Actual source code: ex13.c

  1: static char help[] = "Tests copying and ordering uniprocessor row-based sparse matrices.\n\n";

  3: #include <petscmat.h>

  5: int main(int argc, char **args)
  6: {
  7:   Mat         C, A;
  8:   PetscInt    i, j, m = 5, n = 5, Ii, J;
  9:   PetscScalar v;
 10:   IS          perm, iperm;

 12:   PetscFunctionBeginUser;
 13:   PetscCall(PetscInitialize(&argc, &args, NULL, help));
 14:   PetscCall(MatCreateSeqAIJ(PETSC_COMM_SELF, m * n, m * n, 5, NULL, &C));
 15:   /* create the matrix for the five point stencil, YET AGAIN*/
 16:   for (i = 0; i < m; i++) {
 17:     for (j = 0; j < n; j++) {
 18:       v  = -1.0;
 19:       Ii = j + n * i;
 20:       if (i > 0) {
 21:         J = Ii - n;
 22:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 23:       }
 24:       if (i < m - 1) {
 25:         J = Ii + n;
 26:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 27:       }
 28:       if (j > 0) {
 29:         J = Ii - 1;
 30:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 31:       }
 32:       if (j < n - 1) {
 33:         J = Ii + 1;
 34:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 35:       }
 36:       v = 4.0;
 37:       PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
 38:     }
 39:   }
 40:   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
 41:   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));

 43:   PetscCall(MatConvert(C, MATSAME, MAT_INITIAL_MATRIX, &A));

 45:   PetscCall(MatGetOrdering(A, MATORDERINGND, &perm, &iperm));
 46:   PetscCall(ISView(perm, PETSC_VIEWER_STDOUT_SELF));
 47:   PetscCall(ISView(iperm, PETSC_VIEWER_STDOUT_SELF));
 48:   PetscCall(MatView(A, PETSC_VIEWER_STDOUT_SELF));

 50:   PetscCall(ISDestroy(&perm));
 51:   PetscCall(ISDestroy(&iperm));
 52:   PetscCall(MatDestroy(&C));
 53:   PetscCall(MatDestroy(&A));
 54:   PetscCall(PetscFinalize());
 55:   return 0;
 56: }

 58: /*TEST

 60:    test:
 61:       filter: grep -v " MPI process"

 63: TEST*/