Date: 2016-07-24T17:03:46+00:00

Actual source code: composite.c
petsc-3.7.3 2016-07-24
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      2: /*
      3:       Defines a preconditioner that can consist of a collection of PCs
      4: */
      5: #include <petsc/private/pcimpl.h>
      6: #include <petscksp.h>            /*I "petscksp.h" I*/

      8: typedef struct _PC_CompositeLink *PC_CompositeLink;
      9: struct _PC_CompositeLink {
     10:   PC               pc;
     11:   PC_CompositeLink next;
     12:   PC_CompositeLink previous;
     13: };

     15: typedef struct {
     16:   PC_CompositeLink head;
     17:   PCCompositeType  type;
     18:   Vec              work1;
     19:   Vec              work2;
     20:   PetscScalar      alpha;
     21: } PC_Composite;

     25: static PetscErrorCode PCApply_Composite_Multiplicative(PC pc,Vec x,Vec y)
     26: {
     27:   PetscErrorCode   ierr;
     28:   PC_Composite     *jac = (PC_Composite*)pc->data;
     29:   PC_CompositeLink next = jac->head;
     30:   Mat              mat  = pc->pmat;

     34:   if (!next) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"No composite preconditioners supplied via PCCompositeAddPC() or -pc_composite_pcs");

     36:   /* Set the reuse flag on children PCs */
     37:   while (next) {
     38:     PCSetReusePreconditioner(next->pc,pc->reusepreconditioner);
     39:     next = next->next;
     40:   }
     41:   next = jac->head;

     43:   if (next->next && !jac->work2) { /* allocate second work vector */
     44:     VecDuplicate(jac->work1,&jac->work2);
     45:   }
     46:   if (pc->useAmat) mat = pc->mat;
     47:   PCApply(next->pc,x,y);                      /* y <- B x */
     48:   while (next->next) {
     49:     next = next->next;
     50:     MatMult(mat,y,jac->work1);                /* work1 <- A y */
     51:     VecWAXPY(jac->work2,-1.0,jac->work1,x);   /* work2 <- x - work1 */
     52:     VecSet(jac->work1,0.0);  /* zero since some PC's may not set all entries in the result */
     53:     PCApply(next->pc,jac->work2,jac->work1);  /* work1 <- C work2 */
     54:     VecAXPY(y,1.0,jac->work1);                /* y <- y + work1 = B x + C (x - A B x) = (B + C (1 - A B)) x */
     55:   }
     56:   if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
     57:     while (next->previous) {
     58:       next = next->previous;
     59:       MatMult(mat,y,jac->work1);
     60:       VecWAXPY(jac->work2,-1.0,jac->work1,x);
     61:       VecSet(jac->work1,0.0);  /* zero since some PC's may not set all entries in the result */
     62:       PCApply(next->pc,jac->work2,jac->work1);
     63:       VecAXPY(y,1.0,jac->work1);
     64:     }
     65:   }
     66:   return(0);
     67: }

     71: static PetscErrorCode PCApplyTranspose_Composite_Multiplicative(PC pc,Vec x,Vec y)
     72: {
     73:   PetscErrorCode   ierr;
     74:   PC_Composite     *jac = (PC_Composite*)pc->data;
     75:   PC_CompositeLink next = jac->head;
     76:   Mat              mat  = pc->pmat;

