1*bf2c3715SXin Li #include <iostream> 2*bf2c3715SXin Li #include <Eigen/SVD> 3*bf2c3715SXin Li using namespace Eigen; 4*bf2c3715SXin Li using namespace std; 5*bf2c3715SXin Li inv_cond(const Ref<const MatrixXf> & a)6*bf2c3715SXin Lifloat inv_cond(const Ref<const MatrixXf>& a) 7*bf2c3715SXin Li { 8*bf2c3715SXin Li const VectorXf sing_vals = a.jacobiSvd().singularValues(); 9*bf2c3715SXin Li return sing_vals(sing_vals.size()-1) / sing_vals(0); 10*bf2c3715SXin Li } 11*bf2c3715SXin Li main()12*bf2c3715SXin Liint main() 13*bf2c3715SXin Li { 14*bf2c3715SXin Li Matrix4f m = Matrix4f::Random(); 15*bf2c3715SXin Li cout << "matrix m:" << endl << m << endl << endl; 16*bf2c3715SXin Li cout << "inv_cond(m): " << inv_cond(m) << endl; 17*bf2c3715SXin Li cout << "inv_cond(m(1:3,1:3)): " << inv_cond(m.topLeftCorner(3,3)) << endl; 18*bf2c3715SXin Li cout << "inv_cond(m+I): " << inv_cond(m+Matrix4f::Identity()) << endl; 19*bf2c3715SXin Li } 20