Actual source code: ex13.c


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

  4: #include <petscmat.h>

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

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

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

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

 51:   PetscCall(ISDestroy(&perm));
 52:   PetscCall(ISDestroy(&iperm));
 53:   PetscCall(MatDestroy(&C));
 54:   PetscCall(MatDestroy(&A));
 55:   PetscCall(PetscFinalize());
 56:   return 0;
 57: }

 59: /*TEST

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

 64: TEST*/