Actual source code: amd.c

  1: #include <petscmat.h>
  2: #include <petsc/private/matorderimpl.h>
  3: #include <amd.h>

  5: #if defined(PETSC_USE_64BIT_INDICES)
  6:   #define amd_AMD_defaults amd_l_defaults
  7:   /* the type casts are needed because PetscInt is long long while SuiteSparse_long is long and compilers warn even when they are identical */
  8:   #define amd_AMD_order(a, b, c, d, e, f) amd_l_order((SuiteSparse_long)a, (SuiteSparse_long *)b, (SuiteSparse_long *)c, (SuiteSparse_long *)d, e, f)
  9: #else
 10:   #define amd_AMD_defaults amd_defaults
 11:   #define amd_AMD_order    amd_order
 12: #endif

 14: /*
 15:     MatGetOrdering_AMD - Find the Approximate Minimum Degree ordering

 17:     This provides an interface to Tim Davis' AMD package (used by UMFPACK, CHOLMOD, MATLAB, etc).
 18: */
 19: PETSC_INTERN PetscErrorCode MatGetOrdering_AMD(Mat mat, MatOrderingType type, IS *row, IS *col)
 20: {
 21:   PetscInt        nrow, *perm;
 22:   const PetscInt *ia, *ja;
 23:   int             status;
 24:   PetscReal       val;
 25:   double          Control[AMD_CONTROL], Info[AMD_INFO];
 26:   PetscBool       tval, done;

 28:   PetscFunctionBegin;
 29:   /*
 30:      AMD does not require that the matrix be symmetric (it does so internally,
 31:      at least in so far as computing orderings for A+A^T.
 32:   */
 33:   PetscCall(MatGetRowIJ(mat, 0, PETSC_FALSE, PETSC_TRUE, &nrow, &ia, &ja, &done));
 34:   PetscCheck(done, PETSC_COMM_SELF, PETSC_ERR_SUP, "Cannot get rows for matrix type %s", ((PetscObject)mat)->type_name);

 36:   amd_AMD_defaults(Control);
 37:   PetscOptionsBegin(PetscObjectComm((PetscObject)mat), ((PetscObject)mat)->prefix, "AMD Options", "Mat");
 38:   /*
 39:     We have to use temporary values here because AMD always uses double, even though PetscReal may be single
 40:   */
 41:   val = (PetscReal)Control[AMD_DENSE];
 42:   PetscCall(PetscOptionsReal("-mat_ordering_amd_dense", "threshold for \"dense\" rows/columns", "None", val, &val, NULL));
 43:   Control[AMD_DENSE] = (double)val;

 45:   tval = (PetscBool)Control[AMD_AGGRESSIVE];
 46:   PetscCall(PetscOptionsBool("-mat_ordering_amd_aggressive", "use aggressive absorption", "None", tval, &tval, NULL));
 47:   Control[AMD_AGGRESSIVE] = (double)tval;

 49:   PetscOptionsEnd();

 51:   PetscCall(PetscMalloc1(nrow, &perm));
 52:   status = amd_AMD_order(nrow, ia, ja, perm, Control, Info);
 53:   switch (status) {
 54:   case AMD_OK:
 55:     break;
 56:   case AMD_OK_BUT_JUMBLED:
 57:     /* The result is fine, but PETSc matrices are supposed to satisfy stricter preconditions, so PETSc considers a
 58:     * matrix that triggers this error condition to be invalid.
 59:     */
 60:     SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_PLIB, "According to AMD, the matrix has unsorted and/or duplicate row indices");
 61:   case AMD_INVALID:
 62:     amd_info(Info);
 63:     SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_PLIB, "According to AMD, the matrix is invalid");
 64:   case AMD_OUT_OF_MEMORY:
 65:     SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_MEM, "AMD could not compute ordering");
 66:   default:
 67:     SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_LIB, "Unexpected return value");
 68:   }
 69:   PetscCall(MatRestoreRowIJ(mat, 0, PETSC_FALSE, PETSC_TRUE, NULL, &ia, &ja, &done));

 71:   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, nrow, perm, PETSC_COPY_VALUES, row));
 72:   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, nrow, perm, PETSC_OWN_POINTER, col));
 73:   PetscFunctionReturn(PETSC_SUCCESS);
 74: }