> | I'm trying to get a better handle on writing efficient numerical code > | with C++. I've attached five implementations of a simple sum function > | (mostly ignoring NAs) and timed them below: > > Did you see the (fairly extensive) comparison in > examples/ConvolveBenchmarks/ > which compares running across vectors in similar ways? There is more code in > the main file than currently tickled so you may want to revisit this in some > detail. Also compares to R's C API -- a fresh set of eyes (yours!!) would be > welcome.
I didn't, but I'm looking at it now, thanks. The main problem is that many of the examples use C++ idioms I don't understand - and as I mentioned below, that code uses iterators in a way that I haven't seen anywhere else. > No, if I dare make a quick guess before heading to work it is because Romain > sneakily unrolls some loops for us in sugar --- fewer if() comparisons, > faster code. Ah cool, thanks. Hadley -- RStudio / Rice University http://had.co.nz/ _______________________________________________ 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
