Using algorithms to address issues of searching and matching strings and more complicated patterns such as trees, regular expressions, graphs, point sets, and arrays. [GPL]

A large collection of multiple sequence alignments and trained hidden Markov models covering many common protein domains. Alignments are included as well as models for 8296 protein families, based on the Swissprot 48.9 and SP-TrEMBL 31.9 protein seque...

A library for many pattern recognition tasks. The main focus of this package is on image analysis but utilizes a general architecture and XML-based data interchange format. Written in C++ [GPL]

Open source library of tools for building machine learning software based on Bayesian mathematical principles. Links on lower left of page article. [GPL]

A system of research planning and learning utilizing explanation-based learning, partial evaluation, experimentation, graphical knowledge acquisition, automatic abstraction, mixed-initiative planning, and case-based reasoning. [Free]

The Rapid Miner toolset is an environment for machine learning through use of nested operators. Multiple experiments can be arbitrarily nested together through use of a graphical XML based user interface. (Formerly YALE) [GPL]

Short article on self-modifying software touching on co-training, partial-programming, and genetic programming (GP) methods of problem solving. [FREE]

Programs to cluster similar contexts together using unsupervised knowledge-lean methods for word sense discrimination, email categorization, and name discrimination. Written in Perl. [GNU]

A learning architecture specifically tailored for learning in very high-dimensional feature spaces. The current release uses sparse variations of Winnow, Perceptron, and Naive Bayes. [AFL]

Tools for modeling graphs and Bayesian networks. Scroll down. [AFL], [Commercial]