Math.cpp

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/*
 *  CepGen: a central exclusive processes event generator
 *  Copyright (C) 2023  Laurent Forthomme
 *
 *  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 3 of the License, or
 *  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 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/>.
 */
 
#include <cmath>
 
#include "CepGen/Utils/Math.h"
 
namespace cepgen {
  namespace utils {
    template <typename T>
    bool positive(const T& val) {
      return val > T{} && std::isfinite(val);
    }
    template bool positive<double>(const double&);
    template bool positive<float>(const float&);
    template bool positive<int>(const int&);
 
    double fastHypot(double x, double y) {
      x *= x, y *= y;
      return std::sqrt(x + y);
    }
 
    double fastHypot(double x, double y, double z) {
      x *= x, y *= y, z *= z;
      return std::sqrt(x + y + z);
    }
 
    double fastSqrtSqDiff(double x, double y) {
      if (std::fabs(x) == std::fabs(y))
        return 0.;
      return std::sqrt((x + y) * (x - y));
    }
  }  // namespace utils
}  // namespace cepgen