/*
   Provides an interface to the UMFPACK sparse solver available through SuiteSparse version 4.2.1

   When build with PETSC_USE_64BIT_INDICES this will use Suitesparse_long as the
   integer type in UMFPACK, otherwise it will use int. This means
   all integers in this file as simply declared as PetscInt. Also it means
   that one cannot use 64BIT_INDICES on 32-bit pointer systems [as Suitesparse_long is 32-bit only]

*/
#include <../src/mat/impls/aij/seq/aij.h>

#if defined(PETSC_USE_64BIT_INDICES)
  #if defined(PETSC_USE_COMPLEX)
    #define umfpack_UMF_free_symbolic umfpack_zl_free_symbolic
    #define umfpack_UMF_free_numeric  umfpack_zl_free_numeric
    /* the type casts are needed because PetscInt is long long while SuiteSparse_long is long and compilers warn even when they are identical */
    #define umfpack_UMF_wsolve(a, b, c, d, e, f, g, h, i, j, k, l, m, n) umfpack_zl_wsolve(a, (SuiteSparse_long *)b, (SuiteSparse_long *)c, d, e, f, g, h, i, (SuiteSparse_long *)j, k, l, (SuiteSparse_long *)m, n)
    #define umfpack_UMF_numeric(a, b, c, d, e, f, g, h)                  umfpack_zl_numeric((SuiteSparse_long *)a, (SuiteSparse_long *)b, c, d, e, f, g, h)
    #define umfpack_UMF_report_numeric                                   umfpack_zl_report_numeric
    #define umfpack_UMF_report_control                                   umfpack_zl_report_control
    #define umfpack_UMF_report_status                                    umfpack_zl_report_status
    #define umfpack_UMF_report_info                                      umfpack_zl_report_info
    #define umfpack_UMF_report_symbolic                                  umfpack_zl_report_symbolic
    #define umfpack_UMF_qsymbolic(a, b, c, d, e, f, g, h, i, j)          umfpack_zl_qsymbolic(a, b, (SuiteSparse_long *)c, (SuiteSparse_long *)d, e, f, (SuiteSparse_long *)g, h, i, j)
    #define umfpack_UMF_symbolic(a, b, c, d, e, f, g, h, i)              umfpack_zl_symbolic(a, b, (SuiteSparse_long *)c, (SuiteSparse_long *)d, e, f, g, h, i)
    #define umfpack_UMF_defaults                                         umfpack_zl_defaults

  #else
    #define umfpack_UMF_free_symbolic                           umfpack_dl_free_symbolic
    #define umfpack_UMF_free_numeric                            umfpack_dl_free_numeric
    #define umfpack_UMF_wsolve(a, b, c, d, e, f, g, h, i, j, k) umfpack_dl_wsolve(a, (SuiteSparse_long *)b, (SuiteSparse_long *)c, d, e, f, g, h, i, (SuiteSparse_long *)j, k)
    #define umfpack_UMF_numeric(a, b, c, d, e, f, g)            umfpack_dl_numeric((SuiteSparse_long *)a, (SuiteSparse_long *)b, c, d, e, f, g)
    #define umfpack_UMF_report_numeric                          umfpack_dl_report_numeric
    #define umfpack_UMF_report_control                          umfpack_dl_report_control
    #define umfpack_UMF_report_status                           umfpack_dl_report_status
    #define umfpack_UMF_report_info                             umfpack_dl_report_info
    #define umfpack_UMF_report_symbolic                         umfpack_dl_report_symbolic
    #define umfpack_UMF_qsymbolic(a, b, c, d, e, f, g, h, i)    umfpack_dl_qsymbolic(a, b, (SuiteSparse_long *)c, (SuiteSparse_long *)d, e, (SuiteSparse_long *)f, g, h, i)
    #define umfpack_UMF_symbolic(a, b, c, d, e, f, g, h)        umfpack_dl_symbolic(a, b, (SuiteSparse_long *)c, (SuiteSparse_long *)d, e, f, g, h)
    #define umfpack_UMF_defaults                                umfpack_dl_defaults
  #endif

