I have trimmed the address to the mixed models list since you (and I ) are asked in the Posting Guide to pick one of the lists rather than cross posting. 

Have you looked at the possibility of using the try function around your individual optim calls? 

?try 

-- 
David Winsemius 

----- Original Message ----- 
From: "H c" <harlancampbell@gmail.com> 
To: r-sig-mixed-models@r-project.org, r-help@r-project.org 
Sent: Wednesday, May 6, 2009 1:19:00 PM GMT -06:00 US/Canada Central 
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 

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