From ripley at stats.ox.ac.uk  Mon Apr 18 20:30:36 2005
From: ripley at stats.ox.ac.uk (Prof Brian Ripley)
Date: Mon Apr 18 20:30:48 2005
Subject: [Rd] Why no BIC.default function?
In-Reply-To: <17905.170.54.59.167.1113847926.squirrel@170.54.59.167>
References: <17905.170.54.59.167.1113847926.squirrel@170.54.59.167>
Message-ID: <Pine.LNX.4.61.0504181925230.17897@gannet.stats>

R does not have a BIC S3 generic function: it is in package nlme!
(There is one for S4 classes in package stats4.)

So this is a question for the nlme maintainer.

On Mon, 18 Apr 2005 kwright@eskimo.com wrote:

>
> I'm using R 2.0.1.
>
> I looked in the email archives but didn't see anything on this topic.
>
> I've noticed a surprising (to me) difference between AIC and BIC:
>
>> methods("AIC")
> [1] AIC.default* AIC.logLik*
>
>> methods("BIC")
> [1] BIC.gls*    BIC.lm*     BIC.lme*    BIC.lmList* BIC.logLik* BIC.nls*
>
> The BIC.gls BIC.lm BIC.lme BIC.lmList and BIC.nls functions appear to have
> exactly the same definition.  (I didn't check with 'diff' though.)
>
> Would it make sense to treat BIC similarly to AIC and have just
> BIC.default and BIC.logLik?

-- 
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)
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[Rd] Why no BIC.default function?
Prof Brian Ripley