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#!/usr/bin/env r
## New and shorter version of Fibonacci example using Rcpp 0.9.16 or later features
## The the sibbling file 'fibonacci.r' for context
require(Rcpp) # no longer need inline
## R version
fibR <- function(seq) {
if (seq < 2) return(seq)
return (fibR(seq - 1) + fibR(seq - 2))
}
## C++ code
cpptxt <- '
int fibonacci(const int x) {
if (x < 2) return(x);
return (fibonacci(x - 1)) + fibonacci(x - 2);
}'
## C++ version
fibCpp <- cppFunction(cpptxt) # compiles, load, links, ...
## load rbenchmark to compare
library(rbenchmark)
N <- 35 ## same parameter as original post
res <- benchmark(fibR(N), fibCpp(N),
columns=c("test", "replications", "elapsed", "relative"),
order="relative", replications=1)
print(res) ## show result
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