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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 scan.h
* \brief Functions for computing prefix sums
*/
#pragma once
#include <thrust/detail/config.h>
#include <thrust/detail/dispatchable.h>
namespace thrust
{
template<typename System,
typename InputIterator,
typename OutputIterator>
OutputIterator inclusive_scan(thrust::detail::dispatchable_base<System> &system,
InputIterator first,
InputIterator last,
OutputIterator result);
template<typename System,
typename InputIterator,
typename OutputIterator,
typename AssociativeOperator>
OutputIterator inclusive_scan(thrust::detail::dispatchable_base<System> &system,
InputIterator first,
InputIterator last,
OutputIterator result,
AssociativeOperator binary_op);
template<typename System,
typename InputIterator,
typename OutputIterator>
OutputIterator exclusive_scan(thrust::detail::dispatchable_base<System> &system,
InputIterator first,
InputIterator last,
OutputIterator result);
template<typename System,
typename InputIterator,
typename OutputIterator,
typename T>
OutputIterator exclusive_scan(thrust::detail::dispatchable_base<System> &system,
InputIterator first,
InputIterator last,
OutputIterator result,
T init);
template<typename System,
typename InputIterator,
typename OutputIterator,
typename T,
typename AssociativeOperator>
OutputIterator exclusive_scan(thrust::detail::dispatchable_base<System> &system,
InputIterator first,
InputIterator last,
OutputIterator result,
T init,
AssociativeOperator binary_op);
template<typename System,
typename InputIterator1,
typename InputIterator2,
typename OutputIterator>
OutputIterator inclusive_scan_by_key(thrust::detail::dispatchable_base<System> &system,
InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result);
template<typename System,
typename InputIterator1,
typename InputIterator2,
typename OutputIterator,
typename BinaryPredicate>
OutputIterator inclusive_scan_by_key(thrust::detail::dispatchable_base<System> &system,
InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result,
BinaryPredicate binary_pred);
template<typename System,
typename InputIterator1,
typename InputIterator2,
typename OutputIterator,
typename BinaryPredicate,
typename AssociativeOperator>
OutputIterator inclusive_scan_by_key(thrust::detail::dispatchable_base<System> &system,
InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result,
BinaryPredicate binary_pred,
AssociativeOperator binary_op);
template<typename System,
typename InputIterator1,
typename InputIterator2,
typename OutputIterator>
OutputIterator exclusive_scan_by_key(thrust::detail::dispatchable_base<System> &system,
InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result);
template<typename System,
typename InputIterator1,
typename InputIterator2,
typename OutputIterator,
typename T>
OutputIterator exclusive_scan_by_key(thrust::detail::dispatchable_base<System> &system,
InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result,
T init);
template<typename System,
typename InputIterator1,
typename InputIterator2,
typename OutputIterator,
typename T,
typename BinaryPredicate>
OutputIterator exclusive_scan_by_key(thrust::detail::dispatchable_base<System> &system,
InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result,
T init,
BinaryPredicate binary_pred);
template<typename System,
typename InputIterator1,
typename InputIterator2,
typename OutputIterator,
typename T,
typename BinaryPredicate,
typename AssociativeOperator>
OutputIterator exclusive_scan_by_key(thrust::detail::dispatchable_base<System> &system,
InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result,
T init,
BinaryPredicate binary_pred,
AssociativeOperator binary_op);
/*! \addtogroup algorithms
*/
/*! \addtogroup prefixsums Prefix Sums
* \ingroup algorithms
* \{
*/
/*! \p inclusive_scan computes an inclusive prefix sum operation. The
* term 'inclusive' means that each result includes the corresponding
* input operand in the partial sum. More precisely, <tt>*first</tt> is
* assigned to <tt>*result</tt> and the sum of <tt>*first</tt> and
* <tt>*(first + 1)</tt> is assigned to <tt>*(result + 1)</tt>, and so on.
* This version of \p inclusive_scan assumes plus as the associative operator.
* When the input and output sequences are the same, the scan is performed
* in-place.
* \p inclusive_scan is similar to \c std::partial_sum in the STL. The primary
* difference between the two functions is that \c std::partial_sum guarantees
* a serial summation order, while \p inclusive_scan requires associativity of
* the binary operation to parallelize the prefix sum.
*
* \param first The beginning of the input sequence.
* \param last The end of the input sequence.
* \param result The beginning of the output sequence.
* \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 OutputIterator's \c value_type.
