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

static PetscErrorCode PCSetUp_ICC(PC pc)
{
  PC_ICC                 *icc = (PC_ICC*)pc->data;
  IS                     perm = NULL,cperm = NULL;
  MatInfo                info;
  MatSolverType          stype;
  MatFactorError         err;
  PetscBool              canuseordering;
  const char             *prefix;

  PetscFunctionBegin;
  if (!((PetscObject)pc->pmat)->prefix) {
    PetscCall(PCGetOptionsPrefix(pc,&prefix));
    PetscCall(MatSetOptionsPrefix(pc->pmat,prefix));
  }
  pc->failedreason = PC_NOERROR;

  PetscCall(MatSetErrorIfFailure(pc->pmat,pc->erroriffailure));
  if (!pc->setupcalled) {
    if (!((PC_Factor*)icc)->fact) {
      PetscCall(MatGetFactor(pc->pmat,((PC_Factor*)icc)->solvertype,MAT_FACTOR_ICC,&((PC_Factor*)icc)->fact));
    }
    PetscCall(MatFactorGetCanUseOrdering(((PC_Factor*)icc)->fact,&canuseordering));
    if (canuseordering) {
      PetscCall(PCFactorSetDefaultOrdering_Factor(pc));
      PetscCall(MatGetOrdering(pc->pmat, ((PC_Factor*)icc)->ordering,&perm,&cperm));
    }
    PetscCall(MatICCFactorSymbolic(((PC_Factor*)icc)->fact,pc->pmat,perm,&((PC_Factor*)icc)->info));
  } else if (pc->flag != SAME_NONZERO_PATTERN) {
    PetscBool canuseordering;
    PetscCall(MatDestroy(&((PC_Factor*)icc)->fact));
    PetscCall(MatGetFactor(pc->pmat,((PC_Factor*)icc)->solvertype,MAT_FACTOR_ICC,&((PC_Factor*)icc)->fact));
    PetscCall(MatFactorGetCanUseOrdering(((PC_Factor*)icc)->fact,&canuseordering));
    if (canuseordering) {
      PetscCall(PCFactorSetDefaultOrdering_Factor(pc));
      PetscCall(MatGetOrdering(pc->pmat, ((PC_Factor*)icc)->ordering,&perm,&cperm));
    }
    PetscCall(MatICCFactorSymbolic(((PC_Factor*)icc)->fact,pc->pmat,perm,&((PC_Factor*)icc)->info));
  }
  PetscCall(MatGetInfo(((PC_Factor*)icc)->fact,MAT_LOCAL,&info));
  icc->hdr.actualfill = info.fill_ratio_needed;

  PetscCall(ISDestroy(&cperm));
  PetscCall(ISDestroy(&perm));

  PetscCall(MatFactorGetError(((PC_Factor*)icc)->fact,&err));
  if (err) { /* FactorSymbolic() fails */
    pc->failedreason = (PCFailedReason)err;
    PetscFunctionReturn(0);
  }

  PetscCall(MatCholeskyFactorNumeric(((PC_Factor*)icc)->fact,pc->pmat,&((PC_Factor*)icc)->info));
  PetscCall(MatFactorGetError(((PC_Factor*)icc)->fact,&err));
  if (err) { /* FactorNumeric() fails */
    pc->failedreason = (PCFailedReason)err;
  }

  PetscCall(PCFactorGetMatSolverType(pc,&stype));
  if (!stype) {
    MatSolverType solverpackage;
    PetscCall(MatFactorGetSolverType(((PC_Factor*)icc)->fact,&solverpackage));
    PetscCall(PCFactorSetMatSolverType(pc,solverpackage));
  }
  PetscFunctionReturn(0);
}

static PetscErrorCode PCReset_ICC(PC pc)
{
  PC_ICC         *icc = (PC_ICC*)pc->data;

  PetscFunctionBegin;
  PetscCall(MatDestroy(&((PC_Factor*)icc)->fact));
  PetscFunctionReturn(0);
}

static PetscErrorCode PCDestroy_ICC(PC pc)
{
  PC_ICC         *icc = (PC_ICC*)pc->data;

  PetscFunctionBegin;
  PetscCall(PCReset_ICC(pc));
  PetscCall(PetscFree(((PC_Factor*)icc)->ordering));
  PetscCall(PetscFree(((PC_Factor*)icc)->solvertype));
  PetscCall(PetscFree(pc->data));
  PetscFunctionReturn(0);
}

static PetscErrorCode PCApply_ICC(PC pc,Vec x,Vec y)
{
  PC_ICC         *icc = (PC_ICC*)pc->data;

  PetscFunctionBegin;
  PetscCall(MatSolve(((PC_Factor*)icc)->fact,x,y));
  PetscFunctionReturn(0);
}

static PetscErrorCode PCMatApply_ICC(PC pc,Mat X,Mat Y)
{
  PC_ICC         *icc = (PC_ICC*)pc->data;

  PetscFunctionBegin;
  PetscCall(MatMatSolve(((PC_Factor*)icc)->fact,X,Y));
  PetscFunctionReturn(0);
}

static PetscErrorCode PCApplySymmetricLeft_ICC(PC pc,Vec x,Vec y)
{
  PC_ICC         *icc = (PC_ICC*)pc->data;

