Lesson 5 Convenience typedefs

Eigen defines the following Matrix typedefs:
MatrixNt for Matrix<type, N, N>. For example, MatrixXi for Matrix<int, Dynamic, Dynamic>.
VectorNt for Matrix<type, N, 1>. For example, Vector2f for Matrix<float, 2, 1>.
RowVectorNt for Matrix<type, 1, N>. For example, RowVector3d for Matrix<double, 1, 3>.

Where:
N can be any one of 

2

, 

3

, 

4

, or 

X

 (meaning 

Dynamic

).
t can be any one of 

i

 (meaning int), 

f

 (meaning float), 

d

 (meaning double), 

cf

 (meaning complex<float>), or 

cd

(meaning complex<double>). The fact
that typedefs are only defined for these five types doesn't mean that they are the only supported scalar types. For example, all standard integer types are supported, see Scalar
types.