* \tparam OutputIterator is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>,
* and if \c x and \c y are objects of \c OutputIterator's
* \c value_type, then <tt>x + y</tt> is defined. If \c T is
* \c OutputIterator's \c value_type, then <tt>T(0)</tt> is
* defined.
*
* The following code snippet demonstrates how to use \p inclusive_scan
*
* \code
* #include <thrust/scan.h>
*
* int data[6] = {1, 0, 2, 2, 1, 3};
*
* thrust::inclusive_scan(data, data + 6, data); // in-place scan
*
* // data is now {1, 1, 3, 5, 6, 9}
* \endcode
*
* \see http://www.sgi.com/tech/stl/partial_sum.html
*
*/
template<typename InputIterator,
typename OutputIterator>
OutputIterator inclusive_scan(InputIterator first,
InputIterator last,
OutputIterator result);
/*! \p inclusive_scan computes an inclusive prefix sum operation. The
* term 'inclusive' means that each result includes the corresponding
* input operand in the partial sum. When the input and output sequences
* are the same, the scan is performed in-place.
*
* \p inclusive_scan is similar to \c std::partial_sum in the STL. The primary
* difference between the two functions is that \c std::partial_sum guarantees
* a serial summation order, while \p inclusive_scan requires associativity of
* the binary operation to parallelize the prefix sum.
*
* \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 binary_op The associatve operator used to 'sum' 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 OutputIterator's \c value_type.
* \tparam OutputIterator is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>
* and \c OutputIterator's \c value_type is convertible to
* both \c AssociativeOperator's \c first_argument_type and
* \c second_argument_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 inclusive_scan
*
* \code
* int data[10] = {-5, 0, 2, -3, 2, 4, 0, -1, 2, 8};
*
* thrust::maximum<int> binary_op;
*
* thrust::inclusive_scan(data, data + 10, data, 1, binary_op); // in-place scan
*
* // data is now {1, 1, 2, 2, 2, 4, 4, 4, 4, 8}
* \endcode
*
* \see http://www.sgi.com/tech/stl/partial_sum.html
*/
template<typename InputIterator,
typename OutputIterator,
typename AssociativeOperator>
OutputIterator inclusive_scan(InputIterator first,
InputIterator last,
OutputIterator result,
AssociativeOperator binary_op);
/*! \p exclusive_scan computes an exclusive prefix sum operation. The
* term 'exclusive' means that each result does not include the
* corresponding input operand in the partial sum. More precisely,
* <tt>0</tt> is assigned to <tt>*result</tt> and the sum of
* <tt>0</tt> and <tt>*first</tt> is assigned to <tt>*(result + 1)</tt>,
* and so on. This version of \p exclusive_scan assumes plus as the
* associative operator and \c 0 as the initial value. When the input and
* output sequences are the same, the scan is performed 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.
* \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 OutputIterator's \c value_type.
* \tparam OutputIterator is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>,
* and if \c x and \c y are objects of \c OutputIterator's
* \c value_type, then <tt>x + y</tt> is defined. If \c T is
* \c OutputIterator's \c value_type, then <tt>T(0)</tt> is
* defined.
*
* The following code snippet demonstrates how to use \p exclusive_scan
*
* \code
* #include <thrust/scan.h>
*
* int data[6] = {1, 0, 2, 2, 1, 3};
*
* thrust::exclusive_scan(data, data + 6, data); // in-place scan
*
* // data is now {0, 1, 1, 3, 5, 6}
* \endcode
*
* \see http://www.sgi.com/tech/stl/partial_sum.html
*/
template<typename InputIterator,
typename OutputIterator>
OutputIterator exclusive_scan(InputIterator first,
InputIterator last,
OutputIterator result);
/*! \p exclusive_scan computes an exclusive prefix sum operation. The
* term 'exclusive' means that each result does not include the
* corresponding input operand in the partial sum. More precisely,
* \p init is assigned to <tt>*result</tt> and the sum of \p init and
* <tt>*first</tt> is assigned to <tt>*(result + 1)</tt>, and so on.
* This version of \p exclusive_scan assumes plus as the associative
* operator but requires an initial value \p init. When the input and
* output sequences are the same, the scan is performed 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 init The initial value.
* \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 OutputIterator's \c value_type.
* \tparam OutputIterator is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>,
* and if \c x and \c y are objects of \c OutputIterator's
* \c value_type, then <tt>x + y</tt> is defined.
* \tparam T is convertible to \c OutputIterator's \c value_type.
