Date: 2016-07-24T17:04:30+00:00

Actual source code: lu.c
petsc-3.7.3 2016-07-24
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      2: /*
      3:    Defines a direct factorization preconditioner for any Mat implementation
      4:    Note: this need not be consided a preconditioner since it supplies
      5:          a direct solver.
      6: */

      8: #include <../src/ksp/pc/impls/factor/lu/lu.h>  /*I "petscpc.h" I*/

     13: PetscErrorCode PCFactorReorderForNonzeroDiagonal_LU(PC pc,PetscReal z)
     14: {
     15:   PC_LU *lu = (PC_LU*)pc->data;

     18:   lu->nonzerosalongdiagonal = PETSC_TRUE;
     19:   if (z == PETSC_DECIDE) lu->nonzerosalongdiagonaltol = 1.e-10;
     20:   else lu->nonzerosalongdiagonaltol = z;
     21:   return(0);
     22: }

     26: PetscErrorCode PCFactorSetReuseOrdering_LU(PC pc,PetscBool flag)
     27: {
     28:   PC_LU *lu = (PC_LU*)pc->data;

     31:   lu->reuseordering = flag;
     32:   return(0);
     33: }

     37: PetscErrorCode PCFactorSetReuseFill_LU(PC pc,PetscBool flag)
     38: {
     39:   PC_LU *lu = (PC_LU*)pc->data;

     42:   lu->reusefill = flag;
     43:   return(0);
     44: }

     48: static PetscErrorCode PCSetFromOptions_LU(PetscOptionItems *PetscOptionsObject,PC pc)
     49: {
     50:   PC_LU          *lu = (PC_LU*)pc->data;
     52:   PetscBool      flg = PETSC_FALSE;
     53:   PetscReal      tol;

     56:   PetscOptionsHead(PetscOptionsObject,"LU options");
     57:   PCSetFromOptions_Factor(PetscOptionsObject,pc);

     59:   PetscOptionsName("-pc_factor_nonzeros_along_diagonal","Reorder to remove zeros from diagonal","PCFactorReorderForNonzeroDiagonal",&flg);
     60:   if (flg) {
     61:     tol  = PETSC_DECIDE;
     62:     PetscOptionsReal("-pc_factor_nonzeros_along_diagonal","Reorder to remove zeros from diagonal","PCFactorReorderForNonzeroDiagonal",lu->nonzerosalongdiagonaltol,&tol,0);
     63:     PCFactorReorderForNonzeroDiagonal(pc,tol);
     64:   }
     65:   PetscOptionsTail();
     66:   return(0);
     67: }

     71: static PetscErrorCode PCView_LU(PC pc,PetscViewer viewer)
     72: {
     73:   PC_LU          *lu = (PC_LU*)pc->data;
     75:   PetscBool      iascii;

     78:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
     79:   if (iascii) {
     80:     if (lu->inplace) {
     81:       PetscViewerASCIIPrintf(viewer,"  LU: in-place factorization\n");
     82:     } else {
     83:       PetscViewerASCIIPrintf(viewer,"  LU: out-of-place factorization\n");
     84:     }

     86:     if (lu->reusefill)    {PetscViewerASCIIPrintf(viewer,"       Reusing fill from past factorization\n");}
     87:     if (lu->reuseordering) {PetscViewerASCIIPrintf(viewer,"       Reusing reordering from past factorization\n");}
     88:   }
     89:   PCView_Factor(pc,viewer);
     90:   return(0);
     91: }

     95: static PetscErrorCode PCSetUp_LU(PC pc)
     96: {
     98:   PC_LU          *dir = (PC_LU*)pc->data;
     99:   const MatSolverPackage stype;

    102:   if (dir->reusefill && pc->setupcalled) ((PC_Factor*)dir)->info.fill = dir->actualfill;

