Hook to time knitr chunks

Question

I would like to time knitr chunks and record how long it took to render them using comments in LaTeX output.

I\'ve tried the following hook:

 now = S         


        

Answer 1

Try this:

local({
  now = Sys.time()
  knit_hooks$set(timeit = function(before) {
    if (before) {
      now <<- Sys.time()
    } else {
      x = round(Sys.time() - now, digits = 3)
      x = sprintf("%% Chunk rendering time: %s seconds.", x)
      paste('\\end{kframe}\n', x, '\n\\begin{kframe}')
    }
  })
})

It is a hack, though. Basically you escape the LaTeX comment from the kframe environment.