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68 lines
1.8 KiB
68 lines
1.8 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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#pragma once
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#include <thrust/detail/config.h>
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#include <thrust/iterator/iterator_traits.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 cuda
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{
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namespace detail
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{
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namespace block
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{
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/* Reduces [data, data + n) using binary_op and stores the result in data[0]
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*
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* Upon return the elements in [data + 1, data + n) have unspecified values.
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*/
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template <typename Context, typename ValueIterator, typename BinaryFunction>
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__device__ __thrust_forceinline__
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void reduce_n(Context context, ValueIterator data, unsigned int n, BinaryFunction binary_op)
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{
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if (context.block_dimension() < n)
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{
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for (unsigned int i = context.block_dimension() + context.thread_index(); i < n; i += context.block_dimension())
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data[context.thread_index()] = binary_op(data[context.thread_index()], data[i]);
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context.barrier();
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}
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while (n > 1)
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{
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unsigned int half = n / 2;
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if (context.thread_index() < half)
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data[context.thread_index()] = binary_op(data[context.thread_index()], data[n - context.thread_index() - 1]);
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context.barrier();
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n = n - half;
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}
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}
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} // end namespace block
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} // end namespace detail
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} // end namespace cuda
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} // end namespace system
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} // end namespace thrust
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