💿🐜 Antkeeper source code https://antkeeper.com
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* Copyright (C) 2021 Christopher J. Howard
* This file is part of Antkeeper source code.
* Antkeeper source code 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.
* Antkeeper source code is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
#include "physics/constants.hpp"
#include <cmath>
namespace physics {
/// Various forms of Planck's law.
namespace planck {
* Wavelength variant of Planck's law.
* @param t Temperature of the blackbody, in kelvin.
* @param lambda Wavelength of light, in meters.
* @param c Speed of light in medium.
* @return Spectral radiance, in watt per steradian per square meter per meter.
template <class T>
T wavelength(T t, T lambda, T c = constants::speed_of_light<T>);
template <class T>
T wavelength(T t, T lambda, T c)
const T hc = constants::planck<T> * c;
const T lambda2 = lambda * lambda;
// First radiation constant (c1L)
const T c1 = T(2) * hc * c;
// Second radiation constant (c2)
const T c2 = hc / constants::boltzmann<T>;
return (c1 / (lambda2 * lambda2 * lambda)) / std::expm1(c2 / (lambda * t));
} // namespace planck
} // namespace physics