Eigen is a C++ template library for linear algebra, matrices, vectors, numerical solvers and related algorithms.
To see what versions of Eigen are available type
module avail eigen
To see what other modules are needed, what commands are available and how to get additional help type
module help eigen
To use Eigen, include a command like this in your batch script or interactive session to load the Eigen module:
module load eigen
Be sure you also load any other modules needed, as listed by the
module help ***** command.