Unfortunately, this is not a robust implementation, and is derailed by Error in uniroot(f, c(-1, 1)) : f() values at end points not of opposite sign -- View this message in context: http://r.789695.n4.nabble.com/Code-to-calculate-internal-rate-of-return-tp864645p2231910.html Sent from the R help mailing list archive at Nabble.com.