87 lines
2.4 KiB
C++
Executable File
87 lines
2.4 KiB
C++
Executable File
/* boost random/uniform_on_sphere.hpp header file
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*
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* Copyright Jens Maurer 2000-2001
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* Distributed under the Boost Software License, Version 1.0. (See
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* accompanying file LICENSE_1_0.txt or copy at
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* http://www.boost.org/LICENSE_1_0.txt)
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*
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* See http://www.boost.org for most recent version including documentation.
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*
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* $Id: uniform_on_sphere.hpp 24096 2004-07-27 03:43:34Z dgregor $
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*
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* Revision history
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* 2001-02-18 moved to individual header files
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*/
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#ifndef BOOST_RANDOM_UNIFORM_ON_SPHERE_HPP
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#define BOOST_RANDOM_UNIFORM_ON_SPHERE_HPP
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#include <vector>
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#include <algorithm> // std::transform
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#include <functional> // std::bind2nd, std::divides
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#include <boost/random/normal_distribution.hpp>
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namespace boost {
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template<class RealType = double, class Cont = std::vector<RealType> >
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class uniform_on_sphere
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{
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public:
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typedef RealType input_type;
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typedef Cont result_type;
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explicit uniform_on_sphere(int dim = 2) : _container(dim), _dim(dim) { }
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// compiler-generated copy ctor and assignment operator are fine
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void reset() { _normal.reset(); }
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template<class Engine>
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const result_type & operator()(Engine& eng)
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{
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RealType sqsum = 0;
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for(typename Cont::iterator it = _container.begin();
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it != _container.end();
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++it) {
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RealType val = _normal(eng);
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*it = val;
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sqsum += val * val;
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}
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#ifndef BOOST_NO_STDC_NAMESPACE
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using std::sqrt;
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#endif
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// for all i: result[i] /= sqrt(sqsum)
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std::transform(_container.begin(), _container.end(), _container.begin(),
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std::bind2nd(std::divides<RealType>(), sqrt(sqsum)));
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return _container;
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}
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#if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
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template<class CharT, class Traits>
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friend std::basic_ostream<CharT,Traits>&
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operator<<(std::basic_ostream<CharT,Traits>& os, const uniform_on_sphere& sd)
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{
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os << sd._dim;
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return os;
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}
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template<class CharT, class Traits>
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friend std::basic_istream<CharT,Traits>&
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operator>>(std::basic_istream<CharT,Traits>& is, uniform_on_sphere& sd)
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{
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is >> std::ws >> sd._dim;
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sd._container.resize(sd._dim);
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return is;
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}
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#endif
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private:
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normal_distribution<RealType> _normal;
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result_type _container;
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int _dim;
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};
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} // namespace boost
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#endif // BOOST_RANDOM_UNIFORM_ON_SPHERE_HPP
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