[R] How to save/load RWeka models into/from a file?

[Paulo Cortez]

Hi,

I want to save a RWeka model into a file, in order to retrive it latter 
with a load function.

See this example:

library(RWeka)

NB <- make_Weka_classifier("weka/classifiers/bayes/NaiveBayes")
model<-NB(formula,data=data,...) # does not run but you get the idea

save(model,file="model.dat") # simple save R command
# ...
load("model.dat") # load the model from the previously saved file...
model # should work but I get instead this error:
Error in .jcall(x$classifier, "S", "toString") :
   RcallMethod: attempt to call a method of a NULL object.

What is wrong and how can I solve this problem?

Regards,
-- 
Paulo Alexandre Ribeiro Cortez  (PhD, MSc)
Lecturer (Prof. Auxiliar) at the Department of Information Systems (DSI)
University of Minho, Campus de AzurÈm, 4800-058 Guimaraes, Portugal
http://www.dsi.uminho.pt/~pcortez +351253510313 Fax:+351253510300