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73 lines
2.4 KiB
73 lines
2.4 KiB
11 years ago
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/*
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* Copyright 2008-2012 NVIDIA Corporation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <thrust/detail/config.h>
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#include <thrust/iterator/iterator_traits.h>
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#include <thrust/system/omp/detail/reduce.h>
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#include <thrust/system/omp/detail/default_decomposition.h>
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#include <thrust/system/omp/detail/reduce_intervals.h>
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namespace thrust
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{
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namespace system
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{
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namespace omp
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{
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namespace detail
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{
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template<typename DerivedPolicy,
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typename InputIterator,
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typename OutputType,
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typename BinaryFunction>
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OutputType reduce(execution_policy<DerivedPolicy> &exec,
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InputIterator first,
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InputIterator last,
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OutputType init,
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BinaryFunction binary_op)
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{
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typedef typename thrust::iterator_difference<InputIterator>::type difference_type;
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const difference_type n = thrust::distance(first,last);
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// determine first and second level decomposition
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thrust::system::detail::internal::uniform_decomposition<difference_type> decomp1 = thrust::system::omp::detail::default_decomposition(n);
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thrust::system::detail::internal::uniform_decomposition<difference_type> decomp2(decomp1.size() + 1, 1, 1);
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// allocate storage for the initializer and partial sums
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// XXX use select_system for Tag
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thrust::detail::temporary_array<OutputType,DerivedPolicy> partial_sums(exec, decomp1.size() + 1);
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// set first element of temp array to init
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partial_sums[0] = init;
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// accumulate partial sums (first level reduction)
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thrust::system::omp::detail::reduce_intervals(exec, first, partial_sums.begin() + 1, binary_op, decomp1);
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// reduce partial sums (second level reduction)
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thrust::system::omp::detail::reduce_intervals(exec, partial_sums.begin(), partial_sums.begin(), binary_op, decomp2);
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return partial_sums[0];
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} // end reduce()
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} // end detail
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} // end omp
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} // end system
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} // end thrust
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