#else
  #if defined(PETSC_USE_COMPLEX)
    #define umfpack_UMF_free_symbolic   umfpack_zi_free_symbolic
    #define umfpack_UMF_free_numeric    umfpack_zi_free_numeric
    #define umfpack_UMF_wsolve          umfpack_zi_wsolve
    #define umfpack_UMF_numeric         umfpack_zi_numeric
    #define umfpack_UMF_report_numeric  umfpack_zi_report_numeric
    #define umfpack_UMF_report_control  umfpack_zi_report_control
    #define umfpack_UMF_report_status   umfpack_zi_report_status
    #define umfpack_UMF_report_info     umfpack_zi_report_info
    #define umfpack_UMF_report_symbolic umfpack_zi_report_symbolic
    #define umfpack_UMF_qsymbolic       umfpack_zi_qsymbolic
    #define umfpack_UMF_symbolic        umfpack_zi_symbolic
    #define umfpack_UMF_defaults        umfpack_zi_defaults

  #else
    #define umfpack_UMF_free_symbolic   umfpack_di_free_symbolic
    #define umfpack_UMF_free_numeric    umfpack_di_free_numeric
    #define umfpack_UMF_wsolve          umfpack_di_wsolve
    #define umfpack_UMF_numeric         umfpack_di_numeric
    #define umfpack_UMF_report_numeric  umfpack_di_report_numeric
    #define umfpack_UMF_report_control  umfpack_di_report_control
    #define umfpack_UMF_report_status   umfpack_di_report_status
    #define umfpack_UMF_report_info     umfpack_di_report_info
    #define umfpack_UMF_report_symbolic umfpack_di_report_symbolic
    #define umfpack_UMF_qsymbolic       umfpack_di_qsymbolic
    #define umfpack_UMF_symbolic        umfpack_di_symbolic
    #define umfpack_UMF_defaults        umfpack_di_defaults
  #endif
#endif

EXTERN_C_BEGIN
#include <umfpack.h>
EXTERN_C_END

static const char *const UmfpackOrderingTypes[] = {"CHOLMOD", "AMD", "GIVEN", "METIS", "BEST", "NONE", "USER", "UmfpackOrderingTypes", "UMFPACK_ORDERING_", 0};

typedef struct {
  void        *Symbolic, *Numeric;
  double       Info[UMFPACK_INFO], Control[UMFPACK_CONTROL], *W;
  PetscInt    *Wi, *perm_c;
  Mat          A; /* Matrix used for factorization */
  MatStructure flg;

  /* Flag to clean up UMFPACK objects during Destroy */
  PetscBool CleanUpUMFPACK;
} Mat_UMFPACK;

static PetscErrorCode MatDestroy_UMFPACK(Mat A)
{
  Mat_UMFPACK *lu = (Mat_UMFPACK *)A->data;

  PetscFunctionBegin;
  if (lu->CleanUpUMFPACK) {
    umfpack_UMF_free_symbolic(&lu->Symbolic);
    umfpack_UMF_free_numeric(&lu->Numeric);
    PetscCall(PetscFree(lu->Wi));
    PetscCall(PetscFree(lu->W));
    PetscCall(PetscFree(lu->perm_c));
  }
  PetscCall(MatDestroy(&lu->A));
  PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatFactorGetSolverType_C", NULL));
  PetscCall(PetscFree(A->data));
  PetscFunctionReturn(PETSC_SUCCESS);
}

static PetscErrorCode MatSolve_UMFPACK_Private(Mat A, Vec b, Vec x, int uflag)
{
  Mat_UMFPACK       *lu = (Mat_UMFPACK *)A->data;
  Mat_SeqAIJ        *a  = (Mat_SeqAIJ *)lu->A->data;
  PetscScalar       *av = a->a, *xa;
  const PetscScalar *ba;
  PetscInt          *ai = a->i, *aj = a->j;
  int                status;
  static PetscBool   cite = PETSC_FALSE;

