title: Use fit or train_on_batch in LSTM training
body: <p>A LSTM layer is a recurrent neural network that uses previous data to predict (more or less). My question comes in order to train it. Due to its use in a time series, it is better to use <code>model.fit()</code> to fit all at once (suitable in my PC) or <code>train_on_batch()</code> to upgrade the gradient simulating a time series?</p>