| system.time {base} | R Documentation |
Return CPU (and other) times that expr used.
system.time(expr, gcFirst = TRUE)
expr |
Valid R expression to be timed. |
gcFirst |
Logical - should a garbage collection be performed
immediately before the timing? Default is |
system.time calls the function proc.time,
evaluates expr, and then calls proc.time once more,
returning the difference between the two proc.time calls.
unix.time has been an alias of system.time, for
compatibility with S, and has finally been deprecated in 2016.
Timings of evaluations of the same expression can vary considerably
depending on whether the evaluation triggers a garbage collection. When
gcFirst is TRUE a garbage collection (gc)
will be performed immediately before the evaluation of expr.
This will usually produce more consistent timings.
A object of class "proc_time": see
proc.time for details.
proc.time, time which is for time series.
Sys.time to get the current date & time.
require(stats)
system.time(for(i in 1:100) mad(runif(1000)))
## Not run:
exT <- function(n = 10000) {
# 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 / Escape):
exT() #- about 4 secs on a 2.5GHz Xeon
system.time(exT()) #~ +/- same
## End(Not run)