source: pacpussensors/trunk/Vislab/lib3dv-1.2.0/lib3dv/eigen/doc/snippets/PartialRedux_sum.cpp

Matrix3d m = Matrix3d::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is the sum of each row:" << endl << m.rowwise().sum() << endl;