| system.time {base} | R Documentation |
Return CPU (and other) times that expr used.
system.time(expr) unix.time(expr)
expr |
Valid R expression to be “timed” |
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 (on Unix) those
returned by the C library function times(3v), if available.
unix.time is an alias of system.time, for
compatibility reasons.
A numeric vector of length 5 containing the user cpu, system cpu, elapsed,
subproc1, subproc2 times. The subproc times are the user and
system cpu time used by child processes (and so are usually zero).
The resolution of the times will be system-specific; it is common for
them to be recorded to of the order of 1/100 second, and elapsed
time is rounded to the nearest 1/100.
It is possible to compile R without support for system.time,
when all the values will be NA.
proc.time, time which is for time series.
require(stats)
system.time(for(i in 1:100) mad(runif(1000)))
## Not run:
exT <- function(n = 1000) {
# 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 3 secs on a 1GHz PIII
system.time(exT()) #~ +/- same
## End(Not run)