/*
* 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 count.h
* \brief Counting elements in a range
*/
#pragma once
#include <thrust/detail/config.h>
#include <thrust/detail/execution_policy.h>
#include <thrust/iterator/iterator_traits.h>
namespace thrust
{
/*! \addtogroup algorithms
*/
/*! \addtogroup reductions
* \ingroup algorithms
* \{
*/
/*! \addtogroup counting
* \ingroup reductions
* \{
*/
/*! \p count finds the number of elements in <tt>[first,last)</tt> that are equal
* to \p value. More precisely, \p count returns the number of iterators \c i in
* <tt>[first, last)</tt> such that <tt>*i == value</tt>.
*
* The algorithm's execution is parallelized as determined by \p exec.
*
* \param exec The execution policy to use for parallelization.
* \param first The beginning of the sequence.
* \param last The end of the sequence.
* \param value The value to be counted.
* \return The number of elements equal to \p value.
*
* \tparam DerivedPolicy The name of the derived execution policy.
* \tparam InputIterator must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator's \c value_type must be a model of must be a model of <a href="http://www.sgi.com/tech/stl/EqualityComparable.html">Equality Comparable</a>.
* \tparam EqualityComparable must be a model of <a href="http://www.sgi.com/tech/stl/EqualityComparable.html">Equality Comparable</a> and can be compared for equality with \c InputIterator's \c value_type
*
* The following code snippet demonstrates how to use \p count to
* count the number of instances in a range of a value of interest using the \p thrust::device execution policy:
*
* \code
* #include <thrust/count.h>
* #include <thrust/device_vector.h>
* #include <thrust/execution_policy.h>
* ...
* // put 3 1s in a device_vector
* thrust::device_vector<int> vec(5,0);
* vec[1] = 1;
* vec[3] = 1;
* vec[4] = 1;
*
* // count the 1s
* int result = thrust::count(thrust::device, vec.begin(), vec.end(), 1);
* // result == 3
* \endcode
*
* \see http://www.sgi.com/tech/stl/count.html
*/
template<typename DerivedPolicy, typename InputIterator, typename EqualityComparable>
typename thrust::iterator_traits<InputIterator>::difference_type
count(const thrust::detail::execution_policy_base<DerivedPolicy> &exec, InputIterator first, InputIterator last, const EqualityComparable& value);
/*! \p count finds the number of elements in <tt>[first,last)</tt> that are equal
* to \p value. More precisely, \p count returns the number of iterators \c i in
* <tt>[first, last)</tt> such that <tt>*i == value</tt>.
*
* \param first The beginning of the sequence.
* \param last The end of the sequence.
* \param value The value to be counted.
* \return The number of elements equal to \p value.
*
* \tparam InputIterator must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator's \c value_type must be a model of must be a model of <a href="http://www.sgi.com/tech/stl/EqualityComparable.html">Equality Comparable</a>.
* \tparam EqualityComparable must be a model of <a href="http://www.sgi.com/tech/stl/EqualityComparable.html">Equality Comparable</a> and can be compared for equality with \c InputIterator's \c value_type
*
* The following code snippet demonstrates how to use \p count to
* count the number of instances in a range of a value of interest.
* \code
* #include <thrust/count.h>
* #include <thrust/device_vector.h>
* ...
* // put 3 1s in a device_vector
* thrust::device_vector<int> vec(5,0);
* vec[1] = 1;
* vec[3] = 1;
* vec[4] = 1;
*
* // count the 1s
* int result = thrust::count(vec.begin(), vec.end(), 1);
* // result == 3
* \endcode
*
* \see http://www.sgi.com/tech/stl/count.html
*/
template <typename InputIterator, typename EqualityComparable>
typename thrust::iterator_traits<InputIterator>::difference_type
count(InputIterator first, InputIterator last, const EqualityComparable& value);
/*! \p count_if finds the number of elements in <tt>[first,last)</tt> for which
* a predicate is \c true. More precisely, \p count_if returns the number of iterators
* \c i in <tt>[first, last)</tt> such that <tt>pred(*i) == true</tt>.
*
* The algorithm's execution is parallelized as determined by \p exec.
*
* \param exec The execution policy to use for parallelization.
* \param first The beginning of the sequence.
* \param last The end of the sequence.
* \param pred The predicate.
* \return The number of elements where \p pred is \c true.
*
* \tparam DerivedPolicy The name of the derived execution policy.
* \tparam InputIterator must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator's \c value_type must be convertible to \c Predicate's \c argument_type.
* \tparam Predicate must be a model of <a href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>.
*
* The following code snippet demonstrates how to use \p count to
* count the number of odd numbers in a range using the \p thrust::device execution policy:
*
* \code
* #include <thrust/count.h>
* #include <thrust/device_vector.h>
* #include <thrust/execution_policy.h>
* ...
* struct is_odd
* {
* __host__ __device__
* bool operator()(int &x)
* {
* return x & 1;
* }
* };
* ...
* // fill a device_vector with even & odd numbers
* thrust::device_vector<int> vec(5);
* vec[0] = 0;
* vec[1] = 1;
* vec[2] = 2;
* vec[3] = 3;
* vec[4] = 4;
*
* // count the odd elements in vec
* int result = thrust::count_if(thrust::device, vec.begin(), vec.end(), is_odd());
* // result == 2
* \endcode
*
* \see http://www.sgi.com/tech/stl/count.html
*/
template<typename DerivedPolicy, typename InputIterator, typename Predicate>
typename thrust::iterator_traits<InputIterator>::difference_type
count_if(const thrust::detail::execution_policy_base<DerivedPolicy> &exec, InputIterator first, InputIterator last, Predicate pred);
/*! \p count_if finds the number of elements in <tt>[first,last)</tt> for which
* a predicate is \c true. More precisely, \p count_if returns the number of iterators
* \c i in <tt>[first, last)</tt> such that <tt>pred(*i) == true</tt>.
*
* \param first The beginning of the sequence.
* \param last The end of the sequence.
* \param pred The predicate.
* \return The number of elements where \p pred is \c true.
*
* \tparam InputIterator must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator's \c value_type must be convertible to \c Predicate's \c argument_type.
* \tparam Predicate must be a model of <a href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>.
*
* The following code snippet demonstrates how to use \p count to
* count the number of odd numbers in a range.
* \code
* #include <thrust/count.h>
* #include <thrust/device_vector.h>
* ...
* struct is_odd
* {
* __host__ __device__
* bool operator()(int &x)
* {
* return x & 1;
* }
* };
* ...
* // fill a device_vector with even & odd numbers
* thrust::device_vector<int> vec(5);
* vec[0] = 0;
* vec[1] = 1;
* vec[2] = 2;
* vec[3] = 3;
* vec[4] = 4;
*
* // count the odd elements in vec
* int result = thrust::count_if(vec.begin(), vec.end(), is_odd());
* // result == 2
* \endcode
*
* \see http://www.sgi.com/tech/stl/count.html
*/
template <typename InputIterator, typename Predicate>
typename thrust::iterator_traits<InputIterator>::difference_type
count_if(InputIterator first, InputIterator last, Predicate pred);
/*! \} // end counting
* \} // end reductions
*/
} // end thrust
#include <thrust/detail/count.inl>