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

Matrix3d m = Matrix3d::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is the count of elements larger or equal than 0.5 of each row:" << endl << (m.array() >= 0.5).rowwise().count() << endl;