ceph/src/boost/libs/numeric/odeint/examples/my_vector.cpp

   1 /*
   2  * Copyright 2011-2012 Mario Mulansky
   3  * Copyright 2012-2013 Karsten Ahnert
   4  *
   5  * Distributed under the Boost Software License, Version 1.0.
   6  * (See accompanying file LICENSE_1_0.txt or
   7  * copy at http://www.boost.org/LICENSE_1_0.txt)
   8  *
   9  * Example for self defined vector type.
  10  */
  11
  12 #include <vector>
  13
  14 #include <boost/numeric/odeint.hpp>
  15
  16 //[my_vector
  17 template< size_t MAX_N >
  18 class my_vector
  19 {
  20     typedef std::vector< double > vector;
  21
  22 public:
  23     typedef vector::iterator iterator;
  24     typedef vector::const_iterator const_iterator;
  25
  26 public:
  27     my_vector( const size_t N )
  28         : m_v( N )
  29     {
  30         m_v.reserve( MAX_N );
  31     }
  32
  33     my_vector()
  34         : m_v()
  35     {
  36         m_v.reserve( MAX_N );
  37     }
  38
  39 // ... [ implement container interface ]
  40 //]
  41     const double & operator[]( const size_t n ) const
  42     { return m_v[n]; }
  43
  44     double & operator[]( const size_t n )
  45     { return m_v[n]; }
  46
  47     iterator begin()
  48     { return m_v.begin(); }
  49
  50     const_iterator begin() const
  51     { return m_v.begin(); }
  52
  53     iterator end()
  54     { return m_v.end(); }
  55
  56     const_iterator end() const
  57     { return m_v.end(); }
  58
  59     size_t size() const
  60     { return m_v.size(); }
  61
  62     void resize( const size_t n )
  63     { m_v.resize( n ); }
  64
  65 private:
  66     std::vector< double > m_v;
  67
  68 };
  69
  70 //[my_vector_resizeable
  71 // define my_vector as resizeable
  72
  73 namespace boost { namespace numeric { namespace odeint {
  74
  75 template<size_t N>
  76 struct is_resizeable< my_vector<N> >
  77 {
  78     typedef boost::true_type type;
  79     static const bool value = type::value;
  80 };
  81
  82 } } }
  83 //]
  84
  85
  86 typedef my_vector<3> state_type;
  87
  88 void lorenz( const state_type &x , state_type &dxdt , const double t )
  89 {
  90     const double sigma( 10.0 );
  91     const double R( 28.0 );
  92     const double b( 8.0 / 3.0 );
  93
  94     dxdt[0] = sigma * ( x[1] - x[0] );
  95     dxdt[1] = R * x[0] - x[1] - x[0] * x[2];
  96     dxdt[2] = -b * x[2] + x[0] * x[1];
  97 }
  98
  99 using namespace boost::numeric::odeint;
 100
 101 int main()
 102 {
 103     state_type x(3);
 104     x[0] = 5.0 ; x[1] = 10.0 ; x[2] = 10.0;
 105
 106     // make sure resizing is ON
 107     BOOST_STATIC_ASSERT( is_resizeable<state_type>::value == true );
 108
 109     // my_vector works with range_algebra as it implements
 110     // the required parts of a container interface
 111     // no further work is required
 112
 113     integrate_const( runge_kutta4< state_type >() , lorenz , x , 0.0 , 10.0 , 0.1 );
 114 }