anygrid.hpp

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#ifndef PSEUDO_ANYGRID_HPP
#define PSEUDO_ANYGRID_HPP
 
/*
 Copyright (C) 2018 Xavier Andrade
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
 
 You should have received a copy of the GNU Lesser General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/
 
#include "base.hpp"
#include "spline.h"
#include <string>
#include <vector>
 
namespace pseudopotential {
 
class anygrid : public pseudopotential::base {
 
public:
  anygrid(bool uniform_grid) : uniform_grid_(uniform_grid) {}
 
  double mesh_spacing() const { return 0.01; }
 
  int mesh_size() const {
    if (uniform_grid_) {
      return mesh_size_;
    } else {
      return grid_.size();
    }
  }
 
  virtual void grid(std::vector<double> &val) const {
    if (uniform_grid_) {
      pseudopotential::base::grid(val);
    } else {
      val = grid_;
    }
  }
 
  virtual void grid_weights(std::vector<double> &val) const {
    if (uniform_grid_) {
      pseudopotential::base::grid(val);
    } else {
      val = grid_weights_;
    }
  }
 
protected:
  void interpolate(std::vector<double> &function) const {
    if (!uniform_grid_)
      return;
 
    std::vector<double> function_in_grid = function;
 
    assert(function.size() == grid_.size());
 
    Spline function_spline;
    function_spline.fit(grid_.data(), function_in_grid.data(),
                        function_in_grid.size(), SPLINE_FLAT_BC,
                        SPLINE_NATURAL_BC);
 
    function.clear();
    for (double rr = 0.0; rr <= grid_[grid_.size() - 1]; rr += mesh_spacing()) {
      function.push_back(function_spline.value(rr));
    }
  }
 
  bool uniform_grid_;
  std::vector<double> grid_;
  std::vector<double> grid_weights_;
  int mesh_size_;
};
 
} // namespace pseudopotential
 
#endif