VCycle.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_VCYCLE_H
#define THUNDEREGG_GMG_VCYCLE_H
 
#include <ThunderEgg/GMG/Cycle.h>
#include <ThunderEgg/GMG/CycleOpts.h>
namespace ThunderEgg::GMG {
template<int D>
class VCycle : public Cycle<D>
{
private:
  int num_pre_sweeps = 1;
  int num_post_sweeps = 1;
  int num_coarse_sweeps = 1;
 
protected:
  /*
   * @brief Implements V-cycle. Pre-smooth, visit coarser level and then post-smooth.
   */
  void visit(const Level<D>& level, const Vector<D>& f, Vector<D>& u) const override
  {
    if (level.coarsest()) {
      for (int i = 0; i < num_coarse_sweeps; i++) {
        level.getSmoother().smooth(f, u);
      }
    } else {
      for (int i = 0; i < num_pre_sweeps; i++) {
        level.getSmoother().smooth(f, u);
      }
 
      Vector<D> coarser_f = this->restrict(level, f, u);
 
      const Level<D>& coarser_level = level.getCoarser();
      Vector<D> coarser_u = coarser_f.getZeroClone();
 
      this->visit(coarser_level, coarser_f, coarser_u);
 
      coarser_level.getInterpolator().interpolate(coarser_u, u);
 
      for (int i = 0; i < num_post_sweeps; i++) {
        level.getSmoother().smooth(f, u);
      }
    }
  }
 
public:
  VCycle(const Level<D>& finest_level, const CycleOpts& opts)
    : Cycle<D>(finest_level)
  {
    num_pre_sweeps = opts.pre_sweeps;
    num_post_sweeps = opts.post_sweeps;
    num_coarse_sweeps = opts.coarse_sweeps;
  }
  VCycle<D>* clone() const override { return new VCycle(*this); }
};
extern template class VCycle<2>;
extern template class VCycle<3>;
} // namespace ThunderEgg::GMG
#endif