On 03.11.2010 16:26, Fabon Dzogang wrote:
Hi, I run R 2.10.1 under ubuntu 10.04 LTS (Lucid Lynx) and klaR version 0.6-4. I compute a model over a 2 classes dataset (composed of 700 examples). To that aim, I use the function NaiveBayes provided in the package klaR. When I then use the prediction function : predict(my_model, new_data). I get the following warning : "In FUN(1:747[[747L]], ...) : Numerical 0 probability with observation 458" As I did not find any documentation or any discussion concerning this warning message, I looked in the klaR source code and found the following line in predict.NaiveBayes.R : "warning("Numerical 0 probability with observation ", i)"
Within Naive Bayes in order to calculate the posteriori probabilities of the classes it is necessary to calculate the probabilities of the observations given the classes. The function NaiveBayes prints a warning if all these probabilities are numerical 0, i.e. that the observation has a numerical probability of 0 for *all* classes. Usually this is only the case when the obs. is an extreme outlier. I will change the warning to say "all classes" in further releases of klaR. Best wishes, Uwe Ligges
Unfortunately, it is hard to get a clear picture of the whole process reading the code. I wonder if someone could help me with the meaning of this warning message. Sorry I did not provide an example, but I could not simulate the same message over a small toy example. Thank you, Fabon Dzogang. ______________________________________________ R-help@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.
______________________________________________ R-help@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.