ceph/src/boost/libs/geometry/include/boost/geometry/arithmetic/cross_product.hpp

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2
   3 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
   4 // Copyright (c) 2008-2012 Barend Gehrels, Amsterdam, the Netherlands.
   5 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
   6
   7 // This file was modified by Oracle on 2016.
   8 // Modifications copyright (c) 2016, Oracle and/or its affiliates.
   9 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
  10
  11 // Use, modification and distribution is subject to the Boost Software License,
  12 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  13 // http://www.boost.org/LICENSE_1_0.txt)
  14
  15 #ifndef BOOST_GEOMETRY_ARITHMETIC_CROSS_PRODUCT_HPP
  16 #define BOOST_GEOMETRY_ARITHMETIC_CROSS_PRODUCT_HPP
  17
  18
  19 #include <cstddef>
  20
  21 #include <boost/mpl/assert.hpp>
  22 #include <boost/mpl/size_t.hpp>
  23
  24 #include <boost/geometry/core/access.hpp>
  25 #include <boost/geometry/core/coordinate_dimension.hpp>
  26
  27 #include <boost/geometry/geometries/concepts/point_concept.hpp>
  28
  29
  30 namespace boost { namespace geometry
  31 {
  32
  33 #ifndef DOXYGEN_NO_DETAIL
  34 namespace detail
  35 {
  36
  37 template <std::size_t Dimension>
  38 struct cross_product
  39 {
  40     // We define cross product only for 2d (see Wolfram) and 3d.
  41     // In Math, it is also well-defined for 7-dimension.
  42     // Generalisation of cross product to n-dimension is defined as
  43     // wedge product but it is not direct analogue to binary cross product.
  44     BOOST_MPL_ASSERT_MSG((false),
  45                          NOT_IMPLEMENTED_FOR_THIS_DIMENSION,
  46                          (mpl::size_t<Dimension>));
  47 };
  48
  49 template <>
  50 struct cross_product<2>
  51 {
  52     template <typename P1, typename P2, typename ResultP>
  53     static inline void apply(P1 const& p1, P2 const& p2, ResultP& result)
  54     {
  55         assert_dimension<P1, 2>();
  56         assert_dimension<P2, 2>();
  57         assert_dimension<ResultP, 2>();
  58
  59         // For 2-dimensions, analog of the cross product U(x,y) and V(x,y) is
  60         // Ux * Vy - Uy * Vx
  61         // which is returned as 0-component (or X) of 2d vector, 1-component is undefined.
  62         set<0>(result, get<0>(p1) * get<1>(p2) - get<1>(p1) * get<0>(p2));
  63     }
  64 };
  65
  66 template <>
  67 struct cross_product<3>
  68 {
  69     template <typename P1, typename P2, typename ResultP>
  70     static inline void apply(P1 const& p1, P2 const& p2, ResultP& result)
  71     {
  72         assert_dimension<P1, 3>();
  73         assert_dimension<P2, 3>();
  74         assert_dimension<ResultP, 3>();
  75
  76         set<0>(result, get<1>(p1) * get<2>(p2) - get<2>(p1) * get<1>(p2));
  77         set<1>(result, get<2>(p1) * get<0>(p2) - get<0>(p1) * get<2>(p2));
  78         set<2>(result, get<0>(p1) * get<1>(p2) - get<1>(p1) * get<0>(p2));
  79     }
  80 };
  81
  82 } // namespace detail
  83 #endif // DOXYGEN_NO_DETAIL
  84
  85
  86 /*!
  87 \brief Computes the cross product of two vectors.
  88 \details All vectors should have the same dimension, 3 or 2.
  89 \ingroup arithmetic
  90 \param p1 first vector
  91 \param p2 second vector
  92 \return the cross product vector
  93  */
  94 template <typename ResultP, typename P1, typename P2>
  95 inline ResultP cross_product(P1 const& p1, P2 const& p2)
  96 {
  97     BOOST_CONCEPT_ASSERT( (concepts::Point<ResultP>) );
  98     BOOST_CONCEPT_ASSERT( (concepts::ConstPoint<P1>) );
  99     BOOST_CONCEPT_ASSERT( (concepts::ConstPoint<P2>) );
 100
 101     ResultP result;
 102     detail::cross_product<dimension<ResultP>::value>::apply(p1, p2, result);
 103     return result;
 104 }
 105
 106 /*!
 107 \brief Computes the cross product of two vectors.
 108 \details All vectors should have the same dimension, 3 or 2.
 109 \ingroup arithmetic
 110 \param p1 first vector
 111 \param p2 second vector
 112 \return the cross product vector
 113 */
 114 template <typename P>
 115 inline P cross_product(P const& p1, P const& p2)
 116 {
 117     BOOST_CONCEPT_ASSERT((concepts::Point<P>));
 118     BOOST_CONCEPT_ASSERT((concepts::ConstPoint<P>));
 119
 120     P result;
 121     detail::cross_product<dimension<P>::value>::apply(p1, p2, result);
 122     return result;
 123 }
 124
 125
 126 }} // namespace boost::geometry
 127
 128 #endif // BOOST_GEOMETRY_ARITHMETIC_CROSS_PRODUCT_HPP