Actual source code: virs.c

  1: #include <../src/snes/impls/vi/rs/virsimpl.h>
  2: #include <petsc/private/dmimpl.h>
  3: #include <petsc/private/vecimpl.h>

  5: /*@
  6:   SNESVIGetInactiveSet - Gets the global indices for the inactive set variables (these correspond to the degrees of freedom the linear
  7:   system is solved on)

  9:   Input Parameter:
 10: . snes - the `SNES` context

 12:   Output Parameter:
 13: . inact - inactive set index set

 15:   Level: advanced

 17: .seealso: [](ch_snes), `SNES`, `SNESVINEWTONRSLS`
 18: @*/
 19: PetscErrorCode SNESVIGetInactiveSet(SNES snes, IS *inact)
 20: {
 21:   SNES_VINEWTONRSLS *vi = (SNES_VINEWTONRSLS *)snes->data;

 23:   PetscFunctionBegin;
 24:   *inact = vi->IS_inact;
 25:   PetscFunctionReturn(PETSC_SUCCESS);
 26: }

 28: /*
 29:     Provides a wrapper to a DM to allow it to be used to generated the interpolation/restriction from the DM for the smaller matrices and vectors
 30:   defined by the reduced space method.

 32:     Simple calls the regular DM interpolation and restricts it to operation on the variables not associated with active constraints.
 33: */
 34: typedef struct {
 35:   PetscInt n; /* size of vectors in the reduced DM space */
 36:   IS       inactive;

 38:   PetscErrorCode (*createinterpolation)(DM, DM, Mat *, Vec *); /* DM's original routines */
 39:   PetscErrorCode (*coarsen)(DM, MPI_Comm, DM *);
 40:   PetscErrorCode (*createglobalvector)(DM, Vec *);
 41:   PetscErrorCode (*createinjection)(DM, DM, Mat *);
 42:   PetscErrorCode (*hascreateinjection)(DM, PetscBool *);

 44:   DM dm; /* when destroying this object we need to reset the above function into the base DM */
 45: } DM_SNESVI;

 47: /*
 48:      DMCreateGlobalVector_SNESVI - Creates global vector of the size of the reduced space
 49: */
 50: static PetscErrorCode DMCreateGlobalVector_SNESVI(DM dm, Vec *vec)
 51: {
 52:   PetscContainer isnes;
 53:   DM_SNESVI     *dmsnesvi;

 55:   PetscFunctionBegin;
 56:   PetscCall(PetscObjectQuery((PetscObject)dm, "VI", (PetscObject *)&isnes));
 57:   PetscCheck(isnes, PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Composed SNES is missing");
 58:   PetscCall(PetscContainerGetPointer(isnes, (void **)&dmsnesvi));
 59:   PetscCall(VecCreateMPI(PetscObjectComm((PetscObject)dm), dmsnesvi->n, PETSC_DETERMINE, vec));
 60:   PetscCall(VecSetDM(*vec, dm));
 61:   PetscFunctionReturn(PETSC_SUCCESS);
 62: }

 64: /*
 65:      DMCreateInterpolation_SNESVI - Modifieds the interpolation obtained from the DM by removing all rows and columns associated with active constraints.
 66: */
 67: static PetscErrorCode DMCreateInterpolation_SNESVI(DM dm1, DM dm2, Mat *mat, Vec *vec)
 68: {
 69:   PetscContainer isnes;
 70:   DM_SNESVI     *dmsnesvi1, *dmsnesvi2;
 71:   Mat            interp;

 73:   PetscFunctionBegin;
 74:   PetscCall(PetscObjectQuery((PetscObject)dm1, "VI", (PetscObject *)&isnes));
 75:   PetscCheck(isnes, PetscObjectComm((PetscObject)dm1), PETSC_ERR_PLIB, "Composed VI data structure is missing");
 76:   PetscCall(PetscContainerGetPointer(isnes, (void **)&dmsnesvi1));
 77:   PetscCall(PetscObjectQuery((PetscObject)dm2, "VI", (PetscObject *)&isnes));
 78:   PetscCheck(isnes, PetscObjectComm((PetscObject)dm2), PETSC_ERR_PLIB, "Composed VI data structure is missing");
 79:   PetscCall(PetscContainerGetPointer(isnes, (void **)&dmsnesvi2));

 81:   PetscCall((*dmsnesvi1->createinterpolation)(dm1, dm2, &interp, NULL));
 82:   PetscCall(MatCreateSubMatrix(interp, dmsnesvi2->inactive, dmsnesvi1->inactive, MAT_INITIAL_MATRIX, mat));
 83:   PetscCall(MatDestroy(&interp));
 84:   *vec = NULL;
 85:   PetscFunctionReturn(PETSC_SUCCESS);
 86: }

 88: /*
 89:      DMCoarsen_SNESVI - Computes the regular coarsened DM then computes additional information about its inactive set
 90: */
 91: static PetscErrorCode DMCoarsen_SNESVI(DM dm1, MPI_Comm comm, DM *dm2)
 92: {
 93:   PetscContainer  isnes;
 94:   DM_SNESVI      *dmsnesvi1;
 95:   Vec             finemarked, coarsemarked;
 96:   IS              inactive;
 97:   Mat             inject;
 98:   const PetscInt *index;
 99:   PetscInt        n, k, cnt = 0, rstart, *coarseindex;
100:   PetscScalar    *marked;