  PetscFunctionBegin;
  if (!A->rmap->n) PetscFunctionReturn(PETSC_SUCCESS);
  PetscCall(PetscCitationsRegister("@article{davis2004algorithm,\n  title={Algorithm 832: {UMFPACK} V4.3---An Unsymmetric-Pattern Multifrontal Method},\n  author={Davis, Timothy A},\n  journal={ACM Transactions on Mathematical Software (TOMS)},\n  "
                                   "volume={30},\n  number={2},\n  pages={196--199},\n  year={2004},\n  publisher={ACM}\n}\n",
                                   &cite));
  /* solve Ax = b by umfpack_*_wsolve */

  if (!lu->Wi) { /* first time, allocate working space for wsolve */
    PetscCall(PetscMalloc1(A->rmap->n, &lu->Wi));
    PetscCall(PetscMalloc1(5 * A->rmap->n, &lu->W));
  }

  PetscCall(VecGetArrayRead(b, &ba));
  PetscCall(VecGetArray(x, &xa));
#if defined(PETSC_USE_COMPLEX)
  status = umfpack_UMF_wsolve(uflag, ai, aj, (PetscReal *)av, NULL, (PetscReal *)xa, NULL, (PetscReal *)ba, NULL, lu->Numeric, lu->Control, lu->Info, lu->Wi, lu->W);
#else
  status = umfpack_UMF_wsolve(uflag, ai, aj, av, xa, ba, lu->Numeric, lu->Control, lu->Info, lu->Wi, lu->W);
#endif
  umfpack_UMF_report_info(lu->Control, lu->Info);
  if (status < 0) {
    umfpack_UMF_report_status(lu->Control, status);
    SETERRQ(PETSC_COMM_SELF, PETSC_ERR_LIB, "umfpack_UMF_wsolve failed");
  }

  PetscCall(VecRestoreArrayRead(b, &ba));
  PetscCall(VecRestoreArray(x, &xa));
  PetscFunctionReturn(PETSC_SUCCESS);
}

static PetscErrorCode MatSolve_UMFPACK(Mat A, Vec b, Vec x)
{
  PetscFunctionBegin;
  /* We gave UMFPACK the algebraic transpose (because it assumes column alignment) */
  PetscCall(MatSolve_UMFPACK_Private(A, b, x, UMFPACK_Aat));
  PetscFunctionReturn(PETSC_SUCCESS);
}

static PetscErrorCode MatSolveTranspose_UMFPACK(Mat A, Vec b, Vec x)
{
  PetscFunctionBegin;
  /* We gave UMFPACK the algebraic transpose (because it assumes column alignment) */
  PetscCall(MatSolve_UMFPACK_Private(A, b, x, UMFPACK_A));
  PetscFunctionReturn(PETSC_SUCCESS);
}

static PetscErrorCode MatLUFactorNumeric_UMFPACK(Mat F, Mat A, const MatFactorInfo *info)
{
  Mat_UMFPACK *lu = (Mat_UMFPACK *)F->data;
  Mat_SeqAIJ  *a  = (Mat_SeqAIJ *)A->data;
  PetscInt    *ai = a->i, *aj = a->j;
  int          status;
  PetscScalar *av = a->a;

  PetscFunctionBegin;
  if (!A->rmap->n) PetscFunctionReturn(PETSC_SUCCESS);
  /* numeric factorization of A' */

  if (lu->flg == SAME_NONZERO_PATTERN && lu->Numeric) umfpack_UMF_free_numeric(&lu->Numeric);
#if defined(PETSC_USE_COMPLEX)
  status = umfpack_UMF_numeric(ai, aj, (double *)av, NULL, lu->Symbolic, &lu->Numeric, lu->Control, lu->Info);
#else
  status = umfpack_UMF_numeric(ai, aj, av, lu->Symbolic, &lu->Numeric, lu->Control, lu->Info);
#endif
  if (status < 0) {
    umfpack_UMF_report_status(lu->Control, status);
    SETERRQ(PETSC_COMM_SELF, PETSC_ERR_LIB, "umfpack_UMF_numeric failed");
  }
  /* report numeric factorization of A' when Control[PRL] > 3 */
  (void)umfpack_UMF_report_numeric(lu->Numeric, lu->Control);

