Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

478 lines (442 sloc) 19.237 kB
/*
* 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 partition.h
* \brief Reorganizes a range based on a predicate
*/
#pragma once
#include <thrust/detail/config.h>
#include <thrust/detail/dispatchable.h>
#include <thrust/pair.h>
namespace thrust
{
template<typename System,
typename ForwardIterator,
typename Predicate>
ForwardIterator partition(thrust::detail::dispatchable_base<System> &system,
ForwardIterator first,
ForwardIterator last,
Predicate pred);
template<typename System,
typename InputIterator,
typename OutputIterator1,
typename OutputIterator2,
typename Predicate>
thrust::pair<OutputIterator1,OutputIterator2>
partition_copy(thrust::detail::dispatchable_base<System> &system,
InputIterator first,
InputIterator last,
OutputIterator1 out_true,
OutputIterator2 out_false,
Predicate pred);
template<typename System,
typename ForwardIterator,
typename Predicate>
ForwardIterator stable_partition(thrust::detail::dispatchable_base<System> &system,
ForwardIterator first,
ForwardIterator last,
Predicate pred);
template<typename System,
typename InputIterator,
typename OutputIterator1,
typename OutputIterator2,
typename Predicate>
thrust::pair<OutputIterator1,OutputIterator2>
stable_partition_copy(thrust::detail::dispatchable_base<System> &system,
InputIterator first,
InputIterator last,
OutputIterator1 out_true,
OutputIterator2 out_false,
Predicate pred);
template<typename System, typename ForwardIterator, typename Predicate>
ForwardIterator partition_point(thrust::detail::dispatchable_base<System> &system,
ForwardIterator first,
ForwardIterator last,
Predicate pred);
template<typename System, typename InputIterator, typename Predicate>
bool is_partitioned(thrust::detail::dispatchable_base<System> &system,
InputIterator first,
InputIterator last,
Predicate pred);
/*! \addtogroup reordering
* \ingroup algorithms
*
* \addtogroup partitioning
* \ingroup reordering
* \{
*/
/*! \p partition reorders the elements <tt>[first, last)</tt> based on the function
* object \p pred, such that all of the elements that satisfy \p pred precede the
* elements that fail to satisfy it. The postcondition is that, for some iterator
* \c middle in the range <tt>[first, last)</tt>, <tt>pred(*i)</tt> is \c true for every
* iterator \c i in the range <tt>[first,middle)</tt> and \c false for every iterator
* \c i in the range <tt>[middle, last)</tt>. The return value of \p partition is
* \c middle.
*
* Note that the relative order of elements in the two reordered sequences is not
* necessarily the same as it was in the original sequence. A different algorithm,
* \ref stable_partition, does guarantee to preserve the relative order.
*
* \param first The beginning of the sequence to reorder.
* \param last The end of the sequence to reorder.
* \param pred A function object which decides to which partition each element of the
* sequence <tt>[first, last)</tt> belongs.
* \return An iterator referring to the first element of the second partition, that is,
* the sequence of the elements which do not satisfy \p pred.
*
* \tparam ForwardIterator is a model of <a href="http://www.sgi.com/tech/stl/ForwardIterator.html">Forward Iterator</a>,
* and \p ForwardIterator's \c value_type is convertible to \p Predicate's \c argument_type,
* and \p ForwardIterator is mutable.
* \tparam Predicate is a model of <a href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>.
*
* The following code snippet demonstrates how to use \p partition to reorder a
* sequence so that even numbers precede odd numbers.
*
* \code
* #include <thrust/partition.h>
* ...
* struct is_even
* {
* __host__ __device__
* bool operator()(const int &x)
* {
* return (x % 2) == 0;
* }
* };
* ...
