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/*
* Copyright 2008-2012 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 adjacent_difference.h
* \brief Compute difference between consecutive elements of a range
*/
#pragma once
#include <thrust/detail/config.h>
#include <thrust/detail/dispatchable.h>
namespace thrust
{
template<typename System, typename InputIterator, typename OutputIterator>
OutputIterator adjacent_difference(thrust::detail::dispatchable_base<System> &system,
InputIterator first, InputIterator last,
OutputIterator result);
template<typename System, typename InputIterator, typename OutputIterator, typename BinaryFunction>
OutputIterator adjacent_difference(thrust::detail::dispatchable_base<System> &system,
InputIterator first, InputIterator last,
OutputIterator result,
BinaryFunction binary_op);
/*! \addtogroup transformations Transformations
* \{
*/
/*! \p adjacent_difference calculates the differences of adjacent elements in the
* range <tt>[first, last)</tt>. That is, <tt>*first</tt> is assigned to
* <tt>*result</tt>, and, for each iterator \p i in the range
* <tt>[first + 1, last)</tt>, the difference of <tt>*i</tt> and <tt>*(i - 1)</tt>
* is assigned to <tt>*(result + (i - first))</tt>.
*
* This version of \p adjacent_difference uses <tt>operator-</tt> to calculate
* differences.
*
* \param first The beginning of the input range.
* \param last The end of the input range.
* \param result The beginning of the output range.
* \return The iterator <tt>result + (last - first)</tt>
*
* \tparam InputIterator is a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>,
* and \c x and \c y are objects of \p InputIterator's \c value_type, then \c x - \c is defined,
* and \p InputIterator's \c value_type is convertible to a type in \p OutputIterator's set of \c value_types,
* and the return type of <tt>x - y</tt> is convertible to a type in \p OutputIterator's set of \c value_types.
* \tparam OutputIterator is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
*
* The following code snippet demonstrates how to use \p adjacent_difference to compute
* the difference between adjacent elements of a range.
*
* \code
* #include <thrust/adjacent_difference.h>
* #include <thrust/device_vector.h>
* ...
* int h_data[8] = {1, 2, 1, 2, 1, 2, 1, 2};
* thrust::device_vector<int> d_data(h_data, h_data + 8);
* thrust::device_vector<int> d_result(8);
*
* thrust::adjacent_difference(d_data.begin(), d_data.end(), d_result.begin());
*
* // d_result is now [1, 1, -1, 1, -1, 1, -1, 1]
* \endcode
*
* \see http://www.sgi.com/tech/stl/adjacent_difference.html
* \see inclusive_scan
*
* \note Note that \p result is permitted to be the same iterator as \p first. This is
* useful for computing differences "in place".
*/
template <typename InputIterator, typename OutputIterator>
OutputIterator adjacent_difference(InputIterator first, InputIterator last,
OutputIterator result);
/*! \p adjacent_difference calculates the differences of adjacent elements in the
* range <tt>[first, last)</tt>. That is, <tt>*first</tt> is assigned to
* <tt>*result</tt>, and, for each iterator \p i in the range
* <tt>[first + 1, last)</tt>, <tt>binary_op(*i, *(i - 1))</tt> is assigned to
* <tt>*(result + (i - first))</tt>.
*
* This version of \p adjacent_difference uses the binary function \p binary_op to
* calculate differences.
*
* \param first The beginning of the input range.
* \param last The end of the input range.
* \param result The beginning of the output range.
* \param binary_op The binary function used to compute differences.
* \return The iterator <tt>result + (last - first)</tt>
*
* \tparam InputIterator is a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>,
* and \p InputIterator's \c value_type is convertible to \p BinaryFunction's \c first_argument_type and \c second_argument_type,
* and \p InputIterator's \c value_type is convertible to a type in \p OutputIterator's set of \c value_types.
* \tparam OutputIterator is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
* \tparam BinaryFunction's \c result_type is convertible to a type in \p OutputIterator's set of \c value_types.
*
* The following code snippet demonstrates how to use \p adjacent_difference to compute
* the sum between adjacent elements of a range.
*
* \code
* #include <thrust/adjacent_difference.h>
* #include <thrust/functional.h>
* #include <thrust/device_vector.h>
* ...
* int h_data[8] = {1, 2, 1, 2, 1, 2, 1, 2};
* thrust::device_vector<int> d_data(h_data, h_data + 8);
* thrust::device_vector<int> d_result(8);
*
* thrust::adjacent_difference(d_data.begin(), d_data.end(), d_result.begin(), thrust::plus<int>());
*
* // d_data is now [1, 3, 3, 3, 3, 3, 3, 3]
* \endcode
*
* \see http://www.sgi.com/tech/stl/adjacent_difference.html
* \see inclusive_scan
*
* \note Note that \p result is permitted to be the same iterator as \p first. This is
* useful for computing differences "in place".
*/
template <typename InputIterator, typename OutputIterator, typename BinaryFunction>
OutputIterator adjacent_difference(InputIterator first, InputIterator last,
OutputIterator result,
BinaryFunction binary_op);
/*! \}
*/
} // end namespace thrust
#include <thrust/detail/adjacent_difference.inl>
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