Example

> eye(3,3)
        1          0          0  
        0          1          0  
        0          0          1  
> eye(2,5)
        1          0          0          0          0  
        0          1          0          0          0  
> eye([3,4])
        1          0          0          0  
        0          1          0          0  
        0          0          1          0  
> c = rand(2,4)
 c =
    0.846      0.826       0.29      0.438  
    0.683      0.252      0.494      0.324  
> eye(size(c))
        1          0          0          0  
        0          1          0          0