xref: /petsc/src/ksp/pc/impls/factor/lu/lu.c (revision 8ff23777322cfdc407588772804a6ce977f33084)

#define PETSCKSP_DLL

/*
   Defines a direct factorization preconditioner for any Mat implementation
   Note: this need not be consided a preconditioner since it supplies
         a direct solver.
*/

#include "../src/ksp/pc/impls/factor/lu/lu.h"  /*I "petscpc.h" I*/

EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "PCFactorReorderForNonzeroDiagonal_LU"
PetscErrorCode PETSCKSP_DLLEXPORT PCFactorReorderForNonzeroDiagonal_LU(PC pc,PetscReal z)
{
  PC_LU *lu = (PC_LU*)pc->data;

  PetscFunctionBegin;
  lu->nonzerosalongdiagonal = PETSC_TRUE;
  if (z == PETSC_DECIDE) {
    lu->nonzerosalongdiagonaltol = 1.e-10;
  } else {
    lu->nonzerosalongdiagonaltol = z;
  }
  PetscFunctionReturn(0);
}
EXTERN_C_END

EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "PCFactorSetReuseOrdering_LU"
PetscErrorCode PETSCKSP_DLLEXPORT PCFactorSetReuseOrdering_LU(PC pc,PetscTruth flag)
{
  PC_LU *lu = (PC_LU*)pc->data;

  PetscFunctionBegin;
  lu->reuseordering = flag;
  PetscFunctionReturn(0);
}
EXTERN_C_END

EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "PCFactorSetReuseFill_LU"
PetscErrorCode PETSCKSP_DLLEXPORT PCFactorSetReuseFill_LU(PC pc,PetscTruth flag)
{
  PC_LU *lu = (PC_LU*)pc->data;

  PetscFunctionBegin;
  lu->reusefill = flag;
  PetscFunctionReturn(0);
}
EXTERN_C_END

#undef __FUNCT__
#define __FUNCT__ "PCSetFromOptions_LU"
static PetscErrorCode PCSetFromOptions_LU(PC pc)
{
  PC_LU           *lu = (PC_LU*)pc->data;
  PetscErrorCode  ierr;
  PetscTruth      flg = PETSC_FALSE;
  PetscReal       tol;

  PetscFunctionBegin;
  ierr = PetscOptionsHead("LU options");CHKERRQ(ierr);
    ierr = PCSetFromOptions_Factor(pc);CHKERRQ(ierr);

    ierr = PetscOptionsName("-pc_factor_nonzeros_along_diagonal","Reorder to remove zeros from diagonal","PCFactorReorderForNonzeroDiagonal",&flg);CHKERRQ(ierr);
    if (flg) {
      tol = PETSC_DECIDE;
      ierr = PetscOptionsReal("-pc_factor_nonzeros_along_diagonal","Reorder to remove zeros from diagonal","PCFactorReorderForNonzeroDiagonal",lu->nonzerosalongdiagonaltol,&tol,0);CHKERRQ(ierr);
      ierr = PCFactorReorderForNonzeroDiagonal(pc,tol);CHKERRQ(ierr);
    }
  ierr = PetscOptionsTail();CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "PCView_LU"
static PetscErrorCode PCView_LU(PC pc,PetscViewer viewer)
{
  PC_LU          *lu = (PC_LU*)pc->data;
  PetscErrorCode ierr;
  PetscTruth     iascii,isstring;

  PetscFunctionBegin;
  ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&iascii);CHKERRQ(ierr);
  ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_STRING,&isstring);CHKERRQ(ierr);
  if (iascii) {

