1int rows=5, cols=5;
2MatrixXf m(rows,cols);
3m << (Matrix3f() << 1, 2, 3, 4, 5, 6, 7, 8, 9).finished(),
4     MatrixXf::Zero(3,cols-3),
5     MatrixXf::Zero(rows-3,3),
6     MatrixXf::Identity(rows-3,cols-3);
7cout << m;
8