__kernel void MinMax(  __global float * input,
                        __global float * output,
                        int sizex,
                        int sizey,
                        int sizez,
                        int size,
                        int local_size
                    )
{
    int idx = get_global_id(0);
    int idy = get_global_id(1);
    int idz = get_global_id(2);

    int idx_local = get_local_id(0);
    int idy_local = get_local_id(1);
    int idz_local = get_local_id(2);

    int local_x = get_local_size(0);
    int local_y = get_local_size(1);
    int local_z = get_local_size(2);

    int gid = idx + sizex*idy + sizex*sizey*idz;
    int gid_local = idx_local + local_x*idy_local +local_x*local_y*idz_local;
    int group_count = get_num_groups(0) * get_num_groups(1) * get_num_groups(2);

    //int group_id = groupid_x + group_y*groupid_y + groupid_z*group_z*groupid_z;



    if((gid<size) && (gid_local<local_size))
    {
        __local float Minvals[ 64 ];
        __local float Maxvals[ 64 ];

    //local memory
        Minvals[gid_local] = input[gid];
        Maxvals[gid_local] = input[gid];


        int j = gid + gid_local + group_count;
        float ass = Minvals[gid_local] + Maxvals[gid_local];

        int offset = (local_x*local_y*local_z)/2;
        //Local reduction
        for(;gid_local<offset;offset/=2)
        {
            Minvals[gid_local] = fmin(Minvals[gid_local],Minvals[gid_local+offset]);
            Maxvals[gid_local] = fmax(Maxvals[gid_local],Maxvals[gid_local+offset]);
        }
        barrier(CLK_GLOBAL_MEM_FENCE);
        //Global rueckschreiben
        if(gid_local == 0)
        {
            //global Rueckschreiben
            output[gid*2] =  Minvals[gid_local];
            output[gid*2 +1] = Maxvals[gid_local];
        }
        barrier(CLK_GLOBAL_MEM_FENCE);
        //Global Reduction
        if(gid==0)
        {
            float mint=256;
            float maxt=0;
            for(int i =0; i < group_count; i=i+2)
            {
                mint    = fmin(mint,output[i]);
                maxt    = fmax(maxt,output[i+1]);
            }
            output[0] = mint;
            output[1] = maxt;
        }
    }
}