Complex Systems

Scaling Relationships in Back-propagation Learning Download PDF

Gerald Tesauro
Bob Janssens
Center for Complex Systems Research, University of Illinois at Urbana-Champaign
508 South Sixth Street, Champaign, IL 61820, USA


We present an empirical study of the required training time for neural networks to learn to compute the parity function using the back-propagation learning algorithm, as a function of the number of inputs. The parity function is a Boolean predicate whose order is equal to the number of inputs. We find that the training time behaves roughly as where is the number of inputs, for values of between 2 and 8. This is consistent with recent theoretical analyses of similar algorithms. As a part of this study we searched for optimal parameter tunings for each value of . We suggest that the learning rate should decrease faster than , the moment coefficient should approach 1 exponentially, and the initial random weight scale should remain approximately constant.