[R] R crashing inconsistently within for loops

[Steve Powers]

Hello,

This one has been bugging me for a long time and I have never found a
solution. I am using R version 2.15.1 but it has come up in older versions of R I have used over the past 2-3 years.

Q: Am I wrong to expect that R should handle hundreds of iterations of the
base model or statistical functions, embedded within for loops, in one
script run? I have found that when I write scripts that do this, sometimes
they have a tendency to crash, seemingly unpredictably.

For example, one problem script of mine employs glm and gls about a hundred
different times, and output files are being written at the end of each
iteration. I have used my output files to determine that the crash cause is
not consistent (R never fails at the same iteration). Note that the data are
fixed here (no data generation or randomization steps, so that is not the
issue). But it is clear that scripts with larger numbers of iterations are
more likely to produce a crash.

And a year or two ago, I had a seemingly stable R script again with for
looped model fits, but discovered this script was prone to crashing when I
ran it on a newer PC. Because the new PC also seemed to be blazing through R
code absurdly fast, I tried adding a short "fluff" procedure at the end of
each iteration that required a few seconds of processing time. Low and
behold, when I added that, the script stopped crashing (and each iteration
of course took longer). I still don't understand why that fixed things.

What is going on? Solutions? Thanks.---steve

-- 
Steve Powers
powers_s at nd.edu
University of Notre Dame
Environmental Change Initiative
website (http://www.nd.edu/~spowers2/index.htm)