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//                           License Agreement
//                For Open Source Computer Vision Library
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// Copyright (C) 2010-2012, Institute Of Software Chinese Academy Of Science, all rights reserved.
// Copyright (C) 2010-2012, Advanced Micro Devices, Inc., all rights reserved.
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// @Authors
//    Shengen Yan,yanshengen@gmail.com
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#ifdef DOUBLE_SUPPORT
#ifdef cl_amd_fp64
#pragma OPENCL EXTENSION cl_amd_fp64:enable
#elif defined (cl_khr_fp64)
#pragma OPENCL EXTENSION cl_khr_fp64:enable
#endif
#endif

/**************************************Count NonZero**************************************/

__kernel void arithm_op_nonzero(int cols, int invalid_cols, int offset, int elemnum, int groupnum,
                                  __global srcT *src, __global dstT *dst)
{
    int lid = get_local_id(0);
    int gid = get_group_id(0);
    int  id = get_global_id(0);

    int idx = offset + id + (id / cols) * invalid_cols;
    __local dstT localmem_nonzero[128];
    dstT nonzero = (dstT)(0);
    srcT zero = (srcT)(0), one = (srcT)(1);

    for (int grain = groupnum << 8; id < elemnum; id += grain)
    {
        idx = offset + id + (id / cols) * invalid_cols;
        nonzero += src[idx] == zero ? zero : one;
    }

    if (lid > 127)
        localmem_nonzero[lid - 128] = nonzero;
    barrier(CLK_LOCAL_MEM_FENCE);

    if (lid < 128)
        localmem_nonzero[lid] = nonzero + localmem_nonzero[lid];
    barrier(CLK_LOCAL_MEM_FENCE);

    for (int lsize = 64; lsize > 0; lsize >>= 1)
    {
        if (lid < lsize)
        {
           int lid2 = lsize + lid;
           localmem_nonzero[lid] = localmem_nonzero[lid] + localmem_nonzero[lid2];
        }
        barrier(CLK_LOCAL_MEM_FENCE);
    }

    if (lid == 0)
        dst[gid] = localmem_nonzero[0];
}
