snes->normschedule == SNES_NORM_ALWAYS) {
 98:     PetscCall(SNESComputeFunction(snes, X, F));
 99:     if (fnorm) {
100:       if (snes->xl && snes->xu) {
101:         PetscCall(SNESVIComputeInactiveSetFnorm(snes, F, X, fnorm));
102:       } else {
103:         PetscCall(VecNorm(F, NORM_2, fnorm));
104:       }
105:       SNESCheckFunctionNorm(snes, *fnorm);
106:     }
107:   }
108:   PetscFunctionReturn(PETSC_SUCCESS);
109: }

111: static PetscErrorCode SNESCompositeApply_Additive(SNES snes, Vec X, Vec B, Vec F, PetscReal *fnorm)
112: {
113:   SNES_Composite     *jac  = (SNES_Composite *)snes->data;
114:   SNES_CompositeLink  next = jac->head;
115:   Vec                 Y, Xorig;
116:   SNESConvergedReason reason;

118:   PetscFunctionBegin;
119:   Y = snes->vec_sol_update;
120:   if (!jac->Xorig) PetscCall(VecDuplicate(X, &jac->Xorig));
121:   Xorig = jac->Xorig;
122:   PetscCall(VecCopy(X, Xorig));
123:   PetscCheck(next, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONGSTATE, "No composite SNESes supplied via SNESCompositeAddSNES() or -snes_composite_sneses");
124:   if (snes->normschedule == SNES_NORM_ALWAYS) {
125:     PetscCall(SNESSetInitialFunction(next->snes, F));
126:     while (next->next) {
127:       next = next->next;
128:       PetscCall(SNESSetInitialFunction(next->snes, F));
129:     }
130:   }
131:   next = jac->head;
132:   PetscCall(VecCopy(Xorig, Y));
133:   PetscCall(SNESSolve(next->snes, B, Y));
134:   PetscCall(SNESGetConvergedReason(next->snes, &reason));
135:   if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
136:     jac->innerFailures++;
137:     if (jac->innerFailures >= snes->maxFailures) {
138:       snes->reason = SNES_DIVERGED_INNER;
139:       PetscFunctionReturn(PETSC_SUCCESS);
140:     }
141:   }
142:   PetscCall(VecAXPY(Y, -1.0, Xorig));
143:   PetscCall(VecAXPY(X, next->dmp, Y));
144:   while (next->next) {
145:     next = next->next;
146:     PetscCall(VecCopy(Xorig, Y));
147:     PetscCall(SNESSolve(next->snes, B, Y));
148:     PetscCall(SNESGetConvergedReason(next->snes, &reason));
149:     if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
150:       jac->innerFailures++;
151:       if (jac->innerFailures >= snes->maxFailures) {
152:         snes->reason = SNES_DIVERGED_INNER;
153:         PetscFunctionReturn(PETSC_SUCCESS);
154:       }
155:     }
156:     PetscCall(VecAXPY(Y, -1.0, Xorig));
157:     PetscCall(VecAXPY(X, next->dmp, Y));
158:   }
159:   if (snes->normschedule == SNES_NORM_ALWAYS) {
160:     PetscCall(SNESComputeFunction(snes, X, F));
161:     if (fnorm) {
162:       if (snes->xl && snes->xu) {
163:         PetscCall(SNESVIComputeInactiveSetFnorm(snes, F, X, fnorm));
164:       } else {
165:         PetscCall(VecNorm(F, NORM_2, fnorm));
166:       }
167:       SNESCheckFunctionNorm(snes, *fnorm);
168:     }
169:   }
170:   PetscFunctionReturn(PETSC_SUCCESS);
171: }

173: /* approximately solve the overdetermined system:

175:  2*F(x_i)\cdot F(\x_j)\alpha_i = 0
176:  \alpha_i                      = 1

178:  Which minimizes the L2 norm of the linearization of:
179:  ||F(\sum_i \alpha_i*x_i)||^2

181:  With the constraint that \sum_i\alpha_i = 1
182:  Where x_i is the solution from the ith subsolver.
183:  */
184: static PetscErrorCode SNESCompositeApply_AdditiveOptimal(SNES snes, Vec X, Vec B, Vec F, PetscReal *fnorm)
185: {
186:   SNES_Composite     *jac  = (SNES_Composite *)snes->data;
187:   SNES_CompositeLink  next = jac->head;
188:   Vec                *Xes = jac->Xes, *Fes = jac->Fes;
189:   PetscInt            i, j;
190:   PetscScalar         tot, total, ftf;
191:   PetscReal           min_fnorm;
192:   PetscInt            min_i;
193:   SNESConvergedReason reason;

