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This is a Java implementation of a maximum entropy classifier, as described in:

Christopher Manning and Dan Klein. 2003. Optimization, Maxent Models, and Conditional Estimation without Magic. Tutorial at HLT-NAACL 2003 and ACL 2003. [pdf slides] [pdf handouts]

Version 2 of the classifier was developed by Anna Rafferty and Christopher Manning. Maximum entropy models are otherwise known as conditional loglinear models, and are essentially equivalent to multiclass logistic regression models (though parameterized slightly differently, in a way that is advantageous with sparse explanatory feature vectors).

As well as API access, the program includes an easy-to-use command-line interface, ColumnDataClassifier, for building maximum entropy models. Its features are especially suited to building models over text data, but it also supports numeric variables.

The software requires requires Java (JDK1.5+). It is licensed under the GNU GPL v2. (Note that this is the full GPL, which allows its use for research purposes, free software projects, etc., but does not allow its incorporation into any type of distributed proprietary software, even in part or in translation. Source is included.

The download is a 1.3m gzipped tar file. If you unpack that file, you should have everything needed, including example files and documentation. Start by reading the README.txt file. Send any questions or feedback to java-nlp-support@lists.stanford.edu.

Mailing Lists

We have 3 mailing lists for the Stanford Classifier, all of which are shared with other JavaNLP tools (with the exclusion of the parser). Each address is at @lists.stanford.edu:

1. java-nlp-user This is the best list to post to in order to ask questions, make announcements, or for discussion among JavaNLP users. You have to subscribe to be able to use it. Join the list via this webpage or by emailing java-nlp-user-join@lists.stanford.edu. (Leave the subject and message body empty.) You can also look at the list archives.
2. java-nlp-announce This list will be used only to announce new versions of Stanford JavaNLP tools. So it will be very low volume (expect 1-3 message a year). Join the list via via this webpage or by emailing java-nlp-announce-join@lists.stanford.edu. (Leave the subject and message body empty.)
3. java-nlp-support This list goes only to the software maintainers. It's a good address for licensing questions, etc. For general use and support questions, please join and use java-nlp-user. You cannot join java-nlp-support, but you can mail questions to java-nlp-support@lists.stanford.edu.

Release history