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

[Greg Snow]

One possibility for what is happening is that when you load the object it does not automatically load the package as well, so you get an error when working with the object.  Try loading lme4 package in a new session, then load the saved object and see if things work for you.

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Ni, Melody Zhifang
> Sent: Monday, November 22, 2010 8:02 AM
> To: 'r-help at r-project.org'
> Subject: [R] save a regression model that can be used later
> 
> 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"
> 
> 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
> St. Mary's Hospital
> London W2 1NY
> Tel/Fax: +44 (0) 20 331 27657/26309
> z.ni at imperial.ac.uk<mailto:z.ni at imperial.ac.uk>
> 
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