Vectorised Rcpp random binomial draws

Question

This is a follow-on question from this one: Generating same random variable in Rcpp and R

I\'m trying to speed up a vectorised call to rbinom of this form:

Answer 1

Not a general solution, but I'm noticing that you set the size argument to 1 in your call to rbinom. If that's always the case, you can draw length(x) uniform values and then comparing to x. For instance:

 set.seed(123)
 #create the values
 x<-runif(1000000)
 system.time(res<-rbinom(length(x),1 ,x))   
 # user  system elapsed 
 #0.068   0.000   0.070
 system.time(res2<-as.integer(runif(length(x))

Not a huge gain, but maybe you can save some little time if you call runif from C++, avoiding some overhead.