195:   PetscFunctionBegin;
196:   PetscCheck(next, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONGSTATE, "No composite SNESes supplied via SNESCompositeAddSNES() or -snes_composite_sneses");

198:   if (snes->normschedule == SNES_NORM_ALWAYS) {
199:     next = jac->head;
200:     PetscCall(SNESSetInitialFunction(next->snes, F));
201:     while (next->next) {
202:       next = next->next;
203:       PetscCall(SNESSetInitialFunction(next->snes, F));
204:     }
205:   }

207:   next = jac->head;
208:   i    = 0;
209:   PetscCall(VecCopy(X, Xes[i]));
210:   PetscCall(SNESSolve(next->snes, B, Xes[i]));
211:   PetscCall(SNESGetConvergedReason(next->snes, &reason));
212:   if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
213:     jac->innerFailures++;
214:     if (jac->innerFailures >= snes->maxFailures) {
215:       snes->reason = SNES_DIVERGED_INNER;
216:       PetscFunctionReturn(PETSC_SUCCESS);
217:     }
218:   }
219:   while (next->next) {
220:     i++;
221:     next = next->next;
222:     PetscCall(VecCopy(X, Xes[i]));
223:     PetscCall(SNESSolve(next->snes, B, Xes[i]));
224:     PetscCall(SNESGetConvergedReason(next->snes, &reason));
225:     if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
226:       jac->innerFailures++;
227:       if (jac->innerFailures >= snes->maxFailures) {
228:         snes->reason = SNES_DIVERGED_INNER;
229:         PetscFunctionReturn(PETSC_SUCCESS);
230:       }
231:     }
232:   }

234:   /* all the solutions are collected; combine optimally */
235:   for (i = 0; i < jac->n; i++) {
236:     for (j = 0; j < i + 1; j++) PetscCall(VecDotBegin(Fes[i], Fes[j], &jac->h[i + j * jac->n]));
237:     PetscCall(VecDotBegin(Fes[i], F, &jac->g[i]));
238:   }

240:   for (i = 0; i < jac->n; i++) {
241:     for (j = 0; j < i + 1; j++) {
242:       PetscCall(VecDotEnd(Fes[i], Fes[j], &jac->h[i + j * jac->n]));
243:       if (i == j) jac->fnorms[i] = PetscSqrtReal(PetscRealPart(jac->h[i + j * jac->n]));
244:     }
245:     PetscCall(VecDotEnd(Fes[i], F, &jac->g[i]));
246:   }

248:   ftf = (*fnorm) * (*fnorm);

250:   for (i = 0; i < jac->n; i++) {
251:     for (j = i + 1; j < jac->n; j++) jac->h[i + j * jac->n] = jac->h[j + i * jac->n];
252:   }

254:   for (i = 0; i < jac->n; i++) {
255:     for (j = 0; j < jac->n; j++) jac->h[i + j * jac->n] = jac->h[i + j * jac->n] - jac->g[j] - jac->g[i] + ftf;
256:     jac->beta[i] = ftf - jac->g[i];
257:   }

259:   jac->info  = 0;
260:   jac->rcond = -1.;
261:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
262: #if defined(PETSC_USE_COMPLEX)
263:   PetscCallBLAS("LAPACKgelss", LAPACKgelss_(&jac->n, &jac->n, &jac->nrhs, jac->h, &jac->lda, jac->beta, &jac->lda, jac->s, &jac->rcond, &jac->rank, jac->work, &jac->lwork, jac->rwork, &jac->info));
264: #else
265:   PetscCallBLAS("LAPACKgelss", LAPACKgelss_(&jac->n, &jac->n, &jac->nrhs, jac->h, &jac->lda, jac->beta, &jac->lda, jac->s, &jac->rcond, &jac->rank, jac->work, &jac->lwork, &jac->info));
266: #endif
267:   PetscCall(PetscFPTrapPop());
268:   PetscCheck(jac->info >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_LIB, "Bad argument to GELSS");
269:   PetscCheck(jac->info <= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_LIB, "SVD failed to converge");
270:   tot   = 0.;
271:   total = 0.;
272:   for (i = 0; i < jac->n; i++) {
273:     PetscCheck(!snes->errorifnotconverged || !PetscIsInfOrNanScalar(jac->beta[i]), PetscObjectComm((PetscObject)snes), PETSC_ERR_LIB, "SVD generated inconsistent output");
274:     PetscCall(PetscInfo(snes, "%" PetscInt_FMT ": %g\n", i, (double)PetscRealPart(jac->beta[i])));
275:     tot += jac->beta[i];
276:     total += PetscAbsScalar(jac->beta[i]);
277:   }
278:   PetscCall(VecScale(X, 1. - tot));
279:   PetscCall(VecMAXPY(X, jac->n, jac->beta, Xes));
280:   PetscCall(SNESComputeFunction(snes, X, F));

