parallel_for.openmp.hpp

// This file is part of OpenCV project.




// It is subject to the license terms in the LICENSE file found in the top-level directory




// of this distribution and at http://opencv.org/license.html.








#ifndef OPENCV_CORE_PARALLEL_FOR_OPENMP_HPP




#define OPENCV_CORE_PARALLEL_FOR_OPENMP_HPP








#include "opencv2/core/parallel/parallel_backend.hpp"








#if !defined(_OPENMP) && !defined(OPENCV_SKIP_OPENMP_PRESENSE_CHECK)




#error "This file must be compiled with enabled OpenMP"




#endif








#include <omp.h>








namespace

cv
{
namespace
parallel {
namespace
openmp {







class

ParallelForBackend
:
public
ParallelForAPI



{



protected:



int
numThreads;



int
numThreadsMax;



public:



ParallelForBackend()



{



numThreads = 0;



numThreadsMax = omp_get_max_threads();



}







virtual
~ParallelForBackend() {}







virtual
void
parallel_for(int
tasks, FN_parallel_for_body_cb_t body_callback,
void* callback_data) CV_OVERRIDE



{



#pragma omp parallel for schedule(dynamic) num_threads(numThreads > 0 ? numThreads : numThreadsMax)




for
(int
i = 0; i < tasks; ++i)



body_callback(i, i + 1, callback_data);



}







virtual
int
getThreadNum()
const
CV_OVERRIDE



{



return
omp_get_thread_num();



}







virtual
int
getNumThreads()
const
CV_OVERRIDE



{



return
numThreads > 0



? numThreads



: numThreadsMax;



}







virtual
int
setNumThreads(int
nThreads) CV_OVERRIDE



{



int
oldNumThreads = numThreads;



numThreads = nThreads;



// nothing needed as numThreads is used in #pragma omp parallel for directly




return
oldNumThreads;



}







const
char* getName()
const
CV_OVERRIDE



{



return
"openmp";



}


};






}}}
// namespace








#endif

// OPENCV_CORE_PARALLEL_FOR_OPENMP_HPP