Duncan, Berwin, Martin, Thanks for your thoughtful explanations, which make perfect sense.
May I simply suggest that the non-identity between last(cumsum) and
sum might be worth mentioning in the cumsum doc page?
-s
______________________________________________
[email protected] 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.

