--- /dev/null
+/* boost random/shuffle_order.hpp header file
+ *
+ * Copyright Jens Maurer 2000-2001
+ * Copyright Steven Watanabe 2010
+ * Distributed under the Boost Software License, Version 1.0. (See
+ * accompanying file LICENSE_1_0.txt or copy at
+ * http://www.boost.org/LICENSE_1_0.txt)
+ *
+ * See http://www.boost.org for most recent version including documentation.
+ *
+ * $Id: shuffle_order.hpp 71018 2011-04-05 21:27:52Z steven_watanabe $
+ *
+ */
+
+#ifndef BOOST_RANDOM_SHUFFLE_ORDER_HPP
+#define BOOST_RANDOM_SHUFFLE_ORDER_HPP
+
+#include <iostream>
+#include <algorithm> // std::copy
+#include <cassert>
+#include <boost/config.hpp>
+#include <boost/limits.hpp>
+#include <boost/static_assert.hpp>
+#include <boost/cstdint.hpp>
+#include <boost/random/detail/operators.hpp>
+#include <boost/random/detail/seed.hpp>
+#include <boost/random/detail/signed_unsigned_tools.hpp>
+#include <boost/random/linear_congruential.hpp>
+
+#include <boost/random/detail/disable_warnings.hpp>
+
+namespace boost {
+namespace random {
+
+/**
+ * Instatiations of class template @c shuffle_order_engine model a
+ * \pseudo_random_number_generator. It mixes the output
+ * of some (usually \linear_congruential_engine)
+ * \uniform_random_number_generator to get better statistical properties.
+ * The algorithm is described in
+ *
+ * @blockquote
+ * "Improving a poor random number generator", Carter Bays
+ * and S.D. Durham, ACM Transactions on Mathematical Software,
+ * Vol 2, No. 1, March 1976, pp. 59-64.
+ * http://doi.acm.org/10.1145/355666.355670
+ * @endblockquote
+ *
+ * The output of the base generator is buffered in an array of
+ * length k. Every output X(n) has a second role: It gives an
+ * index into the array where X(n+1) will be retrieved. Used
+ * array elements are replaced with fresh output from the base
+ * generator.
+ *
+ * Template parameters are the base generator and the array
+ * length k, which should be around 100.
+ */
+template<class UniformRandomNumberGenerator, std::size_t k>
+class shuffle_order_engine
+{
+public:
+ typedef UniformRandomNumberGenerator base_type;
+ typedef typename base_type::result_type result_type;
+
+ BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
+ BOOST_STATIC_CONSTANT(std::size_t, buffer_size = k);
+ BOOST_STATIC_CONSTANT(std::size_t, table_size = k);
+
+ BOOST_STATIC_ASSERT(std::numeric_limits<result_type>::is_integer);
+ BOOST_STATIC_ASSERT(k > 0);
+
+ /**
+ * Constructs a @c shuffle_order_engine by invoking the
+ * default constructor of the base generator.
+ *
+ * Complexity: Exactly k+1 invocations of the base generator.
+ */
+ shuffle_order_engine() : _rng() { init(); }
+ /**
+ * Constructs a @c shuffle_output_engine by invoking the one-argument
+ * constructor of the base generator with the parameter seed.
+ *
+ * Complexity: Exactly k+1 invocations of the base generator.
+ */
+ BOOST_RANDOM_DETAIL_ARITHMETIC_CONSTRUCTOR(shuffle_order_engine,
+ result_type, s)
+ { _rng.seed(s); init(); }
+ BOOST_RANDOM_DETAIL_SEED_SEQ_CONSTRUCTOR(shuffle_order_engine, SeedSeq, seq)
+ { _rng.seed(seq); init(); }
+ /**
+ * Constructs a @c shuffle_output_engine by using a copy
+ * of the provided generator.
+ *
+ * Precondition: The template argument UniformRandomNumberGenerator
+ * shall denote a CopyConstructible type.
+ *
+ * Complexity: Exactly k+1 invocations of the base generator.
+ */
+ explicit shuffle_order_engine(const base_type & rng) : _rng(rng) { init(); }
+
+#ifndef BOOST_NO_RVALUE_REFERENCES
+ explicit shuffle_order_engine(base_type&& rng) : _rng(rng) { init(); }
+#endif
+
+ template<class It> shuffle_order_engine(It& first, It last)
+ : _rng(first, last) { init(); }
+ void seed() { _rng.seed(); init(); }
+ /**
+ * Invokes the one-argument seed method of the base generator
+ * with the parameter seed and re-initializes the internal buffer array.
+ *
+ * Complexity: Exactly k+1 invocations of the base generator.
+ */
+ BOOST_RANDOM_DETAIL_ARITHMETIC_SEED(shuffle_order_engine,
+ result_type, seed_arg)
+ { _rng.seed(seed_arg); init(); }
+ /**
+ * Invokes the one-argument seed method of the base generator
+ * with the parameter seq and re-initializes the internal buffer array.
+ *
+ * Complexity: Exactly k+1 invocations of the base generator.
+ */
+ BOOST_RANDOM_DETAIL_SEED_SEQ_SEED(shuffle_order_engine, SeedSeq, seq)
+ { _rng.seed(seq); init(); }
+ template<class It> void seed(It& first, It last)
+ { _rng.seed(first, last); init(); }
+
+ const base_type& base() const { return _rng; }
+
+ result_type operator()() {
+ // calculating the range every time may seem wasteful. However, this
+ // makes the information locally available for the optimizer.
