sl@0: /* boost random/inversive_congruential.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: inversive_congruential.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_INVERSIVE_CONGRUENTIAL_HPP
sl@0: #define BOOST_RANDOM_INVERSIVE_CONGRUENTIAL_HPP
sl@0: 
sl@0: #include <iostream>
sl@0: #include <cassert>
sl@0: #include <boost/config.hpp>
sl@0: #include <boost/static_assert.hpp>
sl@0: #include <boost/random/detail/const_mod.hpp>
sl@0: 
sl@0: namespace boost {
sl@0: namespace random {
sl@0: 
sl@0: // Eichenauer and Lehn 1986
sl@0: template<class IntType, IntType a, IntType b, IntType p, IntType val>
sl@0: class inversive_congruential
sl@0: {
sl@0: public:
sl@0:   typedef IntType 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 = (b == 0 ? 1 : 0);
sl@0:   static const result_type max_value = p-1;
sl@0: #else
sl@0:   BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
sl@0: #endif
sl@0:   BOOST_STATIC_CONSTANT(result_type, multiplier = a);
sl@0:   BOOST_STATIC_CONSTANT(result_type, increment = b);
sl@0:   BOOST_STATIC_CONSTANT(result_type, modulus = p);
sl@0: 
sl@0:   result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return b == 0 ? 1 : 0; }
sl@0:   result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return p-1; }
sl@0: 
sl@0:   explicit inversive_congruential(IntType y0 = 1) : value(y0)
sl@0:   {
sl@0:     BOOST_STATIC_ASSERT(b >= 0);
sl@0:     BOOST_STATIC_ASSERT(p > 1);
sl@0:     BOOST_STATIC_ASSERT(a >= 1);
sl@0:     if(b == 0) 
sl@0:       assert(y0 > 0); 
sl@0:   }
sl@0:   template<class It> inversive_congruential(It& first, It last)
sl@0:   { seed(first, last); }
sl@0: 
sl@0:   void seed(IntType y0 = 1) { value = y0; if(b == 0) assert(y0 > 0); }
sl@0:   template<class It> void seed(It& first, It last)
sl@0:   {
sl@0:     if(first == last)
sl@0:       throw std::invalid_argument("inversive_congruential::seed");
sl@0:     value = *first++;
sl@0:   }
sl@0:   IntType operator()()
sl@0:   {
sl@0:     typedef const_mod<IntType, p> do_mod;
sl@0:     value = do_mod::mult_add(a, do_mod::invert(value), b);
sl@0:     return value;
sl@0:   }
sl@0: 
sl@0:   bool validation(result_type x) const { 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, inversive_congruential x)
sl@0:   { os << x.value; 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, inversive_congruential& x)
sl@0:   { is >> x.value; return is; }
sl@0: #endif
sl@0: 
sl@0:   friend bool operator==(inversive_congruential x, inversive_congruential y)
sl@0:   { return x.value == y.value; }
sl@0:   friend bool operator!=(inversive_congruential x, inversive_congruential y)
sl@0:   { return !(x == y); }
sl@0: #else
sl@0:   // Use a member function; Streamable concept not supported.
sl@0:   bool operator==(inversive_congruential rhs) const
sl@0:   { return value == rhs.value; }
sl@0:   bool operator!=(inversive_congruential rhs) const
sl@0:   { return !(*this == rhs); }
sl@0: #endif
sl@0: private:
sl@0:   IntType value;
sl@0: };
sl@0: 
sl@0: #ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
sl@0: //  A definition is required even for integral static constants
sl@0: template<class IntType, IntType a, IntType b, IntType p, IntType val>
sl@0: const bool inversive_congruential<IntType, a, b, p, val>::has_fixed_range;
sl@0: template<class IntType, IntType a, IntType b, IntType p, IntType val>
sl@0: const typename inversive_congruential<IntType, a, b, p, val>::result_type inversive_congruential<IntType, a, b, p, val>::min_value;
sl@0: template<class IntType, IntType a, IntType b, IntType p, IntType val>
sl@0: const typename inversive_congruential<IntType, a, b, p, val>::result_type inversive_congruential<IntType, a, b, p, val>::max_value;
sl@0: template<class IntType, IntType a, IntType b, IntType p, IntType val>
sl@0: const typename inversive_congruential<IntType, a, b, p, val>::result_type inversive_congruential<IntType, a, b, p, val>::multiplier;
sl@0: template<class IntType, IntType a, IntType b, IntType p, IntType val>
sl@0: const typename inversive_congruential<IntType, a, b, p, val>::result_type inversive_congruential<IntType, a, b, p, val>::increment;
sl@0: template<class IntType, IntType a, IntType b, IntType p, IntType val>
sl@0: const typename inversive_congruential<IntType, a, b, p, val>::result_type inversive_congruential<IntType, a, b, p, val>::modulus;
sl@0: #endif
sl@0: 
sl@0: } // namespace random
sl@0: 
sl@0: typedef random::inversive_congruential<int32_t, 9102, 2147483647-36884165,
sl@0:   2147483647, 0> hellekalek1995;
sl@0: 
sl@0: } // namespace boost
sl@0: 
sl@0: #endif // BOOST_RANDOM_INVERSIVE_CONGRUENTIAL_HPP