warp_reduce.hpp

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#ifndef OPENCV_CUDA_WARP_REDUCE_HPP__




#define OPENCV_CUDA_WARP_REDUCE_HPP__












namespace

cv
{
namespace
cuda {
namespace
device


{



template
<class
T>



__device__ __forceinline__ T warp_reduce(volatile
T *ptr ,
const
unsigned
int
tid = threadIdx.x)



{



const
unsigned
int
lane = tid & 31;
// index of thread in warp (0..31)








if
(lane < 16)



{



T partial = ptr[tid];







ptr[tid] = partial = partial + ptr[tid + 16];



ptr[tid] = partial = partial + ptr[tid + 8];



ptr[tid] = partial = partial + ptr[tid + 4];



ptr[tid] = partial = partial + ptr[tid + 2];



ptr[tid] = partial = partial + ptr[tid + 1];



}







return
ptr[tid - lane];



}


}}}
// namespace cv { namespace cuda { namespace cudev {












#endif

/* OPENCV_CUDA_WARP_REDUCE_HPP__ */