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153 lines
4.1 KiB
153 lines
4.1 KiB
/* |
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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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/*! \file scan.h |
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* \brief Sequential implementations of scan functions. |
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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/system/cpp/detail/execution_policy.h> |
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#include <thrust/iterator/iterator_traits.h> |
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#include <thrust/detail/type_traits.h> |
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#include <thrust/detail/type_traits/function_traits.h> |
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#include <thrust/detail/type_traits/iterator/is_output_iterator.h> |
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#include <thrust/detail/function.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 detail |
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{ |
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namespace internal |
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{ |
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namespace scalar |
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{ |
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template<typename InputIterator, |
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typename OutputIterator, |
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typename BinaryFunction> |
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OutputIterator inclusive_scan(InputIterator first, |
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InputIterator last, |
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OutputIterator result, |
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BinaryFunction binary_op) |
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{ |
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// the pseudocode for deducing the type of the temporary used below: |
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// |
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// if BinaryFunction is AdaptableBinaryFunction |
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// TemporaryType = AdaptableBinaryFunction::result_type |
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// else if OutputIterator is a "pure" output iterator |
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// TemporaryType = InputIterator::value_type |
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// else |
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// TemporaryType = OutputIterator::value_type |
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// |
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// XXX upon c++0x, TemporaryType needs to be: |
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// result_of<BinaryFunction>::type |
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using namespace thrust::detail; |
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typedef typename eval_if< |
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has_result_type<BinaryFunction>::value, |
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result_type<BinaryFunction>, |
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eval_if< |
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is_output_iterator<OutputIterator>::value, |
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thrust::iterator_value<InputIterator>, |
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thrust::iterator_value<OutputIterator> |
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> |
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>::type ValueType; |
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// wrap binary_op |
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thrust::detail::host_function< |
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BinaryFunction, |
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ValueType |
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> wrapped_binary_op(binary_op); |
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if(first != last) |
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{ |
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ValueType sum = *first; |
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*result = sum; |
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for(++first, ++result; first != last; ++first, ++result) |
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*result = sum = wrapped_binary_op(sum,*first); |
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} |
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return result; |
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} |
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template<typename InputIterator, |
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typename OutputIterator, |
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typename T, |
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typename BinaryFunction> |
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OutputIterator exclusive_scan(InputIterator first, |
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InputIterator last, |
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OutputIterator result, |
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T init, |
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BinaryFunction binary_op) |
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{ |
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// the pseudocode for deducing the type of the temporary used below: |
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// |
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// if BinaryFunction is AdaptableBinaryFunction |
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// TemporaryType = AdaptableBinaryFunction::result_type |
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// else if OutputIterator is a "pure" output iterator |
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// TemporaryType = InputIterator::value_type |
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// else |
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// TemporaryType = OutputIterator::value_type |
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// |
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// XXX upon c++0x, TemporaryType needs to be: |
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// result_of<BinaryFunction>::type |
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using namespace thrust::detail; |
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typedef typename eval_if< |
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has_result_type<BinaryFunction>::value, |
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result_type<BinaryFunction>, |
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eval_if< |
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is_output_iterator<OutputIterator>::value, |
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thrust::iterator_value<InputIterator>, |
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thrust::iterator_value<OutputIterator> |
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> |
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>::type ValueType; |
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if(first != last) |
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{ |
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ValueType tmp = *first; // temporary value allows in-situ scan |
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ValueType sum = init; |
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*result = sum; |
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sum = binary_op(sum, tmp); |
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for(++first, ++result; first != last; ++first, ++result) |
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{ |
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tmp = *first; |
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*result = sum; |
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sum = binary_op(sum, tmp); |
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} |
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} |
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return result; |
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} |
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} // end namespace scalar |
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} // end namespace internal |
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} // end namespace detail |
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} // end namespace system |
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} // end namespace thrust |
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