Hi Martyn, Thanks for the analysis on that, and I'll remember that test in future - I've not seen a rounding error quite so finely balanced before. I've been using the "-fp-model precise" advice referenced in that document for a while - apparently it wasn't sufficient for this case.
Thanks also to Brian for sanity checking the linear algebra results in a previous post, and apologies for my imprecise terminology. Regards, Mike. -----Original Message----- From: Martyn Plummer [mailto:plumm...@iarc.fr] Sent: 23 October 2014 10:46 To: Pacey, Mike Cc: r-devel@r-project.org Subject: Re: [Rd] "make check" fails on lapack.R and stats-Ex.R On Thu, 2014-10-23 at 08:19 +0000, Pacey, Mike wrote: > As my attachment doesn't seem to have survived transit, I'm cut'n'pasting the > relevant failures here: > > Testing examples for package 'stats' > comparing 'stats-Ex.Rout' to 'stats-Ex.Rout.save' ... > 6466c6466 > < Grand Mean: 291.5937 > --- > > Grand Mean: 291.5938 I see the same thing, but it is not as bad as it looks. The actual value is 291.59375 so a small amount of numerical error can make the rounding to 4 decimal places go either way: > print(fit[[1]]$coefficients, digits=16) (Intercept) 291.5937500000002 Note that MKL sacrifices reproducibility (and hence precision) for speed. See more details here: https://software.intel.com/en-us/articles/run-reproducibility-with-intel-mkl-and-the-intel-compilers Martyn ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
