title: Computing cosine similarity between two tensors in Keras
body: <p>I have been following a tutorial that shows how to make a <code>word2vec</code> model.</p>
  <p>This tutorial uses this piece of code:</p>
  <p><code>similarity = merge([target, context], mode='cos', dot_axes=0)</code> (no other info was given, but I suppose this comes from <code>keras.layers</code>)</p>
  <p>Now, I've researched a bit on the <code>merge</code> method but I couldn't find much about it.
  From what I understand, it has been replaced by a lot of functions like <code>layers.Add(), layers.Concat()...</code>.</p>
  <p>What should I use? There's <code>.Dot()</code>, which has an <code>axis</code> parameter (which seems to be correct) but no <code>mode</code> parameter.</p>
  <p>What can I use in this case?</p>