Cycle.h

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/***************************************************************************
 *  ThunderEgg, a library for solvers on adaptively refined block-structured
 *  Cartesian grids.
 *
 *  Copyright (c) 2018-2021 Scott Aiton
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 ***************************************************************************/
 
#ifndef THUNDEREGG_GMG_CYCLE_H
#define THUNDEREGG_GMG_CYCLE_H
 
#include <ThunderEgg/GMG/Level.h>
#include <ThunderEgg/Vector.h>
#include <list>
 
namespace ThunderEgg::GMG {
template<int D>
class Cycle : public Operator<D>
{
private:
  std::shared_ptr<const Level<D>> finest_level;
 
protected:
  Vector<D> restrict(const Level<D>& level, const Vector<D>& f, const Vector<D>& u) const
  {
    // calculate residual
    Vector<D> r = u.getZeroClone();
    level.getOperator().apply(u, r);
    r.scaleThenAdd(-1, f);
    // create vectors for coarser levels
    return level.getRestrictor().restrict(r);
  }
 
  virtual void visit(const Level<D>& level, const Vector<D>& f, Vector<D>& u) const = 0;
 
public:
  Cycle(const Level<D>& finest_level)
    : finest_level(new Level<D>(finest_level))
  {}
  void apply(const Vector<D>& f, Vector<D>& u) const
  {
    u.setWithGhost(0);
    visit(*finest_level, f, u);
  }
  const Level<D>& getFinestLevel() const { return *finest_level; }
};
extern template class Cycle<2>;
extern template class Cycle<3>;
} // namespace ThunderEgg::GMG
#endif