NAME¶

hypex - computes the Chernoff exponent between two simple categories.

SYNOPSIS¶

hypex [-hH size] [-s stepsize] CATDUMP1 CATDUMP2

hmine -V

DESCRIPTION¶

hypex reads two category dumps produced by dbacl(1) after learning. A category dump is obtained using the -d and -l switches, and is a textual representation of the feature weights which exist in the binary category files.

Given two such category dumps for simple unigram categories, hypex calculates the Kullback Leibler divergence between the probability models, and prints out exponential error exponents for Neyman-Pearson hypothesis tests under a range of threshold values. See Cover and Thomas (1991) Elements of Information Theory, Chap. 12.

Note that only simple categories are supported, and the output only makes sense under appropriate theoretical conditions. This is a very specialized calculator.

EXIT STATUS¶

hypex returns 0 on success, 1 if an error occurs.

OPTIONS¶

-h

-H

Same as dbacl(1). Selects the hash sizes in powers of two.

-s

Stepsize for the threshold. hypex outputs exponents for different values of the threshold, within an interval bounded by the Kullback Leibler divergences between the categories.

-V

Print the program version number and exit.

SOURCE¶

The source code for the latest version of this program is available at the following locations:

http://www.lbreyer.com/gpl.html
http://dbacl.sourceforge.net

BUGS¶

Doesn't work with complex categories, and theoretical assumptions are unrealistic in practice.

AUTHOR¶

Laird A. Breyer <laird@lbreyer.com>

SEE ALSO¶

dbacl(1), mailcross(1), mailfoot(1), mailinspect(1), mailtoe(1), regex(7)