120 lines
3.6 KiB
Plaintext
120 lines
3.6 KiB
Plaintext
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//---------------------------------------------------------------------------//
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// Copyright (c) 2014 Roshan <thisisroshansmail@gmail.com>
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//
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// Distributed under the Boost Software License, Version 1.0
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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// See http://boostorg.github.com/compute for more information.
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//---------------------------------------------------------------------------//
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#ifndef BOOST_COMPUTE_RANDOM_UNIFORM_INT_DISTRIBUTION_HPP
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#define BOOST_COMPUTE_RANDOM_UNIFORM_INT_DISTRIBUTION_HPP
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#include <limits>
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#include <boost/type_traits.hpp>
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#include <boost/static_assert.hpp>
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#include <boost/compute/command_queue.hpp>
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#include <boost/compute/container/vector.hpp>
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#include <boost/compute/function.hpp>
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#include <boost/compute/types/fundamental.hpp>
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#include <boost/compute/algorithm/copy_if.hpp>
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#include <boost/compute/algorithm/transform.hpp>
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namespace boost {
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namespace compute {
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/// \class uniform_int_distribution
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/// \brief Produces uniformily distributed random integers
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///
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/// The following example shows how to setup a uniform int distribution to
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/// produce random integers 0 and 1.
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///
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/// \snippet test/test_uniform_int_distribution.cpp generate
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///
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template<class IntType = uint_>
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class uniform_int_distribution
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{
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public:
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typedef IntType result_type;
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/// Creates a new uniform distribution producing numbers in the range
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/// [\p a, \p b].
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explicit uniform_int_distribution(IntType a = 0,
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IntType b = (std::numeric_limits<IntType>::max)())
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: m_a(a),
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m_b(b)
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{
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}
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/// Destroys the uniform_int_distribution object.
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~uniform_int_distribution()
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{
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}
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/// Returns the minimum value of the distribution.
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result_type a() const
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{
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return m_a;
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}
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/// Returns the maximum value of the distribution.
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result_type b() const
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{
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return m_b;
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}
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/// Generates uniformily distributed integers and stores
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/// them to the range [\p first, \p last).
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template<class OutputIterator, class Generator>
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void generate(OutputIterator first,
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OutputIterator last,
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Generator &generator,
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command_queue &queue)
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{
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size_t size = std::distance(first, last);
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typedef typename Generator::result_type g_result_type;
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vector<g_result_type> tmp(size, queue.get_context());
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vector<g_result_type> tmp2(size, queue.get_context());
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uint_ bound = ((uint_(-1))/(m_b-m_a+1))*(m_b-m_a+1);
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buffer_iterator<g_result_type> tmp2_iter;
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while(size>0)
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{
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generator.generate(tmp.begin(), tmp.begin() + size, queue);
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tmp2_iter = copy_if(tmp.begin(), tmp.begin() + size, tmp2.begin(),
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_1 <= bound, queue);
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size = std::distance(tmp2_iter, tmp2.end());
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}
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BOOST_COMPUTE_FUNCTION(IntType, scale_random, (const g_result_type x),
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{
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return LO + (x % (HI-LO+1));
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});
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scale_random.define("LO", boost::lexical_cast<std::string>(m_a));
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scale_random.define("HI", boost::lexical_cast<std::string>(m_b));
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transform(tmp2.begin(), tmp2.end(), first, scale_random, queue);
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}
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private:
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IntType m_a;
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IntType m_b;
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BOOST_STATIC_ASSERT_MSG(
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boost::is_integral<IntType>::value,
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"Template argument must be integral"
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);
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};
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} // end compute namespace
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} // end boost namespace
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#endif // BOOST_COMPUTE_RANDOM_UNIFORM_INT_DISTRIBUTION_HPP
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