  PetscFunctionBegin;
  PetscCall(MatForwardSolve(((PC_Factor*)icc)->fact,x,y));
  PetscFunctionReturn(0);
}

static PetscErrorCode PCApplySymmetricRight_ICC(PC pc,Vec x,Vec y)
{
  PC_ICC         *icc = (PC_ICC*)pc->data;

  PetscFunctionBegin;
  PetscCall(MatBackwardSolve(((PC_Factor*)icc)->fact,x,y));
  PetscFunctionReturn(0);
}

static PetscErrorCode PCSetFromOptions_ICC(PetscOptionItems *PetscOptionsObject,PC pc)
{
  PC_ICC         *icc = (PC_ICC*)pc->data;
  PetscBool      flg;
  /* PetscReal      dt[3];*/

  PetscFunctionBegin;
  PetscOptionsHeadBegin(PetscOptionsObject,"ICC Options");
  PetscCall(PCSetFromOptions_Factor(PetscOptionsObject,pc));

  PetscCall(PetscOptionsReal("-pc_factor_levels","levels of fill","PCFactorSetLevels",((PC_Factor*)icc)->info.levels,&((PC_Factor*)icc)->info.levels,&flg));
  /*dt[0] = ((PC_Factor*)icc)->info.dt;
  dt[1] = ((PC_Factor*)icc)->info.dtcol;
  dt[2] = ((PC_Factor*)icc)->info.dtcount;
  PetscInt       dtmax = 3;
  PetscCall(PetscOptionsRealArray("-pc_factor_drop_tolerance","<dt,dtcol,maxrowcount>","PCFactorSetDropTolerance",dt,&dtmax,&flg));
  if (flg) {
    PetscCall(PCFactorSetDropTolerance(pc,dt[0],dt[1],(PetscInt)dt[2]));
  }
  */
  PetscOptionsHeadEnd();
  PetscFunctionReturn(0);
}

extern PetscErrorCode  PCFactorSetDropTolerance_ILU(PC,PetscReal,PetscReal,PetscInt);

/*MC
     PCICC - Incomplete Cholesky factorization preconditioners.

   Options Database Keys:
+  -pc_factor_levels <k> - number of levels of fill for ICC(k)
.  -pc_factor_in_place - only for ICC(0) with natural ordering, reuses the space of the matrix for
                      its factorization (overwrites original matrix)
.  -pc_factor_fill <nfill> - expected amount of fill in factored matrix compared to original matrix, nfill > 1
-  -pc_factor_mat_ordering_type <natural,nd,1wd,rcm,qmd> - set the row/column ordering of the factored matrix

   Level: beginner

   Notes:
    Only implemented for some matrix formats. Not implemented in parallel.

          For BAIJ matrices this implements a point block ICC.

          The Manteuffel shift is only implemented for matrices with block size 1

          By default, the Manteuffel is applied (for matrices with block size 1). Call PCFactorSetShiftType(pc,MAT_SHIFT_POSITIVE_DEFINITE);
          to turn off the shift.

   References:
.  * - TONY F. CHAN AND HENK A. VAN DER VORST, Review article: APPROXIMATE AND INCOMPLETE FACTORIZATIONS,
      Chapter in Parallel Numerical Algorithms, edited by D. Keyes, A. Semah, V. Venkatakrishnan, ICASE/LaRC Interdisciplinary Series in
      Science and Engineering, Kluwer.

.seealso: `PCCreate()`, `PCSetType()`, `PCType`, `PC`, `PCSOR`, `MatOrderingType`,
          `PCFactorSetZeroPivot()`, `PCFactorSetShiftType()`, `PCFactorSetShiftAmount()`,
          `PCFactorSetFill()`, `PCFactorSetMatOrderingType()`, `PCFactorSetReuseOrdering()`,
          `PCFactorSetLevels()`

M*/

PETSC_EXTERN PetscErrorCode PCCreate_ICC(PC pc)
{
  PC_ICC         *icc;

  PetscFunctionBegin;
  PetscCall(PetscNewLog(pc,&icc));
  pc->data = (void*)icc;
  PetscCall(PCFactorInitialize(pc, MAT_FACTOR_ICC));

  ((PC_Factor*)icc)->info.fill      = 1.0;
  ((PC_Factor*)icc)->info.dtcol     = PETSC_DEFAULT;
  ((PC_Factor*)icc)->info.shifttype = (PetscReal) MAT_SHIFT_POSITIVE_DEFINITE;

  pc->ops->apply               = PCApply_ICC;
  pc->ops->matapply            = PCMatApply_ICC;
  pc->ops->applytranspose      = PCApply_ICC;
  pc->ops->setup               = PCSetUp_ICC;
  pc->ops->reset               = PCReset_ICC;
  pc->ops->destroy             = PCDestroy_ICC;
  pc->ops->setfromoptions      = PCSetFromOptions_ICC;
  pc->ops->view                = PCView_Factor;
  pc->ops->applysymmetricleft  = PCApplySymmetricLeft_ICC;
  pc->ops->applysymmetricright = PCApplySymmetricRight_ICC;
  PetscFunctionReturn(0);
}