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150 lines
5.3 KiB
150 lines
5.3 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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#include <thrust/iterator/iterator_traits.h> |
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#include <thrust/detail/temporary_array.h> |
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#include <thrust/system/detail/internal/scalar/merge.h> |
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#include <thrust/system/detail/internal/scalar/insertion_sort.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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namespace detail |
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{ |
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template <typename RandomAccessIterator, |
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typename StrictWeakOrdering> |
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void inplace_merge(RandomAccessIterator first, |
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RandomAccessIterator middle, |
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RandomAccessIterator last, |
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StrictWeakOrdering comp) |
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{ |
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// XXX the type of exec should be: |
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// typedef decltype(select_system(first, middle, last)) DerivedPolicy; |
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typedef typename thrust::iterator_system<RandomAccessIterator>::type DerivedPolicy; |
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typedef typename thrust::iterator_value<RandomAccessIterator>::type value_type; |
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// XXX assumes DerivedPolicy is default constructible |
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// XXX find a way to get a stateful execution policy into this function |
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// or simply pass scratch space |
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DerivedPolicy exec; |
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thrust::detail::temporary_array<value_type, DerivedPolicy> a(exec, first, middle); |
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thrust::detail::temporary_array<value_type, DerivedPolicy> b(exec, middle, last); |
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thrust::system::detail::internal::scalar::merge(a.begin(), a.end(), b.begin(), b.end(), first, comp); |
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} |
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template <typename RandomAccessIterator1, |
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typename RandomAccessIterator2, |
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typename StrictWeakOrdering> |
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void inplace_merge_by_key(RandomAccessIterator1 first1, |
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RandomAccessIterator1 middle1, |
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RandomAccessIterator1 last1, |
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RandomAccessIterator2 first2, |
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StrictWeakOrdering comp) |
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{ |
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// XXX the type of exec should be: |
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// typedef decltype(select_system(first1, middle1, last1, first2)) DerivedPolicy; |
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typedef typename thrust::iterator_system<RandomAccessIterator1>::type DerivedPolicy; |
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typedef typename thrust::iterator_value<RandomAccessIterator1>::type value_type1; |
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typedef typename thrust::iterator_value<RandomAccessIterator2>::type value_type2; |
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RandomAccessIterator2 middle2 = first2 + (middle1 - first1); |
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RandomAccessIterator2 last2 = first2 + (last1 - first1); |
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// XXX assumes DerivedPolicy is default constructible |
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// XXX find a way to get a stateful exec into this function |
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// or simply pass scratch space |
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DerivedPolicy exec; |
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thrust::detail::temporary_array<value_type1, DerivedPolicy> lhs1(exec, first1, middle1); |
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thrust::detail::temporary_array<value_type1, DerivedPolicy> rhs1(exec, middle1, last1); |
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thrust::detail::temporary_array<value_type2, DerivedPolicy> lhs2(exec, first2, middle2); |
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thrust::detail::temporary_array<value_type2, DerivedPolicy> rhs2(exec, middle2, last2); |
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thrust::system::detail::internal::scalar::merge_by_key |
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(lhs1.begin(), lhs1.end(), rhs1.begin(), rhs1.end(), |
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lhs2.begin(), rhs2.begin(), |
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first1, first2, comp); |
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} |
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} // end namespace detail |
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////////////// |
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// Key Sort // |
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////////////// |
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template <typename RandomAccessIterator, |
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typename StrictWeakOrdering> |
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void stable_merge_sort(RandomAccessIterator first, |
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RandomAccessIterator last, |
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StrictWeakOrdering comp) |
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{ |
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if (last - first < 32) |
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{ |
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thrust::system::detail::internal::scalar::insertion_sort(first, last, comp); |
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} |
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else |
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{ |
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RandomAccessIterator middle = first + (last - first) / 2; |
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thrust::system::detail::internal::scalar::stable_merge_sort(first, middle, comp); |
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thrust::system::detail::internal::scalar::stable_merge_sort(middle, last, comp); |
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detail::inplace_merge(first, middle, last, comp); |
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} |
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} |
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//////////////////// |
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// Key-Value Sort // |
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//////////////////// |
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template <typename RandomAccessIterator1, |
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typename RandomAccessIterator2, |
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typename StrictWeakOrdering> |
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void stable_merge_sort_by_key(RandomAccessIterator1 first1, |
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RandomAccessIterator1 last1, |
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RandomAccessIterator2 first2, |
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StrictWeakOrdering comp) |
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{ |
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if (last1 - first1 <= 32) |
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{ |
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thrust::system::detail::internal::scalar::insertion_sort_by_key(first1, last1, first2, comp); |
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} |
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else |
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{ |
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RandomAccessIterator1 middle1 = first1 + (last1 - first1) / 2; |
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RandomAccessIterator2 middle2 = first2 + (last1 - first1) / 2; |
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thrust::system::detail::internal::scalar::stable_merge_sort_by_key(first1, middle1, first2, comp); |
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thrust::system::detail::internal::scalar::stable_merge_sort_by_key(middle1, last1, middle2, comp); |
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detail::inplace_merge_by_key(first1, middle1, last1, first2, comp); |
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} |
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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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