[R] how to get condition number from lm output

[Uwe Ligges]

Mai Zhou wrote:
> 
> Dear r-help,
> 
> I ran
> 
> output <- lm(formu, data=mydata)
> 
> I want to look at the condition number (to see if the matrix is near singular). How?


 kappa(output)

 
> Also, I use the function stepAIC from MASS to select models, how can I see the condition numbers in each step?

See the argument "keep" described in ?stepAIC
So you can use something like

 stepAIC(. . . . ., keep = function(fit, AIC) kappa(fit))
 

> While I am at it. I find a minor bug:
> R 1.7.1 on window XP, when you copy and paste by click
> one button, then the input stopped, until you click the
> "copy and paste" button again and click OK.

ALready fixed for R-1.8.0 (beta).

Uwe Ligges



> Thanks in advance.
> 
> Mai Zhou
> mai at ms.uky.edu
> 
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