/**
 * @file   discretization_poisson_fd.hpp
 * @author Julian Iseringhausen <isering@ins.uni-bonn.de>
 * @date   Mon Apr 18 13:01:40 2011
 *
 * @brief  Finite difference discretization of the
 *         Poisson equation.
 *
 */

#ifndef DISCRETIZATION_POISSON_FD_HPP_
#define DISCRETIZATION_POISSON_FD_HPP_

#include "base/discretization.hpp"

namespace VMG
{

static inline vmg_float sqr(const vmg_float& val) {return val*val;}

class DiscretizationPoissonFD : public Discretization
{
public:
  DiscretizationPoissonFD()
  {
    stencil.SetDiag(6.0);
    stencil.push_back(-1,  0,  0, -1.0);
    stencil.push_back( 1,  0,  0, -1.0);
    stencil.push_back( 0, -1,  0, -1.0);
    stencil.push_back( 0,  1,  0, -1.0);
    stencil.push_back( 0,  0, -1, -1.0);
    stencil.push_back( 0,  0,  1, -1.0);
  }

  vmg_float OperatorPrefactor(const Grid& grid) const
  {
    return 1.0 / (sqr(grid.MeshWidth()));
  }

private:
  void SetInnerBoundaryCompute(Grid& sol_fine, Grid& rhs_fine, Grid& sol_coarse) const {}
};

}

#endif /* DISCRETIZATION_POISSON_FD_HPP_ */