t-eigen.cpp

    #include <iostream>
    #include <vector>
//#include <Eigen/Dense>

    template<typename T>
    class Solution
    {
        public:
            typedef T AtomType;
    };

    template<typename SOLT>
    class Distrib
    {
        public:
            typedef typename SOLT::AtomType AtomType;
            //typedef Eigen::Matrix< AtomType, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor> Matrix;
            typedef std::vector<AtomType> Matrix;

            Matrix matrix;
    };

    template<typename DT>
    class Sampler
    {
        public:
            typedef typename DT::AtomType AtomType;
            typedef typename Distrib<DT>::Matrix Matrix;

            Matrix matrix;
    };

    int main()
    {
        Sampler< Distrib< Solution<double> > > sampler;
    }