SIGMA: Large Scale Machine Learning Toolkit
http://research.microsoft.com/en-us/projects/sigma/

The goal of SIGMA is to provide a group of parallel machine-learning algorithms that can meet the requirements of research work and applications, typically with large-scale data or features. The toolkit includes more than 10 algorithms and it makes them run on single multicore machine or on a HPC cluster with hundreds of machines and thousands of CPU cores running. A SDK is provided for researchers and developers who want to invent their own algorithms and add them to the toolkit. This has been added to Biological Informatics Subject Tracer™ Information Blog.