comparison DEPENDENCIES/generic/include/boost/random/xor_combine.hpp @ 16:2665513ce2d3

Add boost headers

+/* boost random/xor_combine.hpp header file
+ *
+ * Copyright Jens Maurer 2002
+ * 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: xor_combine.hpp 71018 2011-04-05 21:27:52Z steven_watanabe $
+ *
+ */
+
+#ifndef BOOST_RANDOM_XOR_COMBINE_HPP
+#define BOOST_RANDOM_XOR_COMBINE_HPP
+
+#include <istream>
+#include <iosfwd>
+#include <cassert>
+#include <algorithm> // for std::min and std::max
+#include <boost/config.hpp>
+#include <boost/limits.hpp>
+#include <boost/cstdint.hpp>     // uint32_t
+#include <boost/random/detail/config.hpp>
+#include <boost/random/detail/seed.hpp>
+#include <boost/random/detail/seed_impl.hpp>
+
+namespace boost {
+namespace random {
+
+/**
+ * Instantiations of @c xor_combine_engine model a
+ * \pseudo_random_number_generator.  To produce its output it
+ * invokes each of the base generators, shifts their results
+ * and xors them together.
+ */
+template<class URNG1, int s1, class URNG2, int s2>
+class xor_combine_engine
+{
+public:
+    typedef URNG1 base1_type;
+    typedef URNG2 base2_type;
+    typedef typename base1_type::result_type result_type;
+
+    BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
+    BOOST_STATIC_CONSTANT(int, shift1 = s1);
+    BOOST_STATIC_CONSTANT(int, shift2 = s2);
+
+    /**
+     * Constructors a @c xor_combine_engine by default constructing
+     * both base generators.
+     */
+    xor_combine_engine() : _rng1(), _rng2() { }
+
+    /** Constructs a @c xor_combine by copying two base generators. */
+    xor_combine_engine(const base1_type & rng1, const base2_type & rng2)
+      : _rng1(rng1), _rng2(rng2) { }
+
+    /**
+     * Constructs a @c xor_combine_engine, seeding both base generators
+     * with @c v.
+     *
+     * @xmlwarning
+     * The exact algorithm used by this function may change in the future.
+     * @endxmlwarning
+     */
+    BOOST_RANDOM_DETAIL_ARITHMETIC_CONSTRUCTOR(xor_combine_engine,
+        result_type, v)
+    { seed(v); }
+
+    /**
+     * Constructs a @c xor_combine_engine, seeding both base generators
+     * with values produced by @c seq.
+     */
+    BOOST_RANDOM_DETAIL_SEED_SEQ_CONSTRUCTOR(xor_combine_engine,
+        SeedSeq, seq)
+    { seed(seq); }
+
+    /**
+     * Constructs a @c xor_combine_engine, seeding both base generators
+     * with values from the iterator range [first, last) and changes
+     * first to point to the element after the last one used.  If there
+     * are not enough elements in the range to seed both generators,
+     * throws @c std::invalid_argument.
+     */
+    template<class It> xor_combine_engine(It& first, It last)
+      : _rng1(first, last), _rng2( /* advanced by other call */ first, last) { }
+
+    /** Calls @c seed() for both base generators. */
+    void seed() { _rng1.seed(); _rng2.seed(); }
+
+    /** @c seeds both base generators with @c v. */
+    BOOST_RANDOM_DETAIL_ARITHMETIC_SEED(xor_combine_engine, result_type, v)
+    { _rng1.seed(v); _rng2.seed(v); }
+
+    /** @c seeds both base generators with values produced by @c seq. */
+    BOOST_RANDOM_DETAIL_SEED_SEQ_SEED(xor_combine_engine, SeedSeq, seq)
+    { _rng1.seed(seq); _rng2.seed(seq); }
+
+    /**
+     * seeds both base generators with values from the iterator
+     * range [first, last) and changes first to point to the element
+     * after the last one used.  If there are not enough elements in
+     * the range to seed both generators, throws @c std::invalid_argument.
