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