  PetscCall(PetscObjectReference((PetscObject)A));
  PetscCall(MatDestroy(&lu->A));

  lu->A                  = A;
  lu->flg                = SAME_NONZERO_PATTERN;
  lu->CleanUpUMFPACK     = PETSC_TRUE;
  F->ops->solve          = MatSolve_UMFPACK;
  F->ops->solvetranspose = MatSolveTranspose_UMFPACK;
  PetscFunctionReturn(PETSC_SUCCESS);
}

static PetscErrorCode MatLUFactorSymbolic_UMFPACK(Mat F, Mat A, IS r, IS c, const MatFactorInfo *info)
{
  Mat_SeqAIJ  *a  = (Mat_SeqAIJ *)A->data;
  Mat_UMFPACK *lu = (Mat_UMFPACK *)F->data;
  PetscInt     i, *ai = a->i, *aj = a->j, m = A->rmap->n, n = A->cmap->n, idx;
  int          status;
#if !defined(PETSC_USE_COMPLEX)
  PetscScalar *av = a->a;
#endif
  const PetscInt *ra;
  const char     *strategy[] = {"AUTO", "UNSYMMETRIC", "SYMMETRIC"};
  const char     *scale[]    = {"NONE", "SUM", "MAX"};
  PetscBool       flg;

  PetscFunctionBegin;
  F->ops->lufactornumeric = MatLUFactorNumeric_UMFPACK;
  if (!n) PetscFunctionReturn(PETSC_SUCCESS);

  /* Set options to F */
  PetscOptionsBegin(PetscObjectComm((PetscObject)F), ((PetscObject)F)->prefix, "UMFPACK Options", "Mat");
  /* Control parameters used by reporting routiones */
  PetscCall(PetscOptionsReal("-mat_umfpack_prl", "Control[UMFPACK_PRL]", "None", lu->Control[UMFPACK_PRL], &lu->Control[UMFPACK_PRL], NULL));

  /* Control parameters for symbolic factorization */
  PetscCall(PetscOptionsEList("-mat_umfpack_strategy", "ordering and pivoting strategy", "None", strategy, 3, strategy[0], &idx, &flg));
  if (flg) {
    switch (idx) {
    case 0:
      lu->Control[UMFPACK_STRATEGY] = UMFPACK_STRATEGY_AUTO;
      break;
    case 1:
      lu->Control[UMFPACK_STRATEGY] = UMFPACK_STRATEGY_UNSYMMETRIC;
      break;
    case 2:
      lu->Control[UMFPACK_STRATEGY] = UMFPACK_STRATEGY_SYMMETRIC;
      break;
    }
  }
  PetscCall(PetscOptionsEList("-mat_umfpack_ordering", "Internal ordering method", "None", UmfpackOrderingTypes, PETSC_STATIC_ARRAY_LENGTH(UmfpackOrderingTypes), UmfpackOrderingTypes[(int)lu->Control[UMFPACK_ORDERING]], &idx, &flg));
  if (flg) lu->Control[UMFPACK_ORDERING] = (int)idx;
  PetscCall(PetscOptionsReal("-mat_umfpack_dense_col", "Control[UMFPACK_DENSE_COL]", "None", lu->Control[UMFPACK_DENSE_COL], &lu->Control[UMFPACK_DENSE_COL], NULL));
  PetscCall(PetscOptionsReal("-mat_umfpack_dense_row", "Control[UMFPACK_DENSE_ROW]", "None", lu->Control[UMFPACK_DENSE_ROW], &lu->Control[UMFPACK_DENSE_ROW], NULL));
  PetscCall(PetscOptionsReal("-mat_umfpack_amd_dense", "Control[UMFPACK_AMD_DENSE]", "None", lu->Control[UMFPACK_AMD_DENSE], &lu->Control[UMFPACK_AMD_DENSE], NULL));
  PetscCall(PetscOptionsReal("-mat_umfpack_block_size", "Control[UMFPACK_BLOCK_SIZE]", "None", lu->Control[UMFPACK_BLOCK_SIZE], &lu->Control[UMFPACK_BLOCK_SIZE], NULL));
  PetscCall(PetscOptionsReal("-mat_umfpack_fixq", "Control[UMFPACK_FIXQ]", "None", lu->Control[UMFPACK_FIXQ], &lu->Control[UMFPACK_FIXQ], NULL));
  PetscCall(PetscOptionsReal("-mat_umfpack_aggressive", "Control[UMFPACK_AGGRESSIVE]", "None", lu->Control[UMFPACK_AGGRESSIVE], &lu->Control[UMFPACK_AGGRESSIVE], NULL));

