#include USING_PART_OF_NAMESPACE_EIGEN using namespace std; // define a custom template binary functor template struct MakeComplexOp EIGEN_EMPTY_STRUCT { typedef complex result_type; complex operator()(const Scalar& a, const Scalar& b) const { return complex(a,b); } enum { Cost = 0 }; }; int main(int, char**) { Matrix4d m1 = Matrix4d::random(), m2 = Matrix4d::random(); cout << m1.cwise(m2, MakeComplexOp()) << endl; return 0; }