     79:   if (!next) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"No composite preconditioners supplied via PCCompositeAddPC() or -pc_composite_pcs");
     80:   if (next->next && !jac->work2) { /* allocate second work vector */
     81:     VecDuplicate(jac->work1,&jac->work2);
     82:   }
     83:   if (pc->useAmat) mat = pc->mat;
     84:   /* locate last PC */
     85:   while (next->next) {
     86:     next = next->next;
     87:   }
     88:   PCApplyTranspose(next->pc,x,y);
     89:   while (next->previous) {
     90:     next = next->previous;
     91:     MatMultTranspose(mat,y,jac->work1);
     92:     VecWAXPY(jac->work2,-1.0,jac->work1,x);
     93:     VecSet(jac->work1,0.0);  /* zero since some PC's may not set all entries in the result */
     94:     PCApplyTranspose(next->pc,jac->work2,jac->work1);
     95:     VecAXPY(y,1.0,jac->work1);
     96:   }
     97:   if (jac->type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
     98:     next = jac->head;
     99:     while (next->next) {
    100:       next = next->next;
    101:       MatMultTranspose(mat,y,jac->work1);
    102:       VecWAXPY(jac->work2,-1.0,jac->work1,x);
    103:       VecSet(jac->work1,0.0);  /* zero since some PC's may not set all entries in the result */
    104:       PCApplyTranspose(next->pc,jac->work2,jac->work1);
    105:       VecAXPY(y,1.0,jac->work1);
    106:     }
    107:   }
    108:   return(0);
    109: }

    111: /*
    112:     This is very special for a matrix of the form alpha I + R + S
    113: where first preconditioner is built from alpha I + S and second from
    114: alpha I + R
    115: */
    118: static PetscErrorCode PCApply_Composite_Special(PC pc,Vec x,Vec y)
    119: {
    120:   PetscErrorCode   ierr;
    121:   PC_Composite     *jac = (PC_Composite*)pc->data;
    122:   PC_CompositeLink next = jac->head;

    125:   if (!next) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"No composite preconditioners supplied via PCCompositeAddPC() or -pc_composite_pcs");
    126:   if (!next->next || next->next->next) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Special composite preconditioners requires exactly two PCs");

    128:   /* Set the reuse flag on children PCs */
    129:   PCSetReusePreconditioner(next->pc,pc->reusepreconditioner);
    130:   PCSetReusePreconditioner(next->next->pc,pc->reusepreconditioner);

    132:   PCApply(next->pc,x,jac->work1);
    133:   PCApply(next->next->pc,jac->work1,y);
    134:   return(0);
    135: }

    139: static PetscErrorCode PCApply_Composite_Additive(PC pc,Vec x,Vec y)
    140: {
    141:   PetscErrorCode   ierr;
    142:   PC_Composite     *jac = (PC_Composite*)pc->data;
    143:   PC_CompositeLink next = jac->head;

    146:   if (!next) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"No composite preconditioners supplied via PCCompositeAddPC() or -pc_composite_pcs");

    148:   /* Set the reuse flag on children PCs */
    149:   while (next) {
    150:     PCSetReusePreconditioner(next->pc,pc->reusepreconditioner);
    151:     next = next->next;
    152:   }
    153:   next = jac->head;

    155:   PCApply(next->pc,x,y);
    156:   while (next->next) {
    157:     next = next->next;
    158:     VecSet(jac->work1,0.0);  /* zero since some PC's may not set all entries in the result */
    159:     PCApply(next->pc,x,jac->work1);
    160:     VecAXPY(y,1.0,jac->work1);
    161:   }
    162:   return(0);
    163: }

    167: static PetscErrorCode PCApplyTranspose_Composite_Additive(PC pc,Vec x,Vec y)
    168: {
    169:   PetscErrorCode   ierr;
    170:   PC_Composite     *jac = (PC_Composite*)pc->data;
    171:   PC_CompositeLink next = jac->head;

    174:   if (!next) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"No composite preconditioners supplied via PCCompositeAddPC() or -pc_composite_pcs");
    175:   PCApplyTranspose(next->pc,x,y);
    176:   while (next->next) {
    177:     next = next->next;
    178:     VecSet(jac->work1,0.0);  /* zero since some PC's may not set all entries in the result */
    179:     PCApplyTranspose(next->pc,x,jac->work1);
    180:     VecAXPY(y,1.0,jac->work1);
    181:   }
    182:   return(0);
    183: }

    187: static PetscErrorCode PCSetUp_Composite(PC pc)
    188: {
    189:   PetscErrorCode   ierr;
    190:   PC_Composite     *jac = (PC_Composite*)pc->data;
    191:   PC_CompositeLink next = jac->head;
    192:   DM               dm;