*
* The following code snippet demonstrates how to use \p exclusive_scan
*
* \code
* #include <thrust/scan.h>
*
* int data[6] = {1, 0, 2, 2, 1, 3};
*
* thrust::exclusive_scan(data, data + 6, data, 4); // in-place scan
*
* // data is now {4, 5, 5, 7, 9, 10}
* \endcode
*
* \see http://www.sgi.com/tech/stl/partial_sum.html
*/
template<typename InputIterator,
typename OutputIterator,
typename T>
OutputIterator exclusive_scan(InputIterator first,
InputIterator last,
OutputIterator result,
T init);
/*! \p exclusive_scan computes an exclusive prefix sum operation. The
* term 'exclusive' means that each result does not include the
* corresponding input operand in the partial sum. More precisely,
* \p init is assigned to <tt>*result</tt> and the value
* <tt>binary_op(init, *first)</tt> is assigned to <tt>*(result + 1)</tt>,
* and so on. This version of the function requires both and associative
* operator and an initial value \p init. When the input and output
* sequences are the same, the scan is performed 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 init The initial value.
* \param binary_op The associatve operator used to 'sum' 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 OutputIterator's \c value_type.
* \tparam OutputIterator is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>
* and \c OutputIterator's \c value_type is convertible to
* both \c AssociativeOperator's \c first_argument_type and
* \c second_argument_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 exclusive_scan
*
* \code
* #include <thrust/scan.h>
* #include <thrust/functional.h>
*
* int data[10] = {-5, 0, 2, -3, 2, 4, 0, -1, 2, 8};
*
* thrust::maximum<int> binary_op;
*
* thrust::exclusive_scan(data, data + 10, data, 1, binary_op); // in-place scan
*
* // data is now {1, 1, 1, 2, 2, 2, 4, 4, 4, 4 }
* \endcode
*
* \see http://www.sgi.com/tech/stl/partial_sum.html
*/
template<typename InputIterator,
typename OutputIterator,
typename T,
typename AssociativeOperator>
OutputIterator exclusive_scan(InputIterator first,
InputIterator last,
OutputIterator result,
T init,
AssociativeOperator binary_op);
/*! \addtogroup segmentedprefixsums Segmented Prefix Sums
* \ingroup prefixsums
* \{
*/
/*! \p inclusive_scan_by_key computes an inclusive key-value or 'segmented' prefix
* sum operation. The term 'inclusive' means that each result includes
* the corresponding input operand in the partial sum. The term 'segmented'
* means that the partial sums are broken into distinct segments. In other
* words, within each segment a separate inclusive scan operation is computed.
* Refer to the code sample below for example usage.
*
* This version of \p inclusive_scan_by_key assumes \c equal_to as the binary
* predicate used to compare adjacent keys. Specifically, consecutive iterators
* <tt>i</tt> and <tt>i+1</tt> in the range <tt>[first1, last1)</tt>
* belong to the same segment if <tt>*i == *(i+1)</tt>, and belong to
* different segments otherwise.
*
* This version of \p inclusive_scan_by_key assumes \c plus as the associative
* operator used to perform the prefix sum. When the input and output sequences
* are the same, the scan is performed in-place.
*
* \param first1 The beginning of the key sequence.
* \param last1 The end of the key sequence.
* \param first2 The beginning of the input value sequence.
* \param result The beginning of the output value sequence.
* \return The end of the output sequence.
*
* \tparam InputIterator1 is a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>
* \tparam InputIterator2 is a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>
* and \c InputIterator2's \c value_type is convertible to \c OutputIterator's \c value_type.
* \tparam OutputIterator is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>,
* and if \c x and \c y are objects of \c OutputIterator's \c value_type, then
* <tt>binary_op(x,y)</tt> is defined.
*
* The following code snippet demonstrates how to use \p inclusive_scan_by_key
*
* \code
* #include <thrust/scan.h>
*
* int data[10] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
* int keys[10] = {0, 0, 0, 1, 1, 2, 3, 3, 3, 3};
*
* thrust::inclusive_scan_by_key(keys, keys + 10, vals, vals); // in-place scan
*
* // data is now {1, 2, 3, 1, 2, 1, 1, 2, 3, 4};
* \endcode
*
* \see inclusive_scan
* \see exclusive_scan_by_key
*
*/
template<typename InputIterator1,
typename InputIterator2,
typename OutputIterator>
OutputIterator inclusive_scan_by_key(InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result);
/*! \p inclusive_scan_by_key computes an inclusive key-value or 'segmented' prefix
* sum operation. The term 'inclusive' means that each result includes
* the corresponding input operand in the partial sum. The term 'segmented'
* means that the partial sums are broken into distinct segments. In other
* words, within each segment a separate inclusive scan operation is computed.
