Hi Clara, I suspect your error is happening because your input data is short (9 observations). In the help for ar() for argument "order.max" it states
order.max Maximum order (or order) of model to fit. Defaults to 10*log10(N) where N is the number of observations except for method="mle" where it is the minimum of this quantity and 12. so perhaps the problem is 10*log10(9) is smaller than 1 and isn't being handled properly (this is just a guess). If I lengthen your data vector to be x<-ts(c(-0.2052083,-0.3764986,-0.3762448,0.3740089,0.2737568,2.8235722,-1.7783313,0.2728676,-0.3273164, -0.2052083,-0.3764986,-0.3762448,0.3740089,0.2737568,2.8235722,-1.7783313,0.2728676,-0.3273164),start=c(1978,3),frequency=4,end=c(1982,3)) I can not trip the error. I filed a bug report. You might try specifying order.max in your function call. If I specify order.max = 1 I can not trip the error. > res.ar<-ar(x,aic=TRUE,demean=F) > res.ar<-ar(x,aic=TRUE,demean=F) Error in if (order > 0) coefs[order, 1:order] else numeric(0) : missing value where TRUE/FALSE needed In addition: Warning message: In if (order > 0) coefs[order, 1:order] else numeric(0) : the condition has length > 1 and only the first element will be used > res.ar<-ar(x,aic=TRUE,demean=F) Error in if (order > 0) coefs[order, 1:order] else numeric(0) : missing value where TRUE/FALSE needed In addition: Warning message: In if (order > 0) coefs[order, 1:order] else numeric(0) : the condition has length > 1 and only the first element will be used > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > res.ar<-ar(x,aic=TRUE,demean=F, order.max = 1) > sessionInfo() R version 2.6.0 (2007-10-03) powerpc-apple-darwin8.10.1 locale: en_CA.UTF-8/en_CA.UTF-8/en_CA.UTF-8/C/en_CA.UTF-8/en_CA.UTF-8 attached base packages: [1] splines stats graphics grDevices utils datasets methods base other attached packages: [1] survival_2.34 loaded via a namespace (and not attached): [1] tools_2.6.0 > Steven McKinney Statistician Molecular Oncology and Breast Cancer Program British Columbia Cancer Research Centre email: smckinney +at+ bccrc +dot+ ca tel: 604-675-8000 x7561 BCCRC Molecular Oncology 675 West 10th Ave, Floor 4 Vancouver B.C. V5Z 1L3 Canada -----Original Message----- From: [EMAIL PROTECTED] on behalf of Clara Cordeiro Sent: Fri 11/23/2007 7:38 AM To: [EMAIL PROTECTED] Subject: [R] help pleaseeeeeeeee Dears Sirs During my computational work I encountered unexpected behavior when calling "ar" function, namely # time series x<-ts(c(-0.2052083,-0.3764986,-0.3762448,0.3740089,0.2737568,2.8235722,- 1.7783313,0.2728676,-0.3273164),start=c(1978,3),frequency=4,end=c(1980,3)) # ar function res.ar<-ar(x,aic=TRUE,demean=F) # call "ar" again and ............ res.ar<-ar(x,aic=TRUE,demean=F) Error in if (order > 0) coefs[order, 1:order] else numeric(0) : missing value where TRUE/FALSE needed In addition: Warning messages: 1: In log(var.pred) : NaNs produced 2: In if (order > 0) coefs[order, 1:order] else numeric(0) : the condition has length > 1 and only the first element will be used For me it is mysterious why sometimes it works and others it does not, perhaps I am doing something wrong and stupid :-( If anyone had already had this problem could you please tell me how you have solved it? Thank you for your time. Best Regards, Clara Cordeiro [[alternative HTML version deleted]] ______________________________________________ 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.