    if (lu->inplace) {ierr = PetscViewerASCIIPrintf(viewer,"  LU: in-place factorization\n");CHKERRQ(ierr);}
    else             {ierr = PetscViewerASCIIPrintf(viewer,"  LU: out-of-place factorization\n");CHKERRQ(ierr);}
    ierr = PetscViewerASCIIPrintf(viewer,"    matrix ordering: %s\n",((PC_Factor*)lu)->ordering);CHKERRQ(ierr);
    ierr = PetscViewerASCIIPrintf(viewer,"  LU: tolerance for zero pivot %G\n",((PC_Factor*)lu)->info.zeropivot);CHKERRQ(ierr);
    if (((PC_Factor*)lu)->info.shiftpd) {ierr = PetscViewerASCIIPrintf(viewer,"  LU: using Manteuffel shift\n");CHKERRQ(ierr);}
    if (((PC_Factor*)lu)->fact) {
      ierr = PetscViewerASCIIPrintf(viewer,"  LU: factor fill ratio needed %G\n",lu->actualfill);CHKERRQ(ierr);
      ierr = PetscViewerASCIIPrintf(viewer,"       Factored matrix follows\n");CHKERRQ(ierr);
      ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
      ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
      ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
      ierr = PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO);CHKERRQ(ierr);
      ierr = MatView(((PC_Factor*)lu)->fact,viewer);CHKERRQ(ierr);
      ierr = PetscViewerPopFormat(viewer);CHKERRQ(ierr);
      ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
      ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
      ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
    }
    if (lu->reusefill)    {ierr = PetscViewerASCIIPrintf(viewer,"       Reusing fill from past factorization\n");CHKERRQ(ierr);}
    if (lu->reuseordering) {ierr = PetscViewerASCIIPrintf(viewer,"       Reusing reordering from past factorization\n");CHKERRQ(ierr);}
  } else if (isstring) {
    ierr = PetscViewerStringSPrintf(viewer," order=%s",((PC_Factor*)lu)->ordering);CHKERRQ(ierr);CHKERRQ(ierr);
  } else {
    SETERRQ1(PETSC_ERR_SUP,"Viewer type %s not supported for PCLU",((PetscObject)viewer)->type_name);
  }
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "PCSetUp_LU"
static PetscErrorCode PCSetUp_LU(PC pc)
{
  PetscErrorCode ierr;
  PC_LU          *dir = (PC_LU*)pc->data;

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

  if (dir->inplace) {
    if (dir->row && dir->col && dir->row != dir->col) {ierr = ISDestroy(dir->row);CHKERRQ(ierr);}
    if (dir->col) {ierr = ISDestroy(dir->col);CHKERRQ(ierr);}
    ierr = MatGetOrdering(pc->pmat,((PC_Factor*)dir)->ordering,&dir->row,&dir->col);CHKERRQ(ierr);
    if (dir->row) {
      ierr = PetscLogObjectParent(pc,dir->row);CHKERRQ(ierr);
      ierr = PetscLogObjectParent(pc,dir->col);CHKERRQ(ierr);
    }
    ierr = MatLUFactor(pc->pmat,dir->row,dir->col,&((PC_Factor*)dir)->info);CHKERRQ(ierr);
    ((PC_Factor*)dir)->fact = pc->pmat;
  } else {
    MatInfo info;
    if (!pc->setupcalled) {
      ierr = MatGetOrdering(pc->pmat,((PC_Factor*)dir)->ordering,&dir->row,&dir->col);CHKERRQ(ierr);
      if (dir->nonzerosalongdiagonal) {
        ierr = MatReorderForNonzeroDiagonal(pc->pmat,dir->nonzerosalongdiagonaltol,dir->row,dir->col);CHKERRQ(ierr);
      }
      if (dir->row) {
        ierr = PetscLogObjectParent(pc,dir->row);CHKERRQ(ierr);
        ierr = PetscLogObjectParent(pc,dir->col);CHKERRQ(ierr);
      }
      ierr = MatGetFactor(pc->pmat,((PC_Factor*)dir)->solvertype,MAT_FACTOR_LU,&((PC_Factor*)dir)->fact);CHKERRQ(ierr);
      ierr = MatLUFactorSymbolic(((PC_Factor*)dir)->fact,pc->pmat,dir->row,dir->col,&((PC_Factor*)dir)->info);CHKERRQ(ierr);
      ierr = MatGetInfo(((PC_Factor*)dir)->fact,MAT_LOCAL,&info);CHKERRQ(ierr);
      dir->actualfill = info.fill_ratio_needed;
      ierr = PetscLogObjectParent(pc,((PC_Factor*)dir)->fact);CHKERRQ(ierr);
    } else if (pc->flag != SAME_NONZERO_PATTERN) {
      if (!dir->reuseordering) {
        if (dir->row && dir->col && dir->row != dir->col) {ierr = ISDestroy(dir->row);CHKERRQ(ierr);}
        if (dir->col) {ierr = ISDestroy(dir->col);CHKERRQ(ierr);}
        ierr = MatGetOrdering(pc->pmat,((PC_Factor*)dir)->ordering,&dir->row,&dir->col);CHKERRQ(ierr);
        if (dir->nonzerosalongdiagonal) {
          ierr = MatReorderForNonzeroDiagonal(pc->pmat,dir->nonzerosalongdiagonaltol,dir->row,dir->col);CHKERRQ(ierr);
        }
        if (dir->row) {
          ierr = PetscLogObjectParent(pc,dir->row);CHKERRQ(ierr);
          ierr = PetscLogObjectParent(pc,dir->col);CHKERRQ(ierr);
        }
      }
      ierr = MatDestroy(((PC_Factor*)dir)->fact);CHKERRQ(ierr);
      ierr = MatGetFactor(pc->pmat,((PC_Factor*)dir)->solvertype,MAT_FACTOR_LU,&((PC_Factor*)dir)->fact);CHKERRQ(ierr);
      ierr = MatLUFactorSymbolic(((PC_Factor*)dir)->fact,pc->pmat,dir->row,dir->col,&((PC_Factor*)dir)->info);CHKERRQ(ierr);
      ierr = MatGetInfo(((PC_Factor*)dir)->fact,MAT_LOCAL,&info);CHKERRQ(ierr);
      dir->actualfill = info.fill_ratio_needed;
      ierr = PetscLogObjectParent(pc,((PC_Factor*)dir)->fact);CHKERRQ(ierr);
    }
    ierr = MatLUFactorNumeric(((PC_Factor*)dir)->fact,pc->pmat,&((PC_Factor*)dir)->info);CHKERRQ(ierr);
  }
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "PCDestroy_LU"
static PetscErrorCode PCDestroy_LU(PC pc)
{
  PC_LU          *dir = (PC_LU*)pc->data;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  if (!dir->inplace && ((PC_Factor*)dir)->fact) {ierr = MatDestroy(((PC_Factor*)dir)->fact);CHKERRQ(ierr);}
  if (dir->row && dir->col && dir->row != dir->col) {ierr = ISDestroy(dir->row);CHKERRQ(ierr);}
  if (dir->col) {ierr = ISDestroy(dir->col);CHKERRQ(ierr);}
  ierr = PetscStrfree(((PC_Factor*)dir)->ordering);CHKERRQ(ierr);
  ierr = PetscStrfree(((PC_Factor*)dir)->solvertype);CHKERRQ(ierr);
  ierr = PetscFree(dir);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "PCApply_LU"
static PetscErrorCode PCApply_LU(PC pc,Vec x,Vec y)
{
  PC_LU          *dir = (PC_LU*)pc->data;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  if (dir->inplace) {ierr = MatSolve(pc->pmat,x,y);CHKERRQ(ierr);}
  else              {ierr = MatSolve(((PC_Factor*)dir)->fact,x,y);CHKERRQ(ierr);}
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "PCApplyTranspose_LU"
static PetscErrorCode PCApplyTranspose_LU(PC pc,Vec x,Vec y)
{
  PC_LU          *dir = (PC_LU*)pc->data;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  if (dir->inplace) {ierr = MatSolveTranspose(pc->pmat,x,y);CHKERRQ(ierr);}
  else              {ierr = MatSolveTranspose(((PC_Factor*)dir)->fact,x,y);CHKERRQ(ierr);}
  PetscFunctionReturn(0);
}

