utils.hpp

// Copyright 2021 Arnaud Becheler    <abechele@umich.edu>
 
/*********************************************************************** * 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 2 of the License, or    * (at your option) any later version. *
 *                                                                      *
 ***************************************************************************/
 
#ifndef __SIMULATORS_UTILS_H_INCLUDED__
#define __SIMULATORS_UTILS_H_INCLUDED__
 
#include "../coalescence/container/Forest.hpp"
#include "../coalescence/merger_policy.hpp"
#include "../demography/History.hpp"
 
#include <map>
 
namespace quetzal
{
 
template <typename Env, typename F> struct neighbor_migration
{
 
    using coord_type = typename Env::coord_type;
    using env_type = Env;
    using F_type = F;
 
    env_type const &_landscape;
    F_type _f;
 
    neighbor_migration(env_type const &env, F f) : _landscape(env), _f(f)
    {
    }
 
    template <typename T> std::vector<coord_type> arrival_space(coord_type const &x, const T &) const
    {
        auto v = _landscape.four_nearest_defined_cells(x);
        v.push_back(x);
        return v;
    }
 
    template <typename T> double operator()(coord_type const &x, coord_type const &y, T const &t) const
    {
        auto v = arrival_space(x, t);
        auto binop = [this, t](auto const &a, auto const &b) { return a + _f(b, t); };
        double sum = std::accumulate(v.begin(), v.end(), 0.0, binop);
        return _f(y, t) / sum;
    }
};
 
template <typename Env, typename F> auto make_neighbor_migration(Env const &env, F f)
{
    return neighbor_migration<Env, F>(env, f);
}
 
#endif