/*M///////////////////////////////////////////////////////////////////////////////////////
//
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//
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//
//                           License Agreement
//                For Open Source Computer Vision Library
//
// 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.
// Third party copyrights are property of their respective owners.
//
// @Authors
//    Shengen Yan,yanshengen@gmail.com
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
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//   * Redistribution's of source code must retain the above copyright notice,
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//     this list of conditions and the following disclaimer in the documentation
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//   * The name of the copyright holders may not be used to endorse or promote products
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//M*/

#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

#if FUNC_SUM
#define FUNC(a, b) b += a;
#elif FUNC_ABS_SUM
#define FUNC(a, b) b += a >= (dstT)(0) ? a : -a;
#elif FUNC_SQR_SUM
#define FUNC(a, b) b += a * a;
#else
#error No sum function
#endif

/**************************************Array buffer SUM**************************************/

__kernel void arithm_op_sum(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_sum[128];
    dstT sum = (dstT)(0), temp;

    for (int grainSize = groupnum << 8; id < elemnum; id += grainSize)
    {
        idx = offset + id + (id / cols) * invalid_cols;
        temp = convertToDstT(src[idx]);
        FUNC(temp, sum);
    }

    if (lid > 127)
        localmem_sum[lid - 128] = sum;
    barrier(CLK_LOCAL_MEM_FENCE);

    if (lid < 128)
        localmem_sum[lid] = sum + localmem_sum[lid];
    barrier(CLK_LOCAL_MEM_FENCE);

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

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