eye

Scilab Function
Last update : 25/04/2007

eye - identity matrix

### Calling Sequence

  `X=eye(m,n)`
  `X=eye(A)`
  `X=eye()`

### Parameters

- `A,X` : matrices or `syslin` lists
- `m,n` : integers

### Description

according to its arguments defines an `m` x`n` matrix with 1 along the main diagonal or an identity matrix of the same dimension as `A` .

Caution: `eye(10)` is interpreted as `eye(A)` with `A=10` i.e. `1` . (It is NOT a ten by ten identity matrix!).

If `A` is a linear system represented by a `syslin` list, `eye(A)` returns an `eye` matrix of appropriate dimension: (number of outputs x number of inputs).

`eye()` produces a identity matrix with undefined dimensions. Dimensions will be defined when this identity matrix is added to a mtrix with fixed dimensions.

### Examples

    eye(2,3)
    A=rand(2,3);eye(A)
    s=poly(0,'s');A=[s,1;s,s+1];eye(A)
    A=[1/s,1;s,2];eye(A);
    A=ssrand(2,2,3);eye(A)
    [1 2;3 4]+2*eye()

### See Also

`ones` , `zeros` ,