Thanks to Andy Liaw, Hisaji Ono,Alessandro Semeria, Patrick Burns, among others. There are three(?) packages on CRAN: "gafit", "seao", "rgenoud". While "genopt" function from S Poetry also works. "rgenoud" and "genopt" are for general optimization problems. Cheers, -- Zhu Wang Statistical Science Department Southern Methodist University Phone: (214)768-2453 Fax: (214)768-4035 Email: zhuw at mail.smu.edu