[R] Incompatibility with VGAM

Uwe Ligges ligges at statistik.uni-dortmund.de
Sun May 29 15:21:42 CEST 2005

Kjetil Brinchmann Halvorsen wrote:
> I just discovered that when the VGAM package (not on CRAN) is loaded,
> glm() doesn't work. This is because VGAM defines a family function() 
> which gets found
> by glm() in place of the family function from stats.
> Then VGAM:::family returns an object which doesn't have a $family 
> component, (it has a component
> $vfamily).
> I thought namespaces should protect us from this happening?

Yes and no:

Yes: The namespace would protect you if glm would call internally the 
family function such as poisson().

No: Probably you have asked something like glm(....., family=poisson()). 
Now the first instance of poisson() in the search path is used. You are 
passing a call to poisson(), and this is not bound to any namespace. Of 
course you can specify tha namespace such as
glm(....., family=stats::poisson()).

Uwe Ligges

> Kjetil

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