Function softmax

src/infer.cpp:472–487

Compute the softmax of an input vector `x` of length `size` and store it in `o`.

// Compute the softmax of an input vector `x` of length `size` and store it in `o`.
static void softmax(float* o, float* x, int size) {
  float score_max = -FLT_MAX;
  for (int i = 0; i < size; ++i) {
    if (x[i] > score_max) {
      score_max = x[i];
    }
  }
  float score_sum = 0.0f;
  for (int i = 0; i < size; ++i) {
    o[i] = expf(x[i] - score_max);
    score_sum += o[i];
  }
  for (int i = 0; i < size; ++i) {
    o[i] /= score_sum;
  }
}

inline float sigmoid(float x) {
  return 1.0f / (1.0f + expf(-x));