102:   PetscFunctionBegin;
103:   PetscCall(PetscObjectQuery((PetscObject)dm1, "VI", (PetscObject *)&isnes));
104:   PetscCheck(isnes, PetscObjectComm((PetscObject)dm1), PETSC_ERR_PLIB, "Composed VI data structure is missing");
105:   PetscCall(PetscContainerGetPointer(isnes, (void **)&dmsnesvi1));

107:   /* get the original coarsen */
108:   PetscCall((*dmsnesvi1->coarsen)(dm1, comm, dm2));

110:   /* not sure why this extra reference is needed, but without the dm2 disappears too early */
111:   /* Updating the KSPCreateVecs() to avoid using DMGetGlobalVector() when matrix is available removes the need for this reference? */
112:   /*  PetscCall(PetscObjectReference((PetscObject)*dm2));*/

114:   /* need to set back global vectors in order to use the original injection */
115:   PetscCall(DMClearGlobalVectors(dm1));

117:   dm1->ops->createglobalvector = dmsnesvi1->createglobalvector;

119:   PetscCall(DMCreateGlobalVector(dm1, &finemarked));
120:   PetscCall(DMCreateGlobalVector(*dm2, &coarsemarked));

122:   /*
123:      fill finemarked with locations of inactive points
124:   */
125:   PetscCall(ISGetIndices(dmsnesvi1->inactive, &index));
126:   PetscCall(ISGetLocalSize(dmsnesvi1->inactive, &n));
127:   PetscCall(VecSet(finemarked, 0.0));
128:   for (k = 0; k < n; k++) PetscCall(VecSetValue(finemarked, index[k], 1.0, INSERT_VALUES));
129:   PetscCall(VecAssemblyBegin(finemarked));
130:   PetscCall(VecAssemblyEnd(finemarked));

132:   PetscCall(DMCreateInjection(*dm2, dm1, &inject));
133:   PetscCall(MatRestrict(inject, finemarked, coarsemarked));
134:   PetscCall(MatDestroy(&inject));

136:   /*
137:      create index set list of coarse inactive points from coarsemarked
138:   */
139:   PetscCall(VecGetLocalSize(coarsemarked, &n));
140:   PetscCall(VecGetOwnershipRange(coarsemarked, &rstart, NULL));
141:   PetscCall(VecGetArray(coarsemarked, &marked));
142:   for (k = 0; k < n; k++) {
143:     if (marked[k] != 0.0) cnt++;
144:   }
145:   PetscCall(PetscMalloc1(cnt, &coarseindex));
146:   cnt = 0;
147:   for (k = 0; k < n; k++) {
148:     if (marked[k] != 0.0) coarseindex[cnt++] = k + rstart;
149:   }
150:   PetscCall(VecRestoreArray(coarsemarked, &marked));
151:   PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)coarsemarked), cnt, coarseindex, PETSC_OWN_POINTER, &inactive));

153:   PetscCall(DMClearGlobalVectors(dm1));

155:   dm1->ops->createglobalvector = DMCreateGlobalVector_SNESVI;

157:   PetscCall(DMSetVI(*dm2, inactive));

159:   PetscCall(VecDestroy(&finemarked));
160:   PetscCall(VecDestroy(&coarsemarked));
161:   PetscCall(ISDestroy(&inactive));
162:   PetscFunctionReturn(PETSC_SUCCESS);
163: }

165: static PetscErrorCode DMDestroy_SNESVI(DM_SNESVI *dmsnesvi)
166: {
167:   PetscFunctionBegin;
168:   /* reset the base methods in the DM object that were changed when the DM_SNESVI was reset */
169:   dmsnesvi->dm->ops->createinterpolation = dmsnesvi->createinterpolation;
170:   dmsnesvi->dm->ops->coarsen             = dmsnesvi->coarsen;
171:   dmsnesvi->dm->ops->createglobalvector  = dmsnesvi->createglobalvector;
172:   dmsnesvi->dm->ops->createinjection     = dmsnesvi->createinjection;
173:   dmsnesvi->dm->ops->hascreateinjection  = dmsnesvi->hascreateinjection;
174:   /* need to clear out this vectors because some of them may not have a reference to the DM
175:     but they are counted as having references to the DM in DMDestroy() */
176:   PetscCall(DMClearGlobalVectors(dmsnesvi->dm));

178:   PetscCall(ISDestroy(&dmsnesvi->inactive));
179:   PetscCall(PetscFree(dmsnesvi));
180:   PetscFunctionReturn(PETSC_SUCCESS);
181: }

183: /*@
184:   DMSetVI - Marks a `DM` as associated with a VI problem. This causes the interpolation/restriction operators to
185:   be restricted to only those variables NOT associated with active constraints.

