TheRock/rocm-libraries/projects/rocthrust/thrust/for_each.h

/*
 *  Copyright 2008-2013 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 thrust/for_each.h
 *  \brief Applies a function to each element in a range
 */

#pragma once

#include <thrust/detail/config.h>

#include <thrust/detail/execution_policy.h>
#include <thrust/detail/type_traits.h>

THRUST_NAMESPACE_BEGIN

/*! \addtogroup modifying
 *  \ingroup transformations
 *  \{
 */

/*! \p for_each applies the function object \p f to each element
 *  in the range <tt>[first, last)</tt>; \p f's return value, if any,
 *  is ignored. Unlike the C++ Standard Template Library function
 *  <tt>std::for_each</tt>, this version offers no guarantee on
 *  order of execution. For this reason, this version of \p for_each
 *  does not return a copy of the function object.
 *
 *  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 f The function object to apply to the range <tt>[first, last)</tt>.
 *  \return last
 *
 *  \tparam DerivedPolicy The name of the derived execution policy.
 *  \tparam InputIterator is a model of <a href="https://en.cppreference.com/w/cpp/named_req/InputIterator">Input
 * Iterator</a>, and \p InputIterator's \c value_type is convertible to \p UnaryFunction's \c argument_type. \tparam
 * UnaryFunction is a model of <a href="https://en.cppreference.com/w/cpp/utility/functional/unary_function">Unary
 * Function</a>, and \p UnaryFunction does not apply any non-constant operation through its argument.
 *
 *  The following code snippet demonstrates how to use \p for_each to print the elements
 *  of a \p thrust::device_vector using the \p thrust::device parallelization policy:
 *
 *  \code
 *  #include <thrust/for_each.h>
 *  #include <thrust/device_vector.h>
 *  #include <thrust/execution_policy.h>
 *  #include <cstdio>
 *  ...
 *
 *  struct printf_functor
 *  {
 *    THRUST_HOST_DEVICE
 *    void operator()(int x)
 *    {
 *      // note that using printf in a THRUST_DEVICE function requires
 *      // code compiled for a GPU with compute capability 2.0 or
 *      // higher (nvcc --arch=sm_20)
 *      printf("%d\n", x);
 *    }
 *  };
 *  ...
 *  thrust::device_vector<int> d_vec(3);
 *  d_vec[0] = 0; d_vec[1] = 1; d_vec[2] = 2;
 *
 *  thrust::for_each(thrust::device, d_vec.begin(), d_vec.end(), printf_functor());
 *
 *  // 0 1 2 is printed to standard output in some unspecified order
 *  \endcode
 *
 *  \see for_each_n
 *  \see https://en.cppreference.com/w/cpp/algorithm/for_each
 */
template <typename DerivedPolicy, typename InputIterator, typename UnaryFunction>
THRUST_HOST_DEVICE InputIterator for_each(
  const thrust::detail::execution_policy_base<DerivedPolicy>& exec,
  InputIterator first,
  InputIterator last,
  UnaryFunction f);

/*! \p for_each_n applies the function object \p f to each element
 *  in the range <tt>[first, first + n)</tt>; \p f's return value, if any,
 *  is ignored. Unlike the C++ Standard Template Library function
 *  <tt>std::for_each</tt>, this version offers no guarantee on
 *  order of execution.
 *
 *  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 n The size of the input sequence.
 *  \param f The function object to apply to the range <tt>[first, first + n)</tt>.
 *  \return <tt>first + n</tt>
 *
 *  \tparam DerivedPolicy The name of the derived execution policy.
 *  \tparam InputIterator is a model of <a href="https://en.cppreference.com/w/cpp/named_req/InputIterator">Input
 * Iterator</a>, and \p InputIterator's \c value_type is convertible to \p UnaryFunction's \c argument_type. \tparam
 * Size is an integral type. \tparam UnaryFunction is a model of <a
 * href="https://en.cppreference.com/w/cpp/utility/functional/unary_function">Unary Function</a>, and \p UnaryFunction
 * does not apply any non-constant operation through its argument.
 *
 *  The following code snippet demonstrates how to use \p for_each_n to print the elements
 *  of a \p device_vector using the \p thrust::device parallelization policy.
 *
 *  \code
 *  #include <thrust/for_each.h>
 *  #include <thrust/device_vector.h>
 *  #include <thrust/execution_policy.h>
 *  #include <cstdio>
 *
 *  struct printf_functor
 *  {
 *    THRUST_HOST_DEVICE
 *    void operator()(int x)
 *    {
 *      // note that using printf in a THRUST_DEVICE function requires
 *      // code compiled for a GPU with compute capability 2.0 or
 *      // higher (nvcc --arch=sm_20)
 *      printf("%d\n", x);
 *    }
 *  };
 *  ...
 *  thrust::device_vector<int> d_vec(3);
 *  d_vec[0] = 0; d_vec[1] = 1; d_vec[2] = 2;
 *
 *  thrust::for_each_n(thrust::device, d_vec.begin(), d_vec.size(), printf_functor());
 *
 *  // 0 1 2 is printed to standard output in some unspecified order
 *  \endcode
 *
 *  \see for_each
 *  \see https://en.cppreference.com/w/cpp/algorithm/for_each
 */
template <typename DerivedPolicy, typename InputIterator, typename Size, typename UnaryFunction>
THRUST_HOST_DEVICE InputIterator for_each_n(
  const thrust::detail::execution_policy_base<DerivedPolicy>& exec, InputIterator first, Size n, UnaryFunction f);

