Actual source code: ex6.c


  2: static char help[] = "Tests reordering a matrix.\n\n";

  4: #include <petscmat.h>

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

 14:   PetscInitialize(&argc, &args, (char *)0, help);
 15:   MatCreate(PETSC_COMM_SELF, &C);
 16:   MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n);
 17:   MatSetFromOptions(C);
 18:   MatSetUp(C);

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

 48:   MatGetOrdering(C, MATORDERINGND, &perm, &iperm);
 49:   ISView(perm, PETSC_VIEWER_STDOUT_SELF);
 50:   ISView(iperm, PETSC_VIEWER_STDOUT_SELF);
 51:   MatView(C, PETSC_VIEWER_STDOUT_SELF);

 53:   ISDestroy(&perm);
 54:   ISDestroy(&iperm);
 55:   MatDestroy(&C);
 56:   PetscFinalize();
 57:   return 0;
 58: }

 60: /*TEST

 62:    test:

 64: TEST*/