eigen matrix interleave by rows

splicer.cpp

#include <Eigen/Dense>
#include <tuple>
#include <utility>
#include <iostream>

template <typename... Args, int... N>
auto _interleave(std::integer_sequence<int,N...>, const Args&... args) {
    using namespace Eigen;
    constexpr static int S = sizeof...(Args);
    using Scalar = typename std::tuple_element<0,std::tuple<Args...>>::type::Scalar;
    using MatXf = Matrix<Scalar,Dynamic,Dynamic>;
    using MyStride = Stride<Dynamic,Dynamic>;

    int rows = (args.rows() + ... + 0);
    int cols = std::max( {args.cols()...}) ;

    MatXf A = MatXf::Constant(rows,cols,0);

   (Map<MatXf, 0,MyStride>(A.data() + N, args.rows(),args.cols(), MyStride(S*args.rows(),S)).operator=(args),...);

    return A;
}
template <typename... Args>
auto interleave(const Args&... args) {
    return _interleave(std::make_integer_sequence<int,sizeof...(Args)>(), std::forward<const Args&>(args)...);
}


int main() {
    using RowMatXf = Eigen::Matrix<float, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor>;
    using VecXf = Eigen::VectorXf;

    int N=10;
    VecXf A = VecXf::LinSpaced(N,0,N-1);
    VecXf B = A.array() + N;

    RowMatXf C(N,2);
    C.col(0) = A;
    C.col(1) = B;


    Eigen::Map<VecXf> CV(C.data(),C.size());
    std::cout << A.rows() << " " << A.cols() << std::endl;

    std::cout << "A [\n" << A.transpose() << "\n]"<< std::endl;
    std::cout << "B [\n" << B.transpose() << "\n]"<< std::endl;
    std::cout << "C [\n" << CV.transpose() << "\n]"<< std::endl;
    std::cout << std::endl;

    C.col(0) = A.array() + 2*N;
    C.col(1) = A.array() + 3*N;

    std::cout << "C interleave [\n" << interleave(A,B).transpose() << "\n]"<< std::endl;
    std::cout << std::endl;
    std::cout << std::endl;
    std::cout << "Hetero interleave (A,B,C) [\n" << interleave(A,B,C).transpose() << "\n]"<< std::endl;

}