[R] save a regression model that can be used later

[David Winsemius]

On Nov 22, 2010, at 10:02 AM, Ni, Melody Zhifang wrote:

> Hi everyone
>
> I have a question about how to save a regression model in R and how  
> to retrieve it for making predictions in a new session.
>
> To be more specific, I fitted a multilevel logistic regression model  
> using the lmer  from the "lme4" package. I then successfully make  
> predictions using  fitted(mymodel).
>
> Since data are complex (three levels, nested, numerous categorical  
> and continuous data describing types of laparoscopic surgery), the  
> computer takes quite a while to fit the MLM model.  I wonder whether  
> it's possible to save the fitted model so that I don't have to fit  
> it again for making predictions every time I start a new R session.
>
> I searched the mailing-list archive. Suggestions include using save  
> () to save the model as "mymodel.rda" and then use load(mymodel.rda)  
> into the workspace. I tried without success (in Windows), returning  
> the error message: "Error in object$fitted : $ operator is invalid  
> for atomic vectors"

How? ... did you "try" that is. Need code, not vague reports of failure.

>
> Did I do anything wrong?  Any help on this topic is much appreciated
>
> BW, Melody
>
> --
> Dr Melody Ni
> Imperial College
> Department of Surgery and Cancer
> 10th floor, QEQM Building
-- 
David Winsemius, MD
West Hartford, CT