proc.time                package:base                R Documentation

Running Time of R

Description:

     'proc.time' determines how much time (in seconds) the currently
     running R process already consumed.

Usage:

     proc.time()

Value:

     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.

     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 most useful for "timing" the evaluation of R expressions,
     which can be done conveniently with 'system.time'.

Note:

     It is possible to compile R without support for 'proc.time', when
     the function will not exist.

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(runif(500))
     proc.time() - ptm
     ## End(Not run)

