mirror of
https://github.com/ecency/ecency-mobile.git
synced 2024-12-22 12:51:42 +03:00
284 lines
8.9 KiB
C++
284 lines
8.9 KiB
C++
/* boost random/additive_combine.hpp header file
|
|
*
|
|
* Copyright Jens Maurer 2000-2001
|
|
* 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.
|
|
*
|
|
* $Id$
|
|
*
|
|
* Revision history
|
|
* 2001-02-18 moved to individual header files
|
|
*/
|
|
|
|
#ifndef BOOST_RANDOM_ADDITIVE_COMBINE_HPP
|
|
#define BOOST_RANDOM_ADDITIVE_COMBINE_HPP
|
|
|
|
#include <istream>
|
|
#include <iosfwd>
|
|
#include <algorithm> // for std::min and std::max
|
|
#include <boost/config.hpp>
|
|
#include <boost/cstdint.hpp>
|
|
#include <boost/random/detail/config.hpp>
|
|
#include <boost/random/detail/operators.hpp>
|
|
#include <boost/random/detail/seed.hpp>
|
|
#include <boost/random/linear_congruential.hpp>
|
|
|
|
namespace boost {
|
|
namespace random {
|
|
|
|
/**
|
|
* An instantiation of class template @c additive_combine_engine models a
|
|
* \pseudo_random_number_generator. It combines two multiplicative
|
|
* \linear_congruential_engine number generators, i.e. those with @c c = 0.
|
|
* It is described in
|
|
*
|
|
* @blockquote
|
|
* "Efficient and Portable Combined Random Number Generators", Pierre L'Ecuyer,
|
|
* Communications of the ACM, Vol. 31, No. 6, June 1988, pp. 742-749, 774
|
|
* @endblockquote
|
|
*
|
|
* The template parameters MLCG1 and MLCG2 shall denote two different
|
|
* \linear_congruential_engine number generators, each with c = 0. Each
|
|
* invocation returns a random number
|
|
* X(n) := (MLCG1(n) - MLCG2(n)) mod (m1 - 1),
|
|
* where m1 denotes the modulus of MLCG1.
|
|
*/
|
|
template<class MLCG1, class MLCG2>
|
|
class additive_combine_engine
|
|
{
|
|
public:
|
|
typedef MLCG1 first_base;
|
|
typedef MLCG2 second_base;
|
|
typedef typename MLCG1::result_type result_type;
|
|
|
|
// Required by old Boost.Random concept
|
|
BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
|
|
/**
|
|
* Returns the smallest value that the generator can produce
|
|
*/
|
|
static result_type min BOOST_PREVENT_MACRO_SUBSTITUTION ()
|
|
{ return 1; }
|
|
/**
|
|
* Returns the largest value that the generator can produce
|
|
*/
|
|
static result_type max BOOST_PREVENT_MACRO_SUBSTITUTION ()
|
|
{ return MLCG1::modulus-1; }
|
|
|
|
/**
|
|
* Constructs an @c additive_combine_engine using the
|
|
* default constructors of the two base generators.
|
|
*/
|
|
additive_combine_engine() : _mlcg1(), _mlcg2() { }
|
|
/**
|
|
* Constructs an @c additive_combine_engine, using seed as
|
|
* the constructor argument for both base generators.
|
|
*/
|
|
BOOST_RANDOM_DETAIL_ARITHMETIC_CONSTRUCTOR(additive_combine_engine,
|
|
result_type, seed_arg)
|
|
{
|
|
_mlcg1.seed(seed_arg);
|
|
_mlcg2.seed(seed_arg);
|
|
}
|
|
/**
|
|
* Constructs an @c additive_combine_engine, using seq as
|
|
* the constructor argument for both base generators.
|
|
*
|
|
* @xmlwarning
|
|
* The semantics of this function are liable to change.
|
|
* A @c seed_seq is designed to generate all the seeds
|
|
* in one shot, but this seeds the two base engines
|
|
* independantly and probably ends up giving the same
|
|
* sequence to both.
|
|
* @endxmlwarning
|
|
*/
|
|
BOOST_RANDOM_DETAIL_SEED_SEQ_CONSTRUCTOR(additive_combine_engine,
|
|
SeedSeq, seq)
|
|
{
|
|
_mlcg1.seed(seq);
|
|
_mlcg2.seed(seq);
|
|
}
|
|
/**
|
|
* Constructs an @c additive_combine_engine, using
|
|
* @c seed1 and @c seed2 as the constructor argument to
|
|
* the first and second base generators, respectively.
|
|
*/
|
|
additive_combine_engine(typename MLCG1::result_type seed1,
|
|
typename MLCG2::result_type seed2)
|
|
: _mlcg1(seed1), _mlcg2(seed2) { }
|
|
/**
|
|
* Contructs an @c additive_combine_engine with
|
|
* values from the range defined by the input iterators first
|
|
* and last. first will be modified to point to the element
|
|
* after the last one used.
|
|
*
|
|
* Throws: @c std::invalid_argument if the input range is too small.
|
|
*
|
|
* Exception Safety: Basic
|
|
*/
|
|
template<class It> additive_combine_engine(It& first, It last)
|
|
: _mlcg1(first, last), _mlcg2(first, last) { }
|
|
|
|
/**
|
|
* Seeds an @c additive_combine_engine using the default
|
|
* seeds of the two base generators.
|
|
*/
|
|
void seed()
|
|
{
|
|
_mlcg1.seed();
|
|
_mlcg2.seed();
|
|
}
|
|
|
|
/**
|
|
* Seeds an @c additive_combine_engine, using @c seed as the
|
|
* seed for both base generators.