282:   if (snes->xl && snes->xu) {
283:     PetscCall(SNESVIComputeInactiveSetFnorm(snes, F, X, fnorm));
284:   } else {
285:     PetscCall(VecNorm(F, NORM_2, fnorm));
286:   }

288:   /* take the minimum-normed candidate if it beats the combination by a factor of rtol or the combination has stagnated */
289:   min_fnorm = jac->fnorms[0];
290:   min_i     = 0;
291:   for (i = 0; i < jac->n; i++) {
292:     if (jac->fnorms[i] < min_fnorm) {
293:       min_fnorm = jac->fnorms[i];
294:       min_i     = i;
295:     }
296:   }

298:   /* stagnation or divergence restart to the solution of the solver that failed the least */
299:   if (PetscRealPart(total) < jac->stol || min_fnorm * jac->rtol < *fnorm) {
300:     PetscCall(VecCopy(jac->Xes[min_i], X));
301:     PetscCall(VecCopy(jac->Fes[min_i], F));
302:     *fnorm = min_fnorm;
303:   }
304:   PetscFunctionReturn(PETSC_SUCCESS);
305: }

307: static PetscErrorCode SNESSetUp_Composite(SNES snes)
308: {
309:   DM                 dm;
310:   SNES_Composite    *jac  = (SNES_Composite *)snes->data;
311:   SNES_CompositeLink next = jac->head;
312:   PetscInt           n    = 0, i;
313:   Vec                F;

315:   PetscFunctionBegin;
316:   PetscCall(SNESGetDM(snes, &dm));

318:   if (snes->ops->computevariablebounds) {
319:     /* SNESVI only ever calls computevariablebounds once, so calling it once here is justified */
320:     if (!snes->xl) PetscCall(VecDuplicate(snes->vec_sol, &snes->xl));
321:     if (!snes->xu) PetscCall(VecDuplicate(snes->vec_sol, &snes->xu));
322:     PetscUseTypeMethod(snes, computevariablebounds, snes->xl, snes->xu);
323:   }

325:   while (next) {
326:     n++;
327:     PetscCall(SNESSetDM(next->snes, dm));
328:     PetscCall(SNESSetJacobian(next->snes, snes->jacobian, snes->jacobian_pre, NULL, NULL));
329:     PetscCall(SNESSetApplicationContext(next->snes, snes->ctx));
330:     if (snes->xl && snes->xu) {
331:       if (snes->ops->computevariablebounds) {
332:         PetscCall(SNESVISetComputeVariableBounds(next->snes, snes->ops->computevariablebounds));
333:       } else {
334:         PetscCall(SNESVISetVariableBounds(next->snes, snes->xl, snes->xu));
335:       }
336:     }

338:     next = next->next;
339:   }
340:   jac->nsnes = n;
341:   PetscCall(SNESGetFunction(snes, &F, NULL, NULL));
342:   if (jac->type == SNES_COMPOSITE_ADDITIVEOPTIMAL) {
343:     PetscCall(VecDuplicateVecs(F, jac->nsnes, &jac->Xes));
344:     PetscCall(PetscMalloc1(n, &jac->Fes));
345:     PetscCall(PetscMalloc1(n, &jac->fnorms));
346:     next = jac->head;
347:     i    = 0;
348:     while (next) {
349:       PetscCall(SNESGetFunction(next->snes, &F, NULL, NULL));
350:       jac->Fes[i] = F;
351:       PetscCall(PetscObjectReference((PetscObject)F));
352:       next = next->next;
353:       i++;
354:     }
355:     /* allocate the subspace direct solve area */
356:     jac->nrhs = 1;
357:     PetscCall(PetscBLASIntCast(jac->nsnes, &jac->lda));
358:     PetscCall(PetscBLASIntCast(jac->nsnes, &jac->ldb));
359:     PetscCall(PetscBLASIntCast(jac->nsnes, &jac->n));

361:     PetscCall(PetscMalloc4(jac->n * jac->n, &jac->h, jac->n, &jac->beta, jac->n, &jac->s, jac->n, &jac->g));
362:     jac->lwork = 12 * jac->n;
363: #if defined(PETSC_USE_COMPLEX)
364:     PetscCall(PetscMalloc1(jac->lwork, &jac->rwork));
365: #endif
366:     PetscCall(PetscMalloc1(jac->lwork, &jac->work));
367:   }
368:   PetscFunctionReturn(PETSC_SUCCESS);
369: }

371: static PetscErrorCode SNESReset_Composite(SNES snes)
372: {
373:   SNES_Composite    *jac  = (SNES_Composite *)snes->data;
374:   SNES_CompositeLink next = jac->head;

