epoc32/include/stdapis/boost/random/geometric_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/geometric_distribution.hpp	Tue Mar 16 16:12:26 2010 +0000
     1.3 @@ -0,0 +1,97 @@
     1.4 +/* boost random/geometric_distribution.hpp header file
     1.5 + *
     1.6 + * Copyright Jens Maurer 2000-2001
     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: geometric_distribution.hpp,v 1.16 2004/07/27 03:43:32 dgregor Exp $
    1.14 + *
    1.15 + * Revision history
    1.16 + *  2001-02-18  moved to individual header files
    1.17 + */
    1.18 +
    1.19 +#ifndef BOOST_RANDOM_GEOMETRIC_DISTRIBUTION_HPP
    1.20 +#define BOOST_RANDOM_GEOMETRIC_DISTRIBUTION_HPP
    1.21 +
    1.22 +#include <cmath>          // std::log
    1.23 +#include <cassert>
    1.24 +#include <iostream>
    1.25 +#include <boost/random/uniform_01.hpp>
    1.26 +
    1.27 +namespace boost {
    1.28 +
    1.29 +#if defined(__GNUC__) && (__GNUC__ < 3)
    1.30 +// Special gcc workaround: gcc 2.95.x ignores using-declarations
    1.31 +// in template classes (confirmed by gcc author Martin v. Loewis)
    1.32 +  using std::log;
    1.33 +#endif
    1.34 +
    1.35 +// geometric distribution: p(i) = (1-p) * pow(p, i-1)   (integer)
    1.36 +template<class IntType = int, class RealType = double>
    1.37 +class geometric_distribution
    1.38 +{
    1.39 +public:
    1.40 +  typedef RealType input_type;
    1.41 +  typedef IntType result_type;
    1.42 +
    1.43 +  explicit geometric_distribution(const RealType& p = RealType(0.5))
    1.44 +    : _p(p)
    1.45 +  {
    1.46 +    assert(RealType(0) < p && p < RealType(1));
    1.47 +    init();
    1.48 +  }
    1.49 +
    1.50 +  // compiler-generated copy ctor and assignment operator are fine
    1.51 +
    1.52 +  RealType p() const { return _p; }
    1.53 +  void reset() { }
    1.54 +
    1.55 +  template<class Engine>
    1.56 +  result_type operator()(Engine& eng)
    1.57 +  {
    1.58 +#ifndef BOOST_NO_STDC_NAMESPACE
    1.59 +    using std::log;
    1.60 +    using std::floor;
    1.61 +#endif
    1.62 +    return IntType(floor(log(RealType(1)-eng()) / _log_p)) + IntType(1);
    1.63 +  }
    1.64 +
    1.65 +#if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
    1.66 +  template<class CharT, class Traits>
    1.67 +  friend std::basic_ostream<CharT,Traits>&
    1.68 +  operator<<(std::basic_ostream<CharT,Traits>& os, const geometric_distribution& gd)
    1.69 +  {
    1.70 +    os << gd._p;
    1.71 +    return os;
    1.72 +  }
    1.73 +
    1.74 +  template<class CharT, class Traits>
    1.75 +  friend std::basic_istream<CharT,Traits>&
    1.76 +  operator>>(std::basic_istream<CharT,Traits>& is, geometric_distribution& gd)
    1.77 +  {
    1.78 +    is >> std::ws >> gd._p;
    1.79 +    gd.init();
    1.80 +    return is;
    1.81 +  }
    1.82 +#endif
    1.83 +
    1.84 +private:
    1.85 +  void init()
    1.86 +  {
    1.87 +#ifndef BOOST_NO_STDC_NAMESPACE
    1.88 +    using std::log;
    1.89 +#endif
    1.90 +    _log_p = log(_p);
    1.91 +  }
    1.92 +
    1.93 +  RealType _p;
    1.94 +  RealType _log_p;
    1.95 +};
    1.96 +
    1.97 +} // namespace boost
    1.98 +
    1.99 +#endif // BOOST_RANDOM_GEOMETRIC_DISTRIBUTION_HPP
   1.100 +