G'day all, On Wed, 18 Feb 2009 12:41:27 -0500 Stavros Macrakis <macra...@alum.mit.edu> wrote:
> Hmm. Why not use the same method to guarantee the same result? Hmm, I did not look at the source code but, potentially, sum() could use some tricks to reduce rounding errors further that would not be available to cumsum(); e.g. sorting the data before adding summing them; or grouping them into groups of roughly similar magnitude and then sum group-by-group. So it does may be counter-productive to use the same method..... > Or at least document the possibility that cumsum(x)[length(x)] != > sum(x)... that seems like an easy trap to fall into. But this is already documented, isn't it? FAQ 7.31. ;-)) Cheers, Berwin ______________________________________________ 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.