1 #include <iostream>
2 #include <Eigen/Dense>
3 
4 using namespace std;
5 using namespace Eigen;
6 
main()7 int main()
8 {
9    Matrix2d A;
10    A << 2, 1,
11         2, 0.9999999999;
12    FullPivLU<Matrix2d> lu(A);
13    cout << "By default, the rank of A is found to be " << lu.rank() << endl;
14    lu.setThreshold(1e-5);
15    cout << "With threshold 1e-5, the rank of A is found to be " << lu.rank() << endl;
16 }
17