OUTER PRODUCT

Syntax: | `vout = v1 >< v2`

The outer product operator, `><`, operates on two vectors and produces a matrix composed of all possible combinations of products of elements of the vectors.

If vector `X` has M elements and vector `Y` has N elements, then `X><Y` is a matrix with M rows and N columns, where `(X><Y)[i,j] = X[i]*Y[j]` for `i = 1,2,...,M` and `j = 1,2,...,N`.

Example:

Suppose you have two vectors `X = [1;3;5]` and `Y = [2;4]`, then

            |  2  4 |
     X><Y = |  6 12 |
            | 10 20 |

append vectors or strings
inner product