* Refer to the code sample below for example usage.
*
* This version of \p inclusive_scan_by_key uses the binary predicate
* \c pred to compare adjacent keys. Specifically, consecutive iterators
* <tt>i</tt> and <tt>i+1</tt> in the range <tt>[first1, last1)</tt>
* belong to the same segment if <tt>binary_pred(*i, *(i+1))</tt> is true, and belong to
* different segments otherwise.
*
* This version of \p inclusive_scan_by_key assumes \c plus as the associative
* operator used to perform the prefix sum. When the input and output sequences
* are the same, the scan is performed in-place.
*
* \param first1 The beginning of the key sequence.
* \param last1 The end of the key sequence.
* \param first2 The beginning of the input value sequence.
* \param result The beginning of the output value sequence.
* \param binary_pred The binary predicate used to determine equality of keys.
* \return The end of the output sequence.
*
* \tparam InputIterator1 is a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>
* \tparam InputIterator2 is a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>
* and \c InputIterator2's \c value_type is convertible to \c OutputIterator's \c value_type.
* \tparam OutputIterator is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>,
* and if \c x and \c y are objects of \c OutputIterator's \c value_type, then
* <tt>binary_op(x,y)</tt> is defined.
* \tparam BinaryPredicate is a model of <a href="http://www.sgi.com/tech/stl/BinaryPredicate.html">Binary Predicate</a>.
*
* The following code snippet demonstrates how to use \p inclusive_scan_by_key
*
* \code
* #include <thrust/scan.h>
* #include <thrust/functional.h>
*
* int data[10] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
* int keys[10] = {0, 0, 0, 1, 1, 2, 3, 3, 3, 3};
*
* thrust::equal_to<int> binary_pred;
*
* thrust::inclusive_scan_by_key(keys, keys + 10, vals, vals, binary_pred); // in-place scan
*
* // data is now {1, 2, 3, 1, 2, 1, 1, 2, 3, 4};
* \endcode
*
* \see inclusive_scan
* \see exclusive_scan_by_key
*
*/
template<typename InputIterator1,
typename InputIterator2,
typename OutputIterator,
typename BinaryPredicate>
OutputIterator inclusive_scan_by_key(InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result,
BinaryPredicate binary_pred);
/*! \p inclusive_scan_by_key computes an inclusive key-value or 'segmented' prefix
* sum operation. The term 'inclusive' means that each result includes
* the corresponding input operand in the partial sum. The term 'segmented'
* means that the partial sums are broken into distinct segments. In other
* words, within each segment a separate inclusive scan operation is computed.
* Refer to the code sample below for example usage.
*
* This version of \p inclusive_scan_by_key uses the binary predicate
* \c pred to compare adjacent keys. Specifically, consecutive iterators
* <tt>i</tt> and <tt>i+1</tt> in the range <tt>[first1, last1)</tt>
* belong to the same segment if <tt>binary_pred(*i, *(i+1))</tt> is true, and belong to
* different segments otherwise.
*
* This version of \p inclusive_scan_by_key uses the associative operator
* \c binary_op to perform the prefix sum. When the input and output sequences
* are the same, the scan is performed in-place.
*
* \param first1 The beginning of the key sequence.
* \param last1 The end of the key sequence.
* \param first2 The beginning of the input value sequence.
* \param result The beginning of the output value sequence.
* \param binary_pred The binary predicate used to determine equality of keys.
* \param binary_op The associatve operator used to 'sum' values.
* \return The end of the output sequence.
*
* \tparam InputIterator1 is a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>
* \tparam InputIterator2 is a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>
* and \c InputIterator2's \c value_type is convertible to \c OutputIterator's \c value_type.
* \tparam OutputIterator is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>,
* and if \c x and \c y are objects of \c OutputIterator's \c value_type, then
* <tt>binary_op(x,y)</tt> is defined.
* \tparam BinaryPredicate is a model of <a href="http://www.sgi.com/tech/stl/BinaryPredicate.html">Binary Predicate</a>.
