Method Backward

src/model/feed_forward_net.cc:218–238

}

const vector<Tensor> FeedForwardNet::Backward(int flag, const Tensor& grad) {
  vector<Tensor> param_grads;
  std::stack<Tensor> buf;
  Tensor tmp = grad;
  for (int i = (int)layers_.size() - 1; i >= 0; i--) {
    // LOG(INFO) << layers_.at(i)->name() << " : " << tmp.L1();
    auto ret = layers_.at(i)->Backward(flag, tmp);
    tmp = ret.first;
    if (ret.second.size()) {
      for (int k = (int)ret.second.size() - 1; k >= 0; k--) {
        buf.push(ret.second[k]);
        // LOG(INFO) <<  "      " << buf.top().L1();
      }
    }
  }
  while (!buf.empty()) {
    param_grads.push_back(buf.top());
    buf.pop();
  }
  return param_grads;
}

std::pair<Tensor, Tensor> FeedForwardNet::Evaluate(const Tensor& x,
                                                   const Tensor& y,