

   CCPPUU TTiimmee UUsseedd

        system.time(expr)
        unix.time(expr)

   AArrgguummeennttss::

       expr: Valid R expression to be ``timed''

   DDeessccrriippttiioonn::

        Return CPU (and other) times that `expr' used.

   DDeettaaiillss::

        `system.time' calls the builtin `proc.time', evaluates
        `expr', and then calls `proc.time' once more, returning
        the difference between the two `proc.time' calls.

        The values returned by the `proc.time' are (currently)
        those returned by the C library function `times'(3v).

        `unix.time' is an `.Alias' of `system.time', for com-
        patibility reasons.

   VVaalluuee::

        A numeric vector of length 5 containing the cpu, user,
        total, subproc1, subproc2 times.

   SSeeee AAllssoo::

        `proc.time', `time' which is for time series.

   EExxaammpplleess::

        system.time(for(i in 1:50) mad(runif(500)))
        exT <- function(n = 100) {
          # Purpose: Test if system.time works ok;   n: loop size
          system.time(for(i in 1:n) x <- mean(rt(1000, df=4)))
        }
        #-- Try to interrupt one of the following (using Ctrl-C):
        exT()                 #- `1.4' on -O-optimized Ultra1
        system.time(exT())    #~ +/- same

