Date: 2022-08-02T03:14:34+00:00

Actual source code: qr.c

      2: /*
      3:    Defines a direct QR factorization preconditioner for any Mat implementation
      4:    Note: this need not be considered a preconditioner since it supplies
      5:          a direct solver.
      6: */
      7: #include <../src/ksp/pc/impls/factor/qr/qr.h>

      9: static PetscErrorCode PCSetUp_QR(PC pc)
     10: {
     11:   PC_QR                  *dir = (PC_QR*)pc->data;
     12:   MatSolverType          stype;
     13:   MatFactorError         err;

     15:   pc->failedreason = PC_NOERROR;
     16:   if (dir->hdr.reusefill && pc->setupcalled) ((PC_Factor*)dir)->info.fill = dir->hdr.actualfill;

     18:   MatSetErrorIfFailure(pc->pmat,pc->erroriffailure);
     19:   if (dir->hdr.inplace) {
     20:     MatFactorType ftype;

     22:     MatGetFactorType(pc->pmat, &ftype);
     23:     if (ftype == MAT_FACTOR_NONE) {
     24:       MatQRFactor(pc->pmat,dir->col,&((PC_Factor*)dir)->info);
     25:       MatFactorGetError(pc->pmat,&err);
     26:       if (err) { /* Factor() fails */
     27:         pc->failedreason = (PCFailedReason)err;
     28:         return 0;
     29:       }
     30:     }
     31:     ((PC_Factor*)dir)->fact = pc->pmat;
     32:   } else {
     33:     MatInfo info;

     35:     if (!pc->setupcalled) {
     36:       if (!((PC_Factor*)dir)->fact) {
     37:         MatGetFactor(pc->pmat,((PC_Factor*)dir)->solvertype,MAT_FACTOR_QR,&((PC_Factor*)dir)->fact);
     38:         PetscLogObjectParent((PetscObject)pc,(PetscObject)((PC_Factor*)dir)->fact);
     39:       }
     40:       MatQRFactorSymbolic(((PC_Factor*)dir)->fact,pc->pmat,dir->col,&((PC_Factor*)dir)->info);
     41:       MatGetInfo(((PC_Factor*)dir)->fact,MAT_LOCAL,&info);
     42:       dir->hdr.actualfill = info.fill_ratio_needed;
     43:     } else if (pc->flag != SAME_NONZERO_PATTERN) {
     44:       MatQRFactorSymbolic(((PC_Factor*)dir)->fact,pc->pmat,dir->col,&((PC_Factor*)dir)->info);
     45:       MatGetInfo(((PC_Factor*)dir)->fact,MAT_LOCAL,&info);
     46:       dir->hdr.actualfill = info.fill_ratio_needed;
     47:     } else {
     48:       MatFactorGetError(((PC_Factor*)dir)->fact,&err);
     49:     }
     50:     MatFactorGetError(((PC_Factor*)dir)->fact,&err);
     51:     if (err) { /* FactorSymbolic() fails */
     52:       pc->failedreason = (PCFailedReason)err;
     53:       return 0;
     54:     }

     56:     MatQRFactorNumeric(((PC_Factor*)dir)->fact,pc->pmat,&((PC_Factor*)dir)->info);
     57:     MatFactorGetError(((PC_Factor*)dir)->fact,&err);
     58:     if (err) { /* FactorNumeric() fails */
     59:       pc->failedreason = (PCFailedReason)err;
     60:     }
     61:   }

     63:   PCFactorGetMatSolverType(pc,&stype);
     64:   if (!stype) {
     65:     MatSolverType solverpackage;
     66:     MatFactorGetSolverType(((PC_Factor*)dir)->fact,&solverpackage);
     67:     PCFactorSetMatSolverType(pc,solverpackage);
     68:   }
     69:   return 0;
     70: }

     72: static PetscErrorCode PCReset_QR(PC pc)
     73: {
     74:   PC_QR          *dir = (PC_QR*)pc->data;