187:   Logically Collective

189:   Input Parameters:
190: + dm       - the `DM` object
191: - inactive - an `IS` indicating which points are currently not active

193:   Level: intermediate

195: .seealso: [](ch_snes), `SNES`, `SNESVINEWTONRSLS`, `SNESVIGetInactiveSet()`
196: @*/
197: PetscErrorCode DMSetVI(DM dm, IS inactive)
198: {
199:   PetscContainer isnes;
200:   DM_SNESVI     *dmsnesvi;

202:   PetscFunctionBegin;
203:   if (!dm) PetscFunctionReturn(PETSC_SUCCESS);

205:   PetscCall(PetscObjectReference((PetscObject)inactive));

207:   PetscCall(PetscObjectQuery((PetscObject)dm, "VI", (PetscObject *)&isnes));
208:   if (!isnes) {
209:     PetscCall(PetscContainerCreate(PetscObjectComm((PetscObject)dm), &isnes));
210:     PetscCall(PetscContainerSetUserDestroy(isnes, (PetscErrorCode(*)(void *))DMDestroy_SNESVI));
211:     PetscCall(PetscNew(&dmsnesvi));
212:     PetscCall(PetscContainerSetPointer(isnes, (void *)dmsnesvi));
213:     PetscCall(PetscObjectCompose((PetscObject)dm, "VI", (PetscObject)isnes));
214:     PetscCall(PetscContainerDestroy(&isnes));

216:     dmsnesvi->createinterpolation = dm->ops->createinterpolation;
217:     dm->ops->createinterpolation  = DMCreateInterpolation_SNESVI;
218:     dmsnesvi->coarsen             = dm->ops->coarsen;
219:     dm->ops->coarsen              = DMCoarsen_SNESVI;
220:     dmsnesvi->createglobalvector  = dm->ops->createglobalvector;
221:     dm->ops->createglobalvector   = DMCreateGlobalVector_SNESVI;
222:     dmsnesvi->createinjection     = dm->ops->createinjection;
223:     dm->ops->createinjection      = NULL;
224:     dmsnesvi->hascreateinjection  = dm->ops->hascreateinjection;
225:     dm->ops->hascreateinjection   = NULL;
226:   } else {
227:     PetscCall(PetscContainerGetPointer(isnes, (void **)&dmsnesvi));
228:     PetscCall(ISDestroy(&dmsnesvi->inactive));
229:   }
230:   PetscCall(DMClearGlobalVectors(dm));
231:   PetscCall(ISGetLocalSize(inactive, &dmsnesvi->n));

233:   dmsnesvi->inactive = inactive;
234:   dmsnesvi->dm       = dm;
235:   PetscFunctionReturn(PETSC_SUCCESS);
236: }

238: /*
239:      DMDestroyVI - Frees the DM_SNESVI object contained in the DM
240:          - also resets the function pointers in the DM for createinterpolation() etc to use the original DM
241: */
242: PetscErrorCode DMDestroyVI(DM dm)
243: {
244:   PetscFunctionBegin;
245:   if (!dm) PetscFunctionReturn(PETSC_SUCCESS);
246:   PetscCall(PetscObjectCompose((PetscObject)dm, "VI", (PetscObject)NULL));
247:   PetscFunctionReturn(PETSC_SUCCESS);
248: }

250: /* Create active and inactive set vectors. The local size of this vector is set and petsc computes the global size */
251: static PetscErrorCode SNESCreateSubVectors_VINEWTONRSLS(SNES snes, PetscInt n, Vec *newv)
252: {
253:   Vec v;

255:   PetscFunctionBegin;
256:   PetscCall(VecCreate(PetscObjectComm((PetscObject)snes), &v));
257:   PetscCall(VecSetSizes(v, n, PETSC_DECIDE));
258:   PetscCall(VecSetType(v, VECSTANDARD));
259:   *newv = v;
260:   PetscFunctionReturn(PETSC_SUCCESS);
261: }

263: /* Resets the snes PC and KSP when the active set sizes change */
264: static PetscErrorCode SNESVIResetPCandKSP(SNES snes, Mat Amat, Mat Pmat)
265: {
266:   KSP snesksp;

268:   PetscFunctionBegin;
269:   PetscCall(SNESGetKSP(snes, &snesksp));
270:   PetscCall(KSPReset(snesksp));
271:   PetscCall(KSPResetFromOptions(snesksp));

273:   /*
274:   KSP                    kspnew;
275:   PC                     pcnew;
276:   MatSolverType          stype;

278:   PetscCall(KSPCreate(PetscObjectComm((PetscObject)snes),&kspnew));
279:   kspnew->pc_side = snesksp->pc_side;
280:   kspnew->rtol    = snesksp->rtol;
281:   kspnew->abstol    = snesksp->abstol;
282:   kspnew->max_it  = snesksp->max_it;
283:   PetscCall(KSPSetType(kspnew,((PetscObject)snesksp)->type_name));
284:   PetscCall(KSPGetPC(kspnew,&pcnew));
285:   PetscCall(PCSetType(kspnew->pc,((PetscObject)snesksp->pc)->type_name));
286:   PetscCall(PCSetOperators(kspnew->pc,Amat,Pmat));
287:   PetscCall(PCFactorGetMatSolverType(snesksp->pc,&stype));
288:   PetscCall(PCFactorSetMatSolverType(kspnew->pc,stype));
289:   PetscCall(KSPDestroy(&snesksp));
290:   snes->ksp = kspnew;
291:    PetscCall(KSPSetFromOptions(kspnew));*/
292:   PetscFunctionReturn(PETSC_SUCCESS);
293: }