|
|
*/
|
|
BOOST_RANDOM_DETAIL_ARITHMETIC_SEED(additive_combine_engine,
|
|
result_type, seed_arg)
|
|
{
|
|
_mlcg1.seed(seed_arg);
|
|
_mlcg2.seed(seed_arg);
|
|
}
|
|
|
|
/**
|
|
* Seeds an @c additive_combine_engine, using @c seq to
|
|
* seed both base generators.
|
|
*
|
|
* See the warning on the corresponding constructor.
|
|
*/
|
|
BOOST_RANDOM_DETAIL_SEED_SEQ_SEED(additive_combine_engine,
|
|
SeedSeq, seq)
|
|
{
|
|
_mlcg1.seed(seq);
|
|
_mlcg2.seed(seq);
|
|
}
|
|
|
|
/**
|
|
* Seeds an @c additive_combine generator, using @c seed1 and @c seed2 as
|
|
* the seeds to the first and second base generators, respectively.
|
|
*/
|
|
void seed(typename MLCG1::result_type seed1,
|
|
typename MLCG2::result_type seed2)
|
|
{
|
|
_mlcg1.seed(seed1);
|
|
_mlcg2.seed(seed2);
|
|
}
|
|
|
|
/**
|
|
* Seeds an @c additive_combine_engine with
|
|
* values from the range defined by the input iterators first
|
|
* and last. first will be modified to point to the element
|
|
* after the last one used.
|
|
*
|
|
* Throws: @c std::invalid_argument if the input range is too small.
|
|
*
|
|
* Exception Safety: Basic
|
|
*/
|
|
template<class It> void seed(It& first, It last)
|
|
{
|
|
_mlcg1.seed(first, last);
|
|
_mlcg2.seed(first, last);
|
|
}
|
|
|
|
/** Returns the next value of the generator. */
|
|
result_type operator()() {
|
|
result_type val1 = _mlcg1();
|
|
result_type val2 = _mlcg2();
|
|
if(val2 < val1) return val1 - val2;
|
|
else return val1 - val2 + MLCG1::modulus - 1;
|
|
}
|
|
|
|
/** 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)
|
|
{
|
|
_mlcg1.discard(z);
|
|
_mlcg2.discard(z);
|
|
}
|
|
|
|
/**
|
|
* Writes the state of an @c additive_combine_engine to a @c
|
|
* std::ostream. The textual representation of an @c
|
|
* additive_combine_engine is the textual representation of
|
|
* the first base generator followed by the textual representation
|
|
* of the second base generator.
|
|
*/
|
|
BOOST_RANDOM_DETAIL_OSTREAM_OPERATOR(os, additive_combine_engine, r)
|
|
{ os << r._mlcg1 << ' ' << r._mlcg2; return os; }
|
|
|
|
/**
|
|
* Reads the state of an @c additive_combine_engine from a
|
|
* @c std::istream.
|
|
*/
|
|
BOOST_RANDOM_DETAIL_ISTREAM_OPERATOR(is, additive_combine_engine, r)
|
|
{ is >> r._mlcg1 >> std::ws >> r._mlcg2; return is; }
|
|
|
|
/**
|
|
* Returns: true iff the two @c additive_combine_engines will
|
|
* produce the same sequence of values.
|
|
*/
|
|
BOOST_RANDOM_DETAIL_EQUALITY_OPERATOR(additive_combine_engine, x, y)
|
|
{ return x._mlcg1 == y._mlcg1 && x._mlcg2 == y._mlcg2; }
|
|
/**
|
|
* Returns: true iff the two @c additive_combine_engines will
|
|
* produce different sequences of values.
|
|
*/
|
|
BOOST_RANDOM_DETAIL_INEQUALITY_OPERATOR(additive_combine_engine)
|
|
|
|
private:
|
|
MLCG1 _mlcg1;
|
|
MLCG2 _mlcg2;
|
|
};
|
|
|
|
#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
|
|
template<class MLCG1, class MLCG2>
|
|
const bool additive_combine_engine<MLCG1, MLCG2>::has_fixed_range;
|
|
#endif
|
|
|
|
/// \cond show_deprecated
|
|
|
|
/** Provided for backwards compatibility. */
|
|
template<class MLCG1, class MLCG2, typename MLCG1::result_type val = 0>
|
|
class additive_combine : public additive_combine_engine<MLCG1, MLCG2>
|
|
{
|
|
typedef additive_combine_engine<MLCG1, MLCG2> base_t;
|
|
public:
|
|
typedef typename base_t::result_type result_type;
|
|
additive_combine() {}
|
|
template<class T>
|
|
additive_combine(T& arg) : base_t(arg) {}
|
|
template<class T>
|
|
additive_combine(const T& arg) : base_t(arg) {}
|
|
template<class It>
|
|
additive_combine(It& first, It last) : base_t(first, last) {}
|
|
};
|
|
|
|
/// \endcond
|
|
|
|
/**
|
|
* The specialization \ecuyer1988 was suggested in
|
|
*
|
|
* @blockquote
|
|
* "Efficient and Portable Combined Random Number Generators", Pierre L'Ecuyer,
|
|
* Communications of the ACM, Vol. 31, No. 6, June 1988, pp. 742-749, 774
|
|
* @endblockquote
|
|
*/
|
|
typedef additive_combine_engine<
|
|
linear_congruential_engine<uint32_t, 40014, 0, 2147483563>,
|
|
linear_congruential_engine<uint32_t, 40692, 0, 2147483399>
|
|
> ecuyer1988;
|
|
|
|
} // namespace random
|
|
|
|
using random::ecuyer1988;
|
|
|
|
} // namespace boost
|
|
|
|
#endif // BOOST_RANDOM_ADDITIVE_COMBINE_HPP
|