R-beta: more glm bugs

Thomas Lumley thomas at biostat.washington.edu
Mon Jan 26 17:34:35 CET 1998

On Mon, 26 Jan 1998, Jim Lindsey wrote:

>   1. At least on my computer, fitting a saturated gamma model with glm
> gives a core dump:
> glm(rgamma(20,1,1)~gl(20,1,20), family=Gamma)

I can't reproduce this problem on 0.50-a4, 0.60 or 0.61.1.

>   2. Factor variables are not vectors!!
> is.vector(gl(20,2,40)) gives FALSE

Even stranger 
R> is.vector(factor(1:3))
R> is.factor(factor(1:3))
[1] TRUE
R> is.vector(as.vector(factor(1:3)))
[1] TRUE
R> is.factor(as.vector(factor(1:3)))
[1] TRUE
so that factor variables *can* be vectors, but aren't naturally.

Thomas Lumley
Uni of Washington	
Box 357232		
Seattle WA 98195-7232	

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