295: /* Variational Inequality solver using reduce space method. No semismooth algorithm is
296:    implemented in this algorithm. It basically identifies the active constraints and does
297:    a linear solve on the other variables (those not associated with the active constraints). */
298: static PetscErrorCode SNESSolve_VINEWTONRSLS(SNES snes)
299: {
300:   SNES_VINEWTONRSLS   *vi = (SNES_VINEWTONRSLS *)snes->data;
301:   PetscInt             maxits, i, lits;
302:   SNESLineSearchReason lssucceed;
303:   PetscReal            fnorm, gnorm, xnorm = 0, ynorm;
304:   Vec                  Y, X, F;
305:   KSPConvergedReason   kspreason;
306:   KSP                  ksp;
307:   PC                   pc;

309:   PetscFunctionBegin;
310:   /* Multigrid must use Galerkin for coarse grids with active set/reduced space methods; cannot rediscretize on coarser grids*/
311:   PetscCall(SNESGetKSP(snes, &ksp));
312:   PetscCall(KSPGetPC(ksp, &pc));
313:   PetscCall(PCMGSetGalerkin(pc, PC_MG_GALERKIN_BOTH));

315:   snes->numFailures            = 0;
316:   snes->numLinearSolveFailures = 0;
317:   snes->reason                 = SNES_CONVERGED_ITERATING;

319:   maxits = snes->max_its;  /* maximum number of iterations */
320:   X      = snes->vec_sol;  /* solution vector */
321:   F      = snes->vec_func; /* residual vector */
322:   Y      = snes->work[0];  /* work vectors */

324:   PetscCall(SNESLineSearchSetVIFunctions(snes->linesearch, SNESVIProjectOntoBounds, SNESVIComputeInactiveSetFnorm));
325:   PetscCall(SNESLineSearchSetVecs(snes->linesearch, X, NULL, NULL, NULL, NULL));
326:   PetscCall(SNESLineSearchSetUp(snes->linesearch));

328:   PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
329:   snes->iter = 0;
330:   snes->norm = 0.0;
331:   PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));

333:   PetscCall(SNESVIProjectOntoBounds(snes, X));
334:   PetscCall(SNESComputeFunction(snes, X, F));
335:   PetscCall(SNESVIComputeInactiveSetFnorm(snes, F, X, &fnorm));
336:   PetscCall(VecNorm(X, NORM_2, &xnorm)); /* xnorm <- ||x||  */
337:   SNESCheckFunctionNorm(snes, fnorm);
338:   PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
339:   snes->norm = fnorm;
340:   PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
341:   PetscCall(SNESLogConvergenceHistory(snes, fnorm, 0));

343:   /* test convergence */
344:   PetscCall(SNESConverged(snes, 0, 0.0, 0.0, fnorm));
345:   PetscCall(SNESMonitor(snes, 0, fnorm));
346:   if (snes->reason) PetscFunctionReturn(PETSC_SUCCESS);

348:   for (i = 0; i < maxits; i++) {
349:     IS         IS_act;    /* _act -> active set _inact -> inactive set */
350:     IS         IS_redact; /* redundant active set */
351:     VecScatter scat_act, scat_inact;
352:     PetscInt   nis_act, nis_inact;
353:     Vec        Y_act, Y_inact, F_inact;
354:     Mat        jac_inact_inact, prejac_inact_inact;
355:     PetscBool  isequal;

357:     /* Call general purpose update function */
358:     PetscTryTypeMethod(snes, update, snes->iter);
359:     PetscCall(SNESComputeJacobian(snes, X, snes->jacobian, snes->jacobian_pre));
360:     SNESCheckJacobianDomainerror(snes);

362:     /* Create active and inactive index sets */

364:     /*original
365:     PetscCall(SNESVICreateIndexSets_RS(snes,X,F,&IS_act,&vi->IS_inact));
366:      */
367:     PetscCall(SNESVIGetActiveSetIS(snes, X, F, &IS_act));

369:     if (vi->checkredundancy) {
370:       PetscCall((*vi->checkredundancy)(snes, IS_act, &IS_redact, vi->ctxP));
371:       if (IS_redact) {
372:         PetscCall(ISSort(IS_redact));
373:         PetscCall(ISComplement(IS_redact, X->map->rstart, X->map->rend, &vi->IS_inact));
374:         PetscCall(ISDestroy(&IS_redact));
375:       } else {
376:         PetscCall(ISComplement(IS_act, X->map->rstart, X->map->rend, &vi->IS_inact));
377:       }
378:     } else {
379:       PetscCall(ISComplement(IS_act, X->map->rstart, X->map->rend, &vi->IS_inact));
380:     }

382:     /* Create inactive set submatrix */
383:     PetscCall(MatCreateSubMatrix(snes->jacobian, vi->IS_inact, vi->IS_inact, MAT_INITIAL_MATRIX, &jac_inact_inact));

385:     if (0) { /* Dead code (temporary developer hack) */
386:       IS keptrows;
387:       PetscCall(MatFindNonzeroRows(jac_inact_inact, &keptrows));
388:       if (keptrows) {
389:         PetscInt        cnt, *nrows, k;
390:         const PetscInt *krows, *inact;
391:         PetscInt        rstart;