* int A[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
* const int N = sizeof(A)/sizeof(int);
* thrust::partition(A, A + N,
* is_even());
* // A is now {2, 4, 6, 8, 10, 1, 3, 5, 7, 9}
* \endcode
*
* \see http://www.sgi.com/tech/stl/partition.html
* \see \p stable_partition
* \see \p partition_copy
*/
template<typename ForwardIterator,
typename Predicate>
ForwardIterator partition(ForwardIterator first,
ForwardIterator last,
Predicate pred);
/*! \p partition_copy differs from \ref partition only in that the reordered
* sequence is written to difference output sequences, rather than in place.
*
* \p partition_copy copies the elements <tt>[first, last)</tt> based on the
* function object \p pred. All of the elements that satisfy \p pred are copied
* to the range beginning at \p out_true and all the elements that fail to satisfy it
* are copied to the range beginning at \p out_false.
*
* \param first The beginning of the sequence to reorder.
* \param last The end of the sequence to reorder.
* \param out_true The destination of the resulting sequence of elements which satisfy \p pred.
* \param out_false The destination of the resulting sequence of elements which fail to satisfy \p pred.
* \param pred A function object which decides to which partition each element of the
* sequence <tt>[first, last)</tt> belongs.
* \return A \p pair p such that <tt>p.first</tt> is the end of the output range beginning
* at \p out_true and <tt>p.second</tt> is the end of the output range beginning at
* \p out_false.
*
* \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 Predicate's \c argument_type and \p InputIterator's \c value_type
* is convertible to \p OutputIterator1 and \p OutputIterator2's \c value_types.
* \tparam OutputIterator1 is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
* \tparam OutputIterator2 is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
* \tparam Predicate is a model of <a href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>.
*
* The following code snippet demonstrates how to use \p partition_copy to separate a
* sequence into two output sequences of even and odd numbers.
*
* \code
* #include <thrust/partition.h>
* ...
* struct is_even
* {
* __host__ __device__
* bool operator()(const int &x)
* {
* return (x % 2) == 0;
* }
* };
* ...
* int A[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
* int result[10];
* const int N = sizeof(A)/sizeof(int);
* int *evens = result;
* int *odds = result + 5;
* thrust::partition_copy(A, A + N, evens, odds, is_even());
* // A remains {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
* // result is now {2, 4, 6, 8, 10, 1, 3, 5, 7, 9}
* // evens points to {2, 4, 6, 8, 10}
* // odds points to {1, 3, 5, 7, 9}
* \endcode
*
* \note The relative order of elements in the two reordered sequences is not
* necessarily the same as it was in the original sequence. A different algorithm,
* \ref stable_partition_copy, does guarantee to preserve the relative order.
*
* \see http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2569.pdf
* \see \p stable_partition_copy
* \see \p partition
*/
template<typename InputIterator,
typename OutputIterator1,
typename OutputIterator2,
typename Predicate>
thrust::pair<OutputIterator1,OutputIterator2>
partition_copy(InputIterator first,
InputIterator last,
OutputIterator1 out_true,
OutputIterator2 out_false,
Predicate pred);
/*! \p stable_partition is much like \ref partition : it reorders the elements in the
* range <tt>[first, last)</tt> based on the function object \p pred, such that all of
* the elements that satisfy \p pred precede all of the elements that fail to satisfy
* it. The postcondition is that, for some iterator \p middle in the range
* <tt>[first, last)</tt>, <tt>pred(*i)</tt> is \c true for every iterator \c i in the
* range <tt>[first,middle)</tt> and \c false for every iterator \c i in the range
* <tt>[middle, last)</tt>. The return value of \p stable_partition is \c middle.
*
* \p stable_partition differs from \ref partition in that \p stable_partition is
* guaranteed to preserve relative order. That is, if \c x and \c y are elements in
* <tt>[first, last)</tt>, such that <tt>pred(x) == pred(y)</tt>, and if \c x precedes
* \c y, then it will still be true after \p stable_partition that \c x precedes \c y.
*
* \param first The first element of the sequence to reorder.
* \param last One position past the last element of the sequence to reorder.
* \param pred A function object which decides to which partition each element of the
* sequence <tt>[first, last)</tt> belongs.