376:   PetscFunctionBegin;
377:   while (next) {
378:     PetscCall(SNESReset(next->snes));
379:     next = next->next;
380:   }
381:   PetscCall(VecDestroy(&jac->Xorig));
382:   if (jac->Xes) PetscCall(VecDestroyVecs(jac->nsnes, &jac->Xes));
383:   if (jac->Fes) PetscCall(VecDestroyVecs(jac->nsnes, &jac->Fes));
384:   PetscCall(PetscFree(jac->fnorms));
385:   PetscCall(PetscFree4(jac->h, jac->beta, jac->s, jac->g));
386:   PetscCall(PetscFree(jac->work));
387:   PetscCall(PetscFree(jac->rwork));
388:   PetscFunctionReturn(PETSC_SUCCESS);
389: }

391: static PetscErrorCode SNESDestroy_Composite(SNES snes)
392: {
393:   SNES_Composite    *jac  = (SNES_Composite *)snes->data;
394:   SNES_CompositeLink next = jac->head, next_tmp;

396:   PetscFunctionBegin;
397:   PetscCall(SNESReset_Composite(snes));
398:   while (next) {
399:     PetscCall(SNESDestroy(&next->snes));
400:     next_tmp = next;
401:     next     = next->next;
402:     PetscCall(PetscFree(next_tmp));
403:   }
404:   PetscCall(PetscObjectComposeFunction((PetscObject)snes, "SNESCompositeSetType_C", NULL));
405:   PetscCall(PetscObjectComposeFunction((PetscObject)snes, "SNESCompositeAddSNES_C", NULL));
406:   PetscCall(PetscObjectComposeFunction((PetscObject)snes, "SNESCompositeGetSNES_C", NULL));
407:   PetscCall(PetscObjectComposeFunction((PetscObject)snes, "SNESCompositeSetDamping_C", NULL));
408:   PetscCall(PetscFree(snes->data));
409:   PetscFunctionReturn(PETSC_SUCCESS);
410: }

412: static PetscErrorCode SNESSetFromOptions_Composite(SNES snes, PetscOptionItems *PetscOptionsObject)
413: {
414:   SNES_Composite    *jac  = (SNES_Composite *)snes->data;
415:   PetscInt           nmax = 8, i;
416:   SNES_CompositeLink next;
417:   char              *sneses[8];
418:   PetscReal          dmps[8];
419:   PetscBool          flg;

421:   PetscFunctionBegin;
422:   PetscOptionsHeadBegin(PetscOptionsObject, "Composite preconditioner options");
423:   PetscCall(PetscOptionsEnum("-snes_composite_type", "Type of composition", "SNESCompositeSetType", SNESCompositeTypes, (PetscEnum)jac->type, (PetscEnum *)&jac->type, &flg));
424:   if (flg) PetscCall(SNESCompositeSetType(snes, jac->type));
425:   PetscCall(PetscOptionsStringArray("-snes_composite_sneses", "List of composite solvers", "SNESCompositeAddSNES", sneses, &nmax, &flg));
426:   if (flg) {
427:     for (i = 0; i < nmax; i++) {
428:       PetscCall(SNESCompositeAddSNES(snes, sneses[i]));
429:       PetscCall(PetscFree(sneses[i])); /* deallocate string sneses[i], which is allocated in PetscOptionsStringArray() */
430:     }
431:   }
432:   PetscCall(PetscOptionsRealArray("-snes_composite_damping", "Damping of the additive composite solvers", "SNESCompositeSetDamping", dmps, &nmax, &flg));
433:   if (flg) {
434:     for (i = 0; i < nmax; i++) PetscCall(SNESCompositeSetDamping(snes, i, dmps[i]));
435:   }
436:   PetscCall(PetscOptionsReal("-snes_composite_stol", "Step tolerance for restart on the additive composite solvers", "", jac->stol, &jac->stol, NULL));
437:   PetscCall(PetscOptionsReal("-snes_composite_rtol", "Residual tolerance for the additive composite solvers", "", jac->rtol, &jac->rtol, NULL));
438:   PetscOptionsHeadEnd();

440:   next = jac->head;
441:   while (next) {
442:     PetscCall(SNESSetFromOptions(next->snes));
443:     next = next->next;
444:   }
445:   PetscFunctionReturn(PETSC_SUCCESS);
446: }

448: static PetscErrorCode SNESView_Composite(SNES snes, PetscViewer viewer)
449: {
450:   SNES_Composite    *jac  = (SNES_Composite *)snes->data;
451:   SNES_CompositeLink next = jac->head;
452:   PetscBool          iascii;