393:         PetscCall(MatGetOwnershipRange(jac_inact_inact, &rstart, NULL));
394:         PetscCall(MatDestroy(&jac_inact_inact));
395:         PetscCall(ISDestroy(&IS_act));

397:         PetscCall(ISGetLocalSize(keptrows, &cnt));
398:         PetscCall(ISGetIndices(keptrows, &krows));
399:         PetscCall(ISGetIndices(vi->IS_inact, &inact));
400:         PetscCall(PetscMalloc1(cnt, &nrows));
401:         for (k = 0; k < cnt; k++) nrows[k] = inact[krows[k] - rstart];
402:         PetscCall(ISRestoreIndices(keptrows, &krows));
403:         PetscCall(ISRestoreIndices(vi->IS_inact, &inact));
404:         PetscCall(ISDestroy(&keptrows));
405:         PetscCall(ISDestroy(&vi->IS_inact));

407:         PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)snes), cnt, nrows, PETSC_OWN_POINTER, &vi->IS_inact));
408:         PetscCall(ISComplement(vi->IS_inact, F->map->rstart, F->map->rend, &IS_act));
409:         PetscCall(MatCreateSubMatrix(snes->jacobian, vi->IS_inact, vi->IS_inact, MAT_INITIAL_MATRIX, &jac_inact_inact));
410:       }
411:     }
412:     PetscCall(DMSetVI(snes->dm, vi->IS_inact));
413:     /* remove later */

415:     /*
416:     PetscCall(VecView(vi->xu,PETSC_VIEWER_BINARY_(((PetscObject)(vi->xu))->comm)));
417:     PetscCall(VecView(vi->xl,PETSC_VIEWER_BINARY_(((PetscObject)(vi->xl))->comm)));
418:     PetscCall(VecView(X,PETSC_VIEWER_BINARY_(PetscObjectComm((PetscObject)X))));
419:     PetscCall(VecView(F,PETSC_VIEWER_BINARY_(PetscObjectComm((PetscObject)F))));
420:     PetscCall(ISView(vi->IS_inact,PETSC_VIEWER_BINARY_(PetscObjectComm((PetscObject)vi->IS_inact))));
421:      */

423:     /* Get sizes of active and inactive sets */
424:     PetscCall(ISGetLocalSize(IS_act, &nis_act));
425:     PetscCall(ISGetLocalSize(vi->IS_inact, &nis_inact));

427:     /* Create active and inactive set vectors */
428:     PetscCall(SNESCreateSubVectors_VINEWTONRSLS(snes, nis_inact, &F_inact));
429:     PetscCall(SNESCreateSubVectors_VINEWTONRSLS(snes, nis_act, &Y_act));
430:     PetscCall(SNESCreateSubVectors_VINEWTONRSLS(snes, nis_inact, &Y_inact));

432:     /* Create scatter contexts */
433:     PetscCall(VecScatterCreate(Y, IS_act, Y_act, NULL, &scat_act));
434:     PetscCall(VecScatterCreate(Y, vi->IS_inact, Y_inact, NULL, &scat_inact));

436:     /* Do a vec scatter to active and inactive set vectors */
437:     PetscCall(VecScatterBegin(scat_inact, F, F_inact, INSERT_VALUES, SCATTER_FORWARD));
438:     PetscCall(VecScatterEnd(scat_inact, F, F_inact, INSERT_VALUES, SCATTER_FORWARD));

440:     PetscCall(VecScatterBegin(scat_act, Y, Y_act, INSERT_VALUES, SCATTER_FORWARD));
441:     PetscCall(VecScatterEnd(scat_act, Y, Y_act, INSERT_VALUES, SCATTER_FORWARD));

443:     PetscCall(VecScatterBegin(scat_inact, Y, Y_inact, INSERT_VALUES, SCATTER_FORWARD));
444:     PetscCall(VecScatterEnd(scat_inact, Y, Y_inact, INSERT_VALUES, SCATTER_FORWARD));

446:     /* Active set direction = 0 */
447:     PetscCall(VecSet(Y_act, 0));
448:     if (snes->jacobian != snes->jacobian_pre) {
449:       PetscCall(MatCreateSubMatrix(snes->jacobian_pre, vi->IS_inact, vi->IS_inact, MAT_INITIAL_MATRIX, &prejac_inact_inact));
450:     } else prejac_inact_inact = jac_inact_inact;

452:     PetscCall(ISEqual(vi->IS_inact_prev, vi->IS_inact, &isequal));
453:     if (!isequal) {
454:       PetscCall(SNESVIResetPCandKSP(snes, jac_inact_inact, prejac_inact_inact));
455:       PetscCall(PCFieldSplitRestrictIS(pc, vi->IS_inact));
456:     }

458:     /*      PetscCall(ISView(vi->IS_inact,0)); */
459:     /*      PetscCall(ISView(IS_act,0));*/
460:     /*      ierr = MatView(snes->jacobian_pre,0); */

