From tplate at acm.org  Fri Oct  9 18:35:51 2009
From: tplate at acm.org (Tony Plate)
Date: Fri, 09 Oct 2009 10:35:51 -0600
Subject: [Rd] weigths in nls (PR#13991)
In-Reply-To: <20091009144011.786A62831FFC@mail.pubhealth.ku.dk>
References: <20091009144011.786A62831FFC@mail.pubhealth.ku.dk>
Message-ID: <4ACF6667.4060801@acm.org>

This is expected behavior from the way nls() is written.  The nls() 
function has a "..." argument, which means that additional arguments are 
allowed.

Under "Arguments" the docs say:
|...| 	Additional optional arguments. None are used at present.


As far as I can see in the code, nothing at all is done with the 
additional arguments (consistent with the docs).   I guess the "..." 
argument is there to allow for future development (though I'm not sure 
what is gained by including "..." as a formal argument now, and not just 
adding it in the future if and when it is needed.)

In general, the use of ... arguments does add flexibility, but it takes 
away some error-checking.

-- Tony Plate

Stephen.Bond at cibc.com wrote:
> Potential bug:
>
> I mistyped weights in the call ('weigths') and it did not produce any error=
>  message. The coefs were exactly the same like without weights, so I was su=
> spicious and when weights(nls1) gave NULL, I saw my typo.
>
> Usually the function will say "Unused arguments", which shows you the error=
> , but not nls.
>
> Regards
> Stephen
>
> 	[[alternative HTML version deleted]]
>
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>



[Rd] weigths in nls (PR#13991)
Tony Plate