What does each RBM achieve?
It divides the task of modeling the data into
two tasks and leaves the second task to the
next RBM
Task 1: Learn generative weights that can
convert the posterior distribution over the
hidden units into the data.
Task 2: Learn to model the posterior
distribution over the hidden units that is
produced by applying the transpose of the
generative weights to the data
Task 2 is guaranteed to be easier (for the next
RBM) than modeling the original data.
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