The generative model after learning 3 layers
To generate data:
1. Get an equilibrium sample
from the top-level RBM by
performing alternating Gibbs
sampling for a long time.
2. Perform a top-down pass to
get states for all the other
layers.
     So the lower level bottom-up
connections  are not part of
the generative model. They
are just used for inference.
        h3
         h2
          h1
      data