+ typedef typename make_unsigned<result_type>::type base_unsigned;
+ const base_unsigned brange =
+ detail::subtract<result_type>()((max)(), (min)());
+ const base_unsigned off =
+ detail::subtract<result_type>()(y, (min)());
+
+ base_unsigned j;
+ if(k == 1) {
+ j = 0;
+ } else if(brange < (std::numeric_limits<base_unsigned>::max)() / k) {
+ // try to do it in the native type if we know that it won't
+ // overflow
+ j = k * off / (brange + 1);
+ } else if(brange < (std::numeric_limits<uintmax_t>::max)() / k) {
+ // Otherwise try to use uint64_t
+ j = static_cast<base_unsigned>(
+ static_cast<uintmax_t>(off) * k /
+ (static_cast<uintmax_t>(brange) + 1));
+ } else {
+ boost::uintmax_t divisor =
+ static_cast<boost::uintmax_t>(brange) + 1;
+ j = static_cast<base_unsigned>(detail::muldiv(off, k, divisor));
+ }
+ // assert(0 <= j && j < k);
+ y = v[j];
+ v[j] = _rng();
+ return y;
+ }
+
+ /** Advances the generator by z steps. */
+ void discard(boost::uintmax_t z)
+ {
+ for(boost::uintmax_t j = 0; j < z; ++j) {
+ (*this)();
+ }
+ }
+
+ /** Fills a range with pseudo-random values. */
+ template<class Iter>
+ void generate(Iter first, Iter last)
+ { detail::generate_from_int(*this, first, last); }
+
+ /** Returns the smallest value that the generator can produce. */
+ static result_type min BOOST_PREVENT_MACRO_SUBSTITUTION ()
+ { return (base_type::min)(); }
+ /** Returns the largest value that the generator can produce. */
+ static result_type max BOOST_PREVENT_MACRO_SUBSTITUTION ()
+ { return (base_type::max)(); }
+
+ /** Writes a @c shuffle_order_engine to a @c std::ostream. */
+ BOOST_RANDOM_DETAIL_OSTREAM_OPERATOR(os, shuffle_order_engine, s)
+ {
+ os << s._rng;
+ for(std::size_t i = 0; i < k; ++i)
+ os << ' ' << s.v[i];
+ os << ' ' << s.y;
+ return os;
+ }
+
+ /** Reads a @c shuffle_order_engine from a @c std::istream. */
+ BOOST_RANDOM_DETAIL_ISTREAM_OPERATOR(is, shuffle_order_engine, s)
+ {
+ is >> s._rng;
+ for(std::size_t i = 0; i < k; ++i)
+ is >> std::ws >> s.v[i];
+ is >> std::ws >> s.y;
+ return is;
+ }
+
+ /** Returns true if the two generators will produce identical sequences. */
+ BOOST_RANDOM_DETAIL_EQUALITY_OPERATOR(shuffle_order_engine, x, y)
+ { return x._rng == y._rng && x.y == y.y && std::equal(x.v, x.v+k, y.v); }
+ /** Returns true if the two generators will produce different sequences. */
+ BOOST_RANDOM_DETAIL_INEQUALITY_OPERATOR(shuffle_order_engine)
+
+private:
+
+ /// \cond show_private
+
+ void init()
+ {
+ // we cannot use std::generate, because it uses pass-by-value for _rng
+ for(result_type * p = v; p != v+k; ++p)
+ *p = _rng();
+ y = _rng();
+ }
+
+ /// \endcond
+
+ base_type _rng;
+ result_type v[k];
+ result_type y;
+};
+
+#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
+// A definition is required even for integral static constants
+template<class URNG, std::size_t k>
+const bool shuffle_order_engine<URNG, k>::has_fixed_range;
+template<class URNG, std::size_t k>
+const std::size_t shuffle_order_engine<URNG, k>::table_size;
+template<class URNG, std::size_t k>
+const std::size_t shuffle_order_engine<URNG, k>::buffer_size;
+#endif
+
+/**
+ * According to Harry Erwin (private e-mail), the specialization
+ * @c kreutzer1986 was suggested in:
+ *
+ * @blockquote
+ * "System Simulation: Programming Styles and Languages (International
+ * Computer Science Series)", Wolfgang Kreutzer, Addison-Wesley, December 1986.
+ * @endblockquote
+ */
+typedef shuffle_order_engine<
+ linear_congruential_engine<uint32_t, 1366, 150889, 714025>,
+ 97> kreutzer1986;
+
+/**
+ * The specialization @c knuth_b is specified by the C++ standard.
+ * It is described in
+ *
+ * @blockquote
+ * "The Art of Computer Programming, Second Edition, Volume 2,
+ * Seminumerical Algorithms", Donald Knuth, Addison-Wesley, 1981.
+ * @endblockquote
+ */
+typedef shuffle_order_engine<minstd_rand0, 256> knuth_b;
+
+} // namespace random
+
+using random::kreutzer1986;
+
+} // namespace boost
+
+#include <boost/random/detail/enable_warnings.hpp>
+
+#endif // BOOST_RANDOM_SHUFFLE_OUTPUT_HPP
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