/* -----------------------------------------------------------------------------------*/

EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "PCFactorSetUseInPlace_LU"
PetscErrorCode PETSCKSP_DLLEXPORT PCFactorSetUseInPlace_LU(PC pc)
{
  PC_LU *dir = (PC_LU*)pc->data;

  PetscFunctionBegin;
  dir->inplace = PETSC_TRUE;
  PetscFunctionReturn(0);
}
EXTERN_C_END

/* ------------------------------------------------------------------------ */

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

   Options Database Keys:
+  -pc_factor_reuse_ordering - Activate PCFactorSetReuseOrdering()
.  -pc_factor_mat_solver_package - Actives PCFactorSetMatSolverPackage() to choose the direct solver, like spooles
.  -pc_factor_reuse_fill - Activates PCFactorSetReuseFill()
.  -pc_factor_fill <fill> - Sets fill amount
.  -pc_factor_in_place - Activates in-place factorization
.  -pc_factor_mat_ordering_type <nd,rcm,...> - Sets ordering routine
.  -pc_factor_pivot_in_blocks <true,false> - allow pivoting within the small blocks during factorization (may increase
                                         stability of factorization.
.  -pc_factor_shift_nonzero <shift> - Sets shift amount or PETSC_DECIDE for the default
.  -pc_factor_shift_positive_definite [PETSC_TRUE/PETSC_FALSE] - Activate/Deactivate PCFactorSetShiftPd(); the value
        is optional with PETSC_TRUE being the default
-   -pc_factor_nonzeros_along_diagonal - permutes the rows and columns to try to put nonzero value along the
        diagonal.

