NAME
etime, dtime - return elapsed time
SYNOPSIS
real function etime (time)
real time(2)
real function dtime (time)
real time(2)
DESCRIPTION
These functions return elapsed time in seconds.
Versions of etime and dtime used by f95 use the system's low
resolution clock by default, the resolution of which is one
hundreth of a second. However, if the program is run under
the SunOS utility ptime, ( /usr/proc/bin/ptime), etime and
dtime use the high resolution clock.
NOTE: The very first call to etime or dtime may be inaccu-
rate.
If there is an error:
o Argument elements time(1) and time(2) are undefined
o Function return value = -1.0
If there is no error:
o Argument: user time in time(1) and system time in time(2)
o Function return value: sum of time(1) and time(2)
dtime returns the elapsed time since the last call to dtime.
For dtime, the elapsed time is:
o On the first call, elapsed time since the start of execu-
tion
o On the second and subsequent calls, the elapsed time since
the last call to dtime
o For single processor, the time used by the CPU
o For multiple processors, the sum of times for all the CPUs
(not useful, use etime)
Note: Do not call dtime from within a parallelized loop.
etime returns the elapsed time since the start of execution.
For etime, the elapsed time is:
o For single processor: the CPU time for the calling pro-
cess
o For multiple processors: the wall-clock time while run-
ning your program
Note: time(1) contains the wall clock time; time(2) is
0.0.
etime determines single versus multiple processing depending
on whether the environment variables PARALLEL or
OMP_NUM_THREADS are:
Undefined,
then the current run is single processor.
Defined, and in the range 1, 2, 3, ...,
then the current run is multiple processor.
Defined, but some value other than 1, 2, 3, ...,
then the results are unpredictable.
FILES
libfui.a, libfui.so
SEE ALSO
times(2), Fortran User's Guide and the Fortran Library
Reference