(PR#2691) Re: [Rd] optim control trace=-1 gives more output than trace=0
Hmm: does it say what happens for negative values? I don't think so. If you use undocumented values of an argument you should expect surprises. What happens depends on the method argument, BTW. I've added a warning to read the documentation if trace < 0 is supplied.
On Thu, 27 Mar 2003 Robert.King@newcastle.edu.au wrote:
Full_Name: Robert King Version: 1.6.2 OS: linux Submission from: (NULL) (134.148.20.33) In optim, non-zero values of trace in the control list are treated as postitive, even if they are negative.
From documentation:
trace
Integer. If positive, tracing information on the progress of the optimization is
produced. Higher values may produce more tracing information: for method
"L-BFGS-B" there are six levels of tracing. (To understand exactly what these do
see the source code: higher levels give more detail.)
example:
obj <- function(par){sum(par)}
par <- c(1,1,1)
optim(par,obj,control=list(trace=-1))
Not a very useful one!
Brian D. Ripley, ripley@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