I'ld say Eigen 3 is quite stable and ready to use. We are quite close to the actual release and yes, EIGEN_DEFINE_STL_VECTOR_SPECIALIZATION as well as std::list and std::deque are only available in Eigen 3.

Just for the sake of completeness,

MatrixXd = Matrix<double,Dynamic,Dynamic>
Matrix4d = Matrix<double,4,1>

etc.

Regards,
Hauke

I switched to Eigen3 and everything still seems to be fine and working well.
Thank you again for your patience with an Eigen newbie