/usr/include/boost/random/triangle_distribution.hpp is in libboost1.46-dev 1.46.1-7ubuntu3.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 | /* boost random/triangle_distribution.hpp header file
*
* Copyright Jens Maurer 2000-2001
* Distributed under the Boost Software License, Version 1.0. (See
* accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*
* See http://www.boost.org for most recent version including documentation.
*
* $Id: triangle_distribution.hpp 60755 2010-03-22 00:45:06Z steven_watanabe $
*
* Revision history
* 2001-02-18 moved to individual header files
*/
#ifndef BOOST_RANDOM_TRIANGLE_DISTRIBUTION_HPP
#define BOOST_RANDOM_TRIANGLE_DISTRIBUTION_HPP
#include <boost/config/no_tr1/cmath.hpp>
#include <cassert>
#include <boost/random/detail/config.hpp>
#include <boost/random/uniform_01.hpp>
namespace boost {
/**
* Instantiations of @c triangle_distribution model a \random_distribution.
* A @c triangle_distribution has three parameters, @c a, @c b, and @c c,
* which are the smallest, the most probable and the largest values of
* the distribution respectively.
*/
template<class RealType = double>
class triangle_distribution
{
public:
typedef RealType input_type;
typedef RealType result_type;
/**
* Constructs a @c triangle_distribution with the parameters
* @c a, @c b, and @c c.
*
* Preconditions: a <= b <= c.
*/
explicit triangle_distribution(result_type a_arg = result_type(0),
result_type b_arg = result_type(0.5),
result_type c_arg = result_type(1))
: _a(a_arg), _b(b_arg), _c(c_arg)
{
assert(_a <= _b && _b <= _c);
init();
}
// compiler-generated copy ctor and assignment operator are fine
/** Returns the @c a parameter of the distribution */
result_type a() const { return _a; }
/** Returns the @c b parameter of the distribution */
result_type b() const { return _b; }
/** Returns the @c c parameter of the distribution */
result_type c() const { return _c; }
void reset() { }
template<class Engine>
result_type operator()(Engine& eng)
{
#ifndef BOOST_NO_STDC_NAMESPACE
using std::sqrt;
#endif
result_type u = eng();
if( u <= q1 )
return _a + p1*sqrt(u);
else
return _c - d3*sqrt(d2*u-d1);
}
#ifndef BOOST_RANDOM_NO_STREAM_OPERATORS
template<class CharT, class Traits>
friend std::basic_ostream<CharT,Traits>&
operator<<(std::basic_ostream<CharT,Traits>& os, const triangle_distribution& td)
{
os << td._a << " " << td._b << " " << td._c;
return os;
}
template<class CharT, class Traits>
friend std::basic_istream<CharT,Traits>&
operator>>(std::basic_istream<CharT,Traits>& is, triangle_distribution& td)
{
is >> std::ws >> td._a >> std::ws >> td._b >> std::ws >> td._c;
td.init();
return is;
}
#endif
private:
/// \cond hide_private_members
void init()
{
#ifndef BOOST_NO_STDC_NAMESPACE
using std::sqrt;
#endif
d1 = _b - _a;
d2 = _c - _a;
d3 = sqrt(_c - _b);
q1 = d1 / d2;
p1 = sqrt(d1 * d2);
}
/// \endcond
result_type _a, _b, _c;
result_type d1, d2, d3, q1, p1;
};
} // namespace boost
#endif // BOOST_RANDOM_TRIANGLE_DISTRIBUTION_HPP
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