virtual_sites.hpp

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/*
 * Copyright (C) 2010-2022 The ESPResSo project
 *
 * This file is part of ESPResSo.
 *
 * ESPResSo 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.
 *
 * ESPResSo 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 <http://www.gnu.org/licenses/>.
 */
 
#pragma once
 
#include "config/config.hpp"
 
#ifdef VIRTUAL_SITES_RELATIVE
 
#include "BoxGeometry.hpp"
#include "Particle.hpp"
#include "PropagationMode.hpp"
 
#include <utils/quaternion.hpp>
 
#include <tuple>
 
/** Calculate the rotation quaternion and distance between two particles */
std::tuple<Utils::Quaternion<double>, double>
calculate_vs_relate_to_params(Particle const &p_current,
                              Particle const &p_relate_to,
                              BoxGeometry const &box_geo, double min_global_cut,
                              bool override_cutoff_check = false);
 
/**
 * @brief Setup a virtual site to track a real particle.
 * @param[in]     box_geo      Box geometry.
 * @param[in,out] p_vs         Virtual site.
 * @param[in]     p_relate_to  Real particle to follow.
 * @param[in]     min_global_cut  Minimal global cutoff.
 */
inline void vs_relate_to(Particle &p_vs, Particle const &p_relate_to,
                         BoxGeometry const &box_geo, double min_global_cut) {
  // Set the particle id of the particle we want to relate to, the distance
  // and the relative orientation
  auto &vs_relative = p_vs.vs_relative();
  vs_relative.to_particle_id = p_relate_to.id();
  std::tie(vs_relative.rel_orientation, vs_relative.distance) =
      calculate_vs_relate_to_params(p_vs, p_relate_to, box_geo, min_global_cut);
  p_vs.propagation() =
      PropagationMode::TRANS_VS_RELATIVE | PropagationMode::ROT_VS_RELATIVE;
}
 
#endif // VIRTUAL_SITES_RELATIVE