* \return An iterator referring to the first element of the second partition, that is,
* the sequence of the elements which do not satisfy pred.
*
* \tparam ForwardIterator is a model of <a href="http://www.sgi.com/tech/stl/ForwardIterator.html">Forward Iterator</a>,
* and \p ForwardIterator's \c value_type is convertible to \p Predicate's \c argument_type,
* and \p ForwardIterator is mutable.
* \tparam Predicate is a model of <a href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>.
*
* The following code snippet demonstrates how to use \p stable_partition to reorder a
* sequence so that even numbers precede odd numbers.
*
* \code
* #include <thrust/partition.h>
* ...
* struct is_even
* {
* __host__ __device__
* bool operator()(const int &x)
* {
* return (x % 2) == 0;
* }
* };
* ...
* int A[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
* const int N = sizeof(A)/sizeof(int);
* thrust::stable_partition(A, A + N,
* is_even());
* // A is now {2, 4, 6, 8, 10, 1, 3, 5, 7, 9}
* \endcode
*
* \see http://www.sgi.com/tech/stl/stable_partition.html
* \see \p partition
* \see \p stable_partition_copy
*/
template<typename ForwardIterator,
typename Predicate>
ForwardIterator stable_partition(ForwardIterator first,
ForwardIterator last,
Predicate pred);
/*! \p stable_partition_copy differs from \ref stable_partition only in that the reordered
* sequence is written to difference output sequences, rather than in place.
*
* \p stable_partition_copy copies the elements <tt>[first, last)</tt> based on the
* function object \p pred. All of the elements that satisfy \p pred are copied
* to the range beginning at \p out_true and all the elements that fail to satisfy it
* are copied to the range beginning at \p out_false.
*
* \p stable_partition_copy differs from \ref partition_copy in that
* \p stable_partition_copy is guaranteed to preserve relative order. That is, if
* \c x and \c y are elements in <tt>[first, last)</tt>, such that
* <tt>pred(x) == pred(y)</tt>, and if \c x precedes \c y, then it will still be true
* after \p stable_partition_copy that \c x precedes \c y in the output.
*
* \param first The first element of the sequence to reorder.
* \param last One position past the last element of the sequence to reorder.
* \param out_true The destination of the resulting sequence of elements which satisfy \p pred.
* \param out_false The destination of the resulting sequence of elements which fail to satisfy \p pred.
* \param pred A function object which decides to which partition each element of the
* sequence <tt>[first, last)</tt> belongs.
* \return A \p pair p such that <tt>p.first</tt> is the end of the output range beginning
* at \p out_true and <tt>p.second</tt> is the end of the output range beginning at
* \p out_false.
*
* \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 Predicate's \c argument_type and \p InputIterator's \c value_type
* is convertible to \p OutputIterator1 and \p OutputIterator2's \c value_types.
* \tparam OutputIterator1 is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
* \tparam OutputIterator2 is a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
* \tparam Predicate is a model of <a href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>.
*
* The following code snippet demonstrates how to use \p stable_partition_copy to
* reorder a sequence so that even numbers precede odd numbers.
*
* \code
* #include <thrust/partition.h>
* ...
* struct is_even
* {
* __host__ __device__
* bool operator()(const int &x)
* {
* return (x % 2) == 0;
* }
* };
* ...
* int A[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
* int result[10];
* const int N = sizeof(A)/sizeof(int);
* int *evens = result;
* int *odds = result + 5;
* thrust::stable_partition_copy(A, A + N, evens, odds, is_even());
* // A remains {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
* // result is now {2, 4, 6, 8, 10, 1, 3, 5, 7, 9}
* // evens points to {2, 4, 6, 8, 10}
* // odds points to {1, 3, 5, 7, 9}
* \endcode
*
* \see http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2569.pdf
* \see \p partition_copy
* \see \p stable_partition
*/
template<typename InputIterator,
typename OutputIterator1,
typename OutputIterator2,
typename Predicate>
thrust::pair<OutputIterator1,OutputIterator2>
stable_partition_copy(InputIterator first,
InputIterator last,
OutputIterator1 out_true,
OutputIterator2 out_false,
Predicate pred);
/*! \} // end stream_compaction
*/
/*! \} // end reordering
*/
/*! \addtogroup searching
* \{
*/
/*! \p partition_point returns an iterator pointing to the end of the true
* partition of a partitioned range. \p partition_point requires the input range
* <tt>[first,last)</tt> to be a partition; that is, all elements which satisfy
* <tt>pred</tt> shall appear before those that do not.
