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/*
* Copyright 2008-2013 NVIDIA Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*! \file scan.h
* \brief Sequential implementations of scan functions.
*/
#pragma once
#include <thrust/detail/config.h>
#include <thrust/system/detail/sequential/execution_policy.h>
#include <thrust/iterator/iterator_traits.h>
#include <thrust/detail/type_traits.h>
#include <thrust/detail/type_traits/function_traits.h>
#include <thrust/detail/type_traits/iterator/is_output_iterator.h>
#include <thrust/detail/function.h>
THRUST_NAMESPACE_BEGIN
namespace system
{
namespace detail
{
namespace sequential
{
__thrust_exec_check_disable__
template<typename DerivedPolicy,
typename InputIterator,
typename OutputIterator,
typename BinaryFunction>
__host__ __device__
OutputIterator inclusive_scan(sequential::execution_policy<DerivedPolicy> &,
InputIterator first,
InputIterator last,
OutputIterator result,
BinaryFunction binary_op)
{
using namespace thrust::detail;
// Use the input iterator's value type per https://wg21.link/P0571
using ValueType = typename thrust::iterator_value<InputIterator>::type;
// wrap binary_op
thrust::detail::wrapped_function<
BinaryFunction,
ValueType
> wrapped_binary_op(binary_op);
if(first != last)
{
ValueType sum = *first;
*result = *first;
for(++first, ++result; first != last; ++first, ++result)
*result = sum = wrapped_binary_op(sum,*first);
}
return result;
}
__thrust_exec_check_disable__
template<typename DerivedPolicy,
typename InputIterator,
typename OutputIterator,
typename InitialValueType,
typename BinaryFunction>
__host__ __device__
OutputIterator exclusive_scan(sequential::execution_policy<DerivedPolicy> &,
InputIterator first,
InputIterator last,
OutputIterator result,
InitialValueType init,
BinaryFunction binary_op)
{
using namespace thrust::detail;
// Use the initial value type per https://wg21.link/P0571
using ValueType = InitialValueType;
if(first != last)
{
ValueType tmp = *first; // temporary value allows in-situ scan
ValueType sum = init;
*result = sum;
sum = binary_op(sum, tmp);
for(++first, ++result; first != last; ++first, ++result)
{
tmp = *first;
*result = sum;
sum = binary_op(sum, tmp);
}
}
return result;
}
} // end namespace sequential
} // end namespace detail
} // end namespace system
THRUST_NAMESPACE_END
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