Actual source code: ex11.c

  1: static char help[] = "Tests the use of MatZeroRows() for uniprocessor matrices.\n\n";

  3: #include <petscmat.h>

  5: int main(int argc, char **args)
  6: {
  7:   Mat         C;
  8:   PetscInt    i, j, m = 5, n = 5, Ii, J;
  9:   PetscScalar v, five = 5.0;
 10:   IS          isrow;
 11:   PetscBool   keepnonzeropattern;

 13:   PetscFunctionBeginUser;
 14:   PetscCall(PetscInitialize(&argc, &args, NULL, help));
 15:   /* create the matrix for the five point stencil, YET AGAIN*/
 16:   PetscCall(MatCreate(PETSC_COMM_SELF, &C));
 17:   PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n));
 18:   PetscCall(MatSetFromOptions(C));
 19:   PetscCall(MatSetUp(C));
 20:   for (i = 0; i < m; i++) {
 21:     for (j = 0; j < n; j++) {
 22:       v  = -1.0;
 23:       Ii = j + n * i;
 24:       if (i > 0) {
 25:         J = Ii - n;
 26:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 27:       }
 28:       if (i < m - 1) {
 29:         J = Ii + n;
 30:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 31:       }
 32:       if (j > 0) {
 33:         J = Ii - 1;
 34:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 35:       }
 36:       if (j < n - 1) {
 37:         J = Ii + 1;
 38:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 39:       }
 40:       v = 4.0;
 41:       PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
 42:     }
 43:   }
 44:   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
 45:   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));

 47:   PetscCall(ISCreateStride(PETSC_COMM_SELF, (m * n) / 2, 0, 2, &isrow));

 49:   PetscCall(PetscOptionsHasName(NULL, NULL, "-keep_nonzero_pattern", &keepnonzeropattern));
 50:   if (keepnonzeropattern) PetscCall(MatSetOption(C, MAT_KEEP_NONZERO_PATTERN, PETSC_TRUE));

 52:   PetscCall(MatZeroRowsIS(C, isrow, five, 0, 0));

 54:   PetscCall(MatView(C, PETSC_VIEWER_STDOUT_SELF));

 56:   PetscCall(ISDestroy(&isrow));
 57:   PetscCall(MatDestroy(&C));
 58:   PetscCall(PetscFinalize());
 59:   return 0;
 60: }

 62: /*TEST

 64:    test:

 66:    test:
 67:       suffix: 2
 68:       args: -mat_type seqbaij -mat_block_size 5

 70:    test:
 71:       suffix: 3
 72:       args: -keep_nonzero_pattern

 74:    test:
 75:       suffix: 4
 76:       args: -keep_nonzero_pattern -mat_type seqbaij -mat_block_size 5

 78: TEST*/