neighbor_kernel.hpp

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/*
 * PoPS model - deterministic neighbor dispersal kernel
 *
 * Copyright (C) 2020 by the authors.
 *
 * Authors: Vaclav Petras (wenzeslaus gmail com)
 *
 * The code contained herein is licensed under the GNU General Public
 * License. You may obtain a copy of the GNU General Public License
 * Version 2 or later at the following locations:
 *
 * http://www.opensource.org/licenses/gpl-license.html
 * http://www.gnu.org/copyleft/gpl.html
 */
 
#ifndef POPS_NEIGHBOR_KERNEL_HPP
#define POPS_NEIGHBOR_KERNEL_HPP
 
#include "kernel_types.hpp"
#include "radial_kernel.hpp"
#include "utils.hpp"
 
namespace pops {
 
class DeterministicNeighborDispersalKernel
{
protected:
    Direction direction_;
 
public:
    DeterministicNeighborDispersalKernel(Direction dispersal_direction)
        : direction_(dispersal_direction)
    {}
 
    template<typename Generator>
    std::tuple<int, int> operator()(Generator& generator, int row, int col)
    {
        UNUSED(generator);  // Deterministic does not need random numbers.
        switch (direction_) {
        case Direction::E:
            col += 1;
            break;
        case Direction::N:
            row -= 1;
            break;
        case Direction::NE:
            row -= 1;
            col += 1;
            break;
        case Direction::NW:
            row -= 1;
            col -= 1;
            break;
        case Direction::S:
            row += 1;
            break;
        case Direction::SE:
            row += 1;
            col += 1;
            break;
        case Direction::SW:
            row += 1;
            col -= 1;
            break;
        case Direction::W:
            col -= 1;
            break;
        default:
            throw std::invalid_argument(
                "NeighborDispersalKernel: Unsupported Direction");
        }
        return std::make_tuple(row, col);
    }
 
    static bool supports_kernel(const DispersalKernelType type)
    {
        if (type == DispersalKernelType::DeterministicNeighbor)
            return true;
        return false;
    }
};
 
}  // namespace pops
 
#endif  // POPS_NEIGHBOR_KERNEL_HPP