  /* Control parameters used by numeric factorization */
  PetscCall(PetscOptionsReal("-mat_umfpack_pivot_tolerance", "Control[UMFPACK_PIVOT_TOLERANCE]", "None", lu->Control[UMFPACK_PIVOT_TOLERANCE], &lu->Control[UMFPACK_PIVOT_TOLERANCE], NULL));
  PetscCall(PetscOptionsReal("-mat_umfpack_sym_pivot_tolerance", "Control[UMFPACK_SYM_PIVOT_TOLERANCE]", "None", lu->Control[UMFPACK_SYM_PIVOT_TOLERANCE], &lu->Control[UMFPACK_SYM_PIVOT_TOLERANCE], NULL));
  PetscCall(PetscOptionsEList("-mat_umfpack_scale", "Control[UMFPACK_SCALE]", "None", scale, 3, scale[0], &idx, &flg));
  if (flg) {
    switch (idx) {
    case 0:
      lu->Control[UMFPACK_SCALE] = UMFPACK_SCALE_NONE;
      break;
    case 1:
      lu->Control[UMFPACK_SCALE] = UMFPACK_SCALE_SUM;
      break;
    case 2:
      lu->Control[UMFPACK_SCALE] = UMFPACK_SCALE_MAX;
      break;
    }
  }
  PetscCall(PetscOptionsReal("-mat_umfpack_alloc_init", "Control[UMFPACK_ALLOC_INIT]", "None", lu->Control[UMFPACK_ALLOC_INIT], &lu->Control[UMFPACK_ALLOC_INIT], NULL));
  PetscCall(PetscOptionsReal("-mat_umfpack_front_alloc_init", "Control[UMFPACK_FRONT_ALLOC_INIT]", "None", lu->Control[UMFPACK_FRONT_ALLOC_INIT], &lu->Control[UMFPACK_ALLOC_INIT], NULL));
  PetscCall(PetscOptionsReal("-mat_umfpack_droptol", "Control[UMFPACK_DROPTOL]", "None", lu->Control[UMFPACK_DROPTOL], &lu->Control[UMFPACK_DROPTOL], NULL));

  /* Control parameters used by solve */
  PetscCall(PetscOptionsReal("-mat_umfpack_irstep", "Control[UMFPACK_IRSTEP]", "None", lu->Control[UMFPACK_IRSTEP], &lu->Control[UMFPACK_IRSTEP], NULL));
  PetscOptionsEnd();

  if (r) {
    PetscCall(ISGetIndices(r, &ra));
    PetscCall(PetscMalloc1(m, &lu->perm_c));
    /* we cannot simply memcpy on 64-bit archs */
    for (i = 0; i < m; i++) lu->perm_c[i] = ra[i];
    PetscCall(ISRestoreIndices(r, &ra));
  }

  /* print the control parameters */
  if (lu->Control[UMFPACK_PRL] > 1) umfpack_UMF_report_control(lu->Control);

