Pie  |  9.0.0_r8
C++程序  |  5行  |  192 B 

MatrixXf A = MatrixXf::Random(3, 2);
VectorXf b = VectorXf::Random(3);
cout << "The solution using normal equations is:\n"
     << (A.transpose() * A).ldlt().solve(A.transpose() * b) << endl;