epoc32/include/stdapis/boost/random/binomial_distribution.hpp
branchSymbian2
changeset 2 2fe1408b6811
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/epoc32/include/stdapis/boost/random/binomial_distribution.hpp	Tue Mar 16 16:12:26 2010 +0000
     1.3 @@ -0,0 +1,81 @@
     1.4 +/* boost random/binomial_distribution.hpp header file
     1.5 + *
     1.6 + * Copyright Jens Maurer 2002
     1.7 + * Distributed under the Boost Software License, Version 1.0. (See
     1.8 + * accompanying file LICENSE_1_0.txt or copy at
     1.9 + * http://www.boost.org/LICENSE_1_0.txt)
    1.10 + *
    1.11 + * See http://www.boost.org for most recent version including documentation.
    1.12 + *
    1.13 + * $Id: binomial_distribution.hpp,v 1.10 2005/06/24 22:13:43 jmaurer Exp $
    1.14 + *
    1.15 + */
    1.16 +
    1.17 +#ifndef BOOST_RANDOM_BINOMIAL_DISTRIBUTION_HPP
    1.18 +#define BOOST_RANDOM_BINOMIAL_DISTRIBUTION_HPP
    1.19 +
    1.20 +#include <cmath>
    1.21 +#include <cassert>
    1.22 +#include <boost/random/bernoulli_distribution.hpp>
    1.23 +
    1.24 +namespace boost {
    1.25 +
    1.26 +// Knuth
    1.27 +template<class IntType = int, class RealType = double>
    1.28 +class binomial_distribution
    1.29 +{
    1.30 +public:
    1.31 +  typedef typename bernoulli_distribution<RealType>::input_type input_type;
    1.32 +  typedef IntType result_type;
    1.33 +
    1.34 +  explicit binomial_distribution(IntType t = 1,
    1.35 +                                 const RealType& p = RealType(0.5))
    1.36 +    : _bernoulli(p), _t(t)
    1.37 +  {
    1.38 +    assert(t >= 0);
    1.39 +    assert(RealType(0) <= 0 && p <= RealType(1));
    1.40 +  }
    1.41 +
    1.42 +  // compiler-generated copy ctor and assignment operator are fine
    1.43 +
    1.44 +  IntType t() const { return _t; }
    1.45 +  RealType p() const { return _bernoulli.p(); }
    1.46 +  void reset() { }
    1.47 +
    1.48 +  template<class Engine>
    1.49 +  result_type operator()(Engine& eng)
    1.50 +  {
    1.51 +    // TODO: This is O(_t), but it should be O(log(_t)) for large _t
    1.52 +    result_type n = 0;
    1.53 +    for(IntType i = 0; i < _t; ++i)
    1.54 +      if(_bernoulli(eng))
    1.55 +        ++n;
    1.56 +    return n;
    1.57 +  }
    1.58 +
    1.59 +#if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
    1.60 +  template<class CharT, class Traits>
    1.61 +  friend std::basic_ostream<CharT,Traits>&
    1.62 +  operator<<(std::basic_ostream<CharT,Traits>& os, const binomial_distribution& bd)
    1.63 +  {
    1.64 +    os << bd._bernoulli << " " << bd._t;
    1.65 +    return os;
    1.66 +  }
    1.67 +
    1.68 +  template<class CharT, class Traits>
    1.69 +  friend std::basic_istream<CharT,Traits>&
    1.70 +  operator>>(std::basic_istream<CharT,Traits>& is, binomial_distribution& bd)
    1.71 +  {
    1.72 +    is >> std::ws >> bd._bernoulli >> std::ws >> bd._t;
    1.73 +    return is;
    1.74 +  }
    1.75 +#endif
    1.76 +
    1.77 +private:
    1.78 +  bernoulli_distribution<RealType> _bernoulli;
    1.79 +  IntType _t;
    1.80 +};
    1.81 +
    1.82 +} // namespace boost
    1.83 +
    1.84 +#endif // BOOST_RANDOM_BINOMIAL_DISTRIBUTION_HPP