Basilio Noris from the Learning Algorithms and Systems Laboratory at the Ecole Polytechnique Fédérale de Lausanne has published MLDemos – the software is available for download (for all major OSs). It works out of the box, and the first tests went really fine – I’m impressed with the visualisation of the algorithms at work!
During my PhD I’ve come across a number of machine learning algorithms for classification, regression and clustering. While there is a great number of libraries, source code and binaries for different algorithms, it is always difficult to get a good grasp of what they do. Moreover, one ends up spending a great amount of time just getting the algorithm to display the results in an understandable way. Change the algorithm and you will have to do the work all over again. Some people have tried, and succeeded, to combine several algorithms into a single multi-purpose library, making their libraries extremely useful (you will find many of their names in the acknowledgements below), but still they didn’t solve the problem of visualization and ease of use.
Also for the fellow java enthusiasts, there is Weka 3 – a collection of machine learning algorithms for data mining tasks from the Machine Learning Group at University of Waikato.