On Wed, Dec 14, 2016 at 12:23 PM, Johannes Kruisselbrink <johan...@kruisselbrink.eu> wrote: > > Good point. Actually, I didn't even realize there were so many is-nan > functions to choose from. But indeed, we used the R-core ISNAN function on > doubles accessed via Rcpp.
Me either :) Of course, the above isn't particular to Rcpp, but I found that tracking down the underlying machinery of ISNAN in the context of Rcpp to be an interesting and useful exercise. >> Based on the above, I added permutations to a *very* minimal test (no >> return val, etc) that include Romain's suggestion: >> https://github.com/helmingstay/rcpp-timings/tree/master/minimal >> ## source('benchmarks.r') >> [...] > > Wow, thank you for the thorough comparison. I ran some tests myself based on > your code. It seems that I cannot get the "CountNans_expr" version to > compile, any ideas? Same problem with the Rcpp sugar isnan version. Can you be more specific? > The std::isnan version, however, does work and, on my machine, actually > outperforms the call function. So performance-wise this is a very > interesting candidate. Just to clarify, R's NA is subset of ieee NaN. So std::isnan catches both NAs and NaNs. If you need to manually catch *just* NAs, then it looks like you need to return to an R-core solution (please do correct me if I muxed this up). Ref: https://github.com/wch/r-source/blob/trunk/src/main/arithmetic.c#L108 best, Christian -- A man, a plan, a cat, a ham, a yak, a yam, a hat, a canal – Panama! _______________________________________________ Rcpp-devel mailing list Rcpp-devel@lists.r-forge.r-project.org https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
