From: Weiwei Shi <helprhelp_at_gmail.com>

Date: Mon 29 Jan 2007 - 02:24:35 GMT

Date: Mon 29 Jan 2007 - 02:24:35 GMT

try to use

set.seed(10)

before you call nnet and see if you have the same correlation each time.

I did not try by myself, though.

On 1/28/07, Aimin Yan <aiminy@iastate.edu> wrote:

> Hello,

*> I use nnet to do prediction for a continuous variable.
**> after that, I calculate correlation coefficient between predicted value and
**> real observation.
**>
**> I run my code(see following) several time, but I get different correlation
**> coefficient each time.
**>
**> Anyone know why?
**>
**> In addition, How to calculate prediction accuracy for prediction of
**> continuous variable?
**>
**> Aimin
**> thanks,
**>
**>
**> > m.nn.omega <- nnet(omega~aa_three+bas+bcu+aa_ss, data=training, size=2,
**> linout=TRUE)
**> # weights: 57
**> initial value 89153525.582093
**> iter 10 value 15036439.951888
**> iter 20 value 15010796.121891
**> iter 30 value 15000761.804392
**> iter 40 value 14955839.294531
**> iter 50 value 14934746.564215
**> iter 60 value 14933978.758615
**> iter 70 value 14555668.381007
**> iter 80 value 14553072.231507
**> iter 90 value 14031071.223996
**> iter 100 value 13709055.312482
**> final value 13709055.312482
**> stopped after 100 iterations
**> > pr.nn.train<-predict(m.nn.omega,training)
**> > corr.pr.nn.train<-round(cor(pr.nn.train,training$omega),2)
**> > pr.nn.test<-predict(m.nn.omega,test)
**> > corr.pr.nn.test<-round(cor(pr.nn.test,test$omega),2)
**> > cat("correlation coefficient for train using neural
**> network:",corr.pr.nn.train,"\n")
**> correlation coefficient for train using neural network: 0.32
**> > cat("correlation coefficient for test using neural
**> network:",corr.pr.nn.test,"\n")
**> correlation coefficient for test using neural network: 0.39
**>
**> ______________________________________________
**> R-help@stat.math.ethz.ch 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.
**>
*

-- Weiwei Shi, Ph.D Research Scientist GeneGO, Inc. "Did you always know?" "No, I did not. But I believed..." ---Matrix III ______________________________________________ R-help@stat.math.ethz.ch 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.Received on Mon Jan 29 13:29:54 2007

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