454:   PetscFunctionBegin;
455:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii));
456:   if (iascii) {
457:     PetscCall(PetscViewerASCIIPrintf(viewer, "  type - %s\n", SNESCompositeTypes[jac->type]));
458:     PetscCall(PetscViewerASCIIPrintf(viewer, "  SNESes on composite preconditioner follow\n"));
459:     PetscCall(PetscViewerASCIIPrintf(viewer, "  ---------------------------------\n"));
460:   }
461:   if (iascii) PetscCall(PetscViewerASCIIPushTab(viewer));
462:   while (next) {
463:     PetscCall(SNESView(next->snes, viewer));
464:     next = next->next;
465:   }
466:   if (iascii) {
467:     PetscCall(PetscViewerASCIIPopTab(viewer));
468:     PetscCall(PetscViewerASCIIPrintf(viewer, "  ---------------------------------\n"));
469:   }
470:   PetscFunctionReturn(PETSC_SUCCESS);
471: }

473: static PetscErrorCode SNESCompositeSetType_Composite(SNES snes, SNESCompositeType type)
474: {
475:   SNES_Composite *jac = (SNES_Composite *)snes->data;

477:   PetscFunctionBegin;
478:   jac->type = type;
479:   PetscFunctionReturn(PETSC_SUCCESS);
480: }

482: static PetscErrorCode SNESCompositeAddSNES_Composite(SNES snes, SNESType type)
483: {
484:   SNES_Composite    *jac;
485:   SNES_CompositeLink next, ilink;
486:   PetscInt           cnt = 0;
487:   const char        *prefix;
488:   char               newprefix[20];
489:   DM                 dm;

491:   PetscFunctionBegin;
492:   PetscCall(PetscNew(&ilink));
493:   ilink->next = NULL;
494:   PetscCall(SNESCreate(PetscObjectComm((PetscObject)snes), &ilink->snes));
495:   PetscCall(PetscObjectIncrementTabLevel((PetscObject)ilink->snes, (PetscObject)snes, 1));
496:   PetscCall(SNESGetDM(snes, &dm));
497:   PetscCall(SNESSetDM(ilink->snes, dm));
498:   PetscCall(SNESSetTolerances(ilink->snes, snes->abstol, snes->rtol, snes->stol, 1, snes->max_funcs));
499:   PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)snes, (PetscObject)ilink->snes));
500:   jac  = (SNES_Composite *)snes->data;
501:   next = jac->head;
502:   if (!next) {
503:     jac->head       = ilink;
504:     ilink->previous = NULL;
505:   } else {
506:     cnt++;
507:     while (next->next) {
508:       next = next->next;
509:       cnt++;
510:     }
511:     next->next      = ilink;
512:     ilink->previous = next;
513:   }
514:   PetscCall(SNESGetOptionsPrefix(snes, &prefix));
515:   PetscCall(SNESSetOptionsPrefix(ilink->snes, prefix));
516:   PetscCall(PetscSNPrintf(newprefix, sizeof(newprefix), "sub_%" PetscInt_FMT "_", cnt));
517:   PetscCall(SNESAppendOptionsPrefix(ilink->snes, newprefix));
518:   PetscCall(SNESSetType(ilink->snes, type));
519:   PetscCall(SNESSetNormSchedule(ilink->snes, SNES_NORM_FINAL_ONLY));

521:   ilink->dmp = 1.0;
522:   jac->nsnes++;
523:   PetscFunctionReturn(PETSC_SUCCESS);
524: }

526: static PetscErrorCode SNESCompositeGetSNES_Composite(SNES snes, PetscInt n, SNES *subsnes)
527: {
528:   SNES_Composite    *jac;
529:   SNES_CompositeLink next;
530:   PetscInt           i;

532:   PetscFunctionBegin;
533:   jac  = (SNES_Composite *)snes->data;
534:   next = jac->head;
535:   for (i = 0; i < n; i++) {
536:     PetscCheck(next->next, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_INCOMP, "Not enough SNESes in composite preconditioner");
537:     next = next->next;
538:   }
539:   *subsnes = next->snes;
540:   PetscFunctionReturn(PETSC_SUCCESS);
541: }

543: /*@
544:   SNESCompositeSetType - Sets the type of composite preconditioner.

