I wrote: >>> P.S. I don't think the sugar versions can be made any quicker, because >>> they have to allocate intermediate vectors, and do more memory copies.
By "sugar versions" I meant vacc4() vs. vacc3() (https://gist.github.com/4111256) not pmin() and friends. The vacc4() code looks like: NumericVector p(age.size()); p = 0.25 + 0.3 * 1 / (1 - exp(0.04 * age)) + 0.1 * ily; p = p * ifelse(female, 1.25, 0.75); p = pmax(0,p); p = pmin(1,p); Each operation copies the whole NumericVector each time, each of which needs a memory allocation. vacc3a() does the same pipeline of operations on a single double, which is therefore likely to be a single CPU register, and the whole of vacc3a() will be inlined in vacc3(). > Also, I'm probably goinf to add a function that does the equivalent of : > > pmax( b, pmin( a, x ) ) > > I'm thinking of naming it pminmax. Any better idea ? I'd expect a function called minmax() to return two values, the min and max function. The "p" prefix is too subtle for me :-) How about clip(): p = clip(p, 0.0, 1.0); This is such a common operation that I'm surprised R doesn't already have a function like this! 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
