On 7 February 2018 at 16:20, Hmamouche Youssef wrote: | Hi, | | I get a note from R CMD check for an Rcpp package: | | Found ‘_srand’, possibly from ‘srand’ | | Found no calls to: ‘R_registerRoutines’, ‘R_useDynamicSymbols’ | | | Is there some an equivalent function for srand from Rcpp, which i can use | it inside c++ code?
In short, no. Slightly longer: All Rcpp code is set up to be used _from R_ so by design you are always in R before you call code containing Rcpp. So just call the R function set.seed(...) as we work hard to make sure the state is properly set and passed before and after. Even longer: srand() is always wrong and bad (long literature on that ...) and has nothing to do with R's RNG. You are entirely free to define and implement your own RNG (see my RcppZiggurrat package revisiting Marsaglia's Ziggurat RNG) or call others (C++11 has some) or ... But you probably want to use R's RNGs, and for that you have to set them from R (or use Rcpp::Function()). Also see the docs on the R Math Library (Section 6.16 of Writing R Extensions) which gives you special functions and RNGs and even set_seed() but that is for use _apart from R_ which is NOT what we do here. Dirk -- http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org _______________________________________________ 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
