def UpdateEdgeParams(self, edge, step):
    """ Update the parameters associated with this edge."""
    numcases = edge.node1.batchsize
    edge.gradient.add_mult(edge.suff_stats, -1.0/numcases)
    if edge.tied_to:
      edge.tied_to.gradient.add(edge.gradient)
      edge.gradient.assign(0)
      edge = edge.tied_to
    edge.num_grads_received += 1
    if edge.num_grads_received == edge.num_shares:
      edge.Update('weight', step)
 Update the parameters associated with this edge.
deepnet/dbm.py