    195:   if (!jac->work1) {
    196:     MatCreateVecs(pc->pmat,&jac->work1,0);
    197:   }
    198:   PCGetDM(pc,&dm);
    199:   while (next) {
    200:     PCSetDM(next->pc,dm);
    201:     PCSetOperators(next->pc,pc->mat,pc->pmat);
    202:     next = next->next;
    203:   }
    204:   return(0);
    205: }

    209: static PetscErrorCode PCReset_Composite(PC pc)
    210: {
    211:   PC_Composite     *jac = (PC_Composite*)pc->data;
    212:   PetscErrorCode   ierr;
    213:   PC_CompositeLink next = jac->head;

    216:   while (next) {
    217:     PCReset(next->pc);
    218:     next = next->next;
    219:   }
    220:   VecDestroy(&jac->work1);
    221:   VecDestroy(&jac->work2);
    222:   return(0);
    223: }

    227: static PetscErrorCode PCDestroy_Composite(PC pc)
    228: {
    229:   PC_Composite     *jac = (PC_Composite*)pc->data;
    230:   PetscErrorCode   ierr;
    231:   PC_CompositeLink next = jac->head,next_tmp;

    234:   PCReset_Composite(pc);
    235:   while (next) {
    236:     PCDestroy(&next->pc);
    237:     next_tmp = next;
    238:     next     = next->next;
    239:     PetscFree(next_tmp);
    240:   }
    241:   PetscFree(pc->data);
    242:   return(0);
    243: }

    247: static PetscErrorCode PCSetFromOptions_Composite(PetscOptionItems *PetscOptionsObject,PC pc)
    248: {
    249:   PC_Composite     *jac = (PC_Composite*)pc->data;
    250:   PetscErrorCode   ierr;
    251:   PetscInt         nmax = 8,i;
    252:   PC_CompositeLink next;
    253:   char             *pcs[8];
    254:   PetscBool        flg;

    257:   PetscOptionsHead(PetscOptionsObject,"Composite preconditioner options");
    258:   PetscOptionsEnum("-pc_composite_type","Type of composition","PCCompositeSetType",PCCompositeTypes,(PetscEnum)jac->type,(PetscEnum*)&jac->type,&flg);
    259:   if (flg) {
    260:     PCCompositeSetType(pc,jac->type);
    261:   }
    262:   PetscOptionsStringArray("-pc_composite_pcs","List of composite solvers","PCCompositeAddPC",pcs,&nmax,&flg);
    263:   if (flg) {
    264:     for (i=0; i<nmax; i++) {
    265:       PCCompositeAddPC(pc,pcs[i]);
    266:       PetscFree(pcs[i]);   /* deallocate string pcs[i], which is allocated in PetscOptionsStringArray() */
    267:     }
    268:   }
    269:   PetscOptionsTail();

    271:   next = jac->head;
    272:   while (next) {
    273:     PCSetFromOptions(next->pc);
    274:     next = next->next;
    275:   }
    276:   return(0);
    277: }

    281: static PetscErrorCode PCView_Composite(PC pc,PetscViewer viewer)
    282: {
    283:   PC_Composite     *jac = (PC_Composite*)pc->data;
    284:   PetscErrorCode   ierr;
    285:   PC_CompositeLink next = jac->head;
    286:   PetscBool        iascii;

    289:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
    290:   if (iascii) {
    291:     PetscViewerASCIIPrintf(viewer,"Composite PC type - %s\n",PCCompositeTypes[jac->type]);
    292:     PetscViewerASCIIPrintf(viewer,"PCs on composite preconditioner follow\n");
    293:     PetscViewerASCIIPrintf(viewer,"---------------------------------\n");
    294:   }
    295:   if (iascii) {
    296:     PetscViewerASCIIPushTab(viewer);
    297:   }
    298:   while (next) {
    299:     PCView(next->pc,viewer);
    300:     next = next->next;
    301:   }
    302:   if (iascii) {
    303:     PetscViewerASCIIPopTab(viewer);
    304:     PetscViewerASCIIPrintf(viewer,"---------------------------------\n");
    305:   }
    306:   return(0);
    307: }