/*! \p for_each applies the function object \p f to each element
 *  in the range <tt>[first, last)</tt>; \p f's return value, if any,
 *  is ignored. Unlike the C++ Standard Template Library function
 *  <tt>std::for_each</tt>, this version offers no guarantee on
 *  order of execution. For this reason, this version of \p for_each
 *  does not return a copy of the function object.
 *
 *  \param first The beginning of the sequence.
 *  \param last The end of the sequence.
 *  \param f The function object to apply to the range <tt>[first, last)</tt>.
 *  \return last
 *
 *  \tparam InputIterator is a model of <a href="https://en.cppreference.com/w/cpp/named_req/InputIterator">Input
 * Iterator</a>, and \p InputIterator's \c value_type is convertible to \p UnaryFunction's \c argument_type. \tparam
 * UnaryFunction is a model of <a href="https://en.cppreference.com/w/cpp/utility/functional/unary_function">Unary
 * Function</a>, and \p UnaryFunction does not apply any non-constant operation through its argument.
 *
 *  The following code snippet demonstrates how to use \p for_each to print the elements
 *  of a \p device_vector.
 *
 *  \code
 *  #include <thrust/for_each.h>
 *  #include <thrust/device_vector.h>
 *  #include <stdio.h>
 *
 *  struct printf_functor
 *  {
 *    THRUST_HOST_DEVICE
 *    void operator()(int x)
 *    {
 *      // note that using printf in a THRUST_DEVICE function requires
 *      // code compiled for a GPU with compute capability 2.0 or
 *      // higher (nvcc --arch=sm_20)
 *      printf("%d\n", x);
 *    }
 *  };
 *  ...
 *  thrust::device_vector<int> d_vec(3);
 *  d_vec[0] = 0; d_vec[1] = 1; d_vec[2] = 2;
 *
 *  thrust::for_each(d_vec.begin(), d_vec.end(), printf_functor());
 *
 *  // 0 1 2 is printed to standard output in some unspecified order
 *  \endcode
 *
 *  \see for_each_n
 *  \see https://en.cppreference.com/w/cpp/algorithm/for_each
 */
template <typename InputIterator, typename UnaryFunction>
InputIterator for_each(InputIterator first, InputIterator last, UnaryFunction f);

/*! \p for_each_n applies the function object \p f to each element
 *  in the range <tt>[first, first + n)</tt>; \p f's return value, if any,
 *  is ignored. Unlike the C++ Standard Template Library function
 *  <tt>std::for_each</tt>, this version offers no guarantee on
 *  order of execution.
 *
 *  \param first The beginning of the sequence.
 *  \param n The size of the input sequence.
 *  \param f The function object to apply to the range <tt>[first, first + n)</tt>.
 *  \return <tt>first + n</tt>
 *
 *  \tparam InputIterator is a model of <a href="https://en.cppreference.com/w/cpp/named_req/InputIterator">Input
 * Iterator</a>, and \p InputIterator's \c value_type is convertible to \p UnaryFunction's \c argument_type. \tparam
 * Size is an integral type. \tparam UnaryFunction is a model of <a
 * href="https://en.cppreference.com/w/cpp/utility/functional/unary_function">Unary Function</a>, and \p UnaryFunction
 * does not apply any non-constant operation through its argument.
 *
 *  The following code snippet demonstrates how to use \p for_each_n to print the elements
 *  of a \p device_vector.
 *
 *  \code
 *  #include <thrust/for_each.h>
 *  #include <thrust/device_vector.h>
 *  #include <stdio.h>
 *
 *  struct printf_functor
 *  {
 *    THRUST_HOST_DEVICE
 *    void operator()(int x)
 *    {
 *      // note that using printf in a THRUST_DEVICE function requires
 *      // code compiled for a GPU with compute capability 2.0 or
 *      // higher (nvcc --arch=sm_20)
 *      printf("%d\n", x);
 *    }
 *  };
 *  ...
 *  thrust::device_vector<int> d_vec(3);
 *  d_vec[0] = 0; d_vec[1] = 1; d_vec[2] = 2;
 *
 *  thrust::for_each_n(d_vec.begin(), d_vec.size(), printf_functor());
 *
 *  // 0 1 2 is printed to standard output in some unspecified order
 *  \endcode
 *
 *  \see for_each
 *  \see https://en.cppreference.com/w/cpp/algorithm/for_each
 */
template <typename InputIterator, typename Size, typename UnaryFunction>
InputIterator for_each_n(InputIterator first, Size n, UnaryFunction f);

/*! \} // end modifying
 */

THRUST_NAMESPACE_END

#include <thrust/detail/for_each.inl>