Actual source code: ex22.c

  1: static char help[] = "Tests matrix ordering routines.\n\n";

  3: #include <petscmat.h>
  4: extern PetscErrorCode MatGetOrdering_myordering(Mat, MatOrderingType, IS *, IS *);

  6: int main(int argc, char **args)
  7: {
  8:   Mat                C, Cperm;
  9:   PetscInt           i, j, m = 5, n = 5, Ii, J, ncols;
 10:   PetscScalar        v;
 11:   PetscMPIInt        size;
 12:   IS                 rperm, cperm, icperm;
 13:   const PetscInt    *rperm_ptr, *cperm_ptr, *cols;
 14:   const PetscScalar *vals;
 15:   PetscBool          TestMyorder = PETSC_FALSE;

 17:   PetscFunctionBeginUser;
 18:   PetscCall(PetscInitialize(&argc, &args, NULL, help));
 19:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
 20:   PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "This is a uniprocessor example only!");

 22:   /* create the matrix for the five point stencil, YET AGAIN */
 23:   PetscCall(MatCreateSeqAIJ(PETSC_COMM_SELF, m * n, m * n, 5, NULL, &C));
 24:   PetscCall(MatSetUp(C));
 25:   for (i = 0; i < m; i++) {
 26:     for (j = 0; j < n; j++) {
 27:       v  = -1.0;
 28:       Ii = j + n * i;
 29:       if (i > 0) {
 30:         J = Ii - n;
 31:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 32:       }
 33:       if (i < m - 1) {
 34:         J = Ii + n;
 35:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 36:       }
 37:       if (j > 0) {
 38:         J = Ii - 1;
 39:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 40:       }
 41:       if (j < n - 1) {
 42:         J = Ii + 1;
 43:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 44:       }
 45:       v = 4.0;
 46:       PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
 47:     }
 48:   }
 49:   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
 50:   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));

 52:   PetscCall(MatGetOrdering(C, MATORDERINGND, &rperm, &cperm));
 53:   PetscCall(ISView(rperm, PETSC_VIEWER_STDOUT_SELF));
 54:   PetscCall(ISDestroy(&rperm));
 55:   PetscCall(ISDestroy(&cperm));

 57:   PetscCall(MatGetOrdering(C, MATORDERINGRCM, &rperm, &cperm));
 58:   PetscCall(ISView(rperm, PETSC_VIEWER_STDOUT_SELF));
 59:   PetscCall(ISDestroy(&rperm));
 60:   PetscCall(ISDestroy(&cperm));

 62:   PetscCall(MatGetOrdering(C, MATORDERINGQMD, &rperm, &cperm));
 63:   PetscCall(ISView(rperm, PETSC_VIEWER_STDOUT_SELF));
 64:   PetscCall(ISDestroy(&rperm));
 65:   PetscCall(ISDestroy(&cperm));

 67:   /* create Cperm = rperm*C*icperm */
 68:   PetscCall(PetscOptionsGetBool(NULL, NULL, "-testmyordering", &TestMyorder, NULL));
 69:   if (TestMyorder) {
 70:     PetscCall(MatGetOrdering_myordering(C, MATORDERINGQMD, &rperm, &cperm));
 71:     printf("myordering's rperm:\n");
 72:     PetscCall(ISView(rperm, PETSC_VIEWER_STDOUT_SELF));
 73:     PetscCall(ISInvertPermutation(cperm, PETSC_DECIDE, &icperm));
 74:     PetscCall(ISGetIndices(rperm, &rperm_ptr));
 75:     PetscCall(ISGetIndices(icperm, &cperm_ptr));
 76:     PetscCall(MatCreateSeqAIJ(PETSC_COMM_SELF, m * n, m * n, 5, NULL, &Cperm));
 77:     for (i = 0; i < m * n; i++) {
 78:       PetscCall(MatGetRow(C, rperm_ptr[i], &ncols, &cols, &vals));
 79:       for (j = 0; j < ncols; j++) {
 80:         /* printf(" (%d %d %g)\n",i,cperm_ptr[cols[j]],vals[j]); */
 81:         PetscCall(MatSetValues(Cperm, 1, &i, 1, &cperm_ptr[cols[j]], &vals[j], INSERT_VALUES));
 82:       }
 83:     }
 84:     PetscCall(MatAssemblyBegin(Cperm, MAT_FINAL_ASSEMBLY));
 85:     PetscCall(MatAssemblyEnd(Cperm, MAT_FINAL_ASSEMBLY));
 86:     PetscCall(ISRestoreIndices(rperm, &rperm_ptr));
 87:     PetscCall(ISRestoreIndices(icperm, &cperm_ptr));

 89:     PetscCall(ISDestroy(&rperm));
 90:     PetscCall(ISDestroy(&cperm));
 91:     PetscCall(ISDestroy(&icperm));
 92:     PetscCall(MatDestroy(&Cperm));
 93:   }

 95:   PetscCall(MatDestroy(&C));
 96:   PetscCall(PetscFinalize());
 97:   return 0;
 98: }

100: #include <petsc/private/matimpl.h>
101: /* This is modified from MatGetOrdering_Natural() */
102: PetscErrorCode MatGetOrdering_myordering(Mat mat, MatOrderingType type, IS *irow, IS *icol)
103: {
104:   PetscInt  n, i, *ii;
105:   PetscBool done;
106:   MPI_Comm  comm;

108:   PetscFunctionBegin;
109:   PetscCall(PetscObjectGetComm((PetscObject)mat, &comm));
110:   PetscCall(MatGetRowIJ(mat, 0, PETSC_FALSE, PETSC_TRUE, &n, NULL, NULL, &done));
111:   PetscCall(MatRestoreRowIJ(mat, 0, PETSC_FALSE, PETSC_TRUE, NULL, NULL, NULL, &done));
112:   if (done) { /* matrix may be "compressed" in symbolic factorization, due to i-nodes or block storage */
113:     PetscCall(PetscMalloc1(n, &ii));
114:     for (i = 0; i < n; i++) ii[i] = n - i - 1; /* replace your index here */
115:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, n, ii, PETSC_COPY_VALUES, irow));
116:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, n, ii, PETSC_OWN_POINTER, icol));
117:   } else SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_SUP, "MatRestoreRowIJ fails!");
118:   PetscCall(ISSetPermutation(*irow));
119:   PetscCall(ISSetPermutation(*icol));
120:   PetscFunctionReturn(PETSC_SUCCESS);
121: }

123: /*TEST

125:    test:

127: TEST*/