    309: /* ------------------------------------------------------------------------------*/

    313: static PetscErrorCode  PCCompositeSpecialSetAlpha_Composite(PC pc,PetscScalar alpha)
    314: {
    315:   PC_Composite *jac = (PC_Composite*)pc->data;

    318:   jac->alpha = alpha;
    319:   return(0);
    320: }

    324: static PetscErrorCode  PCCompositeSetType_Composite(PC pc,PCCompositeType type)
    325: {
    326:   PC_Composite *jac = (PC_Composite*)pc->data;

    329:   if (type == PC_COMPOSITE_ADDITIVE) {
    330:     pc->ops->apply          = PCApply_Composite_Additive;
    331:     pc->ops->applytranspose = PCApplyTranspose_Composite_Additive;
    332:   } else if (type ==  PC_COMPOSITE_MULTIPLICATIVE || type == PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE) {
    333:     pc->ops->apply          = PCApply_Composite_Multiplicative;
    334:     pc->ops->applytranspose = PCApplyTranspose_Composite_Multiplicative;
    335:   } else if (type ==  PC_COMPOSITE_SPECIAL) {
    336:     pc->ops->apply          = PCApply_Composite_Special;
    337:     pc->ops->applytranspose = NULL;
    338:   } else SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONG,"Unkown composite preconditioner type");
    339:   jac->type = type;
    340:   return(0);
    341: }

    345: static PetscErrorCode  PCCompositeGetType_Composite(PC pc,PCCompositeType *type)
    346: {
    347:   PC_Composite *jac = (PC_Composite*)pc->data;

    350:   *type = jac->type;
    351:   return(0);
    352: }

    356: static PetscErrorCode  PCCompositeAddPC_Composite(PC pc,PCType type)
    357: {
    358:   PC_Composite     *jac;
    359:   PC_CompositeLink next,ilink;
    360:   PetscErrorCode   ierr;
    361:   PetscInt         cnt = 0;
    362:   const char       *prefix;
    363:   char             newprefix[8];

    366:   PetscNewLog(pc,&ilink);
    367:   ilink->next = 0;
    368:   PCCreate(PetscObjectComm((PetscObject)pc),&ilink->pc);
    369:   PetscLogObjectParent((PetscObject)pc,(PetscObject)ilink->pc);

    371:   jac  = (PC_Composite*)pc->data;
    372:   next = jac->head;
    373:   if (!next) {
    374:     jac->head       = ilink;
    375:     ilink->previous = NULL;
    376:   } else {
    377:     cnt++;
    378:     while (next->next) {
    379:       next = next->next;
    380:       cnt++;
    381:     }
    382:     next->next      = ilink;
    383:     ilink->previous = next;
    384:   }
    385:   PCGetOptionsPrefix(pc,&prefix);
    386:   PCSetOptionsPrefix(ilink->pc,prefix);
    387:   sprintf(newprefix,"sub_%d_",(int)cnt);
    388:   PCAppendOptionsPrefix(ilink->pc,newprefix);
    389:   /* type is set after prefix, because some methods may modify prefix, e.g. pcksp */
    390:   PCSetType(ilink->pc,type);
    391:   return(0);
    392: }

    396: static PetscErrorCode  PCCompositeGetNumberPC_Composite(PC pc,PetscInt *n)
    397: {
    398:   PC_Composite     *jac;
    399:   PC_CompositeLink next;

    402:   jac  = (PC_Composite*)pc->data;
    403:   next = jac->head;
    404:   *n = 0;
    405:   while (next) {
    406:     next = next->next;
    407:     (*n) ++;
    408:   }
    409:   return(0);
    410: }

    414: static PetscErrorCode  PCCompositeGetPC_Composite(PC pc,PetscInt n,PC *subpc)
    415: {
    416:   PC_Composite     *jac;
    417:   PC_CompositeLink next;
    418:   PetscInt         i;

    421:   jac  = (PC_Composite*)pc->data;
    422:   next = jac->head;
    423:   for (i=0; i<n; i++) {
    424:     if (!next->next) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_INCOMP,"Not enough PCs in composite preconditioner");
    425:     next = next->next;
    426:   }
    427:   *subpc = next->pc;
    428:   return(0);
    429: }

    431: /* -------------------------------------------------------------------------------- */
    434: /*@
    435:    PCCompositeSetType - Sets the type of composite preconditioner.

