1MatrixXd X = MatrixXd::Random(4,4); 2MatrixXd A = X * X.transpose(); 3cout << "Here is a random positive-definite matrix, A:" << endl << A << endl << endl; 4 5SelfAdjointEigenSolver<MatrixXd> es(A); 6MatrixXd sqrtA = es.operatorSqrt(); 7cout << "The square root of A is: " << endl << sqrtA << endl; 8cout << "If we square this, we get: " << endl << sqrtA*sqrtA << endl; 9