Actual source code: precond.c

  1: /*
  2:       Implements the ST class for preconditioned eigenvalue methods.

  4:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  5:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  6:    Copyright (c) 2002-2013, Universitat Politecnica de Valencia, Spain

  8:    This file is part of SLEPc.

 10:    SLEPc is free software: you can redistribute it and/or modify it under  the
 11:    terms of version 3 of the GNU Lesser General Public License as published by
 12:    the Free Software Foundation.

 14:    SLEPc  is  distributed in the hope that it will be useful, but WITHOUT  ANY
 15:    WARRANTY;  without even the implied warranty of MERCHANTABILITY or  FITNESS
 16:    FOR  A  PARTICULAR PURPOSE. See the GNU Lesser General Public  License  for
 17:    more details.

 19:    You  should have received a copy of the GNU Lesser General  Public  License
 20:    along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
 21:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 22: */

 24: #include <slepc-private/stimpl.h>          /*I "slepcst.h" I*/

 26: typedef struct {
 27:   PetscBool setmat;
 28: } ST_PRECOND;

 32: PetscErrorCode STSetFromOptions_Precond(ST st)
 33: {
 35:   PC             pc;
 36:   PCType         pctype;
 37:   Mat            P;
 38:   PetscBool      t0,t1;
 39:   KSP            ksp;

 42:   STGetKSP(st,&ksp);
 43:   KSPGetPC(ksp,&pc);
 44:   PetscObjectGetType((PetscObject)pc,&pctype);
 45:   STPrecondGetMatForPC(st,&P);
 46:   if (!pctype && st->A[0]) {
 47:     if (P || st->shift_matrix == ST_MATMODE_SHELL) {
 48:       PCSetType(pc,PCJACOBI);
 49:     } else {
 50:       MatHasOperation(st->A[0],MATOP_DUPLICATE,&t0);
 51:       if (st->nmat>1) {
 52:         MatHasOperation(st->A[0],MATOP_AXPY,&t1);
 53:       } else t1 = PETSC_TRUE;
 54:       PCSetType(pc,(t0 && t1)?PCJACOBI:PCNONE);
 55:     }
 56:   }
 57:   return(0);
 58: }

 62: PetscErrorCode STSetUp_Precond(ST st)
 63: {
 64:   Mat            P;
 65:   PC             pc;
 66:   PetscBool      t0,setmat,destroyP=PETSC_FALSE,builtP;

 70:   /* if the user did not set the shift, use the target value */
 71:   if (!st->sigma_set) st->sigma = st->defsigma;

 73:   /* If either pc is none and no matrix has to be set, or pc is shell , exit */
 74:   STSetFromOptions_Precond(st);
 75:   if (!st->ksp) { STGetKSP(st,&st->ksp); }
 76:   KSPGetPC(st->ksp,&pc);
 77:   PetscObjectTypeCompare((PetscObject)pc,PCSHELL,&t0);
 78:   if (t0) return(0);
 79:   PetscObjectTypeCompare((PetscObject)pc,PCNONE,&t0);
 80:   STPrecondGetKSPHasMat(st,&setmat);
 81:   if (t0 && !setmat) return(0);

 83:   /* Check if a user matrix is set */
 84:   STPrecondGetMatForPC(st,&P);

 86:   /* If not, create A - shift*B */
 87:   if (P) {
 88:     builtP = PETSC_FALSE;
 89:     destroyP = PETSC_TRUE;
 90:     PetscObjectReference((PetscObject)P);
 91:   } else {
 92:     builtP = PETSC_TRUE;

 94:     if (!(PetscAbsScalar(st->sigma) < PETSC_MAX_REAL) && st->nmat>1) {
 95:       P = st->A[1];
 96:       destroyP = PETSC_FALSE;
 97:     } else if (st->sigma == 0.0) {
 98:       P = st->A[0];
 99:       destroyP = PETSC_FALSE;
100:     } else if (PetscAbsScalar(st->sigma) < PETSC_MAX_REAL && st->shift_matrix != ST_MATMODE_SHELL) {
101:       if (st->shift_matrix == ST_MATMODE_INPLACE) {
102:         P = st->A[0];
103:         destroyP = PETSC_FALSE;
104:       } else {
105:         MatDuplicate(st->A[0],MAT_COPY_VALUES,&P);
106:         destroyP = PETSC_TRUE;
107:       }
108:       if (st->nmat>1) {
109:         MatAXPY(P,-st->sigma,st->A[1],st->str);
110:       } else {
111:         MatShift(P,-st->sigma);
112:       }
113:       /* TODO: in case of ST_MATMODE_INPLACE should keep the Hermitian flag of st->A and restore at the end */
114:       STMatSetHermitian(st,P);
115:     } else builtP = PETSC_FALSE;
116:   }