+     */
+    template<class It> void seed(It& first, It last)
+    {
+        _rng1.seed(first, last);
+        _rng2.seed(first, last);
+    }
+
+    /** Returns the first base generator. */
+    const base1_type& base1() const { return _rng1; }
+
+    /** Returns the second base generator. */
+    const base2_type& base2() const { return _rng2; }
+
+    /** Returns the next value of the generator. */
+    result_type operator()()
+    {
+        return (_rng1() << s1) ^ (_rng2() << s2);
+    }
+  
+    /** Fills a range with random values */
+    template<class Iter>
+    void generate(Iter first, Iter last)
+    { detail::generate_from_int(*this, first, last); }
+
+    /** Advances the state of the generator by @c z. */
+    void discard(boost::uintmax_t z)
+    {
+        _rng1.discard(z);
+        _rng2.discard(z);
+    }
+
+    /** Returns the smallest value that the generator can produce. */
+    static result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () { return (std::min)((URNG1::min)(), (URNG2::min)()); }
+    /** Returns the largest value that the generator can produce. */
+    static result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () { return (std::max)((URNG1::min)(), (URNG2::max)()); }
+
+    /**
+     * Writes the textual representation of the generator to a @c std::ostream.
+     */
+    BOOST_RANDOM_DETAIL_OSTREAM_OPERATOR(os, xor_combine_engine, s)
+    {
+        os << s._rng1 << ' ' << s._rng2;
+        return os;
+    }
+    
+    /**
+     * Reads the textual representation of the generator from a @c std::istream.
+     */
+    BOOST_RANDOM_DETAIL_ISTREAM_OPERATOR(is, xor_combine_engine, s)
+    {
+        is >> s._rng1 >> std::ws >> s._rng2;
+        return is;
+    }
+    
+    /** Returns true if the two generators will produce identical sequences. */
+    BOOST_RANDOM_DETAIL_EQUALITY_OPERATOR(xor_combine_engine, x, y)
+    { return x._rng1 == y._rng1 && x._rng2 == y._rng2; }
+    
+    /** Returns true if the two generators will produce different sequences. */
+    BOOST_RANDOM_DETAIL_INEQUALITY_OPERATOR(xor_combine_engine)
+
+private:
+    base1_type _rng1;
+    base2_type _rng2;
+};
+
+#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
+//  A definition is required even for integral static constants
+template<class URNG1, int s1, class URNG2, int s2>
+const bool xor_combine_engine<URNG1, s1, URNG2, s2>::has_fixed_range;
+template<class URNG1, int s1, class URNG2, int s2>
+const int xor_combine_engine<URNG1, s1, URNG2, s2>::shift1;
+template<class URNG1, int s1, class URNG2, int s2>
+const int xor_combine_engine<URNG1, s1, URNG2, s2>::shift2;
+#endif
+
+/// \cond show_private
+
+/** Provided for backwards compatibility. */
+template<class URNG1, int s1, class URNG2, int s2,
+    typename URNG1::result_type v = 0>
+class xor_combine : public xor_combine_engine<URNG1, s1, URNG2, s2>
+{
+    typedef xor_combine_engine<URNG1, s1, URNG2, s2> base_type;
+public:
+    typedef typename base_type::result_type result_type;
+    xor_combine() {}
+    xor_combine(result_type val) : base_type(val) {}
+    template<class It>
+    xor_combine(It& first, It last) : base_type(first, last) {}
+    xor_combine(const URNG1 & rng1, const URNG2 & rng2)
+      : base_type(rng1, rng2) { }
+
+    result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return (std::min)((this->base1().min)(), (this->base2().min)()); }
+    result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return (std::max)((this->base1().min)(), (this->base2().max)()); }
+};
+
+/// \endcond
+
+} // namespace random
+} // namespace boost
+
+#endif // BOOST_RANDOM_XOR_COMBINE_HPP