Thank you all for these answers. If you try "rcpp random number generation" in a search engine, the first line will point to
http://gallery.rcpp.org/articles/random-number-generation/ which probably has your answer. Best, Serguei Yes of course i tried http://gallery.rcpp.org/articl es/random-number-generation/, which helps to replace the rand function, and effectively, i found the set.seed () (from R), just i didn't know how t use it in C++. ----------------------------------------------------------------- ----------------- 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. Thx, I will look at RcppZiggurrat package, and also try other C++ functions. ----------------------------------------------------------------- ----------------- Hi Youssef, Rcpp has sugar for the R random number generators. This is nice if you want to let your users set the random seed in R code outside of the package for reproducibility: http://gallery.rcpp.org/articles/random-number-generation/ Alternatively, if you enable C++11, there are some random number generators in std: https://www.guyrutenberg.com/2014/05/03/c-mt19937-example/ Best, -- Hao Ye Thx, in my case, i have it initialize the number generator, so i will try check the proposed link. ----------------------------------------------------------------- ----------------- Best regards, Youssef 2018-02-07 16:44 GMT+01:00 Hao Ye <[email protected]>: > Hi Youssef, > > Rcpp has sugar for the R random number generators. This is nice if you > want to let your users set the random seed in R code outside of the package > for reproducibility: http://gallery.rcpp.org/articles/ > random-number-generation/ > > Alternatively, if you enable C++11, there are some random number > generators in std: https://www.guyrutenberg.com/2014/05/03/c-mt19937- > example/ > > Best, > -- > Hao Ye > > On Wed, Feb 7, 2018 at 10:20 AM, Hmamouche Youssef < > [email protected]> 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? >> >> Best regards, >> Youssef >> >> _______________________________________________ >> Rcpp-devel mailing list >> [email protected] >> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel >> > >
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