root/modules/cudev/include/opencv2/cudev/warp/scan.hpp

INCLUDED FROM

DEFINITIONS

1. warpScanInclusive
2. warpScanExclusive

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#pragma once

#ifndef __OPENCV_CUDEV_WARP_SCAN_HPP__
#define __OPENCV_CUDEV_WARP_SCAN_HPP__

#include "../common.hpp"
#include "warp.hpp"
#include "shuffle.hpp"

namespace cv { namespace cudev {

//! @addtogroup cudev
//! @{

template <typename T>
__device__ T warpScanInclusive(T data, volatile T* smem, uint tid)
{
#if CV_CUDEV_ARCH >= 300
    (void) smem;
    (void) tid;

    const uint laneId = Warp::laneId();

    // scan on shufl functions
    #pragma unroll
    for (int i = 1; i <= (WARP_SIZE / 2); i *= 2)
    {
        const T val = shfl_up(data, i);
        if (laneId >= i)
              data += val;
    }

    return data;
#else
    uint pos = 2 * tid - (tid & (WARP_SIZE - 1));
    smem[pos] = 0;

    pos += WARP_SIZE;
    smem[pos] = data;

    smem[pos] += smem[pos - 1];
    smem[pos] += smem[pos - 2];
    smem[pos] += smem[pos - 4];
    smem[pos] += smem[pos - 8];
    smem[pos] += smem[pos - 16];

    return smem[pos];
#endif
}

template <typename T>
__device__ __forceinline__ T warpScanExclusive(T data, volatile T* smem, uint tid)
{
    return warpScanInclusive(data, smem, tid) - data;
}

//! @}

}}

#endif