462:     PetscCall(KSPSetOperators(snes->ksp, jac_inact_inact, prejac_inact_inact));
463:     PetscCall(KSPSetUp(snes->ksp));
464:     {
465:       PC        pc;
466:       PetscBool flg;
467:       PetscCall(KSPGetPC(snes->ksp, &pc));
468:       PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCFIELDSPLIT, &flg));
469:       if (flg) {
470:         KSP *subksps;
471:         PetscCall(PCFieldSplitGetSubKSP(pc, NULL, &subksps));
472:         PetscCall(KSPGetPC(subksps[0], &pc));
473:         PetscCall(PetscFree(subksps));
474:         PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCBJACOBI, &flg));
475:         if (flg) {
476:           PetscInt        n, N = 101 * 101, j, cnts[3] = {0, 0, 0};
477:           const PetscInt *ii;

479:           PetscCall(ISGetSize(vi->IS_inact, &n));
480:           PetscCall(ISGetIndices(vi->IS_inact, &ii));
481:           for (j = 0; j < n; j++) {
482:             if (ii[j] < N) cnts[0]++;
483:             else if (ii[j] < 2 * N) cnts[1]++;
484:             else if (ii[j] < 3 * N) cnts[2]++;
485:           }
486:           PetscCall(ISRestoreIndices(vi->IS_inact, &ii));

488:           PetscCall(PCBJacobiSetTotalBlocks(pc, 3, cnts));
489:         }
490:       }
491:     }

493:     PetscCall(KSPSolve(snes->ksp, F_inact, Y_inact));
494:     PetscCall(VecScatterBegin(scat_act, Y_act, Y, INSERT_VALUES, SCATTER_REVERSE));
495:     PetscCall(VecScatterEnd(scat_act, Y_act, Y, INSERT_VALUES, SCATTER_REVERSE));
496:     PetscCall(VecScatterBegin(scat_inact, Y_inact, Y, INSERT_VALUES, SCATTER_REVERSE));
497:     PetscCall(VecScatterEnd(scat_inact, Y_inact, Y, INSERT_VALUES, SCATTER_REVERSE));

499:     PetscCall(VecDestroy(&F_inact));
500:     PetscCall(VecDestroy(&Y_act));
501:     PetscCall(VecDestroy(&Y_inact));
502:     PetscCall(VecScatterDestroy(&scat_act));
503:     PetscCall(VecScatterDestroy(&scat_inact));
504:     PetscCall(ISDestroy(&IS_act));
505:     if (!isequal) {
506:       PetscCall(ISDestroy(&vi->IS_inact_prev));
507:       PetscCall(ISDuplicate(vi->IS_inact, &vi->IS_inact_prev));
508:     }
509:     PetscCall(ISDestroy(&vi->IS_inact));
510:     PetscCall(MatDestroy(&jac_inact_inact));
511:     if (snes->jacobian != snes->jacobian_pre) PetscCall(MatDestroy(&prejac_inact_inact));

513:     PetscCall(KSPGetConvergedReason(snes->ksp, &kspreason));
514:     if (kspreason < 0) {
515:       if (++snes->numLinearSolveFailures >= snes->maxLinearSolveFailures) {
516:         PetscCall(PetscInfo(snes, "iter=%" PetscInt_FMT ", number linear solve failures %" PetscInt_FMT " greater than current SNES allowed, stopping solve\n", snes->iter, snes->numLinearSolveFailures));
517:         snes->reason = SNES_DIVERGED_LINEAR_SOLVE;
518:         break;
519:       }
520:     }

522:     PetscCall(KSPGetIterationNumber(snes->ksp, &lits));
523:     snes->linear_its += lits;
524:     PetscCall(PetscInfo(snes, "iter=%" PetscInt_FMT ", linear solve iterations=%" PetscInt_FMT "\n", snes->iter, lits));
525:     /*
526:     if (snes->ops->precheck) {
527:       PetscBool changed_y = PETSC_FALSE;
528:       PetscUseTypeMethod(snes,precheck ,X,Y,snes->precheck,&changed_y);
529:     }