    104:   MatSetErrorIfFailure(pc->pmat,pc->erroriffailure);
    105:   if (dir->inplace) {
    106:     if (dir->row && dir->col && dir->row != dir->col) {ISDestroy(&dir->row);}
    107:     ISDestroy(&dir->col);
    108:     MatGetOrdering(pc->pmat,((PC_Factor*)dir)->ordering,&dir->row,&dir->col);
    109:     if (dir->row) {
    110:       PetscLogObjectParent((PetscObject)pc,(PetscObject)dir->row);
    111:       PetscLogObjectParent((PetscObject)pc,(PetscObject)dir->col);
    112:     }
    113:     MatLUFactor(pc->pmat,dir->row,dir->col,&((PC_Factor*)dir)->info);
    114:     if (pc->pmat->errortype) { /* Factor() fails */
    115:       pc->failedreason = (PCFailedReason)pc->pmat->errortype;
    116:       return(0);
    117:     }

    119:     ((PC_Factor*)dir)->fact = pc->pmat;
    120:   } else {
    121:     MatInfo info;
    122:     Mat     F;
    123:     if (!pc->setupcalled) {
    124:       MatGetOrdering(pc->pmat,((PC_Factor*)dir)->ordering,&dir->row,&dir->col);
    125:       if (dir->nonzerosalongdiagonal) {
    126:         MatReorderForNonzeroDiagonal(pc->pmat,dir->nonzerosalongdiagonaltol,dir->row,dir->col);
    127:       }
    128:       if (dir->row) {
    129:         PetscLogObjectParent((PetscObject)pc,(PetscObject)dir->row);
    130:         PetscLogObjectParent((PetscObject)pc,(PetscObject)dir->col);
    131:       }
    132:       if (!((PC_Factor*)dir)->fact) {
    133:         MatGetFactor(pc->pmat,((PC_Factor*)dir)->solvertype,MAT_FACTOR_LU,&((PC_Factor*)dir)->fact);
    134:       }
    135:       MatLUFactorSymbolic(((PC_Factor*)dir)->fact,pc->pmat,dir->row,dir->col,&((PC_Factor*)dir)->info);
    136:       MatGetInfo(((PC_Factor*)dir)->fact,MAT_LOCAL,&info);
    137:       dir->actualfill = info.fill_ratio_needed;
    138:       PetscLogObjectParent((PetscObject)pc,(PetscObject)((PC_Factor*)dir)->fact);
    139:     } else if (pc->flag != SAME_NONZERO_PATTERN) {
    140:       if (!dir->reuseordering) {
    141:         if (dir->row && dir->col && dir->row != dir->col) {ISDestroy(&dir->row);}
    142:         ISDestroy(&dir->col);
    143:         MatGetOrdering(pc->pmat,((PC_Factor*)dir)->ordering,&dir->row,&dir->col);
    144:         if (dir->nonzerosalongdiagonal) {
    145:           MatReorderForNonzeroDiagonal(pc->pmat,dir->nonzerosalongdiagonaltol,dir->row,dir->col);
    146:         }
    147:         if (dir->row) {
    148:           PetscLogObjectParent((PetscObject)pc,(PetscObject)dir->row);
    149:           PetscLogObjectParent((PetscObject)pc,(PetscObject)dir->col);
    150:         }
    151:       }
    152:       MatDestroy(&((PC_Factor*)dir)->fact);
    153:       MatGetFactor(pc->pmat,((PC_Factor*)dir)->solvertype,MAT_FACTOR_LU,&((PC_Factor*)dir)->fact);
    154:       MatLUFactorSymbolic(((PC_Factor*)dir)->fact,pc->pmat,dir->row,dir->col,&((PC_Factor*)dir)->info);
    155:       MatGetInfo(((PC_Factor*)dir)->fact,MAT_LOCAL,&info);
    156:       dir->actualfill = info.fill_ratio_needed;
    157:       PetscLogObjectParent((PetscObject)pc,(PetscObject)((PC_Factor*)dir)->fact);
    158:     }
    159:     F = ((PC_Factor*)dir)->fact;
    160:     if (F->errortype) { /* FactorSymbolic() fails */
    161:       pc->failedreason = (PCFailedReason)F->errortype;
    162:       return(0);
    163:     }

    165:     MatLUFactorNumeric(((PC_Factor*)dir)->fact,pc->pmat,&((PC_Factor*)dir)->info);
    166:     if (F->errortype) { /* FactorNumeric() fails */
    167:       pc->failedreason = (PCFailedReason)F->errortype;
    168:     }

    170:   }

    172:   PCFactorGetMatSolverPackage(pc,&stype);
    173:   if (!stype) {
    174:     PCFactorSetMatSolverPackage(pc,((PC_Factor*)dir)->fact->solvertype);
    175:   }
    176:   return(0);
    177: }

