Actual source code: sp1wd.c

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

  4: /*
  5:     MatGetOrdering_1WD - Find the 1-way dissection ordering of a given matrix.
  6: */
  7: PETSC_INTERN PetscErrorCode MatGetOrdering_1WD(Mat mat, MatOrderingType type, IS *row, IS *col)
  8: {
  9:   PetscInt        i, *mask, *xls, nblks, *xblk, *ls, nrow, *perm;
 10:   const PetscInt *ia, *ja;
 11:   PetscBool       done;

 13:   PetscFunctionBegin;
 14:   PetscCall(MatGetRowIJ(mat, 1, PETSC_TRUE, PETSC_TRUE, &nrow, &ia, &ja, &done));
 15:   PetscCheck(done, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Cannot get rows for matrix");

 17:   PetscCall(PetscMalloc5(nrow, &mask, nrow + 1, &xls, nrow, &ls, nrow + 1, &xblk, nrow, &perm));
 18:   PetscCall(SPARSEPACKgen1wd(&nrow, ia, ja, mask, &nblks, xblk, perm, xls, ls));
 19:   PetscCall(MatRestoreRowIJ(mat, 1, PETSC_TRUE, PETSC_TRUE, NULL, &ia, &ja, &done));

 21:   for (i = 0; i < nrow; i++) perm[i]--;

 23:   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, nrow, perm, PETSC_COPY_VALUES, row));
 24:   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, nrow, perm, PETSC_COPY_VALUES, col));
 25:   PetscCall(PetscFree5(mask, xls, ls, xblk, perm));
 26:   PetscFunctionReturn(PETSC_SUCCESS);
 27: }