118:   /* If P was not possible to obtain, set pc to PCNONE */
119:   if (!P) {
120:     PCSetType(pc,PCNONE);

122:     /* If some matrix has to be set to ksp, a shell matrix is created */
123:     if (setmat) {
124:       STMatShellCreate(st,-st->sigma,0,NULL,&P);
125:       STMatSetHermitian(st,P);
126:       destroyP = PETSC_TRUE;
127:     }
128:   }

130:   KSPSetOperators(st->ksp,setmat?P:NULL,P,DIFFERENT_NONZERO_PATTERN);

132:   if (destroyP) {
133:     MatDestroy(&P);
134:   } else if (st->shift_matrix == ST_MATMODE_INPLACE && builtP) {
135:     if (st->sigma != 0.0 && PetscAbsScalar(st->sigma) < PETSC_MAX_REAL) {
136:       if (st->nmat>1) {
137:         MatAXPY(st->A[0],st->sigma,st->A[1],st->str);
138:       } else {
139:         MatShift(st->A[0],st->sigma);
140:       }
141:     }
142:   }
143:   return(0);
144: }

148: PetscErrorCode STSetShift_Precond(ST st,PetscScalar newshift)
149: {

153:   /* Nothing to be done if STSetUp has not been called yet */
154:   if (!st->setupcalled) return(0);
155:   st->sigma = newshift;
156:   if (st->shift_matrix != ST_MATMODE_SHELL) {
157:     STSetUp_Precond(st);
158:   }
159:   return(0);
160: }

164: static PetscErrorCode STPrecondGetMatForPC_Precond(ST st,Mat *mat)
165: {
167:   PC             pc;
168:   PetscBool      flag;

171:   if (!st->ksp) { STGetKSP(st,&st->ksp); }
172:   KSPGetPC(st->ksp,&pc);
173:   PCGetOperatorsSet(pc,NULL,&flag);
174:   if (flag) {
175:     PCGetOperators(pc,NULL,mat,NULL);
176:   } else *mat = NULL;
177:   return(0);
178: }

182: /*@
183:    STPrecondGetMatForPC - Returns the matrix previously set by STPrecondSetMatForPC().

185:    Not Collective, but the Mat is shared by all processors that share the ST

187:    Input Parameter:
188: .  st - the spectral transformation context

190:    Output Parameter:
191: .  mat - the matrix that will be used in constructing the preconditioner or
192:    NULL if no matrix was set by STPrecondSetMatForPC().

194:    Level: advanced

196: .seealso: STPrecondSetMatForPC()
197: @*/
198: PetscErrorCode STPrecondGetMatForPC(ST st,Mat *mat)
199: {

205:   PetscTryMethod(st,"STPrecondGetMatForPC_C",(ST,Mat*),(st,mat));
206:   return(0);
207: }

211: static PetscErrorCode STPrecondSetMatForPC_Precond(ST st,Mat mat)
212: {
213:   PC             pc;
214:   Mat            A;
215:   PetscBool      flag;

219:   if (!st->ksp) { STGetKSP(st,&st->ksp); }
220:   KSPGetPC(st->ksp,&pc);
221:   /* Yes, all these lines are needed to safely set mat as the preconditioner
222:      matrix in pc */
223:   PCGetOperatorsSet(pc,&flag,NULL);
224:   if (flag) {
225:     PCGetOperators(pc,&A,NULL,NULL);
226:     PetscObjectReference((PetscObject)A);
227:   } else A = NULL;
228:   PetscObjectReference((PetscObject)mat);
229:   PCSetOperators(pc,A,mat,DIFFERENT_NONZERO_PATTERN);
230:   MatDestroy(&A);
231:   MatDestroy(&mat);
232:   STPrecondSetKSPHasMat(st,PETSC_TRUE);
233:   return(0);
234: }

238: /*@
239:    STPrecondSetMatForPC - Sets the matrix that must be used to build the preconditioner.

241:    Logically Collective on ST and Mat

243:    Input Parameter:
244: +  st - the spectral transformation context
245: -  mat - the matrix that will be used in constructing the preconditioner

247:    Level: advanced

249:    Notes:
250:    This matrix will be passed to the KSP object (via KSPSetOperators) as
251:    the matrix to be used when constructing the preconditioner.
252:    If no matrix is set or mat is set to NULL, A - sigma*B will
253:    be used to build the preconditioner, being sigma the value set by STSetShift().

