I do not think we have support for bigmemory's big.matrix objects. So you can't just assum it works. Contributions welcome. This is both 'an obvious one' as it would make sense at the C++ and R levels, and something that should not be so hard as we support XPtr. Dirk -- Dirk Eddelbuettel | edd at debian.org | http://dirk.eddelbuettel.com