/*
   Creates a DMShell and uses it with a KSP 
   This tests that the KSP object can still create vectors using the Mat object

   Contributed by Lawrence Mitchell as part of pull request 221

*/
#include <petscdm.h>
#include <petscdmshell.h>
#include <petscksp.h>
int main(int argc, char **argv)
{
    Mat            A;
    KSP            ksp;
    DM             shell;
    Vec            *left, *right;
    MPI_Comm       c;
    PetscErrorCode ierr;

    PetscInitialize(&argc, &argv, NULL, NULL);
    c = PETSC_COMM_WORLD;

    ierr = MatCreate(c, &A); CHKERRQ(ierr);
    ierr = MatSetSizes(A, 1, 1, PETSC_DECIDE, PETSC_DECIDE); CHKERRQ(ierr);
    ierr = MatSetFromOptions(A); CHKERRQ(ierr);
    ierr = MatSetUp(A); CHKERRQ(ierr);
    ierr = KSPCreate(c, &ksp); CHKERRQ(ierr);
    ierr = KSPSetOperators(ksp, A, A); CHKERRQ(ierr);
    ierr = KSPSetFromOptions(ksp); CHKERRQ(ierr);
    ierr = DMShellCreate(c, &shell); CHKERRQ(ierr);
    ierr = DMSetFromOptions(shell); CHKERRQ(ierr);
    ierr = DMSetUp(shell); CHKERRQ(ierr);
    ierr = KSPSetDM(ksp, shell); CHKERRQ(ierr);

    ierr = KSPCreateVecs(ksp, 1, &right, 1, &left); CHKERRQ(ierr);
    ierr = VecView(right[0], PETSC_VIEWER_STDOUT_(c));
    ierr = VecDestroyVecs(1,&right); CHKERRQ(ierr);
    ierr = VecDestroyVecs(1,&left); CHKERRQ(ierr);

    ierr = DMDestroy(&shell); CHKERRQ(ierr);
    ierr = KSPDestroy(&ksp); CHKERRQ(ierr);
    ierr = MatDestroy(&A); CHKERRQ(ierr);
    PetscFinalize();
    return 0;
}
