Actual source code: ex22.c


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

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

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

 18:   PetscFunctionBeginUser;
 19:   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
 20:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
 21:   PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "This is a uniprocessor example only!");

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

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

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

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

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

 90:     PetscCall(ISDestroy(&rperm));
 91:     PetscCall(ISDestroy(&cperm));
 92:     PetscCall(ISDestroy(&icperm));
 93:     PetscCall(MatDestroy(&Cperm));
 94:   }

 96:   PetscCall(MatDestroy(&C));
 97:   PetscCall(PetscFinalize());
 98:   return 0;
 99: }

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

109:   PetscFunctionBegin;
110:   PetscCall(PetscObjectGetComm((PetscObject)mat, &comm));
111:   PetscCall(MatGetRowIJ(mat, 0, PETSC_FALSE, PETSC_TRUE, &n, NULL, NULL, &done));
112:   PetscCall(MatRestoreRowIJ(mat, 0, PETSC_FALSE, PETSC_TRUE, NULL, NULL, NULL, &done));
113:   if (done) { /* matrix may be "compressed" in symbolic factorization, due to i-nodes or block storage */
114:     PetscCall(PetscMalloc1(n, &ii));
115:     for (i = 0; i < n; i++) ii[i] = n - i - 1; /* replace your index here */
116:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, n, ii, PETSC_COPY_VALUES, irow));
117:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, n, ii, PETSC_OWN_POINTER, icol));
118:   } else SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_SUP, "MatRestoreRowIJ fails!");
119:   PetscCall(ISSetPermutation(*irow));
120:   PetscCall(ISSetPermutation(*icol));
121:   PetscFunctionReturn(PETSC_SUCCESS);
122: }

124: /*TEST

126:    test:

128: TEST*/