title: Keras : How should I prepare input data for RNN?
body: <p>I'm having trouble with preparing input data for RNN on Keras.</p>
  
  <p>Currently, my training data dimension is: <code>(6752, 600, 13)</code></p>
  
  <ul>
  <li>6752: number of training data </li>
  <li>600: number of time steps </li>
  <li>13: size of feature vectors (the vector is in float)</li>
  </ul>
  
  <p><code>X_train</code> and <code>Y_train</code> are both in this dimension.</p>
  
  <p>I want to prepare this data to be fed into <code>SimpleRNN</code> on Keras.
  Suppose that we're going through time steps, from step #0 to step #599.
  Let's say I want to use <code>input_length = 5</code>, which means that I want to use recent 5 inputs. (e.g. step #10, #11,#12,#13,#14 @ step #14).</p>
  
  <p>How should I reshape <code>X_train</code>?</p>
  
  <p>should it be <code>(6752, 5, 600, 13)</code> or should it be <code>(6752, 600, 5, 13)</code>?</p>
  
  <p>And what shape should <code>Y_train</code> be in?</p>
  
  <p>Should it be <code>(6752, 600, 13)</code> or <code>(6752, 1, 600, 13)</code> or <code>(6752, 600, 1, 13)</code>?</p>