# star

(*) multiplication operator

### Description

Multiplication. Usual meaning. Valid for constant, boolean, polynomial, rational matrices and for `syslin` lists (the meaning is series connection).

Element-wise multiplication is denoted `x.*y`. If `x` or `y` is scalar (1x1 matrix) `.*` is the same as `*`.

Kronecker product is `x.*.y`.

`A*.B` is an operator with no predefined meaning. It may be used to define a new operator (see overloading) with the same precedence as `*` or `/`.

 Remark that `/*` start to comment a block of code and `*/` end to comment this block.

### Examples

```// Basic numerical operations
2 * 2 // 4
2 * [%pi, %eps] // 6.2831853    4.441D-16
rand(2,2) * rand(2)
[1, 2; 3, 4] * [%pi,%eps; %e, %pi]```
```// Polynomial operations
s=poly(0,"s");
p=1+s+2*s^2;
q=1+s+2*s^3;
p * q
//               2    3    4    5
//    1 + 2s + 3s + 4s + 2s + 4s```
```// Rational
s=poly(0,'s');
W=[1/s,1/(s+1)];
W' * W
//    1           1
//    -         -----
//     2             2
//    s         s + s
//
//      1           1
//    -----     ---------
//         2              2
//    s + s     1 + 2s + s```