[Rcpp-devel] Setting the R random seed from Rcpp
matteo.fasiolo at gmail.com
Fri Jun 7 17:29:24 CEST 2013
Thanks for you replies.
I need to seed the seed because I'm estimating the likelihood
function in an MCMC algorithm, and I need to use the same random numbers in
to get a good acceptance ratio. (I could also pass vectors of random
numbers around but
that's quite messy).
For some reason what Romain suggested doesn't seem to work:
List myFun(int n)
Environment g = Environment::global_env();
Environment::Binding RandomSeed = g[".Random.seed"];
NumericVector someVariable = RandomSeed;
RandomSeed = someVariable;
return List::create(output1, output2);
 1.3963522 0.3949708 -0.4526889 0.6898165 0.4216432 0.5742222
-0.6332163 0.2886058 1.9990184 -1.6650286
 0.33822725 0.19465447 0.04197205 0.01744784 0.75131016
0.06764945 -0.82518198 0.54712702 -2.48995321
On Fri, Jun 7, 2013 at 3:42 PM, Romain Francois <romain at r-enthusiasts.com>wrote:
> You can do something like this (i'm on my phone, so you might have to
> change it):
> Environment g = Environment::global_env() ;
> Environment::Binding RandomSeed = g[".Random.seed"] ;
> You get the current value of the binding like this:
> NumericVector someVariable = RandomSeed ;
> And then when you want to set the variable: you just do :
> RandomSeed = someVariable ;
> The Environment::Binding class acts a a proxy class.
> Le 7 juin 2013 à 16:22, Matteo Fasiolo <matteo.fasiolo at gmail.com> a écrit
> > Dear Rcpp experts,
> > I would like to be able to store the R random seed from a Rcpp
> > function and then reset it. In other words I would like to replicate
> > the following code in Rcpp:
> > savedSeed <- .Random.seed
> > x <- Rfunction(parameters1);
> > .Random.seed <- savedSeed
> > x1 <- Rfunction(parameters2);
> > where Rfunction simulates some random numbers and uses them
> > but with different parameter values.
> > Is it possible to do something similar in Rcpp?
> > Probably using GetRNGstate() and PutRNGstate()?
> > Thanks,
> > Matteo
> > _______________________________________________
> > Rcpp-devel mailing list
> > Rcpp-devel at lists.r-forge.r-project.org
> > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
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