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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 transform_scan.h
* \brief Fused transform / prefix-sum
*/
#pragma once
#include <thrust/detail/config.h>
#include <thrust/detail/dispatchable.h>
namespace thrust
{
template<typename System,
typename InputIterator,
typename OutputIterator,
typename UnaryFunction,
typename AssociativeOperator>
OutputIterator transform_inclusive_scan(thrust::detail::dispatchable_base<System> &system,
InputIterator first,
InputIterator last,
OutputIterator result,
UnaryFunction unary_op,
AssociativeOperator binary_op);
template<typename System,
typename InputIterator,
typename OutputIterator,
typename UnaryFunction,
typename T,
typename AssociativeOperator>
OutputIterator transform_exclusive_scan(thrust::detail::dispatchable_base<System> &system,
InputIterator first,
InputIterator last,
OutputIterator result,
UnaryFunction unary_op,
T init,
AssociativeOperator binary_op);
/*! \addtogroup algorithms
*/
/*! \addtogroup prefixsums Prefix Sums
* \ingroup algorithms
* \{
*/
/*! \addtogroup transformed_prefixsums Transformed Prefix Sums
* \ingroup prefixsums
* \{
*/
/*! \p transform_inclusive_scan fuses the \p transform and \p inclusive_scan
* operations. \p transform_inclusive_scan is equivalent to performing a
* tranformation defined by \p unary_op into a temporary sequence and then
* performing an \p inclusive_scan on the tranformed sequence. In most
* cases, fusing these two operations together is more efficient, since
* fewer memory reads and writes are required. In \p transform_inclusive_scan,
* <tt>unary_op(*first)</tt> is assigned to <tt>*result</tt> and the result
* of <tt>binary_op(unary_op(*first), unary_op(*(first + 1)))</tt> is
* assigned to <tt>*(result + 1)</tt>, and so on. The transform scan
* operation is permitted to be in-place.
*
* \param first The beginning of the input sequence.
* \param last The end of the input sequence.
* \param result The beginning of the output sequence.
* \param unary_op The function used to tranform the input sequence.
* \param binary_op The associatve operator used to 'sum' transformed values.
* \return The end of the output sequence.
*
* \tparam InputIterator is a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>
* and \c InputIterator's \c value_type is convertible to \c unary_op's input type.
* \tparam OutputIterator is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
* \tparam UnaryFunction is a model of <a href="http://www.sgi.com/tech/stl/UnaryFunction.html">Unary Function</a>
* and accepts inputs of \c InputIterator's \c value_type. \c UnaryFunction's result_type
* is convertable to \c OutputIterator's \c value_type.
* \tparam AssociativeOperator is a model of <a href="http://www.sgi.com/tech/stl/BinaryFunction.html">Binary Function</a>
* and \c AssociativeOperator's \c result_type is
* convertible to \c OutputIterator's \c value_type.
*
* The following code snippet demonstrates how to use \p transform_inclusive_scan
*
* \code
* #include <thrust/transform_scan.h>
*
* int data[6] = {1, 0, 2, 2, 1, 3};
*
* thrust::negate<int> unary_op;
* thrust::plus<int> binary_op;
*
* thrust::transform_inclusive_scan(data, data + 6, data, unary_op, binary_op); // in-place scan
*
* // data is now {-1, -1, -3, -5, -6, -9}
* \endcode
*
* \see \p transform
* \see \p inclusive_scan
*
*/
template<typename InputIterator,
typename OutputIterator,
typename UnaryFunction,
typename AssociativeOperator>
OutputIterator transform_inclusive_scan(InputIterator first,
InputIterator last,
OutputIterator result,
UnaryFunction unary_op,
AssociativeOperator binary_op);
/*! \p transform_exclusive_scan fuses the \p transform and \p exclusive_scan
* operations. \p transform_exclusive_scan is equivalent to performing a
* tranformation defined by \p unary_op into a temporary sequence and then
* performing an \p exclusive_scan on the tranformed sequence. In most
* cases, fusing these two operations together is more efficient, since
* fewer memory reads and writes are required. In
* \p transform_exclusive_scan, \p init is assigned to <tt>*result</tt>
* and the result of <tt>binary_op(init, unary_op(*first))</tt> is assigned
* to <tt>*(result + 1)</tt>, and so on. The transform scan operation is
* permitted to be in-place.
*
* \param first The beginning of the input sequence.
* \param last The end of the input sequence.
* \param result The beginning of the output sequence.
* \param unary_op The function used to tranform the input sequence.
* \param init The initial value of the \p exclusive_scan
* \param binary_op The associatve operator used to 'sum' transformed values.
* \return The end of the output sequence.
*
* \tparam InputIterator is a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>
* and \c InputIterator's \c value_type is convertible to \c unary_op's input type.
* \tparam OutputIterator is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
* \tparam UnaryFunction is a model of <a href="http://www.sgi.com/tech/stl/UnaryFunction.html">Unary Function</a>
* and accepts inputs of \c InputIterator's \c value_type. \c UnaryFunction's result_type
* is convertable to \c OutputIterator's \c value_type.
* \tparam T is convertible to \c OutputIterator's \c value_type.
* \tparam AssociativeOperator is a model of <a href="http://www.sgi.com/tech/stl/BinaryFunction.html">Binary Function</a>
* and \c AssociativeOperator's \c result_type is
* convertible to \c OutputIterator's \c value_type.
*
* The following code snippet demonstrates how to use \p transform_exclusive_scan
*
* \code
* #include <thrust/transform_scan.h>
*
* int data[6] = {1, 0, 2, 2, 1, 3};
*
* thrust::negate<int> unary_op;
* thrust::plus<int> binary_op;
*
* thrust::transform_exclusive_scan(data, data + 6, data, unary_op, 4, binary_op); // in-place scan
*
* // data is now {4, 3, 3, 1, -1, -2}
* \endcode
*
* \see \p transform
* \see \p exclusive_scan
*
*/
template<typename InputIterator,
typename OutputIterator,
typename UnaryFunction,
typename T,
typename AssociativeOperator>
OutputIterator transform_exclusive_scan(InputIterator first,
InputIterator last,
OutputIterator result,
UnaryFunction unary_op,
T init,
AssociativeOperator binary_op);
/*! \} // end transformed_prefixsums
*/
/*! \} // end prefixsums
*/
} // end namespace thrust
#include <thrust/detail/transform_scan.inl>
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