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147 lines
3.8 KiB
147 lines
3.8 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_by_key.h |
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* \brief Sequential implementation of scan_by_key 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/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 InputIterator1, |
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typename InputIterator2, |
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typename OutputIterator, |
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typename BinaryPredicate, |
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typename BinaryFunction> |
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OutputIterator inclusive_scan_by_key(InputIterator1 first1, |
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InputIterator1 last1, |
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InputIterator2 first2, |
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OutputIterator result, |
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BinaryPredicate binary_pred, |
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BinaryFunction binary_op) |
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{ |
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using namespace thrust::detail; |
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typedef typename thrust::iterator_traits<InputIterator1>::value_type KeyType; |
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typedef typename thrust::iterator_traits<OutputIterator>::value_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(first1 != last1) |
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{ |
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KeyType prev_key = *first1; |
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ValueType prev_value = *first2; |
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*result = prev_value; |
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for(++first1, ++first2, ++result; |
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first1 != last1; |
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++first1, ++first2, ++result) |
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{ |
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KeyType key = *first1; |
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if (binary_pred(prev_key, key)) |
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*result = prev_value = wrapped_binary_op(prev_value,*first2); |
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else |
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*result = prev_value = *first2; |
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prev_key = key; |
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} |
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} |
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return result; |
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} |
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template<typename InputIterator1, |
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typename InputIterator2, |
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typename OutputIterator, |
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typename T, |
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typename BinaryPredicate, |
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typename BinaryFunction> |
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OutputIterator exclusive_scan_by_key(InputIterator1 first1, |
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InputIterator1 last1, |
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InputIterator2 first2, |
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OutputIterator result, |
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T init, |
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BinaryPredicate binary_pred, |
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BinaryFunction binary_op) |
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{ |
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using namespace thrust::detail; |
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typedef typename thrust::iterator_traits<InputIterator1>::value_type KeyType; |
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typedef typename thrust::iterator_traits<OutputIterator>::value_type ValueType; |
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if(first1 != last1) |
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{ |
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KeyType temp_key = *first1; |
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ValueType temp_value = *first2; |
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ValueType next = init; |
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// first one is init |
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*result = next; |
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next = binary_op(next, temp_value); |
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for(++first1, ++first2, ++result; |
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first1 != last1; |
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++first1, ++first2, ++result) |
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{ |
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KeyType key = *first1; |
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// use temp to permit in-place scans |
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temp_value = *first2; |
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if (!binary_pred(temp_key, key)) |
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next = init; // reset sum |
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*result = next; |
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next = binary_op(next, temp_value); |
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temp_key = key; |
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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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