elements.hpp

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/*
 * Copyright (C) 2023  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
 * 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 Antkeeper source code.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef ANTKEEPER_PHYSICS_ORBIT_ELEMENTS_HPP
#define ANTKEEPER_PHYSICS_ORBIT_ELEMENTS_HPP
 
#include <engine/math/vector.hpp>
#include <engine/math/numbers.hpp>
#include <cmath>
 
namespace physics {
namespace orbit {
 
template <class T>
struct elements
{
    typedef T scalar_type;
    
    scalar_type ec;
    
    scalar_type a;
    
    scalar_type in;
    
    scalar_type om;
    
    scalar_type w;
    
    scalar_type ma;
};
 
template <class T>
T period(T a, T gm);
 
template <class T>
T mean_motion(T a, T gm);
 
template <class T>
T mean_motion(T t);
 
template <class T>
T argument_periapsis(T om, T lp);
 
template <class T>
T longitude_periapsis(T om, T w);
 
template <class T>
T semiminor_axis(T a, T ec);
 
template <class T>
T semilatus_rectum(T a, T ec);
 
template <class T>
T period(T a, T gm)
{
    return math::two_pi<T> * std::sqrt((a * a * a) / gm);
}
 
template <class T>
T mean_motion(T a, T gm)
{
    return std::sqrt((a * a * a) / gm);
}
 
template <class T>
T mean_motion(T t)
{
    return math::two_pi<T> / t;
}
 
template <class T>
T argument_periapsis(T om, T lp)
{
    return lp - om;
}
 
template <class T>
T longitude_periapsis(T om, T w)
{
    return w + om;
}
 
template <class T>
T semiminor_axis(T a, T ec)
{
    return a * std::sqrt(T(1) - ec * ec);
}
 
template <class T>
T semilatus_rectum(T a, T ec)
{
    return a * (T(1) - ec * ec);
}
 
} // namespace orbit
} // namespace physics
 
#endif // ANTKEEPER_PHYSICS_ORBIT_ELEMENTS_HPP