It probably means that your parameters are taking on values that are infeasible. You may have to impose constraints on your parameters to get a solution (e.g. bounds constraints). If you need better help, you have to send us a minimal, self-contained, reproducible example.
Ravi. -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Carol Gao Sent: Friday, May 07, 2010 5:53 AM To: R-help@r-project.org Subject: [R] problem in using optim Dear R users, When I was trying to use the function *optim* to get the MLEs, quite a few warning messages showed up as below: Warning in log(psi * lam) : NaNs produced I am just wondering what does this mean? Was it something wrong with my likelihood function or was it sth wrong with the data? Thanks in advance. Carol Gao [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
