//---------------------------------------------------------------------------//
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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_BERNOULLI_DISTRIBUTION_HPP
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#define BOOST_COMPUTE_RANDOM_BERNOULLI_DISTRIBUTION_HPP
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#include <boost/assert.hpp>
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#include <boost/type_traits.hpp>
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#include <boost/compute/command_queue.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/detail/iterator_range_size.hpp>
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#include <boost/compute/detail/literal.hpp>
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namespace boost {
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namespace compute {
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///
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/// \class bernoulli_distribution
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/// \brief Produces random boolean values according to the following
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/// discrete probability function with parameter p :
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/// P(true/p) = p and P(false/p) = (1 - p)
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///
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/// The following example shows how to setup a bernoulli distribution to
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/// produce random boolean values with parameter p = 0.25
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///
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/// \snippet test/test_bernoulli_distribution.cpp generate
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///
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template<class RealType = float>
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class bernoulli_distribution
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{
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public:
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/// Creates a new bernoulli distribution
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bernoulli_distribution(RealType p = 0.5f)
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: m_p(p)
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{
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}
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/// Destroys the bernoulli_distribution object
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~bernoulli_distribution()
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{
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}
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/// Returns the value of the parameter p
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RealType p() const
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{
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return m_p;
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}
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/// Generates bernoulli distributed booleans and stores
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/// them in 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 count = detail::iterator_range_size(first, last);
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vector<uint_> tmp(count, queue.get_context());
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generator.generate(tmp.begin(), tmp.end(), queue);
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BOOST_COMPUTE_FUNCTION(bool, scale_random, (const uint_ x),
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{
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return (convert_RealType(x) / MAX_RANDOM) < PARAM;
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});
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scale_random.define("PARAM", detail::make_literal(m_p));
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scale_random.define("MAX_RANDOM", "UINT_MAX");
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scale_random.define(
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"convert_RealType", std::string("convert_") + type_name<RealType>()
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);
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transform(
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tmp.begin(), tmp.end(), first, scale_random, queue
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);
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}
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private:
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RealType m_p;
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BOOST_STATIC_ASSERT_MSG(
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boost::is_floating_point<RealType>::value,
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"Template argument must be a floating point type"
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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_BERNOULLI_DISTRIBUTION_HPP
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