* \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 inclusive_scan_by_key
*
* \code
* #include <thrust/scan.h>
* #include <thrust/functional.h>
*
* int data[10] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
* int keys[10] = {0, 0, 0, 1, 1, 2, 3, 3, 3, 3};
*
* thrust::equal_to<int> binary_pred;
* thrust::plus<int> binary_op;
*
* thrust::inclusive_scan_by_key(keys, keys + 10, vals, vals, binary_pred, binary_op); // in-place scan
*
* // data is now {1, 2, 3, 1, 2, 1, 1, 2, 3, 4};
* \endcode
*
* \see inclusive_scan
* \see exclusive_scan_by_key
*
*/
template<typename InputIterator1,
typename InputIterator2,
typename OutputIterator,
typename BinaryPredicate,
typename AssociativeOperator>
OutputIterator inclusive_scan_by_key(InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result,
BinaryPredicate binary_pred,
AssociativeOperator binary_op);
/*! \p exclusive_scan_by_key computes an exclusive segmented prefix
*
* This version of \p exclusive_scan_by_key uses the value \c 0 to
* initialize the exclusive scan operation.
*
* This version of \p exclusive_scan_by_key assumes \c plus as the associative
* operator used to perform the prefix sum. When the input and output sequences
* are the same, the scan is performed in-place.
*
* This version of \p exclusive_scan_by_key assumes \c equal_to as the binary
* predicate used to compare adjacent keys. Specifically, consecutive iterators
* <tt>i</tt> and <tt>i+1</tt> in the range <tt>[first1, last1</tt>
* belong to the same segment if <tt>*i == *(i+1)</tt>, and belong to
* different segments otherwise.
*
* Refer to the most general form of \p exclusive_scan_by_key for additional details.
*
* \param first1 The beginning of the key sequence.
* \param last1 The end of the key sequence.
* \param first2 The beginning of the input value sequence.
* \param result The beginning of the output value sequence.
*
* The following code snippet demonstrates how to use \p exclusive_scan_by_key.
*
* \code
* #include <thrust/scan.h>
*
* int keys[10] = {0, 0, 0, 1, 1, 2, 3, 3, 3, 3};
* int vals[10] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
*
* thrust::exclusive_scan_by_key(key, key + 10, vals, vals); // in-place scan
*
* // vals is now {0, 1, 2, 0, 1, 0, 0, 1, 2, 3};
* \endcode
*
* \see exclusive_scan
*
*/
template<typename InputIterator1,
typename InputIterator2,
typename OutputIterator>
OutputIterator exclusive_scan_by_key(InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result);
/*! \p exclusive_scan_by_key computes an exclusive key-value or 'segmented' prefix
* sum operation. The term 'exclusive' means that each result does not include
* the corresponding input operand in the partial sum. The term 'segmented'
* means that the partial sums are broken into distinct segments. In other
* words, within each segment a separate exclusive scan operation is computed.
* Refer to the code sample below for example usage.
*
* This version of \p exclusive_scan_by_key uses the value \c init to
* initialize the exclusive scan operation.
*
* \param first1 The beginning of the key sequence.
* \param last1 The end of the key sequence.
* \param first2 The beginning of the input value sequence.
* \param result The beginning of the output value sequence.
* \param init The initial of the exclusive sum value.
* \return The end of the output sequence.
*
* The following code snippet demonstrates how to use \p exclusive_scan_by_key
*
* \code
* #include <thrust/scan.h>
* #include <thrust/functional.h>
*
* int keys[10] = {0, 0, 0, 1, 1, 2, 3, 3, 3, 3};
* int vals[10] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
*
* int init = 5;
*
* thrust::exclusive_scan_by_key(key, key + 10, vals, vals, init); // in-place scan
*
* // vals is now {5, 6, 7, 5, 6, 5, 5, 6, 7, 8};
* \endcode
*
* \see exclusive_scan
* \see inclusive_scan_by_key
*
*/
template<typename InputIterator1,
typename InputIterator2,
typename OutputIterator,
typename T>
OutputIterator exclusive_scan_by_key(InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result,
T init);
/*! \p exclusive_scan_by_key computes an exclusive key-value or 'segmented' prefix
* sum operation. The term 'exclusive' means that each result does not include
* the corresponding input operand in the partial sum. The term 'segmented'
* means that the partial sums are broken into distinct segments. In other
* words, within each segment a separate exclusive scan operation is computed.
* Refer to the code sample below for example usage.
*
* This version of \p exclusive_scan_by_key uses the value \c init to
* initialize the exclusive scan operation.
*
* This version of \p exclusive_scan_by_key uses the binary predicate \c binary_pred
* to compare adjacent keys. Specifically, consecutive iterators <tt>i</tt> and
* <tt>i+1</tt> in the range <tt>[first1, last1)</tt> belong to the same segment if
* <tt>binary_pred(*i, *(i+1))</tt> is true, and belong to different segments otherwise.
