A shortcut
• Only run the Markov chain for a few time steps.
– This gets negative samples very quickly.
– It works well in practice.
• Why does it work?
– If we start at the data, the Markov chain wanders
away from them data and towards things that it likes
more.
– We can see what direction it is wandering in after only
a few steps. It’s a big waste of time to let it go all the
way to equilibrium.
– All we need to do is lower the probability of the
“confabulations” it produces and raise the probability
of the data. Then it will stop wandering away.
• The learning cancels out once the confabulations and the
data have the same distribution.