Search code examples
c++eigeneigen3

Frobenius Inner Product between two matrices in Eigen3

Is there a simple and quick solution to calculate the Frobenius Inner Product between two 3x3 matrices in Eigen3?

Solution

  • If you are searching for the inner product of matrices, a possible (maybe not optimal) solution may be

        #include <iostream>
    #include "Eigen/Dense"
     
    int main()
    {
      
    Eigen::Matrix3d A, B;
    A << 1, 2, 3,
            4,5,6,
            7,8,9;
    B << 10, 11, 12,
             13,14,15,
             16,17,18;

    Eigen::Matrix3d C;
    C = A.transpose()*B;
    
    std::cout << C.trace() << std::endl;

        return 0;
    }