03_all_frames_conversions.cpp

Direct frame-rotation pairs and identity rotations.

// SPDX-License-Identifier: AGPL-3.0-or-later
// Copyright (C) 2026 Vallés Puig, Ramon
 
 
#include <siderust/siderust.hpp>
 
#include <iomanip>
#include <iostream>
 
using namespace siderust;
using namespace siderust::frames;
using namespace siderust::centers;
 
using C = Barycentric;
using U = qtty::AstronomicalUnit;
 
template <typename F1, typename F2>
void show_frame_conversion(const Time<TT, JD> &jd, const cartesian::Position<C, F1, U> &src) {
  auto out = src.template to_frame<F2>(jd);
  auto back = out.template to_frame<F1>(jd);
  auto err = (src - back).magnitude();
 
  std::cout << std::left << std::setw(24) << FrameTraits<F1>::name() << " -> " << std::setw(24)
            << FrameTraits<F2>::name() << " out=(" << std::showpos << std::setprecision(9) << out
            << std::noshowpos << ")  roundtrip=" << std::scientific << std::setprecision(3) << err
            << std::fixed << std::endl;
}
 
int main() {
  Time<TT, JD> jd(2460000.5);
  std::cout << std::fixed;
  std::cout << "Frame conversion demo at JD(TT) = " << std::setprecision(1) << jd << std::endl;
 
  cartesian::Position<C, ICRS, U> p_icrs(0.30, -0.70, 0.64);
  auto p_icrf = p_icrs.to_frame<ICRF>(jd);
  auto p_ecl = p_icrs.to_frame<EclipticMeanJ2000>(jd);
  auto p_eq_j2000 = p_icrs.to_frame<EquatorialMeanJ2000>(jd);
  auto p_eq_mod = p_icrs.to_frame<EquatorialMeanOfDate>(jd);
  auto p_eq_tod = p_icrs.to_frame<EquatorialTrueOfDate>(jd);
 
  // Identity conversions
  show_frame_conversion<ICRS, ICRS>(jd, p_icrs);
  show_frame_conversion<ICRF, ICRF>(jd, p_icrf);
  show_frame_conversion<EclipticMeanJ2000, EclipticMeanJ2000>(jd, p_ecl);
  show_frame_conversion<EquatorialMeanJ2000, EquatorialMeanJ2000>(jd, p_eq_j2000);
  show_frame_conversion<EquatorialMeanOfDate, EquatorialMeanOfDate>(jd, p_eq_mod);
  show_frame_conversion<EquatorialTrueOfDate, EquatorialTrueOfDate>(jd, p_eq_tod);
 
  // All direct non-identity provider pairs
  show_frame_conversion<ICRS, EclipticMeanJ2000>(jd, p_icrs);
  show_frame_conversion<EclipticMeanJ2000, ICRS>(jd, p_ecl);
  show_frame_conversion<ICRS, EquatorialMeanJ2000>(jd, p_icrs);
  show_frame_conversion<EquatorialMeanJ2000, ICRS>(jd, p_eq_j2000);
  show_frame_conversion<EquatorialMeanJ2000, EclipticMeanJ2000>(jd, p_eq_j2000);
  show_frame_conversion<EclipticMeanJ2000, EquatorialMeanJ2000>(jd, p_ecl);
  show_frame_conversion<EquatorialMeanJ2000, EquatorialMeanOfDate>(jd, p_eq_j2000);
  show_frame_conversion<EquatorialMeanOfDate, EquatorialMeanJ2000>(jd, p_eq_mod);
  show_frame_conversion<EquatorialMeanOfDate, EquatorialTrueOfDate>(jd, p_eq_mod);
  show_frame_conversion<EquatorialTrueOfDate, EquatorialMeanOfDate>(jd, p_eq_tod);
  show_frame_conversion<EquatorialMeanJ2000, EquatorialTrueOfDate>(jd, p_eq_j2000);
  show_frame_conversion<EquatorialTrueOfDate, EquatorialMeanJ2000>(jd, p_eq_tod);
  show_frame_conversion<ICRS, EquatorialMeanOfDate>(jd, p_icrs);
  show_frame_conversion<EquatorialMeanOfDate, ICRS>(jd, p_eq_mod);
  show_frame_conversion<ICRS, EquatorialTrueOfDate>(jd, p_icrs);
  show_frame_conversion<EquatorialTrueOfDate, ICRS>(jd, p_eq_tod);
  show_frame_conversion<ICRF, ICRS>(jd, p_icrf);
  show_frame_conversion<ICRS, ICRF>(jd, p_icrs);
  show_frame_conversion<ICRF, EquatorialMeanJ2000>(jd, p_icrf);
  show_frame_conversion<EquatorialMeanJ2000, ICRF>(jd, p_eq_j2000);
  show_frame_conversion<ICRF, EclipticMeanJ2000>(jd, p_icrf);
  show_frame_conversion<EclipticMeanJ2000, ICRF>(jd, p_ecl);
  show_frame_conversion<ICRF, EquatorialMeanOfDate>(jd, p_icrf);
  show_frame_conversion<EquatorialMeanOfDate, ICRF>(jd, p_eq_mod);
  show_frame_conversion<ICRF, EquatorialTrueOfDate>(jd, p_icrf);
  show_frame_conversion<EquatorialTrueOfDate, ICRF>(jd, p_eq_tod);
 
  return 0;
}