1const int size = 6; 2MatrixXd mat1(size, size); 3mat1.topLeftCorner(size/2, size/2) = MatrixXd::Zero(size/2, size/2); 4mat1.topRightCorner(size/2, size/2) = MatrixXd::Identity(size/2, size/2); 5mat1.bottomLeftCorner(size/2, size/2) = MatrixXd::Identity(size/2, size/2); 6mat1.bottomRightCorner(size/2, size/2) = MatrixXd::Zero(size/2, size/2); 7std::cout << mat1 << std::endl << std::endl; 8 9MatrixXd mat2(size, size); 10mat2.topLeftCorner(size/2, size/2).setZero(); 11mat2.topRightCorner(size/2, size/2).setIdentity(); 12mat2.bottomLeftCorner(size/2, size/2).setIdentity(); 13mat2.bottomRightCorner(size/2, size/2).setZero(); 14std::cout << mat2 << std::endl << std::endl; 15 16MatrixXd mat3(size, size); 17mat3 << MatrixXd::Zero(size/2, size/2), MatrixXd::Identity(size/2, size/2), 18 MatrixXd::Identity(size/2, size/2), MatrixXd::Zero(size/2, size/2); 19std::cout << mat3 << std::endl; 20 21