I'm just wondering how to convert the following openMP program to an openCL program.

The parallel algorithm implemented using openMP looks like this:

#pragma omp parallel
  {
    int thread_id = omp_get_thread_num();

    //double mt_probThreshold = mt_nProbThreshold_;
    double mt_probThreshold = nProbThreshold;

    int mt_nMaxCandidate = mt_nMaxCandidate_;
    double mt_nMinProb = mt_nMinProb_;

    int has_next = 1;
    std::list<ScrBox3d> mt_detected;
    ScrBox3d  sample;
    while(has_next) {
#pragma omp critical
    {  // '{' is very important and define the block of code that needs lock.
      // Don't remove this pair of '{' and '}'.
      if(piter_ == box_.end()) {
        has_next = 0;
      } else{
        sample = *piter_;
        ++piter_;
      }
    }  // '}' is very important and define the block of code that needs lock.

    if(has_next){
      this->SetSample(&sample, thread_id);
      //UpdateSample(sample, thread_id); // May be necesssary for more sophisticated features
      sample._prob = (float)this->Prob( true, thread_id, mt_probThreshold);
      //sample._prob = (float)_clf->LogLikelihood( thread_id);
      InsertCandidate( mt_detected, sample, mt_probThreshold, mt_nMaxCandidate, mt_nMinProb );
    }
  }

#pragma omp critical
  {  // '{' is very important and define the block of code that needs lock.
    // Don't remove this pair of '{' and '}'.
    if(mt_detected_.size()==0) {
      mt_detected_    = mt_detected;
      //mt_nProbThreshold_  = mt_probThreshold;
      nProbThreshold = mt_probThreshold;
    } else {
      for(std::list<ScrBox3d>::iterator it = mt_detected.begin(); 
          it!=mt_detected.end(); ++it)
        InsertCandidate( mt_detected_, *it, /*mt_nProbThreshold_*/nProbThreshold, 
        mt_nMaxCandidate_, mt_nMinProb_ );
      }
    }  // '}' is very important and define the block of code that needs lock.
  }//parallel section end

      

        
        
        
      

    

My question is, can this section be implemented with openCL? I followed a series of openCL tutorials and I figured out how to work, I wrote the code in .cu files (I previously installed the CUDA toolkit), but in this case the situation is more complicated because there are a lot of header files, template classes and object oriented programming.

How can I convert this section implemented in openMP to openCL? Should I create a new .cu file?

Any advice could help. Thanks in advance.

Edit:

Using VS profiler I noticed that the most execution time is spent on the InsertCandidate () function, I am thinking of writing a kernel to do this function on the GPU. The most expensive operation of this function is the instruction for

. But, as you can see, each loop contains three instructions if

, which can lead to discrepancy, which will lead to serialization even when executed on the GPU.

for( iter = detected.begin(); iter != detected.end(); iter++ )
    {
        if( nCandidate == nMaxCandidate-1 )
            nProbThreshold = iter->_prob;

        if( box._prob >= iter->_prob )
            break;
        if( nCandidate >= nMaxCandidate && box._prob <= nMinProb )
            break;
        nCandidate ++;
    }

      

        
        
        
      

    

As a conclusion, can this program be converted to openCL?