Do you know what you are doing using method SANN? It is a very strange
choice for a 2D problem. Method L-BFGS-B would allow non-negativity
constraints.
optim() does not have control options trans and times ...
The standard way would be to transform your problem, for example to
optimize over log-parameters, if you really meant `positive' and not
`non-negative'.
On Sat, 2 Oct 2004, Christian Schulz wrote:
>
optim(c(1,1),LL,method="SANN",control=list(fnscale=-1),trans=trans,times=times)
> $par
> [1] 17.422635 -1.606859
>
> How could i constraint that the parameters should be both positive in
> my maximizing problem?
> I check constrOptim but here i could only constraint the variables trans
and
> times and not my parameters?
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
That applies to YOU.
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595