255: .seealso: STPrecondSetMatForPC(), STSetShift()
256: @*/
257: PetscErrorCode STPrecondSetMatForPC(ST st,Mat mat)
258: {

265:   PetscTryMethod(st,"STPrecondSetMatForPC_C",(ST,Mat),(st,mat));
266:   return(0);
267: }

271: static PetscErrorCode STPrecondSetKSPHasMat_Precond(ST st,PetscBool setmat)
272: {
273:   ST_PRECOND *data = (ST_PRECOND*)st->data;

276:   data->setmat = setmat;
277:   return(0);
278: }

282: /*@
283:    STPrecondSetKSPHasMat - Sets a flag indicating that during STSetUp the coefficient
284:    matrix of the KSP linear system (A) must be set to be the same matrix as the
285:    preconditioner (P).

287:    Collective on ST

289:    Input Parameter:
290: +  st - the spectral transformation context
291: -  setmat - the flag

293:    Notes:
294:    In most cases, the preconditioner matrix is used only in the PC object, but
295:    in external solvers this matrix must be provided also as the A-matrix in
296:    the KSP object.

298:    Level: developer

300: .seealso: STPrecondGetKSPHasMat(), STSetShift()
301: @*/
302: PetscErrorCode STPrecondSetKSPHasMat(ST st,PetscBool setmat)
303: {

309:   PetscTryMethod(st,"STPrecondSetKSPHasMat_C",(ST,PetscBool),(st,setmat));
310:   return(0);
311: }

315: static PetscErrorCode STPrecondGetKSPHasMat_Precond(ST st,PetscBool *setmat)
316: {
317:   ST_PRECOND *data = (ST_PRECOND*)st->data;

320:   *setmat = data->setmat;
321:   return(0);
322: }

326: /*@
327:    STPrecondGetKSPHasMat - Returns the flag indicating if the coefficient
328:    matrix of the KSP linear system (A) is set to be the same matrix as the
329:    preconditioner (P).

331:    Not Collective

333:    Input Parameter:
334: .  st - the spectral transformation context

336:    Output Parameter:
337: .  setmat - the flag

339:    Level: developer

341: .seealso: STPrecondSetKSPHasMat(), STSetShift()
342: @*/
343: PetscErrorCode STPrecondGetKSPHasMat(ST st,PetscBool *setmat)
344: {

350:   PetscTryMethod(st,"STPrecondGetKSPHasMat_C",(ST,PetscBool*),(st,setmat));
351:   return(0);
352: }

356: PetscErrorCode STDestroy_Precond(ST st)
357: {

361:   PetscFree(st->data);
362:   PetscObjectComposeFunction((PetscObject)st,"STPrecondGetMatForPC_C",NULL);
363:   PetscObjectComposeFunction((PetscObject)st,"STPrecondSetMatForPC_C",NULL);
364:   PetscObjectComposeFunction((PetscObject)st,"STPrecondGetKSPHasMat_C",NULL);
365:   PetscObjectComposeFunction((PetscObject)st,"STPrecondSetKSPHasMat_C",NULL);
366:   return(0);
367: }

371: PETSC_EXTERN PetscErrorCode STCreate_Precond(ST st)
372: {

376:   PetscNewLog(st,ST_PRECOND,&st->data);
377:   st->ops->getbilinearform = STGetBilinearForm_Default;
378:   st->ops->setup           = STSetUp_Precond;
379:   st->ops->setshift        = STSetShift_Precond;
380:   st->ops->destroy         = STDestroy_Precond;
381:   st->ops->setfromoptions  = STSetFromOptions_Precond;

383:   PetscObjectComposeFunction((PetscObject)st,"STPrecondGetMatForPC_C",STPrecondGetMatForPC_Precond);
384:   PetscObjectComposeFunction((PetscObject)st,"STPrecondSetMatForPC_C",STPrecondSetMatForPC_Precond);
385:   PetscObjectComposeFunction((PetscObject)st,"STPrecondGetKSPHasMat_C",STPrecondGetKSPHasMat_Precond);
386:   PetscObjectComposeFunction((PetscObject)st,"STPrecondSetKSPHasMat_C",STPrecondSetKSPHasMat_Precond);

388:   STPrecondSetKSPHasMat_Precond(st,PETSC_TRUE);
389:   return(0);
390: }