    181: static PetscErrorCode PCReset_LU(PC pc)
    182: {
    183:   PC_LU          *dir = (PC_LU*)pc->data;

    187:   if (!dir->inplace && ((PC_Factor*)dir)->fact) {MatDestroy(&((PC_Factor*)dir)->fact);}
    188:   if (dir->row && dir->col && dir->row != dir->col) {ISDestroy(&dir->row);}
    189:   ISDestroy(&dir->col);
    190:   return(0);
    191: }

    195: static PetscErrorCode PCDestroy_LU(PC pc)
    196: {
    197:   PC_LU          *dir = (PC_LU*)pc->data;

    201:   PCReset_LU(pc);
    202:   PetscFree(((PC_Factor*)dir)->ordering);
    203:   PetscFree(((PC_Factor*)dir)->solvertype);
    204:   PetscFree(pc->data);
    205:   return(0);
    206: }

    210: static PetscErrorCode PCApply_LU(PC pc,Vec x,Vec y)
    211: {
    212:   PC_LU          *dir = (PC_LU*)pc->data;

    216:   if (dir->inplace) {
    217:     MatSolve(pc->pmat,x,y);
    218:   } else {
    219:     MatSolve(((PC_Factor*)dir)->fact,x,y);
    220:   }
    221:   return(0);
    222: }

    226: static PetscErrorCode PCApplyTranspose_LU(PC pc,Vec x,Vec y)
    227: {
    228:   PC_LU          *dir = (PC_LU*)pc->data;

    232:   if (dir->inplace) {
    233:     MatSolveTranspose(pc->pmat,x,y);
    234:   } else {
    235:     MatSolveTranspose(((PC_Factor*)dir)->fact,x,y);
    236:   }
    237:   return(0);
    238: }

    240: /* -----------------------------------------------------------------------------------*/

    244: PetscErrorCode  PCFactorSetUseInPlace_LU(PC pc,PetscBool flg)
    245: {
    246:   PC_LU *dir = (PC_LU*)pc->data;

    249:   dir->inplace = flg;
    250:   return(0);
    251: }

    255: PetscErrorCode  PCFactorGetUseInPlace_LU(PC pc,PetscBool *flg)
    256: {
    257:   PC_LU *dir = (PC_LU*)pc->data;

    260:   *flg = dir->inplace;
    261:   return(0);
    262: }

    264: /* ------------------------------------------------------------------------ */

    266: /*MC
    267:    PCLU - Uses a direct solver, based on LU factorization, as a preconditioner

    269:    Options Database Keys:
    270: +  -pc_factor_reuse_ordering - Activate PCFactorSetReuseOrdering()
    271: .  -pc_factor_mat_solver_package - Actives PCFactorSetMatSolverPackage() to choose the direct solver, like superlu
    272: .  -pc_factor_reuse_fill - Activates PCFactorSetReuseFill()
    273: .  -pc_factor_fill <fill> - Sets fill amount
    274: .  -pc_factor_in_place - Activates in-place factorization
    275: .  -pc_factor_mat_ordering_type <nd,rcm,...> - Sets ordering routine
    276: .  -pc_factor_pivot_in_blocks <true,false> - allow pivoting within the small blocks during factorization (may increase
    277:                                          stability of factorization.
    278: .  -pc_factor_shift_type <shifttype> - Sets shift type or PETSC_DECIDE for the default; use '-help' for a list of available types
    279: .  -pc_factor_shift_amount <shiftamount> - Sets shift amount or PETSC_DECIDE for the default
    280: -   -pc_factor_nonzeros_along_diagonal - permutes the rows and columns to try to put nonzero value along the
    281:         diagonal.

