In my previous post, I tried to show, that Rcpp is 1000 faster than pure R and that generated the fuss in the comments. Being lazy, I didn’t vectorize R code and at the end I was comparing apples vs oranges.
To fix that problem, I built a new script, where I’m trying to compare apples against apples. First piece of code named “ifelse R” uses R “ifelse” function to vectorize code. Second piece of code is fully vectorized code written in R, third - pure C++ code and the last one is C++, where Rcpp “ifelse” function is used.
| Name | Seconds |
|---|---|
| ifelse R | 27.50 |
| vectorized R | 10.40 |
| pure C++ | 0.44 |
| vectorized C++ | 2.24 |
Here we go - vectorization truly helps, but pure C++ code still 23 times faster. Of course you pay the price when writing it in C++. I found a bit strange, that vectorized C++ code doesn’t perform that well…
You can get the code from github.