This is a demo program for the back-propagation algorithm. The program uses back-prop to learn the feature-to-letter mapping. It uses number_generators (number_generators.f90) A 14-feature definition for each upper-case letter is provided in ltrdefs (see Rummelhart & McClelland (1981, Psych. Rev). Requires: number_generators (number_generators.f90) Output: a confusion matrix for each epoch with a count of the errors. Sample output is provided in FA.out Tutorial for back-prop on the web: www.speech.sri.com/people/anand/771/html/node37.html Files: FA.f90: code number_generators.f90: F90 module with random number generators and filters for Gaussian, exponential and other functions ltrdefs: features for each letter; -1 not present, +1 = present FA.out: sample output