546:   Logically Collective

548:   Input Parameters:
549: + snes - the preconditioner context
550: - type - `SNES_COMPOSITE_ADDITIVE` (default), `SNES_COMPOSITE_MULTIPLICATIVE`, or `SNES_COMPOSITE_ADDITIVEOPTIMAL`

552:   Options Database Key:
553: . -snes_composite_type <type: one of multiplicative, additive, additiveoptimal> - Sets composite preconditioner type

555:   Level: developer

557: .seealso: [](ch_snes), `SNES_COMPOSITE_ADDITIVE`, `SNES_COMPOSITE_MULTIPLICATIVE`, `SNESCompositeType`, `SNESCOMPOSITE`, `SNES_COMPOSITE_ADDITIVEOPTIMAL`,
558:           `PCCompositeType`
559: @*/
560: PetscErrorCode SNESCompositeSetType(SNES snes, SNESCompositeType type)
561: {
562:   PetscFunctionBegin;
565:   PetscTryMethod(snes, "SNESCompositeSetType_C", (SNES, SNESCompositeType), (snes, type));
566:   PetscFunctionReturn(PETSC_SUCCESS);
567: }

569: /*@
570:   SNESCompositeAddSNES - Adds another `SNES` to the `SNESCOMPOSITE`

572:   Collective

574:   Input Parameters:
575: + snes - the `SNES` context of type `SNESCOMPOSITE`
576: - type - the `SNESType` of the new solver

578:   Level: developer

580: .seealso: [](ch_snes), `SNES`, `SNESCOMPOSITE`, `SNESCompositeGetSNES()`
581: @*/
582: PetscErrorCode SNESCompositeAddSNES(SNES snes, SNESType type)
583: {
584:   PetscFunctionBegin;
586:   PetscTryMethod(snes, "SNESCompositeAddSNES_C", (SNES, SNESType), (snes, type));
587:   PetscFunctionReturn(PETSC_SUCCESS);
588: }

590: /*@
591:   SNESCompositeGetSNES - Gets one of the `SNES` objects in the `SNES` of `SNESType` `SNESCOMPOSITE`

593:   Not Collective

595:   Input Parameters:
596: + snes - the `SNES` context
597: - n    - the number of the composed `SNES` requested

599:   Output Parameter:
600: . subsnes - the `SNES` requested

602:   Level: developer

604: .seealso: [](ch_snes), `SNES`, `SNESCOMPOSITE`, `SNESCompositeAddSNES()`, `SNESCompositeGetNumber()`
605: @*/
606: PetscErrorCode SNESCompositeGetSNES(SNES snes, PetscInt n, SNES *subsnes)
607: {
608:   PetscFunctionBegin;
610:   PetscAssertPointer(subsnes, 3);
611:   PetscUseMethod(snes, "SNESCompositeGetSNES_C", (SNES, PetscInt, SNES *), (snes, n, subsnes));
612:   PetscFunctionReturn(PETSC_SUCCESS);
613: }

615: /*@
616:   SNESCompositeGetNumber - Get the number of subsolvers in the `SNESCOMPOSITE`

618:   Logically Collective

620:   Input Parameter:
621: . snes - the `SNES` context

623:   Output Parameter:
624: . n - the number of subsolvers

626:   Level: developer

628: .seealso: [](ch_snes), `SNES`, `SNESCOMPOSITE`, `SNESCompositeAddSNES()`, `SNESCompositeGetSNES()`
629: @*/
630: PetscErrorCode SNESCompositeGetNumber(SNES snes, PetscInt *n)
631: {
632:   SNES_Composite    *jac;
633:   SNES_CompositeLink next;

635:   PetscFunctionBegin;
636:   jac  = (SNES_Composite *)snes->data;
637:   next = jac->head;

639:   *n = 0;
640:   while (next) {
641:     *n   = *n + 1;
642:     next = next->next;
643:   }
644:   PetscFunctionReturn(PETSC_SUCCESS);
645: }

647: static PetscErrorCode SNESCompositeSetDamping_Composite(SNES snes, PetscInt n, PetscReal dmp)
648: {
649:   SNES_Composite    *jac;
650:   SNES_CompositeLink next;
651:   PetscInt           i;

653:   PetscFunctionBegin;
654:   jac  = (SNES_Composite *)snes->data;
655:   next = jac->head;
656:   for (i = 0; i < n; i++) {
657:     PetscCheck(next->next, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_INCOMP, "Not enough SNESes in composite preconditioner");
658:     next = next->next;
659:   }
660:   next->dmp = dmp;
661:   PetscFunctionReturn(PETSC_SUCCESS);
662: }

664: /*@
665:   SNESCompositeSetDamping - Sets the damping of a subsolver when using `SNES_COMPOSITE_ADDITIVE` with a `SNES` of `SNESType` `SNESCOMPOSITE`

667:   Not Collective

669:   Input Parameters:
670: + snes - the `SNES` context
671: . n    - the number of the sub-`SNES` object requested
672: - dmp  - the damping