  /* symbolic factorization of A' */
  if (r) { /* use PETSc row ordering */
#if !defined(PETSC_USE_COMPLEX)
    status = umfpack_UMF_qsymbolic(n, m, ai, aj, av, lu->perm_c, &lu->Symbolic, lu->Control, lu->Info);
#else
    status = umfpack_UMF_qsymbolic(n, m, ai, aj, NULL, NULL, lu->perm_c, &lu->Symbolic, lu->Control, lu->Info);
#endif
  } else { /* use Umfpack col ordering */
#if !defined(PETSC_USE_COMPLEX)
    status = umfpack_UMF_symbolic(n, m, ai, aj, av, &lu->Symbolic, lu->Control, lu->Info);
#else
    status = umfpack_UMF_symbolic(n, m, ai, aj, NULL, NULL, &lu->Symbolic, lu->Control, lu->Info);
#endif
  }
  if (status < 0) {
    umfpack_UMF_report_info(lu->Control, lu->Info);
    umfpack_UMF_report_status(lu->Control, status);
    SETERRQ(PETSC_COMM_SELF, PETSC_ERR_LIB, "umfpack_UMF_symbolic failed");
  }
  /* report sumbolic factorization of A' when Control[PRL] > 3 */
  (void)umfpack_UMF_report_symbolic(lu->Symbolic, lu->Control);

  lu->flg            = DIFFERENT_NONZERO_PATTERN;
  lu->CleanUpUMFPACK = PETSC_TRUE;
  PetscFunctionReturn(PETSC_SUCCESS);
}

static PetscErrorCode MatView_Info_UMFPACK(Mat A, PetscViewer viewer)
{
  Mat_UMFPACK *lu = (Mat_UMFPACK *)A->data;

  PetscFunctionBegin;
  /* check if matrix is UMFPACK type */
  if (A->ops->solve != MatSolve_UMFPACK) PetscFunctionReturn(PETSC_SUCCESS);

  PetscCall(PetscViewerASCIIPrintf(viewer, "UMFPACK run parameters:\n"));
  /* Control parameters used by reporting routiones */
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_PRL]: %g\n", lu->Control[UMFPACK_PRL]));

  /* Control parameters used by symbolic factorization */
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_STRATEGY]: %g\n", lu->Control[UMFPACK_STRATEGY]));
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_DENSE_COL]: %g\n", lu->Control[UMFPACK_DENSE_COL]));
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_DENSE_ROW]: %g\n", lu->Control[UMFPACK_DENSE_ROW]));
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_AMD_DENSE]: %g\n", lu->Control[UMFPACK_AMD_DENSE]));
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_BLOCK_SIZE]: %g\n", lu->Control[UMFPACK_BLOCK_SIZE]));
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_FIXQ]: %g\n", lu->Control[UMFPACK_FIXQ]));
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_AGGRESSIVE]: %g\n", lu->Control[UMFPACK_AGGRESSIVE]));

  /* Control parameters used by numeric factorization */
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_PIVOT_TOLERANCE]: %g\n", lu->Control[UMFPACK_PIVOT_TOLERANCE]));
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_SYM_PIVOT_TOLERANCE]: %g\n", lu->Control[UMFPACK_SYM_PIVOT_TOLERANCE]));
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_SCALE]: %g\n", lu->Control[UMFPACK_SCALE]));
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_ALLOC_INIT]: %g\n", lu->Control[UMFPACK_ALLOC_INIT]));
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_DROPTOL]: %g\n", lu->Control[UMFPACK_DROPTOL]));

  /* Control parameters used by solve */
  PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_IRSTEP]: %g\n", lu->Control[UMFPACK_IRSTEP]));

  /* mat ordering */
  if (!lu->perm_c) PetscCall(PetscViewerASCIIPrintf(viewer, "  Control[UMFPACK_ORDERING]: %s (not using the PETSc ordering)\n", UmfpackOrderingTypes[(int)lu->Control[UMFPACK_ORDERING]]));
  PetscFunctionReturn(PETSC_SUCCESS);
}

static PetscErrorCode MatView_UMFPACK(Mat A, PetscViewer viewer)
{
  PetscBool         isascii;
  PetscViewerFormat format;

