Documentation on Hackage https://hackage.haskell.org/package/eigen
Eigen documentation page http://eigen.tuxfamily.org/dox/
This module provides Haskell binding for Eigen. Eigen is a C++ template library for linear algebra: matrices, vectors, numerical solvers, and related algorithms. Eigen home page is http://eigen.tuxfamily.org/.
Eigen is licensed under the MPL2, which is a simple weak copyleft license. Common questions about the MPL2 are answered in the official MPL2 FAQ.
Note that currently, a few features in Eigen rely on third-party code licensed under the LGPL: SimplicialCholesky, AMD ordering, and constrained_cg. Such features are explicitly disabled by compiling Eigen with the EIGEN_MPL2_ONLY preprocessor symbol defined.
Virtually any software may use Eigen. For example, closed-source software may use Eigen without having to disclose its own source code. Many proprietary and closed-source software projects are using Eigen right now, as well as many BSD-licensed projects.