epoc32/include/stdapis/boost/random/cauchy_distribution.hpp
author William Roberts <williamr@symbian.org>
Wed, 31 Mar 2010 12:33:34 +0100
branchSymbian3
changeset 4 837f303aceeb
permissions -rw-r--r--
Current Symbian^3 public API header files (from PDK 3.0.h)
This is the epoc32/include tree with the "platform" subtrees removed, and
all but a selected few mbg and rsg files removed.
     1 /* boost random/cauchy_distribution.hpp header file
     2  *
     3  * Copyright Jens Maurer 2000-2001
     4  * Distributed under the Boost Software License, Version 1.0. (See
     5  * accompanying file LICENSE_1_0.txt or copy at
     6  * http://www.boost.org/LICENSE_1_0.txt)
     7  *
     8  * See http://www.boost.org for most recent version including documentation.
     9  *
    10  * $Id: cauchy_distribution.hpp,v 1.15 2004/07/27 03:43:32 dgregor Exp $
    11  *
    12  * Revision history
    13  *  2001-02-18  moved to individual header files
    14  */
    15 
    16 #ifndef BOOST_RANDOM_CAUCHY_DISTRIBUTION_HPP
    17 #define BOOST_RANDOM_CAUCHY_DISTRIBUTION_HPP
    18 
    19 #include <cmath>
    20 #include <iostream>
    21 #include <boost/limits.hpp>
    22 #include <boost/static_assert.hpp>
    23 
    24 namespace boost {
    25 
    26 #if defined(__GNUC__) && (__GNUC__ < 3)
    27 // Special gcc workaround: gcc 2.95.x ignores using-declarations
    28 // in template classes (confirmed by gcc author Martin v. Loewis)
    29   using std::tan;
    30 #endif
    31 
    32 // Cauchy distribution: p(x) = sigma/(pi*(sigma**2 + (x-median)**2))
    33 template<class RealType = double>
    34 class cauchy_distribution
    35 {
    36 public:
    37   typedef RealType input_type;
    38   typedef RealType result_type;
    39 
    40 #ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
    41   BOOST_STATIC_ASSERT(!std::numeric_limits<RealType>::is_integer);
    42 #endif
    43 
    44   explicit cauchy_distribution(result_type median = result_type(0), 
    45                                result_type sigma = result_type(1))
    46     : _median(median), _sigma(sigma) { }
    47 
    48   // compiler-generated copy ctor and assignment operator are fine
    49 
    50   result_type median() const { return _median; }
    51   result_type sigma() const { return _sigma; }
    52   void reset() { }
    53 
    54   template<class Engine>
    55   result_type operator()(Engine& eng)
    56   {
    57     // Can we have a boost::mathconst please?
    58     const result_type pi = result_type(3.14159265358979323846);
    59 #ifndef BOOST_NO_STDC_NAMESPACE
    60     using std::tan;
    61 #endif
    62     return _median + _sigma * tan(pi*(eng()-result_type(0.5)));
    63   }
    64 
    65 #if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
    66   template<class CharT, class Traits>
    67   friend std::basic_ostream<CharT,Traits>&
    68   operator<<(std::basic_ostream<CharT,Traits>& os, const cauchy_distribution& cd)
    69   {
    70     os << cd._median << " " << cd._sigma;
    71     return os;
    72   }
    73 
    74   template<class CharT, class Traits>
    75   friend std::basic_istream<CharT,Traits>&
    76   operator>>(std::basic_istream<CharT,Traits>& is, cauchy_distribution& cd)
    77   {
    78     is >> std::ws >> cd._median >> std::ws >> cd._sigma;
    79     return is;
    80   }
    81 #endif
    82 
    83 private:
    84   result_type _median, _sigma;
    85 };
    86 
    87 } // namespace boost
    88 
    89 #endif // BOOST_RANDOM_CAUCHY_DISTRIBUTION_HPP