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

   Level: beginner

   Concepts: LU factorization, direct solver

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

.seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC,
           PCILU, PCCHOLESKY, PCICC, PCFactorSetReuseOrdering(), PCFactorSetReuseFill(), PCFactorGetMatrix(),
           PCFactorSetFill(), PCFactorSetUseInPlace(), PCFactorSetMatOrderingType(), PCFactorSetColumnPivot(),
           PCFactorSetPivotingInBlocks(),PCFactorSetShiftNonzero(),PCFactorSetShiftPd(),PCFactorSetShiftInBlocks()
           PCFactorReorderForNonzeroDiagonal()
M*/

EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "PCCreate_LU"
PetscErrorCode PETSCKSP_DLLEXPORT PCCreate_LU(PC pc)
{
  PetscErrorCode ierr;
  PetscMPIInt    size;
  PC_LU          *dir;

  PetscFunctionBegin;
  ierr = PetscNewLog(pc,PC_LU,&dir);CHKERRQ(ierr);

  ierr = MatFactorInfoInitialize(&((PC_Factor*)dir)->info);CHKERRQ(ierr);
  ((PC_Factor*)dir)->fact                  = 0;
  dir->inplace               = PETSC_FALSE;
  dir->nonzerosalongdiagonal = PETSC_FALSE;

  ((PC_Factor*)dir)->info.fill           = 5.0;
  ((PC_Factor*)dir)->info.dtcol          = 1.e-6; /* default to pivoting; this is only thing PETSc LU supports */
  ((PC_Factor*)dir)->info.shiftnz        = 0.0;
  ((PC_Factor*)dir)->info.zeropivot      = 1.e-12;
  ((PC_Factor*)dir)->info.pivotinblocks  = 1.0;
  ((PC_Factor*)dir)->info.shiftpd        = 0.0; /* false */
  dir->col                 = 0;
  dir->row                 = 0;

  ierr = PetscStrallocpy(MAT_SOLVER_PETSC,&((PC_Factor*)dir)->solvertype);CHKERRQ(ierr);
  ierr = MPI_Comm_size(((PetscObject)pc)->comm,&size);CHKERRQ(ierr);
  if (size == 1) {
    ierr = PetscStrallocpy(MATORDERING_ND,&((PC_Factor*)dir)->ordering);CHKERRQ(ierr);
  } else {
    ierr = PetscStrallocpy(MATORDERING_NATURAL,&((PC_Factor*)dir)->ordering);CHKERRQ(ierr);
  }
  dir->reusefill        = PETSC_FALSE;
  dir->reuseordering    = PETSC_FALSE;
  pc->data              = (void*)dir;

  pc->ops->destroy           = PCDestroy_LU;
  pc->ops->apply             = PCApply_LU;
  pc->ops->applytranspose    = PCApplyTranspose_LU;
  pc->ops->setup             = PCSetUp_LU;
  pc->ops->setfromoptions    = PCSetFromOptions_LU;
  pc->ops->view              = PCView_LU;
  pc->ops->applyrichardson   = 0;
  pc->ops->getfactoredmatrix = PCFactorGetMatrix_Factor;

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorGetMatSolverPackage_C","PCFactorGetMatSolverPackage_Factor",
                    PCFactorGetMatSolverPackage_Factor);CHKERRQ(ierr);
  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetMatSolverPackage_C","PCFactorSetMatSolverPackage_Factor",
                    PCFactorSetMatSolverPackage_Factor);CHKERRQ(ierr);
  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetZeroPivot_C","PCFactorSetZeroPivot_Factor",
                    PCFactorSetZeroPivot_Factor);CHKERRQ(ierr);
  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetShiftNonzero_C","PCFactorSetShiftNonzero_Factor",
                    PCFactorSetShiftNonzero_Factor);CHKERRQ(ierr);
  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetShiftPd_C","PCFactorSetShiftPd_Factor",
                    PCFactorSetShiftPd_Factor);CHKERRQ(ierr);
  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetShiftInBlocks_C","PCFactorSetShiftInBlocks_Factor",
                    PCFactorSetShiftInBlocks_Factor);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetFill_C","PCFactorSetFill_Factor",
                    PCFactorSetFill_Factor);CHKERRQ(ierr);
  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetUseInPlace_C","PCFactorSetUseInPlace_LU",
                    PCFactorSetUseInPlace_LU);CHKERRQ(ierr);
  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetMatOrderingType_C","PCFactorSetMatOrderingType_Factor",
                    PCFactorSetMatOrderingType_Factor);CHKERRQ(ierr);
  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetReuseOrdering_C","PCFactorSetReuseOrdering_LU",
                    PCFactorSetReuseOrdering_LU);CHKERRQ(ierr);
  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetReuseFill_C","PCFactorSetReuseFill_LU",
                    PCFactorSetReuseFill_LU);CHKERRQ(ierr);
  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetColumnPivot_C","PCFactorSetColumnPivot_Factor",
                    PCFactorSetColumnPivot_Factor);CHKERRQ(ierr);
  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetPivotInBlocks_C","PCFactorSetPivotInBlocks_Factor",
                    PCFactorSetPivotInBlocks_Factor);CHKERRQ(ierr);
  ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorReorderForNonzeroDiagonal_C","PCFactorReorderForNonzeroDiagonal_LU",
                    PCFactorReorderForNonzeroDiagonal_LU);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}
EXTERN_C_END