Actual source code: ex11.c


  2: static char help[] = "Tests the use of MatZeroRows() for uniprocessor matrices.\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, five = 5.0;
 11:   IS          isrow;
 12:   PetscBool   keepnonzeropattern;

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

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

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

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

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

 57:   PetscCall(ISDestroy(&isrow));
 58:   PetscCall(MatDestroy(&C));
 59:   PetscCall(PetscFinalize());
 60:   return 0;
 61: }

 63: /*TEST

 65:    test:

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

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

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

 79: TEST*/