"CR Bleay, School Biological Sciences" <[EMAIL PROTECTED]> writes:
> hello all, > > last week i sent an e-mail about dealing with errors thrown up from a > glm.nb model carried out on multiple random datasets. > > every so often a dataset is created which results in the following > error after a call to glm.nb: > > "Error: NA/NaN/Inf in foreign function call (arg 1) > In addition: Warning message: > Step size truncated due to divergence" > > > I am at a loss as to how to deal with this. > > firstly because the dataset that is generated, although throwing an > error when the glm.nb model is applied, is a valid dataset. so how do > i incorporate this dataset in my results (results being descriptive > stats on the coefficients from the multiple datasets) i.e. shoould > coefficients be set to zero? NA, more likely, but it's not easy to say in general. If the algorithm diverged in a particular way, setting diverged parameters to Inf or -Inf might be a better idea. It is of course, quite normal that the MLE does not exist for some data sets, although perhaps the algorithm might have failed more gracefully. > secondly, how do i capture and deal with the error. is it possible to > construct an "if" statement so that "if error, do this, if not > continue" > > lastly, i am unsure as to what characteristics of a dataset would > result in these errors in the glm.nb? > > i would be very grateful for any assistance on this matter. i having > been staring at code for too many days now and so can't see the wood > for the trees. > Look at try() -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
