1 #include <iostream>
2 #include <Eigen/Core>
3 using namespace Eigen;
4 
5 template <typename Derived>
print_size(const EigenBase<Derived> & b)6 void print_size(const EigenBase<Derived>& b)
7 {
8   std::cout << "size (rows, cols): " << b.size() << " (" << b.rows()
9             << ", " << b.cols() << ")" << std::endl;
10 }
11 
main()12 int main()
13 {
14     Vector3f v;
15     print_size(v);
16     // v.asDiagonal() returns a 3x3 diagonal matrix pseudo-expression
17     print_size(v.asDiagonal());
18 }
19