674:   Level: intermediate

676: .seealso: [](ch_snes), `SNES`, `SNESCOMPOSITE`, `SNESCompositeAddSNES()`, `SNESCompositeGetSNES()`,
677:           `SNES_COMPOSITE_ADDITIVE`, `SNES_COMPOSITE_MULTIPLICATIVE`, `SNESCompositeType`, `SNESCompositeSetType()`
678: @*/
679: PetscErrorCode SNESCompositeSetDamping(SNES snes, PetscInt n, PetscReal dmp)
680: {
681:   PetscFunctionBegin;
683:   PetscUseMethod(snes, "SNESCompositeSetDamping_C", (SNES, PetscInt, PetscReal), (snes, n, dmp));
684:   PetscFunctionReturn(PETSC_SUCCESS);
685: }

687: static PetscErrorCode SNESSolve_Composite(SNES snes)
688: {
689:   Vec              F, X, B, Y;
690:   PetscInt         i;
691:   PetscReal        fnorm = 0.0, xnorm = 0.0, snorm = 0.0;
692:   SNESNormSchedule normtype;
693:   SNES_Composite  *comp = (SNES_Composite *)snes->data;

695:   PetscFunctionBegin;
696:   X = snes->vec_sol;
697:   F = snes->vec_func;
698:   B = snes->vec_rhs;
699:   Y = snes->vec_sol_update;

701:   PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
702:   snes->iter          = 0;
703:   snes->norm          = 0.;
704:   comp->innerFailures = 0;
705:   PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
706:   snes->reason = SNES_CONVERGED_ITERATING;
707:   PetscCall(SNESGetNormSchedule(snes, &normtype));
708:   if (normtype == SNES_NORM_ALWAYS || normtype == SNES_NORM_INITIAL_ONLY || normtype == SNES_NORM_INITIAL_FINAL_ONLY) {
709:     if (!snes->vec_func_init_set) {
710:       PetscCall(SNESComputeFunction(snes, X, F));
711:     } else snes->vec_func_init_set = PETSC_FALSE;

713:     if (snes->xl && snes->xu) {
714:       PetscCall(SNESVIComputeInactiveSetFnorm(snes, F, X, &fnorm));
715:     } else {
716:       PetscCall(VecNorm(F, NORM_2, &fnorm)); /* fnorm <- ||F||  */
717:     }
718:     SNESCheckFunctionNorm(snes, fnorm);
719:     PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
720:     snes->iter = 0;
721:     snes->norm = fnorm;
722:     PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
723:     PetscCall(SNESLogConvergenceHistory(snes, snes->norm, 0));

725:     /* test convergence */
726:     PetscCall(SNESConverged(snes, 0, 0.0, 0.0, fnorm));
727:     PetscCall(SNESMonitor(snes, 0, snes->norm));
728:     if (snes->reason) PetscFunctionReturn(PETSC_SUCCESS);
729:   } else {
730:     PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
731:     PetscCall(SNESLogConvergenceHistory(snes, snes->norm, 0));
732:     PetscCall(SNESMonitor(snes, 0, snes->norm));
733:   }

735:   for (i = 0; i < snes->max_its; i++) {
736:     /* Call general purpose update function */
737:     PetscTryTypeMethod(snes, update, snes->iter);

739:     /* Copy the state before modification by application of the composite solver;
740:        we will subtract the new state after application */
741:     PetscCall(VecCopy(X, Y));

743:     if (comp->type == SNES_COMPOSITE_ADDITIVE) {
744:       PetscCall(SNESCompositeApply_Additive(snes, X, B, F, &fnorm));
745:     } else if (comp->type == SNES_COMPOSITE_MULTIPLICATIVE) {
746:       PetscCall(SNESCompositeApply_Multiplicative(snes, X, B, F, &fnorm));
747:     } else if (comp->type == SNES_COMPOSITE_ADDITIVEOPTIMAL) {
748:       PetscCall(SNESCompositeApply_AdditiveOptimal(snes, X, B, F, &fnorm));
749:     } else SETERRQ(PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONGSTATE, "Unsupported SNESComposite type");
750:     if (snes->reason < 0) break;

752:     /* Compute the solution update for convergence testing */
753:     PetscCall(VecAYPX(Y, -1.0, X));

755:     if ((i == snes->max_its - 1) && (normtype == SNES_NORM_INITIAL_FINAL_ONLY || normtype == SNES_NORM_FINAL_ONLY)) {
756:       PetscCall(SNESComputeFunction(snes, X, F));

758:       if (snes->xl && snes->xu) {
759:         PetscCall(VecNormBegin(X, NORM_2, &xnorm));
760:         PetscCall(VecNormBegin(Y, NORM_2, &snorm));
761:         PetscCall(SNESVIComputeInactiveSetFnorm(snes, F, X, &fnorm));
762:         PetscCall(VecNormEnd(X, NORM_2, &xnorm));
763:         PetscCall(VecNormEnd(Y, NORM_2, &snorm));
764:       } else {
765:         PetscCall(VecNormBegin(F, NORM_2, &fnorm));
766:         PetscCall(VecNormBegin(X, NORM_2, &xnorm));
767:         PetscCall(VecNormBegin(Y, NORM_2, &snorm));

