R devel - Oct 2001 - tiny typo in optim/N-M documentation (PR#1109)

In the optim() documentation,  the control parameter "maxit" says
"There is no other stopping criteria."  That should be
"are", or
"criterion" ...

While I'm at it -- poking at the code a little bit, it looks as if the
initial simplex is set from the initial point by displacing each
parameter value by max(0.1,0.1*pmax(fabs(Bvec))), where Bvec is the
initial parameter set.  It would be nice to have a bit more external
control of this procedure.
  Is anyone interested in hacking this?  If I did it myself would
anyone be interested in the results?  Or does fussing with the
Nelder-Mead simplex seem silly because anyone who is really serious
about optimization will being using another method anyway?

  Ben Bolker

--please do not edit the information below--

Version:
 platform = i686-pc-linux-gnu
 arch = i686
 os = linux-gnu
 system = i686, linux-gnu
 status  major = 1
 minor = 3.1
 year = 2001
 month = 08
 day = 31
 language = R

Search Path:
 .GlobalEnv, package:LG3d, package:ts, package:nls, package:ellipse,
package:mleprof, package:ctest, Autoloads, package:base

-- 
318 Carr Hall                                bolker@zoo.ufl.edu
Zoology Department, University of Florida    http://www.zoo.ufl.edu/bolker
Box 118525                                   (ph)  352-392-5697
Gainesville, FL 32611-8525                   (fax) 352-392-3704


-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To:
r-devel-request@stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._

Hi Ben,

bolker@zoo.ufl.edu wrote:
> While I'm at it -- poking at the code a little bit, it looks as if the
> initial simplex is set from the initial point by displacing each
> parameter value by max(0.1,0.1*pmax(fabs(Bvec))), where Bvec is the
> initial parameter set.  It would be nice to have a bit more external
> control of this procedure.
>   Is anyone interested in hacking this?  If I did it myself would
> anyone be interested in the results?  Or does fussing with the
> Nelder-Mead simplex seem silly because anyone who is really serious
> about optimization will being using another method anyway?
I am a happy (but serious) user of simplex optimisation in "optim".  I
think that it would be a very good idea to be able to over-ride the
default initial simplex through an argument to the "control" list.  So
if you do the hack please publish it, and if not, let me know and I will
have a go instead.

Cheers, Jonathan.

-- 
Jonathan Rougier                       Science Laboratories
Department of Mathematical Sciences    South Road
University of Durham                   Durham DH1 3LE
tel: +44 (0)191 374 2361, fax: +44 (0)191 374 7388
http://www.maths.dur.ac.uk/stats/people/jcr/jcr.html
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To:
r-devel-request@stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._