---
name: "hypex"
section: "1"
platform: "linux"
package: "dbacl"
version: "1.12-2.2+b1"
release: "Debian 9 (Stretch)"
platforms: ["linux"]
url: "https://new.carta.tech/hypex"
---

# hypex(1)

computes the Chernoff exponent between two simple categories.

## 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)](/dbacl/1.md) 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)](/dbacl/1.md). 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)](/dbacl/1.md), [**mailcross**(1)](/mailcross/1.md), [**mailfoot**(1)](/mailfoot/1.md), [**mailinspect**(1)](/mailinspect/1.md), [**mailtoe**(1)](/mailtoe/1.md), [**regex**(7)](/regex/7.md)