euclidean_metric.hpp

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//=======================================================================
// Copyright (c) 2013 Piotr Wygocki
//               2014 Piotr Smulewicz
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================
#ifndef PAAL_EUCLIDEAN_METRIC_HPP
#define PAAL_EUCLIDEAN_METRIC_HPP

#include "paal/data_structures/metric/metric_traits.hpp"
#include "paal/utils/type_functions.hpp"

#include <cmath>

namespace paal {
namespace data_structures {


template <typename T> struct euclidean_metric {
    auto operator()(const std::pair<T, T> &p1, const std::pair<T, T> &p2) const
        -> decltype(std::hypot(p1.first - p2.first, p1.second - p2.second)) {
        return std::hypot(p1.first - p2.first, p1.second - p2.second);
    }
};

template <typename T>
struct metric_traits<euclidean_metric<T>>
    : public _metric_traits<euclidean_metric<T>, std::pair<T, T>> {};
} // data_structures

} // paal

#endif // PAAL_EUCLIDEAN_METRIC_HPP