title: Backward propagation in Keras?
body: <p>can anyone tell me how is backpropagation done in Keras? I read that it is really easy in Torch and complex in Caffe, but I can't find anything about doing it with Keras. I am implementing my own layers in Keras (A very beginner) and would like to know how to do the backward propagation. </p>
  
  <p>Thank you in advance</p>