Реклама
erid:2VtzqwUcu3z
ООО "Хи-Квадрат", ИНН 7718990614
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.
Time is in number of seconds. The resolution is to a
nanosecond.
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
process
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.
f77 determines single versus multiple processing depending
on whether a program is linked with the multithreaded ver-
sion of the FORTRAN 77 library, libF77_mt, and if the
environment variable PARALLEL is:
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
libF77.a, libF77_mt.a, libF77.so, libF77_mt.so
SEE ALSO
times(2), f77(1), Fortran User's Guide and the Fortran
Library Reference
