sl@0: /* boost random/additive_combine.hpp header file
sl@0:  *
sl@0:  * Copyright Jens Maurer 2000-2001
sl@0:  * Distributed under the Boost Software License, Version 1.0. (See
sl@0:  * accompanying file LICENSE_1_0.txt or copy at
sl@0:  * http://www.boost.org/LICENSE_1_0.txt)
sl@0:  *
sl@0:  * See http://www.boost.org for most recent version including documentation.
sl@0:  *
sl@0:  * $Id: additive_combine.hpp,v 1.11 2005/05/21 15:57:00 dgregor Exp $
sl@0:  *
sl@0:  * Revision history
sl@0:  *  2001-02-18  moved to individual header files
sl@0:  */
sl@0: 
sl@0: #ifndef BOOST_RANDOM_ADDITIVE_COMBINE_HPP
sl@0: #define BOOST_RANDOM_ADDITIVE_COMBINE_HPP
sl@0: 
sl@0: #include <iostream>
sl@0: #include <algorithm> // for std::min and std::max
sl@0: #include <boost/config.hpp>
sl@0: #include <boost/cstdint.hpp>
sl@0: #include <boost/random/linear_congruential.hpp>
sl@0: 
sl@0: namespace boost {
sl@0: namespace random {
sl@0: 
sl@0: // L'Ecuyer 1988
sl@0: template<class MLCG1, class MLCG2,
sl@0: #ifndef BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS
sl@0:   typename MLCG1::result_type 
sl@0: #else
sl@0:   int32_t
sl@0: #endif
sl@0:   val>
sl@0: class additive_combine
sl@0: {
sl@0: public:
sl@0:   typedef MLCG1 first_base;
sl@0:   typedef MLCG2 second_base;
sl@0:   typedef typename MLCG1::result_type result_type;
sl@0: #ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
sl@0:   static const bool has_fixed_range = true;
sl@0:   static const result_type min_value = 1;
sl@0:   static const result_type max_value = MLCG1::max_value-1;
sl@0: #else
sl@0:   enum { has_fixed_range = false };
sl@0: #endif
sl@0:   result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return 1; }
sl@0:   result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return (_mlcg1.max)()-1; }
sl@0: 
sl@0:   additive_combine() : _mlcg1(), _mlcg2() { }
sl@0:   additive_combine(typename MLCG1::result_type seed1, 
sl@0:                    typename MLCG2::result_type seed2)
sl@0:     : _mlcg1(seed1), _mlcg2(seed2) { }
sl@0:   template<class It> additive_combine(It& first, It last)
sl@0:     : _mlcg1(first, last), _mlcg2(first, last) { }
sl@0: 
sl@0:   void seed()
sl@0:   {
sl@0:     _mlcg1.seed();
sl@0:     _mlcg2.seed();
sl@0:   }
sl@0: 
sl@0:   void seed(typename MLCG1::result_type seed1,
sl@0:             typename MLCG2::result_type seed2)
sl@0:   {
sl@0:     _mlcg1(seed1);
sl@0:     _mlcg2(seed2);
sl@0:   }
sl@0: 
sl@0:   template<class It> void seed(It& first, It last)
sl@0:   {
sl@0:     _mlcg1.seed(first, last);
sl@0:     _mlcg2.seed(first, last);
sl@0:   }
sl@0: 
sl@0:   result_type operator()() {
sl@0:     result_type z = _mlcg1() - _mlcg2();
sl@0:     if(z < 1)
sl@0:       z += MLCG1::modulus-1;
sl@0:     return z;
sl@0:   }
sl@0:   static bool validation(result_type x) { return val == x; }
sl@0: 
sl@0: #ifndef BOOST_NO_OPERATORS_IN_NAMESPACE
sl@0: 
sl@0: #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
sl@0:   template<class CharT, class Traits>
sl@0:   friend std::basic_ostream<CharT,Traits>&
sl@0:   operator<<(std::basic_ostream<CharT,Traits>& os, const additive_combine& r)
sl@0:   { os << r._mlcg1 << " " << r._mlcg2; return os; }
sl@0: 
sl@0:   template<class CharT, class Traits>
sl@0:   friend std::basic_istream<CharT,Traits>&
sl@0:   operator>>(std::basic_istream<CharT,Traits>& is, additive_combine& r)
sl@0:   { is >> r._mlcg1 >> std::ws >> r._mlcg2; return is; }
sl@0: #endif
sl@0: 
sl@0:   friend bool operator==(const additive_combine& x, const additive_combine& y)
sl@0:   { return x._mlcg1 == y._mlcg1 && x._mlcg2 == y._mlcg2; }
sl@0:   friend bool operator!=(const additive_combine& x, const additive_combine& y)
sl@0:   { return !(x == y); }
sl@0: #else
sl@0:   // Use a member function; Streamable concept not supported.
sl@0:   bool operator==(const additive_combine& rhs) const
sl@0:   { return _mlcg1 == rhs._mlcg1 && _mlcg2 == rhs._mlcg2; }
sl@0:   bool operator!=(const additive_combine& rhs) const
sl@0:   { return !(*this == rhs); }
sl@0: #endif
sl@0: private:
sl@0:   MLCG1 _mlcg1;
sl@0:   MLCG2 _mlcg2;
sl@0: };
sl@0: 
sl@0: } // namespace random
sl@0: 
sl@0: typedef random::additive_combine<
sl@0:     random::linear_congruential<int32_t, 40014, 0, 2147483563, 0>,
sl@0:     random::linear_congruential<int32_t, 40692, 0, 2147483399, 0>,
sl@0:   2060321752> ecuyer1988;
sl@0: 
sl@0: } // namespace boost
sl@0: 
sl@0: #endif // BOOST_RANDOM_ADDITIVE_COMBINE_HPP