Seeking a Closest Pair algorithm

I am seeking a simple, straightforward, recursive Closest Pair algorithm (in Matlab, of course) for comparison with methods I am developing. Do you know of any that are not in Matlab toolboxes? There's a program ipdm.m in the user contributions, but it scales as O(n^2), so I don't think it's the divide-and-conquer recursive type. Thanks.

Cye