How to visualize a neural network
Draw the network with nodes as circles connected with lines. The line widths must be proportional to the weights. Very small weights can be displayed even without a line.
I want to draw a dynamic picture for a neural network to watch the weights changed and the activation of neurons during learning. How could I simulate the process in Python? 
More precisely, if the network shape is: [1000, 300, 50], 
then I wish to draw a three layer NN which contains 1000, 300 and 50 neurons respectively. 
Further, I hope the picture could reflect the saturation of neurons on each layer during each epoch.
I've no idea about how to do it. Can someone shed some light on me?