softmax.cl

/*************************************************************************************
 * Copyright (c) 2015, Advanced Micro Devices, Inc.
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 * 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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 * list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation and/or
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 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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#if defined(cl_khr_fp16)
#pragma OPENCL EXTENSION cl_khr_fp16 : enable
#endif

__kernel void kernel_channel_max(const int num, const int channels,
    const int spatial_dim, __global const T* data, __global T* out) {
  int index = get_global_id(0);
  if(index < num * spatial_dim) {
    int n = index / spatial_dim;
    int s = index % spatial_dim;
    T maxval = -FLT_MAX;
    for (int c = 0; c < channels; ++c) {
      maxval = max(data[(n * channels + c) * spatial_dim + s], maxval);
    }
    out[index] = maxval;
  }
}

__kernel void kernel_channel_subtract(const int count,
    const int num, const int channels,
    const int spatial_dim, __global const T* channel_max, __global const T* src, __global T* data) {
  int index = get_global_id(0);
  if(index < count) {
    int n = index / channels / spatial_dim;
    int s = index % spatial_dim;
    data[index] = exp(src[index] - channel_max[n * spatial_dim + s]);
  }
}

__kernel void kernel_channel_sum(const int num, const int channels,
    const int spatial_dim, __global const T* data, __global T* channel_sum) {
  int index = get_global_id(0);
  if(index < num * spatial_dim) {
    int n = index / spatial_dim;
    int s = index % spatial_dim;
    T sum = 0;
    for (int c = 0; c < channels; ++c) {
      sum += data[(n * channels + c) * spatial_dim + s];
    }
    channel_sum[index] = sum;
  }
}

__kernel void kernel_channel_div(const int count,
    const int num, const int channels,
    const int spatial_dim, __global const T* channel_sum, __global T* data) {
  int index = get_global_id(0);
  if(index < count) {
    int n = index / channels / spatial_dim;
    int s = index % spatial_dim;
    T v = data[index] / channel_sum[n * spatial_dim + s];
#ifdef LOG_SOFTMAX
    v = log(v);
#endif
    data[index] = v;
  }
}