*
* \param first1 The beginning of the key sequence.
* \param last1 The end of the key sequence.
* \param first2 The beginning of the input value sequence.
* \param result The beginning of the output value sequence.
* \param init The initial of the exclusive sum value.
* \param binary_pred The binary predicate used to determine equality of keys.
* \return The end of the output sequence.
*
* The following code snippet demonstrates how to use \p exclusive_scan_by_key
*
* \code
* #include <thrust/scan.h>
* #include <thrust/functional.h>
*
* int keys[10] = {0, 0, 0, 1, 1, 2, 3, 3, 3, 3};
* int vals[10] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
*
* int init = 5;
*
* thrust::equal_to<int> binary_pred;
*
* thrust::exclusive_scan_by_key(key, key + 10, vals, vals, init, binary_pred); // in-place scan
*
* // vals is now {5, 6, 7, 5, 6, 5, 5, 6, 7, 8};
* \endcode
*
* \see exclusive_scan
* \see inclusive_scan_by_key
*
*/
template<typename InputIterator1,
typename InputIterator2,
typename OutputIterator,
typename T,
typename BinaryPredicate>
OutputIterator exclusive_scan_by_key(InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result,
T init,
BinaryPredicate binary_pred);
/*! \p exclusive_scan_by_key computes an exclusive key-value or 'segmented' prefix
* sum operation. The term 'exclusive' means that each result does not include
* the corresponding input operand in the partial sum. The term 'segmented'
* means that the partial sums are broken into distinct segments. In other
* words, within each segment a separate exclusive scan operation is computed.
* Refer to the code sample below for example usage.
*
* This version of \p exclusive_scan_by_key uses the value \c init to
* initialize the exclusive scan operation.
*
* This version of \p exclusive_scan_by_key uses the binary predicate \c binary_pred
* to compare adjacent keys. Specifically, consecutive iterators <tt>i</tt> and
* <tt>i+1</tt> in the range <tt>[first1, last1)</tt> belong to the same segment if
* <tt>binary_pred(*i, *(i+1))</tt> is true, and belong to different segments otherwise.
*
* This version of \p exclusive_scan_by_key uses the associative operator
* \c binary_op to perform the prefix sum. When the input and output sequences
* are the same, the scan is performed in-place.
*
* \param first1 The beginning of the key sequence.
* \param last1 The end of the key sequence.
* \param first2 The beginning of the input value sequence.
* \param result The beginning of the output value sequence.
* \param init The initial of the exclusive sum value.
* \param binary_pred The binary predicate used to determine equality of keys.
* \param binary_op The associatve operator used to 'sum' values.
* \return The end of the output sequence.
*
* \tparam InputIterator1 is a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>
* \tparam InputIterator2 is a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>
* and \c InputIterator2's \c value_type is convertible to \c OutputIterator's \c value_type.
* \tparam OutputIterator is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>,
* and if \c x and \c y are objects of \c OutputIterator's \c value_type, then
* <tt>binary_op(x,y)</tt> is defined.
* \tparam T is convertible to \c OutputIterator's \c value_type.
* \tparam BinaryPredicate is a model of <a href="http://www.sgi.com/tech/stl/BinaryPredicate.html">Binary Predicate</a>.
* \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 exclusive_scan_by_key
*
* \code
* #include <thrust/scan.h>
* #include <thrust/functional.h>
*
* int keys[10] = {0, 0, 0, 1, 1, 2, 3, 3, 3, 3};
* int vals[10] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
*
* int init = 5;
*
* thrust::equal_to<int> binary_pred;
* thrust::plus<int> binary_op;
*
* thrust::exclusive_scan_by_key(key, key + 10, vals, vals, init, binary_pred, binary_op); // in-place scan
*
* // vals is now {5, 6, 7, 5, 6, 5, 5, 6, 7, 8};
* \endcode
*
* \see exclusive_scan
* \see inclusive_scan_by_key
*
*/
template<typename InputIterator1,
typename InputIterator2,
typename OutputIterator,
typename T,
typename BinaryPredicate,
typename AssociativeOperator>
OutputIterator exclusive_scan_by_key(InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
OutputIterator result,
T init,
BinaryPredicate binary_pred,
AssociativeOperator binary_op);
/*! \} // end segmentedprefixsums
*/
/*! \} // end prefix sums
*/
} // end namespace thrust
#include <thrust/detail/scan.inl>