Unix/Linux (Environment in which Python can be used.)
Fabian Pedregosa, Gael Varoquaux, Alexandre Gramfort, Vincent Michel, and other many contributors (see this page)
Data classification, data regression, clustering
Machine learning, data mining, data analysis
Parallel computation is supported. The number of parallel jobs can be described by a parameter.
Implemented on Python numerical libraries, Numpy and SciPy. Some core algorithms, which needs fast operation, are written by Cython. BLAS and LAPACK are needed.