Multiply each element in a vector by itself to create a matrix

Question

I'm trying to multiply each element in a vector by itself such that it produces a matrix that is symmetric about the diagonal. For example, given this vector:: ``` x <- 1:3 ``` I would like to create this: ``` 1 2 3 2 4 6 3 6 9 ``` i.e: ``` x[1]*x[1] x[2]*x[1] x[3]*x[1] x[1]*x[2] x[2]*x[2] x[3]*x[2] x[1]*x[3] x[2]*x[3] x[3]*x[3] ``` Any help would be greatly appreciated. Thanks.

Accepted Answer

Like this:

```
x %o% x
```

which is a shortcut for

```
outer(x, x)
```

You can also do

```
 tcrossprod(x)
```

Multiply each element in a vector by itself to create a matrix

Solution

Problem