[R] Use of ellipses ... in argument list of optim(), integrate(), etc.

[Vincent Goulet]

 From the NEWS file:

CHANGES IN R VERSION 2.6.0
SIGNIFICANT USER-VISIBLE CHANGES
  o	integrate(), nlm(), nlminb(), optim(), optimize() and uniroot()  
now have '...' much earlier in their argument list. This reduces the  
chances of unintentional partial matching but means that the later  
arguments must be named in full.

---
   Vincent Goulet, Associate Professor
   École d'actuariat
   Université Laval, Québec
   Vincent.Goulet at act.ulaval.ca   http://vgoulet.act.ulaval.ca

Le jeu. 13 mars à 12:05, Ravi Varadhan a écrit :

> Hi,
>
>
>
> I have noticed that there is a change in the use of ellipses or . in R
> versions 2.6.1 and later.  In versions 2.5.1 and earlier, the . were  
> always
> at the end of the argument list, but in 2.6.1 they are placed after  
> the main
> arguments and before method control arguments.  This results in the  
> user
> having to specify the exact (complete) names of the control  
> arguments, i.e.
> partial matching is not allowed.
>
> An example with integrate() :
>
>> integrate(function(x) exp(-x^2), lower=-Inf, upper=L, subdiv=1000)
>
> Error in f(x, ...) : unused argument(s) (subdiv = 1000)
>
>> integrate(function(x) exp(-x^2), lower=-Inf, upper=L,  
>> subdivisions=1000)
>
> 1.633051 with absolute error < 1.6e-06
>
> Here is an example with optim():
>
>> res <- optim(50, fw, meth="BFGS", control=list(maxit=20000, temp=20,
> parscale=20))
>
> Error in fn(par, ...) : unused argument(s) (meth = "BFGS")
>
> FYI, I am using R version 2.6.1 on Windows XP.
>
> May I ask what the rationale behind this change is and also about  
> the pros
> and cons of the two different ways of specifying (.)?
>
> Thank you very much.
>
> Best,
>
> Ravi.
>
> ------------------------------------------------------------
> Ravi Varadhan, Ph.D.
> Assistant Professor, The Center on Aging and Health
> Division of Geriatric Medicine and Gerontology
> Johns Hopkins University
> Ph: (410) 502-2619
> Fax: (410) 614-9625
> Email: rvaradhan at jhmi.edu
> Webpage:  http://www.jhsph.edu/agingandhealth/People/Faculty/Varadhan.html
> ----------------------------------------------------------------------------