From 864170334da99e6334785e9cbc2e7cd72832e1cf Mon Sep 17 00:00:00 2001
From: Dario Izzo <dario.izzo@gmail.com>
Date: Tue, 29 Aug 2023 10:44:51 +0200
Subject: [PATCH] udpla::keplerian interface

---
 include/kep3/core_astro/convert_anomalies.hpp |  8 +-
 include/kep3/planets/keplerian.hpp            | 73 +++++++++++++++++++
 2 files changed, 80 insertions(+), 1 deletion(-)
 create mode 100644 include/kep3/planets/keplerian.hpp

diff --git a/include/kep3/core_astro/convert_anomalies.hpp b/include/kep3/core_astro/convert_anomalies.hpp
index c3892804..c845a985 100644
--- a/include/kep3/core_astro/convert_anomalies.hpp
+++ b/include/kep3/core_astro/convert_anomalies.hpp
@@ -26,13 +26,19 @@ inline double m2e(double M, double ecc) {
   // (tests indicated that any higher order expansion does not really improve)
   double IG = M;
   const int digits = std::numeric_limits<double>::digits;
+  std::uintmax_t max_iter = 100u;
   double sol = boost::math::tools::halley_iterate(
       [M, ecc](double E) {
         return std::make_tuple(kepE(E, M, ecc), d_kepE(E, ecc),
                                dd_kepE(E, ecc));
       },
       IG, IG - boost::math::constants::pi<double>(),
-      IG + boost::math::constants::pi<double>(), digits);
+      IG + boost::math::constants::pi<double>(), digits, max_iter);
+  if (max_iter == 100u) {
+    throw std::domain_error(
+        "Maximum number of iterations exceeded when solving Kepler's "
+        "equation for the eccentric anomaly in m2e.");
+  }
   return sol;
 }
 // eccentric to mean (only ellipses) e<1
diff --git a/include/kep3/planets/keplerian.hpp b/include/kep3/planets/keplerian.hpp
new file mode 100644
index 00000000..bfecada0
--- /dev/null
+++ b/include/kep3/planets/keplerian.hpp
@@ -0,0 +1,73 @@
+
+// Copyright 2023, 2024 Dario Izzo (dario.izzo@gmail.com), Francesco Biscani
+// (bluescarni@gmail.com)
+//
+// This file is part of the kep3 library.
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#ifndef kep3_UDPLA_KEPLERIAN_H
+#define kep3_UDPLA_KEPLERIAN_H
+
+#include <array>
+#include <utility>
+
+#include <kep3/detail/visibility.hpp>
+#include <kep3/epoch.hpp>
+#include <kep3/planet.hpp>
+
+
+namespace kep3::udpla {
+
+class kep3_DLL_PUBLIC keplerian {
+
+  static const std::array<double, 6> default_elements;
+
+  kep3::epoch m_ref_epoch;
+  std::array<double, 6> m_elem;
+  std::string m_name;
+  double m_mu_central_body;
+  double m_mu_self;
+  double m_radius;
+  double m_safe_radius;
+
+  friend class boost::serialization::access;
+  template <typename Archive> void serialize(Archive &ar, unsigned) {
+    ar &m_ref_epoch;
+    ar &m_elem;
+    ar &m_name;
+    ar &m_mu_central_body;
+    ar &m_mu_self;
+    ar &m_radius;
+    ar &m_safe_radius;
+  }
+
+public:
+  // NOTE: in here elem is a,e,i,W,w,M (Mean anomaly, not true anomaly)
+  // NOTE: added_param contains mu_self, radius and safe_radius
+  explicit keplerian(const epoch &ref_epoch = kep3::epoch(0),
+                     const std::array<double, 6> &elem = default_elements,
+                     double mu_central_body = 1., std::string name = "Unknown",
+                     std::array<double, 3> added_params = {-1., -1., -1.});
+
+  // Mandatory UDPLA methods
+  static std::array<std::array<double, 3>, 2> eph(const epoch &);
+
+  // Optional UDPLA methods
+  [[nodiscard]] std::string get_name() const;
+  [[nodiscard]] double get_mu_central_body() const;
+  [[nodiscard]] double get_mu_self() const;
+  [[nodiscard]] double get_radius() const;
+  [[nodiscard]] double get_safe_radius() const;
+  [[nodiscard]] std::string get_extra_info() const;
+
+  // Other methods
+  [[nodiscard]] std::string get_ref_epoch() const;
+  [[nodiscard]] std::string get_elem() const;
+};
+} // namespace kep3::udpla
+kep3_S11N_PLANET_EXPORT_KEY(kep3::udpla::keplerian);
+
+#endif // kep3_EPOCH_H
\ No newline at end of file