The following code was compiled with
gfortran -g -o test_dtime test_dtime.f
The code is given by (very similar to that given in the info file for gfortran
program test_dtime
integer(8) :: i, j, k
real, dimension(2) :: tarray
real :: result
real :: accum
call dtime(tarray, result)
print '(''tarray,result:'', 1P, 3E20.11)', tarray, result
do i=1,100000000 ! Just a delay
j = i * i - i
end do
call dtime(tarray, result)
print '(''tarray,result:'', 1P, 3E20.11)', tarray, result
accum = 0.e0 ! Should accumulate 10 times previous tarray(1)
call dtime(tarray, result)
do k=1, 10
do i=1,100000000 ! Just a delay
j = i * i - i
end do
call dtime(tarray, result)
accum = accum + tarray(1)
end do
print '(''accum ='', 1P, E20.11 )', accum
end program test_dtime
The resulting output is
tarray,result: 9.99000039883E-04 9.99000039883E-04 1.99800007977E-03
tarray,result: 3.86941999197E-01 0.00000000000E+00 3.86941999197E-01
accum = 1.35349416733E+01
Note that accum should be close to 10 times the value the tarray(1) above, that
is, close to 3.8. I have no idea where the 13.5... came from.
--
Summary: dtime not consistent in times reported
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libfortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: fkrogh#gcc at mathalacarte dot com
GCC build triplet: x86_64-pc-linux-gnu-4.4.1
GCC host triplet: x86_64-pc-linux-gnu-4.4.1
GCC target triplet: x86_64-pc-linux-gnu-4.4.1
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41157
