

   OOuutteerr PPrroodduucctt ooff VVeeccttoorrss

        outer(x, y, FUN = "*", ...)

   AArrgguummeennttss::

          x: a vector.

          y: a vector.

        FUN: a function to use on the outer products, it may be
             a quoted string.

        ...: optional arguments to be passed to `fun'.

   DDeessccrriippttiioonn::

        The outer product of the vectors `x' and `y' is the
        matrix `A' with elements `A[i, j] = FUN(x[i], y[j],
        ...)'.  `FUN' must be a function which expects at least
        two arguments and which operates elementwise on arrays.

        This needs to be extended to taking arrays of arbitrary
        dimension for `x' and `y' and returns an array of
        dimension `c(dim(x), dim(y))'.

   EExxaammpplleess::

        outer(1:5, 1:5, "+")

