proc.time {base}R Documentation

Running Time of R

Description

proc.time determines how much real and CPU time (in seconds) the currently running R process has already taken.

Usage

proc.time()

Details

proc.time returns five elements for backwards compatibility, but its print method prints a named vector of length 3. The first two entries are the total user and system CPU times of the current R process and any child processes on which it has waited, and the third entry is the ‘real’ elapsed time since the process was started.

Value

An object of class "proc_time" which is a numeric vector of length 5, containing the user, system, and total elapsed times for the currently running R process, and the cumulative sum of user and system times of any child processes spawned by it on which it has waited. (The print method combines the child times with those of the main process.)
The resolution of the times will be system-specific and times are typically available to 10ms on NT-based versions of Windows.
It is useful for timing the evaluation of R expressions, which can be done more conveniently with system.time.

Note

CPU times will be returned as NA on Windows 9x/ME systems, but are genuine times on NT4/2000/XP/2003/Vista systems. Times of child processes are not available and will always be given as NA.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

system.time for timing a valid R expression, gc.time for how much of the time was spent in garbage collection.

Examples

## Not run: 
## a way to time an R expression: system.time is preferred
ptm <- proc.time()
for (i in 1:50) mad(stats::runif(500))
proc.time() - ptm
## End(Not run)

[Package base version 2.6.2 Index]