* \param first The beginning of the range to consider.
* \param last The end of the range to consider.
* \param pred A function object which decides to which partition each element of the
* range <tt>[first, last)</tt> belongs.
* \return An iterator \c mid such that <tt>all_of(first, mid, pred)</tt>
* and <tt>none_of(mid, last, pred)</tt> are both true.
*
* \tparam ForwardIterator is a model of <a href="http://www.sgi.com/tech/stl/ForwardIterator.html">Forward Iterator</a>,
* and \p ForwardIterator's \c value_type is convertible to \p Predicate's \c argument_type.
* \tparam Predicate is a model of <a href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>.
*
* \note Though similar, \p partition_point is not redundant with \p find_if_not.
* \p partition_point's precondition provides an opportunity for a
* faster implemention.
*
* \code
* #include <thrust/partition.h>
*
* struct is_even
* {
* __host__ __device__
* bool operator()(const int &x)
* {
* return (x % 2) == 0;
* }
* };
*
* ...
*
* int A[] = {2, 4, 6, 8, 10, 1, 3, 5, 7, 9};
* int * B = thrust::partition_point(A, A + 10, is_even());
* // B - A is 5
* // [A, B) contains only even values
* \endcode
*
* \see \p partition
* \see \p find_if_not
*/
template<typename ForwardIterator, typename Predicate>
ForwardIterator partition_point(ForwardIterator first,
ForwardIterator last,
Predicate pred);
/*! \} // searching
*/
/*! \addtogroup reductions
* \{
* \addtogroup predicates
* \{
*/
/*! \p is_partitioned returns \c true if the given range
* is partitioned with respect to a predicate, and \c false otherwise.
*
* Specifically, \p is_partitioned returns \c true if <tt>[first, last)</tt>
* is empty of if <tt>[first, last)</tt> is partitioned by \p pred, i.e. if
* all elements that satisfy \p pred appear before those that do not.
*
* \param first The beginning of the range to consider.
* \param last The end of the range to consider.
* \param pred A function object which decides to which partition each element of the
* range <tt>[first, last)</tt> belongs.
* \return \c true if the range <tt>[first, last)</tt> is partitioned with respect
* to \p pred, or if <tt>[first, last)</tt> is empty. \c false, otherwise.
*
* \tparam InputIterator is a model of <a href="http://www.sgi.com/tech/stl/ForwardIterator.html">Input Iterator</a>,
* and \p InputIterator's \c value_type is convertible to \p Predicate's \c argument_type.
* \tparam Predicate is a model of <a href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>.
*
* \code
* #include <thrust/partition.h>
*
* struct is_even
* {
* __host__ __device__
* bool operator()(const int &x)
* {
* return (x % 2) == 0;
* }
* };
*
* ...
*
* int A[] = {2, 4, 6, 8, 10, 1, 3, 5, 7, 9};
* int B[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
*
* thrust::is_partitioned(A, A + 10); // returns true
* thrust::is_partitioned(B, B + 10); // returns false
* \endcode
*
* \see \p partition
*/
template<typename InputIterator, typename Predicate>
bool is_partitioned(InputIterator first,
InputIterator last,
Predicate pred);
/*! \} // end predicates
* \} // end reductions
*/
} // end thrust
#include <thrust/detail/partition.inl>
Jump to Line
Something went wrong with that request. Please try again.