769:         PetscCall(VecNormEnd(F, NORM_2, &fnorm));
770:         PetscCall(VecNormEnd(X, NORM_2, &xnorm));
771:         PetscCall(VecNormEnd(Y, NORM_2, &snorm));
772:       }
773:       SNESCheckFunctionNorm(snes, fnorm);
774:     } else if (normtype == SNES_NORM_ALWAYS) {
775:       PetscCall(VecNormBegin(X, NORM_2, &xnorm));
776:       PetscCall(VecNormBegin(Y, NORM_2, &snorm));
777:       PetscCall(VecNormEnd(X, NORM_2, &xnorm));
778:       PetscCall(VecNormEnd(Y, NORM_2, &snorm));
779:     }
780:     /* Monitor convergence */
781:     PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
782:     snes->iter  = i + 1;
783:     snes->norm  = fnorm;
784:     snes->xnorm = xnorm;
785:     snes->ynorm = snorm;
786:     PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
787:     PetscCall(SNESLogConvergenceHistory(snes, snes->norm, 0));
788:     /* Test for convergence */
789:     PetscCall(SNESConverged(snes, snes->iter, xnorm, snorm, fnorm));
790:     PetscCall(SNESMonitor(snes, snes->iter, snes->norm));
791:     if (snes->reason) break;
792:   }
793:   PetscFunctionReturn(PETSC_SUCCESS);
794: }

796: /*MC
797:      SNESCOMPOSITE - Builds a nonlinear solver/preconditioner by composing together several `SNES` nonlinear solvers {cite}`bruneknepleysmithtu15`

799:    Options Database Keys:
800: +  -snes_composite_type <type: one of multiplicative, additive, additiveoptimal> - Sets composite preconditioner type
801: -  -snes_composite_sneses - <snes0,snes1,...> list of `SNES` to compose

803:    Level: intermediate

805: .seealso: [](ch_snes), `SNES`, `SNESCOMPOSITE`, `SNESCompositeAddSNES()`, `SNESCompositeGetSNES()`,
806:           `SNES_COMPOSITE_ADDITIVE`, `SNES_COMPOSITE_ADDITIVEOPTIMAL`, `SNES_COMPOSITE_MULTIPLICATIVE`, `SNESCompositeType`,
807:           `SNESCompositeSetType()`, `SNESCompositeSetDamping()`, `SNESCompositeGetNumber()`, `PCCompositeType`
808: M*/

810: PETSC_EXTERN PetscErrorCode SNESCreate_Composite(SNES snes)
811: {
812:   SNES_Composite *jac;

814:   PetscFunctionBegin;
815:   PetscCall(PetscNew(&jac));

817:   snes->ops->solve          = SNESSolve_Composite;
818:   snes->ops->setup          = SNESSetUp_Composite;
819:   snes->ops->reset          = SNESReset_Composite;
820:   snes->ops->destroy        = SNESDestroy_Composite;
821:   snes->ops->setfromoptions = SNESSetFromOptions_Composite;
822:   snes->ops->view           = SNESView_Composite;

824:   snes->usesksp = PETSC_FALSE;

826:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

828:   PetscCall(SNESParametersInitialize(snes));

830:   snes->data  = (void *)jac;
831:   jac->type   = SNES_COMPOSITE_ADDITIVEOPTIMAL;
832:   jac->Fes    = NULL;
833:   jac->Xes    = NULL;
834:   jac->fnorms = NULL;
835:   jac->nsnes  = 0;
836:   jac->head   = NULL;
837:   jac->stol   = 0.1;
838:   jac->rtol   = 1.1;

840:   jac->h     = NULL;
841:   jac->s     = NULL;
842:   jac->beta  = NULL;
843:   jac->work  = NULL;
844:   jac->rwork = NULL;

846:   PetscCall(PetscObjectComposeFunction((PetscObject)snes, "SNESCompositeSetType_C", SNESCompositeSetType_Composite));
847:   PetscCall(PetscObjectComposeFunction((PetscObject)snes, "SNESCompositeAddSNES_C", SNESCompositeAddSNES_Composite));
848:   PetscCall(PetscObjectComposeFunction((PetscObject)snes, "SNESCompositeGetSNES_C", SNESCompositeGetSNES_Composite));
849:   PetscCall(PetscObjectComposeFunction((PetscObject)snes, "SNESCompositeSetDamping_C", SNESCompositeSetDamping_Composite));
850:   PetscFunctionReturn(PETSC_SUCCESS);
851: }