    283:    Notes: Not all options work for all matrix formats
    284:           Run with -help to see additional options for particular matrix formats or factorization
    285:           algorithms

    287:    Level: beginner

    289:    Concepts: LU factorization, direct solver

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

    295: .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC,
    296:            PCILU, PCCHOLESKY, PCICC, PCFactorSetReuseOrdering(), PCFactorSetReuseFill(), PCFactorGetMatrix(),
    297:            PCFactorSetFill(), PCFactorSetUseInPlace(), PCFactorSetMatOrderingType(), PCFactorSetColumnPivot(),
    298:            PCFactorSetPivotingInBlocks(),PCFactorSetShiftType(),PCFactorSetShiftAmount()
    299:            PCFactorReorderForNonzeroDiagonal()
    300: M*/

    304: PETSC_EXTERN PetscErrorCode PCCreate_LU(PC pc)
    305: {
    307:   PetscMPIInt    size;
    308:   PC_LU          *dir;

    311:   PetscNewLog(pc,&dir);

    313:   MatFactorInfoInitialize(&((PC_Factor*)dir)->info);

    315:   ((PC_Factor*)dir)->fact       = NULL;
    316:   ((PC_Factor*)dir)->factortype = MAT_FACTOR_LU;
    317:   dir->inplace                  = PETSC_FALSE;
    318:   dir->nonzerosalongdiagonal    = PETSC_FALSE;

    320:   ((PC_Factor*)dir)->info.fill          = 5.0;
    321:   ((PC_Factor*)dir)->info.dtcol         = 1.e-6;  /* default to pivoting; this is only thing PETSc LU supports */
    322:   ((PC_Factor*)dir)->info.shifttype     = (PetscReal)MAT_SHIFT_NONE;
    323:   ((PC_Factor*)dir)->info.shiftamount   = 0.0;
    324:   ((PC_Factor*)dir)->info.zeropivot     = 100.0*PETSC_MACHINE_EPSILON;
    325:   ((PC_Factor*)dir)->info.pivotinblocks = 1.0;
    326:   dir->col                              = 0;
    327:   dir->row                              = 0;

    329:   MPI_Comm_size(PetscObjectComm((PetscObject)pc),&size);
    330:   if (size == 1) {
    331:     PetscStrallocpy(MATORDERINGND,(char**)&((PC_Factor*)dir)->ordering);
    332:   } else {
    333:     PetscStrallocpy(MATORDERINGNATURAL,(char**)&((PC_Factor*)dir)->ordering);
    334:   }
    335:   dir->reusefill     = PETSC_FALSE;
    336:   dir->reuseordering = PETSC_FALSE;
    337:   pc->data           = (void*)dir;

    339:   pc->ops->reset             = PCReset_LU;
    340:   pc->ops->destroy           = PCDestroy_LU;
    341:   pc->ops->apply             = PCApply_LU;
    342:   pc->ops->applytranspose    = PCApplyTranspose_LU;
    343:   pc->ops->setup             = PCSetUp_LU;
    344:   pc->ops->setfromoptions    = PCSetFromOptions_LU;
    345:   pc->ops->view              = PCView_LU;
    346:   pc->ops->applyrichardson   = 0;
    347:   pc->ops->getfactoredmatrix = PCFactorGetMatrix_Factor;

    349:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorSetUpMatSolverPackage_C",PCFactorSetUpMatSolverPackage_Factor);
    350:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorGetMatSolverPackage_C",PCFactorGetMatSolverPackage_Factor);
    351:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorSetMatSolverPackage_C",PCFactorSetMatSolverPackage_Factor);
    352:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorSetZeroPivot_C",PCFactorSetZeroPivot_Factor);
    353:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorSetShiftType_C",PCFactorSetShiftType_Factor);
    354:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorSetShiftAmount_C",PCFactorSetShiftAmount_Factor);
    355:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorSetFill_C",PCFactorSetFill_Factor);
    356:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorSetUseInPlace_C",PCFactorSetUseInPlace_LU);
    357:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorGetUseInPlace_C",PCFactorGetUseInPlace_LU);
    358:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorSetMatOrderingType_C",PCFactorSetMatOrderingType_Factor);
    359:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorSetReuseOrdering_C",PCFactorSetReuseOrdering_LU);
    360:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorSetReuseFill_C",PCFactorSetReuseFill_LU);
    361:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorSetColumnPivot_C",PCFactorSetColumnPivot_Factor);
    362:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorSetPivotInBlocks_C",PCFactorSetPivotInBlocks_Factor);
    363:   PetscObjectComposeFunction((PetscObject)pc,"PCFactorReorderForNonzeroDiagonal_C",PCFactorReorderForNonzeroDiagonal_LU);
    364:   return(0);
    365: }