ceph/src/boost/boost/geometry/formulas/eccentricity_sqr.hpp

   1 // Boost.Geometry
   2
   3 // Copyright (c) 2016, 2018 Oracle and/or its affiliates.
   4
   5 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
   6
   7 // Use, modification and distribution is subject to the Boost Software License,
   8 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   9 // http://www.boost.org/LICENSE_1_0.txt)
  10
  11 #ifndef BOOST_GEOMETRY_FORMULAS_ECCENCRICITY_SQR_HPP
  12 #define BOOST_GEOMETRY_FORMULAS_ECCENCRICITY_SQR_HPP
  13
  14 #include <boost/geometry/algorithms/not_implemented.hpp>
  15
  16 #include <boost/geometry/core/radius.hpp>
  17 #include <boost/geometry/core/tag.hpp>
  18 #include <boost/geometry/core/tags.hpp>
  19
  20 #include <boost/geometry/util/math.hpp>
  21
  22 namespace boost { namespace geometry
  23 {
  24
  25 #ifndef DOXYGEN_NO_DISPATCH
  26 namespace formula_dispatch
  27 {
  28
  29 template <typename ResultType, typename Geometry, typename Tag = typename tag<Geometry>::type>
  30 struct eccentricity_sqr
  31     : not_implemented<Tag>
  32 {};
  33
  34 template <typename ResultType, typename Geometry>
  35 struct eccentricity_sqr<ResultType, Geometry, srs_sphere_tag>
  36 {
  37     static inline ResultType apply(Geometry const& /*geometry*/)
  38     {
  39         return ResultType(0);
  40     }
  41 };
  42
  43 template <typename ResultType, typename Geometry>
  44 struct eccentricity_sqr<ResultType, Geometry, srs_spheroid_tag>
  45 {
  46     static inline ResultType apply(Geometry const& geometry)
  47     {
  48         // 1 - (b / a)^2
  49         return ResultType(1) - math::sqr(ResultType(get_radius<2>(geometry))
  50                                        / ResultType(get_radius<0>(geometry)));
  51     }
  52 };
  53
  54 } // namespace formula_dispatch
  55 #endif // DOXYGEN_NO_DISPATCH
  56
  57 #ifndef DOXYGEN_NO_DETAIL
  58 namespace formula
  59 {
  60
  61 template <typename ResultType, typename Geometry>
  62 ResultType eccentricity_sqr(Geometry const& geometry)
  63 {
  64     return formula_dispatch::eccentricity_sqr<ResultType, Geometry>::apply(geometry);
  65 }
  66
  67 } // namespace formula
  68 #endif // DOXYGEN_NO_DETAIL
  69
  70 }} // namespace boost::geometry
  71
  72 #endif // BOOST_GEOMETRY_FORMULAS_ECCENCRICITY_SQR_HPP