Hi, Can you provide a little more information about your problem?
If you are trying to find a local maximum of "maxphi", then you need to tell that to optim(),. It tries to find a local minimum by default. You can do this via the `fnscale' control parameter (control = list(fnscale = -1)). If this still does not work, try the function spg() in the "BB" package. Ravi. ---------------------------------------------------------------------------- ------- Ravi Varadhan, Ph.D. Assistant Professor, The Center on Aging and Health Division of Geriatric Medicine and Gerontology Johns Hopkins University Ph: (410) 502-2619 Fax: (410) 614-9625 Email: rvarad...@jhmi.edu Webpage: http://www.jhsph.edu/agingandhealth/People/Faculty/Varadhan.html ---------------------------------------------------------------------------- -------- -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of H c Sent: Wednesday, May 06, 2009 2:19 PM To: r-sig-mixed-mod...@r-project.org; r-help@r-project.org Subject: [R] NLMINB() produces NaN! I am having the same problem as one Rebecca Sela(see bellow). On 21/12/2007 12:07 AM, Rebecca Sela wrote: >* I am trying to optimize a likelihood function using NLMINB. After >running without a problem for quite a few iterations (enough that my >intermediate output extends further than I can scroll back), it tries a >vector of parameter values NaN. This has happened with multiple Monte >Carlo datasets, and a few different (but very similar) likelihood >functions. (They are complicated, but I can send them to someone if >desired.)* Instead I try to use optim() for my optimization needs but it fails when finding the 0/0: " Error in optim(c(phi[, k]), maxphi, lower = 0.01, upper = 0.99, method = "L-BFGS-B") : L-BFGS-B needs finite values of 'fn' In addition: There were 50 or more warnings (use warnings() to see the first 50) " Any suggestions? Harlan Campbell McGIll University [[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.
