**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**

Doesnâ€™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)