Compare the speed of product vs exp/sum/log calculations

## Compare the speed of product vs exp/sum/log calculations

library(microbenchmark)
x <- runif(1000) + 0.5
all.equal(prod(x), exp(sum(log(x))))
## [1] TRUE                                

microbenchmark::microbenchmark(
                    prod(x), 
                    exp(sum(log(x)))
)

## Unit: microseconds
##             expr    min     lq     mean  median      uq     max neval
##          prod(x)  2.075  2.107  2.52904  2.1945  2.5285  13.964   100
## exp(sum(log(x))) 51.525 52.075 62.89344 52.6135 62.5120 400.676   100

We can see it is much faster to use the straightforward calculation of "prod".