eigen-3.3.7.0: eigen3/doc/snippets/MatrixBase_array_const.cpp

Vector3d v(-1,2,-3);
cout << "the absolute values:" << endl << v.array().abs() << endl;
cout << "the absolute values plus one:" << endl << v.array().abs()+1 << endl;
cout << "sum of the squares: " << v.array().square().sum() << endl;