FEniCS is an automated finite element library used to solve equations used in modeling, featuring a domain-specific language and automated code generation. Users input a problem that looks very much like mathematical notation; FEniCS then translates that into computer code.
The Shogun Machine Learning Toolbox is devoted to making machine learning tools available for free, to everyone. It provides efficient implementation of all standard ML algorithms.
Julia is a fast and user-friendly programming language for high-performance scientific computing.
Stan is a platform for Bayesian modeling, inference, and visualization on the frontiers of applied statistics.
nteract is a stand-alone desktop application for developing computational notebooks. nteract allows users to craft narratives involving text, code, images, and data on the desktop rather than through a web application.