531:     if (PetscLogPrintInfo) PetscCall(SNESVICheckResidual_Private(snes,snes->jacobian,F,Y,G,W));
532:     */
533:     /* Compute a (scaled) negative update in the line search routine:
534:          Y <- X - lambda*Y
535:        and evaluate G = function(Y) (depends on the line search).
536:     */
537:     PetscCall(VecCopy(Y, snes->vec_sol_update));
538:     ynorm = 1;
539:     gnorm = fnorm;
540:     PetscCall(SNESLineSearchApply(snes->linesearch, X, F, &gnorm, Y));
541:     PetscCall(SNESLineSearchGetReason(snes->linesearch, &lssucceed));
542:     PetscCall(SNESLineSearchGetNorms(snes->linesearch, &xnorm, &gnorm, &ynorm));
543:     PetscCall(PetscInfo(snes, "fnorm=%18.16e, gnorm=%18.16e, ynorm=%18.16e, lssucceed=%d\n", (double)fnorm, (double)gnorm, (double)ynorm, (int)lssucceed));
544:     if (snes->reason == SNES_DIVERGED_FUNCTION_COUNT) break;
545:     if (snes->domainerror) {
546:       snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN;
547:       PetscCall(DMDestroyVI(snes->dm));
548:       PetscFunctionReturn(PETSC_SUCCESS);
549:     }
550:     if (lssucceed) {
551:       if (++snes->numFailures >= snes->maxFailures) {
552:         PetscBool ismin;
553:         snes->reason = SNES_DIVERGED_LINE_SEARCH;
554:         PetscCall(SNESVICheckLocalMin_Private(snes, snes->jacobian, F, X, gnorm, &ismin));
555:         if (ismin) snes->reason = SNES_DIVERGED_LOCAL_MIN;
556:         break;
557:       }
558:     }
559:     PetscCall(DMDestroyVI(snes->dm));
560:     /* Update function and solution vectors */
561:     fnorm = gnorm;
562:     /* Monitor convergence */
563:     PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
564:     snes->iter  = i + 1;
565:     snes->norm  = fnorm;
566:     snes->xnorm = xnorm;
567:     snes->ynorm = ynorm;
568:     PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
569:     PetscCall(SNESLogConvergenceHistory(snes, snes->norm, lits));
570:     /* Test for convergence, xnorm = || X || */
571:     if (snes->ops->converged != SNESConvergedSkip) PetscCall(VecNorm(X, NORM_2, &xnorm));
572:     PetscCall(SNESConverged(snes, snes->iter, xnorm, ynorm, fnorm));
573:     PetscCall(SNESMonitor(snes, snes->iter, snes->norm));
574:     if (snes->reason) break;
575:   }
576:   /* make sure that the VI information attached to the DM is removed if the for loop above was broken early due to some exceptional conditional */
577:   PetscCall(DMDestroyVI(snes->dm));
578:   PetscFunctionReturn(PETSC_SUCCESS);
579: }

581: /*@C
582:   SNESVISetRedundancyCheck - Provide a function to check for any redundancy in the VI active set

584:   Logically Collective

586:   Input Parameters:
587: + snes - the `SNESVINEWTONRSLS` context
588: . func - the function to check of redundancies
589: - ctx  - optional context used by the function

591:   Level: advanced

593:   Note:
594:   Sometimes the inactive set will result in a singular sub-Jacobian problem that needs to be solved, this allows the user,
595:   when they know more about their specific problem to provide a function that removes the redundancy that results in the singular linear system

597: .seealso: [](ch_snes), `SNES`, `SNESVINEWTONRSLS`, `SNESVIGetInactiveSet()`, `DMSetVI()`
598:  @*/
599: PetscErrorCode SNESVISetRedundancyCheck(SNES snes, PetscErrorCode (*func)(SNES, IS, IS *, void *), void *ctx)
600: {
601:   SNES_VINEWTONRSLS *vi = (SNES_VINEWTONRSLS *)snes->data;

603:   PetscFunctionBegin;
605:   vi->checkredundancy = func;
606:   vi->ctxP            = ctx;
607:   PetscFunctionReturn(PETSC_SUCCESS);
608: }

610: #if defined(PETSC_HAVE_MATLAB)
611:   #include <engine.h>
612:   #include <mex.h>
613: typedef struct {
614:   char    *funcname;
615:   mxArray *ctx;
616: } SNESMatlabContext;

618: PetscErrorCode SNESVIRedundancyCheck_Matlab(SNES snes, IS is_act, IS *is_redact, void *ctx)
619: {
620:   SNESMatlabContext *sctx = (SNESMatlabContext *)ctx;
621:   int                nlhs = 1, nrhs = 5;
622:   mxArray           *plhs[1], *prhs[5];
623:   long long int      l1 = 0, l2 = 0, ls = 0;
624:   PetscInt          *indices = NULL;

626:   PetscFunctionBegin;
629:   PetscAssertPointer(is_redact, 3);
630:   PetscCheckSameComm(snes, 1, is_act, 2);

632:   /* Create IS for reduced active set of size 0, its size and indices will
633:    bet set by the MATLAB function */
634:   PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)snes), 0, indices, PETSC_OWN_POINTER, is_redact));
635:   /* call MATLAB function in ctx */
636:   PetscCall(PetscArraycpy(&ls, &snes, 1));
637:   PetscCall(PetscArraycpy(&l1, &is_act, 1));
638:   PetscCall(PetscArraycpy(&l2, is_redact, 1));
639:   prhs[0] = mxCreateDoubleScalar((double)ls);
640:   prhs[1] = mxCreateDoubleScalar((double)l1);
641:   prhs[2] = mxCreateDoubleScalar((double)l2);
642:   prhs[3] = mxCreateString(sctx->funcname);
643:   prhs[4] = sctx->ctx;
644:   PetscCall(mexCallMATLAB(nlhs, plhs, nrhs, prhs, "PetscSNESVIRedundancyCheckInternal"));
645:   PetscCall(mxGetScalar(plhs[0]));
646:   mxDestroyArray(prhs[0]);
647:   mxDestroyArray(prhs[1]);
648:   mxDestroyArray(prhs[2]);
649:   mxDestroyArray(prhs[3]);
650:   mxDestroyArray(plhs[0]);
651:   PetscFunctionReturn(PETSC_SUCCESS);
652: }

654: PetscErrorCode SNESVISetRedundancyCheckMatlab(SNES snes, const char *func, mxArray *ctx)
655: {
656:   SNESMatlabContext *sctx;

