Identity matrix

`I = eye`

returns the scalar `1`

.

`I = eye(`

returns an
`n`

)`n`

-by-`n`

identity matrix with ones on
the main diagonal and zeros elsewhere.

`I = eye(___,`

also specifies the data type (class) of `typename`

)`I`

for any of the
previous syntaxes. For example, `eye(5,'int8')`

returns a
5-by-5 identity matrix consisting of 8-bit integers.