We really should change functions that accept `const Eigen::Type &` to use `const Eigen::Ref<Eigen::Type>&` as recommended by [Eigen documentation](http://eigen.tuxfamily.org/dox/TopicFunctionTakingEigenTypes.html). This unifies `Eigen::Matrix` and `Eigen::Map`, to avoid an additional copy.
We really should change functions that accept
const Eigen::Type &to useconst Eigen::Ref<Eigen::Type>&as recommended by Eigen documentation.This unifies
Eigen::MatrixandEigen::Map, to avoid an additional copy.