How do I avoid halting the execution of a standalone r script that encounters an error? - r

Question

I am running an optimization program I wrote in a multi-language framework. Because I rely on different languages to accomplish the task, everything must be standalone so it can be launched through a batch file. Everything has been going fine for 2-3 months, but I finally ran out of luck when one of the crucial parts of this process, executed through a standalone R script, encountered something new and gave me an error message. This error message makes everything screech to a halt despite my best efforts:
selMEM<-forward.sel(muskfreq, musk.MEM, adjR2thresh=adjR2)
Procedure stopped (adjR2thresh criteria) adjR2cum = 0.000000 with 0 variables (superior to -0.005810)
Error in forward.sel(muskfreq, musk.MEM, adjR2thresh = adjR2) :
No variables selected. Please change your parameters.
I know why I am getting this message: it is warning me that no variables are above the threshold I have programmed to retain during a forward selection. Although this didn't happen in hundreds of runs, it's not that big a deal, I just need to tell R what to do next. This is where I am lost. After an exhaustive search through several posts (such as here), it seams that try() and tryCatch() are the way to go. So I have tried the following:
selMEM<-try(forward.sel(muskfreq, musk.MEM, adjR2thresh=adjR2))
if(inherits(selMEM, "try-error")) {
max<-0
cumR2<-0
adjR2<-0
pvalue<-NA
} else {
max<-dim(selMEM)[1]
cumR2<-selMEM$R2Cum[max]
adjR2<-selMEM$AdjR2Cum[max]
pvalue<-selMEM$pval[max]
}
The code after the problematic line works perfectly if I execute it line by line in R, but when I execute it as a standalone script from the command prompt, I still get the same error message and my whole process screeches to a halt before it executes what follows.
Any suggestions on how to make this work?

Answer 1

Note this in the try help:
try is implemented using tryCatch; for programming, instead of
try(expr, silent = TRUE), something like tryCatch(expr, error =
function(e) e) (or other simple error handler functions) may be more
efficient and flexible.
Look to tryCatch, possibly:
selMEM <- tryCatch({
forward.sel(muskfreq, musk.MEM, adjR2thresh=adjR2)
}, error = function(e) {
message(e)
return(NULL)
})
if(is.null(selMEM)) {
max<-0
cumR2<-0
adjR2<-0
pvalue<-NA
} else {
max<-dim(selMEM)[1]
cumR2<-selMEM$R2Cum[max]
adjR2<-selMEM$AdjR2Cum[max]
pvalue<-selMEM$pval[max]
}

Answer 2

Have you tried setting the silent parameter to true in the Try function?
max<-0
cumR2<-0
adjR2<-0
pvalue<-NA
try({
selMEM <- forward.sel(muskfreq, musk.MEM, adjR2thresh=adjR2)
max<-dim(selMEM)[1]
cumR2<-selMEM$R2Cum[max]
adjR2<-selMEM$AdjR2Cum[max]
pvalue<-selMEM$pval[max]
}, silent=T)