Is it possible to count the number of arithmetic operations in R?

Question

It is possible to record the time that was used to run some code using system.time. Here is a little example:

system.time(
  mean(rnorm(10^6))
  )

But I am not only interested in the time but also in the number of arithmetic operations (that is +,-,*,/) that were used for the code.

In the above-mentioned case it would be easy to count the number of summations and the division in order to get the mean, but the code I would like to apply this to is far more complex.

Therefore, my question is: is there a function in R that counts the number of arithmetic operations?

Answer 1

You can trace the R functions of interest:

counter <- 0 

trace("+", at = 1, print = FALSE,
      tracer = quote(.GlobalEnv$counter <- .GlobalEnv$counter + 1))
#Tracing function "+" in package "base"
#[1] "+"

Reduce("+", 1:10)
#[1] 55

counter
#[1] 9

untrace("+")
#Untracing function "+" in package "base"

I'm not sure how useful it would be to count R level calls here. Many (most?) functions do arithmetic in C or Fortran code or even the BLAS. And I don't have a solution for counting calls in compiled code. You'd need to set that up during compilation if it is possible at all.