658:   PetscFunctionBegin;
659:   /* currently sctx is memory bleed */
660:   PetscCall(PetscNew(&sctx));
661:   PetscCall(PetscStrallocpy(func, &sctx->funcname));
662:   sctx->ctx = mxDuplicateArray(ctx);
663:   PetscCall(SNESVISetRedundancyCheck(snes, SNESVIRedundancyCheck_Matlab, sctx));
664:   PetscFunctionReturn(PETSC_SUCCESS);
665: }

667: #endif

669: static PetscErrorCode SNESSetUp_VINEWTONRSLS(SNES snes)
670: {
671:   SNES_VINEWTONRSLS *vi = (SNES_VINEWTONRSLS *)snes->data;
672:   PetscInt          *indices;
673:   PetscInt           i, n, rstart, rend;
674:   SNESLineSearch     linesearch;

676:   PetscFunctionBegin;
677:   PetscCall(SNESSetUp_VI(snes));

679:   /* Set up previous active index set for the first snes solve
680:    vi->IS_inact_prev = 0,1,2,....N */

682:   PetscCall(VecGetOwnershipRange(snes->vec_sol, &rstart, &rend));
683:   PetscCall(VecGetLocalSize(snes->vec_sol, &n));
684:   PetscCall(PetscMalloc1(n, &indices));
685:   for (i = 0; i < n; i++) indices[i] = rstart + i;
686:   PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)snes), n, indices, PETSC_OWN_POINTER, &vi->IS_inact_prev));

688:   /* set the line search functions */
689:   if (!snes->linesearch) {
690:     PetscCall(SNESGetLineSearch(snes, &linesearch));
691:     PetscCall(SNESLineSearchSetType(linesearch, SNESLINESEARCHBT));
692:   }
693:   PetscFunctionReturn(PETSC_SUCCESS);
694: }

696: static PetscErrorCode SNESReset_VINEWTONRSLS(SNES snes)
697: {
698:   SNES_VINEWTONRSLS *vi = (SNES_VINEWTONRSLS *)snes->data;

700:   PetscFunctionBegin;
701:   PetscCall(SNESReset_VI(snes));
702:   PetscCall(ISDestroy(&vi->IS_inact_prev));
703:   PetscFunctionReturn(PETSC_SUCCESS);
704: }

706: /*MC
707:       SNESVINEWTONRSLS - Reduced space active set solvers for variational inequalities based on Newton's method

709:    Options Database Keys:
710: +   -snes_type <vinewtonssls,vinewtonrsls> - a semi-smooth solver or a reduced space active set method
711: -   -snes_vi_monitor                       - prints the number of active constraints at each iteration.

713:    Level: beginner

715:    Note:
716:    At each set of this methods the algorithm produces an inactive set of variables that are constrained to their current values
717:    (because changing these values would result in those variables no longer satisfying the inequality constraints)
718:    and produces a step direction by solving the linear system arising from the Jacobian with the inactive variables removed. In other
719:    words on a reduced space of the solution space. Based on the Newton update it then adjusts the inactive set for the next iteration.

721:    See {cite}`benson2006flexible`

723: .seealso: [](ch_snes), `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()`, `SNESCreate()`, `SNES`, `SNESSetType()`, `SNESVINEWTONSSLS`, `SNESNEWTONTR`, `SNESLineSearchSetType()`, `SNESLineSearchSetPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESVIGetInactiveSet()`, `DMSetVI()`, `SNESVISetRedundancyCheck()`
724: M*/
725: PETSC_EXTERN PetscErrorCode SNESCreate_VINEWTONRSLS(SNES snes)
726: {
727:   SNES_VINEWTONRSLS *vi;
728:   SNESLineSearch     linesearch;

730:   PetscFunctionBegin;
731:   snes->ops->reset          = SNESReset_VINEWTONRSLS;
732:   snes->ops->setup          = SNESSetUp_VINEWTONRSLS;
733:   snes->ops->solve          = SNESSolve_VINEWTONRSLS;
734:   snes->ops->destroy        = SNESDestroy_VI;
735:   snes->ops->setfromoptions = SNESSetFromOptions_VI;
736:   snes->ops->view           = NULL;
737:   snes->ops->converged      = SNESConvergedDefault_VI;

739:   snes->usesksp = PETSC_TRUE;
740:   snes->usesnpc = PETSC_FALSE;

742:   PetscCall(SNESGetLineSearch(snes, &linesearch));
743:   if (!((PetscObject)linesearch)->type_name) PetscCall(SNESLineSearchSetType(linesearch, SNESLINESEARCHBT));
744:   PetscCall(SNESLineSearchBTSetAlpha(linesearch, 0.0));

746:   snes->alwayscomputesfinalresidual = PETSC_TRUE;

748:   PetscCall(PetscNew(&vi));
749:   snes->data          = (void *)vi;
750:   vi->checkredundancy = NULL;

752:   PetscCall(PetscObjectComposeFunction((PetscObject)snes, "SNESVISetVariableBounds_C", SNESVISetVariableBounds_VI));
753:   PetscCall(PetscObjectComposeFunction((PetscObject)snes, "SNESVISetComputeVariableBounds_C", SNESVISetComputeVariableBounds_VI));
754:   PetscFunctionReturn(PETSC_SUCCESS);
755: }