    437:    Logically Collective on PC

    439:    Input Parameters:
    440: +  pc - the preconditioner context
    441: -  type - PC_COMPOSITE_ADDITIVE (default), PC_COMPOSITE_MULTIPLICATIVE, PC_COMPOSITE_SPECIAL

    443:    Options Database Key:
    444: .  -pc_composite_type <type: one of multiplicative, additive, special> - Sets composite preconditioner type

    446:    Level: Developer

    448: .keywords: PC, set, type, composite preconditioner, additive, multiplicative
    449: @*/
    450: PetscErrorCode  PCCompositeSetType(PC pc,PCCompositeType type)
    451: {

    457:   PetscTryMethod(pc,"PCCompositeSetType_C",(PC,PCCompositeType),(pc,type));
    458:   return(0);
    459: }

    463: /*@
    464:    PCCompositeGetType - Gets the type of composite preconditioner.

    466:    Logically Collective on PC

    468:    Input Parameter:
    469: .  pc - the preconditioner context

    471:    Output Parameter:
    472: .  type - PC_COMPOSITE_ADDITIVE (default), PC_COMPOSITE_MULTIPLICATIVE, PC_COMPOSITE_SPECIAL

    474:    Options Database Key:
    475: .  -pc_composite_type <type: one of multiplicative, additive, special> - Sets composite preconditioner type

    477:    Level: Developer

    479: .keywords: PC, set, type, composite preconditioner, additive, multiplicative
    480: @*/
    481: PetscErrorCode  PCCompositeGetType(PC pc,PCCompositeType *type)
    482: {

    487:   PetscUseMethod(pc,"PCCompositeGetType_C",(PC,PCCompositeType*),(pc,type));
    488:   return(0);
    489: }

    493: /*@
    494:    PCCompositeSpecialSetAlpha - Sets alpha for the special composite preconditioner
    495:      for alphaI + R + S

    497:    Logically Collective on PC

    499:    Input Parameter:
    500: +  pc - the preconditioner context
    501: -  alpha - scale on identity

    503:    Level: Developer

    505: .keywords: PC, set, type, composite preconditioner, additive, multiplicative
    506: @*/
    507: PetscErrorCode  PCCompositeSpecialSetAlpha(PC pc,PetscScalar alpha)
    508: {

    514:   PetscTryMethod(pc,"PCCompositeSpecialSetAlpha_C",(PC,PetscScalar),(pc,alpha));
    515:   return(0);
    516: }

    520: /*@C
    521:    PCCompositeAddPC - Adds another PC to the composite PC.

    523:    Collective on PC

    525:    Input Parameters:
    526: +  pc - the preconditioner context
    527: -  type - the type of the new preconditioner

    529:    Level: Developer

    531: .keywords: PC, composite preconditioner, add
    532: @*/
    533: PetscErrorCode  PCCompositeAddPC(PC pc,PCType type)
    534: {

    539:   PetscTryMethod(pc,"PCCompositeAddPC_C",(PC,PCType),(pc,type));
    540:   return(0);
    541: }

    545: /*@
    546:    PCCompositeGetNumberPC - Gets the number of PC objects in the composite PC.

    548:    Not Collective

    550:    Input Parameter:
    551: .  pc - the preconditioner context

    553:    Output Parameter:
    554: .  num - the number of sub pcs

    556:    Level: Developer

    558: .keywords: PC, get, composite preconditioner, sub preconditioner

    560: .seealso: PCCompositeGetPC()
    561: @*/
    562: PetscErrorCode  PCCompositeGetNumberPC(PC pc,PetscInt *num)
    563: {

    569:   PetscUseMethod(pc,"PCCompositeGetNumberPC_C",(PC,PetscInt*),(pc,num));
    570:   return(0);
    571: }

    575: /*@
    576:    PCCompositeGetPC - Gets one of the PC objects in the composite PC.

