From J.C.Rougier@durham.ac.uk  Thu Oct  4 09:16:08 2001
From: J.C.Rougier@durham.ac.uk (Jonathan Rougier)
Date: Thu, 04 Oct 2001 09:16:08 +0100
Subject: [Rd] tiny typo in optim/N-M documentation (PR#1109)
References: <200110031509.RAA09208@pubhealth.ku.dk>
Message-ID: <3BBC1AC8.BBA063E7@durham.ac.uk>

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
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[Rd] tiny typo in optim/N-M documentation (PR#1109)
Jonathan Rougier