maxent libraries?

Grzegorz Chrupała pitekus at
Mon May 23 10:16:00 BST 2011

Hi Rogan,

You should take a look at wapiti:
It supports both logistic regression (aka Maxent) and Conditional
Random Fields, and implements several estimation algorithms. Written
in C and has a BSD style license.
I used it a bit and it is easy to use and fast.
You can see how it performs on the MLComp site:
This site is in general good for playing around with ML algorithms and datasets.

My own perceptron sequence tagger written in Haskell also performs
decently on many MLComp datasets:

Hope this helps,

On Mon, May 23, 2011 at 00:26, Rogan Creswick <creswick at> wrote:
> Is anyone aware of any BSD/Apache (or "free-er") licensed maxent
> libraries/packages for haskell or c (or other ffi-compatible
> language..)?  I'd like to recreate some of the OpenNLP classifiers,
> which rely heavily on maxent (I haven't found suitable tokenizers /
> sentence splitters / POS taggers / NE-recognisers for Haskell yet..).
> There is a c++ implementation of maxent here:
> but the license
> doesn't make allowances for commercial distribution/use, which is a
> non-starter.  (The GPL is also probably out, for similar reasons.)
> Thanks!
> Rogan
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