[Haskell-cafe] low-cost matrix rank?

Noticing that diagrams 1.3 has moved from vector-space to linear, I decided to check them both for a function to compute the rank of a matrix. Neither seems to have it. While I'm doing quite a bit of work with 2 and 3-element vectors, the only thing I do with matrices is take their rank, as part of verifying that the faces of a polyhedron actually make a polyhedron. So I'm looking for a relatively light-weight way of doing so that will work with a recent (7.8 or 7.10) ghc release. Or maybe getting such a function added to an existing library. Anyone have any suggestions? Thanks, Mike