/**
 * @file   discretization.hpp
 * @author Julian Iseringhausen <isering@ins.uni-bonn.de>
 * @date   Tue Apr  5 20:32:09 2011
 *
 * @brief  Base class for controlling the discretization of
 *         the continuous system of equations. The discretized
 *         operator must be specified as a stencil.
 *
 */

#ifndef DISCRETIZATION_HPP_
#define DISCRETIZATION_HPP_

#include <algorithm>
#include <string>

#include "base/object.hpp"
#include "base/stencil.hpp"
#include "grid/grid.hpp"
#include "grid/multigrid.hpp"
#include "mg.hpp"

namespace VMG
{

class Discretization : public Object
{
public:
  Discretization() :
    stencil(1.0),
    order(2)
  {}

  Discretization(const int& order) :
    stencil(1.0),
    order(order)
  {}

  Discretization(const Stencil& stencil_, const int& order) :
    stencil(stencil_),
    order(order)
  {}

  Discretization(std::string id) :
    Object(id),
    stencil(1.0),
    order(2)
  {}

  Discretization(std::string id, const int& order) :
    Object(id),
    stencil(1.0),
    order(order)
  {}

  Discretization(std::string id, const Stencil& stencil_, const int& order) :
    Object(id),
    stencil(stencil_),
    order(order)
  {}

  const Stencil& GetStencil() const {return stencil;} ///< Returns the stencil of the discretized operator.

  virtual vmg_float OperatorPrefactor(const Grid& grid) const = 0; ///< Returns the prefactor of the operator.

  virtual void ModifyRightHandSide() {}

  /**
   * This function gets called whenever boundary points at inner boundaries are needed.
   * Inner boundaries occur when using adaptive grid refinement.
   *
   * @param sol_fine Solution vector / fine level
   * @param rhs_fine Right handside vector / fine level
   * @param sol_coarse Solution vector / coarse level
   */
  void SetInnerBoundary(Grid& sol_fine, Grid& rhs_fine, Grid& sol_coarse) const
  {
    if (sol_fine.Global().BoundaryType() == LocallyRefined)
      SetInnerBoundaryCompute(sol_fine, rhs_fine, sol_coarse);
  }

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

protected:
  VMG::Stencil stencil;
  int order;
};

}

#endif /* DISCRETIZATION_HPP_ */