手写RNN(递归神经网络)

根据http://nooverfit.com/wp/%E6%AF%8F%E4%B8%AA%E4%BA%BA%E9%83%BD%E8%83%BD%E5%BE%92%E6%89%8B%E5%86%99%E4%B8%80%E4%B8%AAlstm-rnn%E9%80%92%E5%BD%92%E7%A5%9E%E7%BB%8F%E7%BD%91%E7%BB%9C-%E6%89%8B%E6%8A%8A%E6%89%8B%E6%95%99%E4%BD%A0/#more-860