dtime: Elapsed Time Since the Last dtime Call (Fortran Library Reference)

Fortran Library Reference

`dtime`: Elapsed Time Since the Last `dtime` Call

For dtime, the elapsed time is:

First call: elapsed time since start of execution

Subsequent calls: elapsed time since the last call to dtime

Single processor: time used by the CPU

Multiple Processor: the sum of times for all the CPUs, which is not useful data; use etime instead.

Note -
Do not call dtime from within a parallelized loop.

The function is called by:

`e= dtime(tarray` `)`
`tarray`	`real(2)`	Output	`e`= -1.0: Error: `tarray` values are undefined `e`¬= -1.0: User time in `tarray(1)` if no error. System time in `tarray(2)` if no error
Return value	`real`	Output	`e`= -1.0: Error `e`¬= -1.0: The sum of `tarray(1)` and `tarray(2)`

e= dtime(tarray )

tarray

real(2)

Output

e= -1.0: Error: tarray values are undefined

e¬= -1.0: User time in tarray(1) if no error. System time in tarray(2) if no error

Return value

real

Output

e= -1.0: Error

e¬= -1.0: The sum of tarray(1) and tarray(2)

Example: dtime(), single processor:

    real e, dtime, t(2)
    print *, 'elapsed:', e, ', user:', t(1), ', sys:', t(2)
    do i = 1, 10000
        k=k+1
    end do
    e = dtime( t )
    print *, 'elapsed:', e, ', user:', t(1), ', sys:', t(2)
    end
demo% f77 -silent tdtime.f
demo% a.out
elapsed:  0., user:  0., sys:  0.
elapsed:   0.180000, user:    6.00000E-02, sys:   0.120000
demo%