  PetscFunctionBegin;
  PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
  if (isascii) {
    PetscCall(PetscViewerGetFormat(viewer, &format));
    if (format == PETSC_VIEWER_ASCII_INFO) PetscCall(MatView_Info_UMFPACK(A, viewer));
  }
  PetscFunctionReturn(PETSC_SUCCESS);
}

static PetscErrorCode MatFactorGetSolverType_seqaij_umfpack(Mat A, MatSolverType *type)
{
  PetscFunctionBegin;
  *type = MATSOLVERUMFPACK;
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*MC
  MATSOLVERUMFPACK = "umfpack" - A matrix type providing direct solvers, LU, for sequential matrices
  via the external package UMFPACK.

  Use `./configure --download-suitesparse` to install PETSc to use UMFPACK

  Use `-pc_type lu` `-pc_factor_mat_solver_type umfpack` to use this direct solver

  Consult UMFPACK documentation for more information about the Control parameters
  which correspond to the options database keys below.

  Options Database Keys:
+ -mat_umfpack_ordering                  - `CHOLMOD`, `AMD`, `GIVEN`, `METIS`, `BEST`, `NONE`
. -mat_umfpack_prl                       - UMFPACK print level: Control[UMFPACK_PRL]
. -mat_umfpack_strategy AUTO             - (choose one of) `AUTO`, `UNSYMMETRIC`, `SYMMETRIC 2BY2`
. -mat_umfpack_dense_col alpha_c         - UMFPACK dense column threshold: Control[UMFPACK_DENSE_COL]
. -mat_umfpack_dense_row 0.2             - Control[UMFPACK_DENSE_ROW]
. -mat_umfpack_amd_dense 10              - Control[UMFPACK_AMD_DENSE]
. -mat_umfpack_block_size bs             - UMFPACK block size for BLAS-Level 3 calls: Control[UMFPACK_BLOCK_SIZE]
. -mat_umfpack_2by2_tolerance 0.01       - Control[UMFPACK_2BY2_TOLERANCE]
. -mat_umfpack_fixq 0                    - Control[UMFPACK_FIXQ]
. -mat_umfpack_aggressive 1              - Control[UMFPACK_AGGRESSIVE]
. -mat_umfpack_pivot_tolerance delta     - UMFPACK partial pivot tolerance: Control[UMFPACK_PIVOT_TOLERANCE]
. -mat_umfpack_sym_pivot_tolerance 0.001 - Control[UMFPACK_SYM_PIVOT_TOLERANCE]
. -mat_umfpack_scale NONE                - (choose one of) NONE SUM MAX
. -mat_umfpack_alloc_init delta          - UMFPACK factorized matrix allocation modifier: Control[UMFPACK_ALLOC_INIT]
. -mat_umfpack_droptol 0                 - Control[UMFPACK_DROPTOL]
- -mat_umfpack_irstep 0                  - UMFPACK maximum number of iterative refinement steps: Control[UMFPACK_IRSTEP]

   Level: beginner

   Notes:
   UMFPACK is part of SuiteSparse <http://faculty.cse.tamu.edu/davis/suitesparse.html>

   Control[UMFPACK_IRSTEP] default in UMFPACK is 2, PETSc uses 0, i.e. iterative refinement is disabled

.seealso: [](ch_matrices), `Mat`, `PCLU`, `MATSOLVERSUPERLU`, `MATSOLVERMUMPS`, `PCFactorSetMatSolverType()`, `MatSolverType`
M*/

static PetscErrorCode MatGetFactor_seqaij_umfpack(Mat A, MatFactorType ftype, Mat *F)
{
  Mat          B;
  Mat_UMFPACK *lu;
  PetscInt     m = A->rmap->n, n = A->cmap->n;

