I'm looking for an R package to do Polytopic Vector Analysis (PVA) without success. I've checked CRAN, then did a site searched there, scanned the packages list, looked over old Help posting (there was a query about the same back in 2005 or so - only one response that didn?t give much direction as far as I can tell). No luck. As best as I can tell PVA is a method similar to factor analysis restricted to only non-negative factors. It allegedly can aid in "source unmixing". Has anyone put together a non-CRAN listed package in the intervening 10 years? Other suggestions (or anyone with a lead to the nebulous program given the Ehrlich (2008) citation common in geochemistry articles on PVA) would be greatly appreciated. Thanks, Louise