static char help[] = "Test MatNullSpaceTest() with options prefixes.\n\n";

#include <petscmat.h>

int main(int argc, char **argv)
{
  Mat mat;
  MatNullSpace nsp;
  PetscBool prefix = PETSC_FALSE, flg;
  PetscErrorCode ierr;
  PetscInt zero = 0;
  PetscScalar value = 0;
  ierr = PetscInitialize(&argc, &argv, NULL, help); if (ierr) return ierr;

  ierr = PetscOptionsGetBool(NULL, NULL, "-with_prefix",&prefix,NULL);CHKERRQ(ierr);
  ierr = MatCreateDense(PETSC_COMM_WORLD, 1, 1, 1, 1, NULL, &mat);CHKERRQ(ierr);
  ierr = MatSetOptionsPrefix(mat, prefix ? "prefix_" : NULL);CHKERRQ(ierr);
  ierr = MatSetUp(mat);CHKERRQ(ierr);
  ierr = MatSetValues(mat, 1, &zero, 1, &zero, &value, INSERT_VALUES);CHKERRQ(ierr);
  ierr = MatAssemblyBegin(mat, MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
  ierr = MatAssemblyEnd(mat, MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
  ierr = MatNullSpaceCreate(PETSC_COMM_WORLD, PETSC_TRUE, 0, NULL, &nsp);CHKERRQ(ierr);
  ierr = MatNullSpaceTest(nsp, mat, &flg);CHKERRQ(ierr);
  if (!flg) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_PLIB,"Null space test failed!");
  ierr = MatNullSpaceDestroy(&nsp);CHKERRQ(ierr);
  ierr = MatDestroy(&mat);CHKERRQ(ierr);
  ierr = PetscFinalize();
  return ierr;
}

/*TEST

   test:
       suffix: no_prefix
       output_file: output/ex227_no_prefix.out
       args: -mat_null_space_test_view -mat_view

   test:
       suffix: prefix
       output_file: output/ex227_prefix.out
       args: -prefix_mat_null_space_test_view -with_prefix -prefix_mat_view

TEST*/