  PetscFunctionBegin;
  /* Create the factorization matrix F */
  PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &B));
  PetscCall(MatSetSizes(B, PETSC_DECIDE, PETSC_DECIDE, m, n));
  PetscCall(PetscStrallocpy("umfpack", &((PetscObject)B)->type_name));
  PetscCall(MatSetUp(B));

  PetscCall(PetscNew(&lu));

  B->data                  = lu;
  B->ops->getinfo          = MatGetInfo_External;
  B->ops->lufactorsymbolic = MatLUFactorSymbolic_UMFPACK;
  B->ops->destroy          = MatDestroy_UMFPACK;
  B->ops->view             = MatView_UMFPACK;
  B->ops->matsolve         = NULL;

  PetscCall(PetscObjectComposeFunction((PetscObject)B, "MatFactorGetSolverType_C", MatFactorGetSolverType_seqaij_umfpack));

  B->factortype   = MAT_FACTOR_LU;
  B->assembled    = PETSC_TRUE; /* required by -ksp_view */
  B->preallocated = PETSC_TRUE;

  PetscCall(PetscFree(B->solvertype));
  PetscCall(PetscStrallocpy(MATSOLVERUMFPACK, &B->solvertype));
  B->canuseordering = PETSC_TRUE;
  PetscCall(PetscStrallocpy(MATORDERINGEXTERNAL, (char **)&B->preferredordering[MAT_FACTOR_LU]));

  /* initializations */
  /* get the default control parameters */
  umfpack_UMF_defaults(lu->Control);
  lu->perm_c                  = NULL; /* use default UMFPACK col permutation */
  lu->Control[UMFPACK_IRSTEP] = 0;    /* max num of iterative refinement steps to attempt */

  *F = B;
  PetscFunctionReturn(PETSC_SUCCESS);
}

PETSC_INTERN PetscErrorCode MatGetFactor_seqaij_cholmod(Mat, MatFactorType, Mat *);
PETSC_INTERN PetscErrorCode MatGetFactor_seqsbaij_cholmod(Mat, MatFactorType, Mat *);
PETSC_INTERN PetscErrorCode MatGetFactor_seqaij_klu(Mat, MatFactorType, Mat *);
PETSC_INTERN PetscErrorCode MatGetFactor_seqaij_spqr(Mat, MatFactorType, Mat *);

PETSC_INTERN PetscErrorCode MatSolverTypeRegister_SuiteSparse(void)
{
  PetscFunctionBegin;
  PetscCall(MatSolverTypeRegister(MATSOLVERUMFPACK, MATSEQAIJ, MAT_FACTOR_LU, MatGetFactor_seqaij_umfpack));
  PetscCall(MatSolverTypeRegister(MATSOLVERCHOLMOD, MATSEQAIJ, MAT_FACTOR_CHOLESKY, MatGetFactor_seqaij_cholmod));
  PetscCall(MatSolverTypeRegister(MATSOLVERCHOLMOD, MATSEQSBAIJ, MAT_FACTOR_CHOLESKY, MatGetFactor_seqsbaij_cholmod));
  PetscCall(MatSolverTypeRegister(MATSOLVERKLU, MATSEQAIJ, MAT_FACTOR_LU, MatGetFactor_seqaij_klu));
  PetscCall(MatSolverTypeRegister(MATSOLVERSPQR, MATSEQAIJ, MAT_FACTOR_QR, MatGetFactor_seqaij_spqr));
  if (!PetscDefined(USE_COMPLEX)) PetscCall(MatSolverTypeRegister(MATSOLVERSPQR, MATNORMAL, MAT_FACTOR_QR, MatGetFactor_seqaij_spqr));
  PetscCall(MatSolverTypeRegister(MATSOLVERSPQR, MATNORMALHERMITIAN, MAT_FACTOR_QR, MatGetFactor_seqaij_spqr));
  PetscFunctionReturn(PETSC_SUCCESS);
}