     76:   if (!dir->hdr.inplace && ((PC_Factor*)dir)->fact) MatDestroy(&((PC_Factor*)dir)->fact);
     77:   ISDestroy(&dir->col);
     78:   return 0;
     79: }

     81: static PetscErrorCode PCDestroy_QR(PC pc)
     82: {
     83:   PC_QR          *dir = (PC_QR*)pc->data;

     85:   PCReset_QR(pc);
     86:   PetscFree(((PC_Factor*)dir)->ordering);
     87:   PetscFree(((PC_Factor*)dir)->solvertype);
     88:   PetscFree(pc->data);
     89:   return 0;
     90: }

     92: static PetscErrorCode PCApply_QR(PC pc,Vec x,Vec y)
     93: {
     94:   PC_QR          *dir = (PC_QR*)pc->data;
     95:   Mat            fact;

     97:   fact = dir->hdr.inplace ? pc->pmat : ((PC_Factor*)dir)->fact;
     98:   MatSolve(fact,x,y);
     99:   return 0;
    100: }

    102: static PetscErrorCode PCMatApply_QR(PC pc,Mat X,Mat Y)
    103: {
    104:   PC_QR          *dir = (PC_QR*)pc->data;
    105:   Mat            fact;

    107:   fact = dir->hdr.inplace ? pc->pmat : ((PC_Factor*)dir)->fact;
    108:   MatMatSolve(fact,X,Y);
    109:   return 0;
    110: }

    112: static PetscErrorCode PCApplyTranspose_QR(PC pc,Vec x,Vec y)
    113: {
    114:   PC_QR          *dir = (PC_QR*)pc->data;
    115:   Mat            fact;

    117:   fact = dir->hdr.inplace ? pc->pmat : ((PC_Factor*)dir)->fact;
    118:   MatSolveTranspose(fact,x,y);
    119:   return 0;
    120: }

    122: /* -----------------------------------------------------------------------------------*/

    124: /*MC
    125:    PCQR - Uses a direct solver, based on QR factorization, as a preconditioner

    127:    Level: beginner

    129:    Notes:
    130:     Usually this will compute an "exact" solution in one iteration and does
    131:           not need a Krylov method (i.e. you can use -ksp_type preonly, or
    132:           KSPSetType(ksp,KSPPREONLY) for the Krylov method

    134: .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC,
    135:            PCILU, PCLU, PCCHOLESKY, PCICC, PCFactorSetReuseOrdering(), PCFactorSetReuseFill(), PCFactorGetMatrix(),
    136:            PCFactorSetFill(), PCFactorSetUseInPlace(), PCFactorSetMatOrderingType(), PCFactorSetColumnPivot(),
    137:            PCFactorSetPivotingInBlocks(),PCFactorSetShiftType(),PCFactorSetShiftAmount()
    138:            PCFactorReorderForNonzeroDiagonal()
    139: M*/

    141: PETSC_EXTERN PetscErrorCode PCCreate_QR(PC pc)
    142: {
    143:   PC_QR          *dir;

    145:   PetscNewLog(pc,&dir);
    146:   pc->data = (void*)dir;
    147:   PCFactorInitialize(pc, MAT_FACTOR_QR);

    149:   dir->col                   = NULL;
    150:   pc->ops->reset             = PCReset_QR;
    151:   pc->ops->destroy           = PCDestroy_QR;
    152:   pc->ops->apply             = PCApply_QR;
    153:   pc->ops->matapply          = PCMatApply_QR;
    154:   pc->ops->applytranspose    = PCApplyTranspose_QR;
    155:   pc->ops->setup             = PCSetUp_QR;
    156:   pc->ops->setfromoptions    = PCSetFromOptions_Factor;
    157:   pc->ops->view              = PCView_Factor;
    158:   pc->ops->applyrichardson   = NULL;
    159:   return 0;
    160: }