123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687 |
- //---------------------------------------------------------------------------//
- // Copyright (c) 2013 Kyle Lutz <kyle.r.lutz@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_ALGORITHM_DETAIL_COUNT_IF_WITH_REDUCE_HPP
- #define BOOST_COMPUTE_ALGORITHM_DETAIL_COUNT_IF_WITH_REDUCE_HPP
- #include <boost/compute/algorithm/reduce.hpp>
- #include <boost/compute/iterator/transform_iterator.hpp>
- #include <boost/compute/types/fundamental.hpp>
- namespace boost {
- namespace compute {
- namespace detail {
- template<class Predicate, class Arg>
- struct invoked_countable_predicate
- {
- invoked_countable_predicate(Predicate p, Arg a)
- : predicate(p), arg(a)
- {
- }
- Predicate predicate;
- Arg arg;
- };
- template<class Predicate, class Arg>
- inline meta_kernel& operator<<(meta_kernel &kernel,
- const invoked_countable_predicate<Predicate, Arg> &expr)
- {
- return kernel << "(" << expr.predicate(expr.arg) << " ? 1 : 0)";
- }
- // the countable_predicate wraps Predicate and converts its result from
- // bool to ulong so that it can be used with reduce()
- template<class Predicate>
- struct countable_predicate
- {
- typedef ulong_ result_type;
- countable_predicate(Predicate predicate)
- : m_predicate(predicate)
- {
- }
- template<class Arg>
- invoked_countable_predicate<Predicate, Arg> operator()(const Arg &arg) const
- {
- return invoked_countable_predicate<Predicate, Arg>(m_predicate, arg);
- }
- Predicate m_predicate;
- };
- // counts the number of elements matching predicate using reduce()
- template<class InputIterator, class Predicate>
- inline size_t count_if_with_reduce(InputIterator first,
- InputIterator last,
- Predicate predicate,
- command_queue &queue)
- {
- countable_predicate<Predicate> reduce_predicate(predicate);
- ulong_ count = 0;
- ::boost::compute::reduce(
- ::boost::compute::make_transform_iterator(first, reduce_predicate),
- ::boost::compute::make_transform_iterator(last, reduce_predicate),
- &count,
- ::boost::compute::plus<ulong_>(),
- queue
- );
- return static_cast<size_t>(count);
- }
- } // end detail namespace
- } // end compute namespace
- } // end boost namespace
- #endif // BOOST_COMPUTE_ALGORITHM_DETAIL_COUNT_IF_WITH_REDUCE_HPP
|