SubHask is a radical rewrite of the Haskell Prelude. The goal is to make numerical computing in Haskell fun and fast. The main idea is to use a type safe interface for programming in arbitrary subcategories of Hask. For example, the category Vect of linear functions is a subcategory of Hask, and SubHask exploits this fact to give a nice interface for linear algebra. To achieve this goal, almost every class hierarchy is redefined to be more general. I recommend reading the README file and the examples before looking at the documetation here.