Date: 2013-09-02T10:06:14+00:00

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: }