nlme problems

Dieter Menne · 2005-12-18T09:12:53Z

Ken Beath efs.mq.edu.au> writes: > > I'm maximising a reasonably complex function using nlme (version > 3.1-65, have also tried 3.1-66) and am having trouble with fixed > parameter estimates slightly away from the maximum of the log > likelihood. I have profiled the log likelihood and it is a parabola > but with sum dips. Interestingly changing the parameterisation moves > the dips around slightly. Unfortunately the PNLS step is finding a > maximum at the dips rather t

Dieter Menne

Sun, Dec 18, 2005 1:12 AM

Ken Beath <kbeath <at> efs.mq.edu.au> writes:

Ken, 

you should not use nlme for "maximising a complex function", because it's a 
rather specialized tool for mixed-model statistical analysis. Try to use optim 
directly, which has quite a few methods to choose from, and one of them might 
work for your problem.

Dieter

nlme problems

Thread (2 messages)