    578:    Not Collective

    580:    Input Parameter:
    581: +  pc - the preconditioner context
    582: -  n - the number of the pc requested

    584:    Output Parameters:
    585: .  subpc - the PC requested

    587:    Level: Developer

    589: .keywords: PC, get, composite preconditioner, sub preconditioner

    591: .seealso: PCCompositeAddPC(), PCCompositeGetNumberPC()
    592: @*/
    593: PetscErrorCode  PCCompositeGetPC(PC pc,PetscInt n,PC *subpc)
    594: {

    600:   PetscUseMethod(pc,"PCCompositeGetPC_C",(PC,PetscInt,PC*),(pc,n,subpc));
    601:   return(0);
    602: }

    604: /* -------------------------------------------------------------------------------------------*/

    606: /*MC
    607:      PCCOMPOSITE - Build a preconditioner by composing together several preconditioners

    609:    Options Database Keys:
    610: +  -pc_composite_type <type: one of multiplicative, additive, symmetric_multiplicative, special> - Sets composite preconditioner type
    611: .  -pc_use_amat - Activates PCSetUseAmat()
    612: -  -pc_composite_pcs - <pc0,pc1,...> list of PCs to compose

    614:    Level: intermediate

    616:    Concepts: composing solvers

    618:    Notes: To use a Krylov method inside the composite preconditioner, set the PCType of one or more
    619:           inner PCs to be PCKSP.
    620:           Using a Krylov method inside another Krylov method can be dangerous (you get divergence or
    621:           the incorrect answer) unless you use KSPFGMRES as the outer Krylov method

    624: .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC,
    625:            PCSHELL, PCKSP, PCCompositeSetType(), PCCompositeSpecialSetAlpha(), PCCompositeAddPC(),
    626:            PCCompositeGetPC(), PCSetUseAmat()

    628: M*/

    632: PETSC_EXTERN PetscErrorCode PCCreate_Composite(PC pc)
    633: {
    635:   PC_Composite   *jac;

    638:   PetscNewLog(pc,&jac);

    640:   pc->ops->apply           = PCApply_Composite_Additive;
    641:   pc->ops->applytranspose  = PCApplyTranspose_Composite_Additive;
    642:   pc->ops->setup           = PCSetUp_Composite;
    643:   pc->ops->reset           = PCReset_Composite;
    644:   pc->ops->destroy         = PCDestroy_Composite;
    645:   pc->ops->setfromoptions  = PCSetFromOptions_Composite;
    646:   pc->ops->view            = PCView_Composite;
    647:   pc->ops->applyrichardson = 0;

    649:   pc->data   = (void*)jac;
    650:   jac->type  = PC_COMPOSITE_ADDITIVE;
    651:   jac->work1 = 0;
    652:   jac->work2 = 0;
    653:   jac->head  = 0;

    655:   PetscObjectComposeFunction((PetscObject)pc,"PCCompositeSetType_C",PCCompositeSetType_Composite);
    656:   PetscObjectComposeFunction((PetscObject)pc,"PCCompositeGetType_C",PCCompositeGetType_Composite);
    657:   PetscObjectComposeFunction((PetscObject)pc,"PCCompositeAddPC_C",PCCompositeAddPC_Composite);
    658:   PetscObjectComposeFunction((PetscObject)pc,"PCCompositeGetNumberPC_C",PCCompositeGetNumberPC_Composite);
    659:   PetscObjectComposeFunction((PetscObject)pc,"PCCompositeGetPC_C",PCCompositeGetPC_Composite);
    660:   PetscObjectComposeFunction((PetscObject)pc,"PCCompositeSpecialSetAlpha_C",PCCompositeSpecialSetAlpha_Composite);
    661:   return(0);
    662: }