[R] stats lm() function

[David Winsemius]

I think you will find that many readers of this list would rather try  
to dissuade you from this misguided strategy. You are unlikely to get  
to a sensible solution in using step-down procedures with this sort of  
situation (large number of predictors with modest size of data).

-- 
David Winsemius

On Mar 12, 2009, at 1:59 PM, Paul Hermes wrote:

> Hi,
>
> Im using the lm() function where the formula is quite big (300  
> arguments) and the data is a frame of 3000 values.
>
> This is running in a loop where in each step the formula is reduced  
> by one argument, and the lm command is called again (to check which  
> arguments are useful) .
>
> This takes 1-2 minutes.
> Is there a way to speed this up?
> i checked the code of the lm function and its seems that its  
> preparing the data and then calls lm.Fit(). i thought about just  
> doing this praparing stuff first and only call lm.fit() 300 times.
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
Heritage Laboratories
West Hartford, CT