> What gives? What I found that does speed up the code dramatically > is the -march switch. I guess that can't be repo-ed because it is > CPU dependent, right? Here's the important settings that I used to > compile R from source: > > CC="gcc" > CFLAGS="-g -O2 -march=amdfam10" > CXX="g++" > CXXFLAGS="-g -O2 -march=amdfam10" > > With these settings... > > MCMC Code Switches Relative Time > R none or -O2 1.0 > RcppEigen none or -O2 0.09 > R -O2 -march=amdfam10 0.5 > RcppEigen -O2 -march=amdfam10 0.013
Wow, those are huge differences. Am I misreading, or does that say RcppEigen runs *seven* times quicker with the -march=amdfam10 option? Can that be explained? (e.g. does the AMDFAM10 processor have some feature that speeds it up 7 times in ideal conditions?) Darren -- Darren Cook, Software Researcher/Developer http://dcook.org/work/ (About me and my work) http://dcook.org/blogs.html (My blogs and articles) _______________________________________________ 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
