MHO_MBDelaySearchOpenMP.hh

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#ifndef MHO_MBDelaySearchOpenMP_HH__
#define MHO_MBDelaySearchOpenMP_HH__
 
#include <vector>
 
#ifdef _OPENMP
    #include <omp.h>
#else
//stubs so code compiles without OpenMP; pragmas are silently ignored
inline int omp_get_max_threads()
{
    return 1;
}
 
inline int omp_get_thread_num()
{
    return 0;
}
#endif
 
#include "MHO_MBDelaySearch.hh"
 
namespace hops
{
 
class MHO_MBDelaySearchOpenMP: public MHO_MBDelaySearch
{
    public:
        MHO_MBDelaySearchOpenMP();
        virtual ~MHO_MBDelaySearchOpenMP();
 
        //only available for this class
        void SetNThreadsOpenMP(int n_threads)
        {
            int max_threads = omp_get_max_threads();
            if(n_threads <= 0)
            {
                //default value of -1 triggers max threads
                fNThreads = max_threads;
            }
            else
            {
                fNThreads = std::min(max_threads, n_threads);
            }
        };
 
    protected:
        using XArgType = visibility_type;
 
        virtual bool InitializeImpl(const XArgType* in) override;
        virtual bool ExecuteImpl(const XArgType* in) override;
 
        //per-thread argmax accumulator; alignas(64) + _pad prevents false sharing across cache lines
        struct alignas(64) LocalMax
        {
                double val = -0.0;
                int mbd_bin = -1;
                int sbd_bin = -1;
                int dr_bin = -1;
                double n_points = 0.0;
                char _pad[32]; //pad struct to one full 64-byte cache line
        };
 
        int fNThreads;
        std::vector< LocalMax > fThreadMaxima;
        std::vector< visibility_type > fPerThreadSBDWorkspace;
        std::vector< visibility_type > fPerThreadSBDDrData;
        std::vector< MHO_DelayRate > fPerThreadDelayRateCalc;
        std::vector< mbd_dr_type > fPerThreadSearchBuffer;
        std::vector< FFT_2D_ENGINE_TYPE > fPerThreadBatchedFFTEngine;
        std::vector< std::vector< double > > fPerThreadSmoothScratch; //per-thread scratch for apply_dr_boxcar_smooth
};
 
} // namespace hops
 
#endif