From: Padiyath Sreekumaran (Kumar.Padiyath@psi.ch)
Date: Fri Oct 15 2004 - 04:41:15 EDT
Hello,
One of the user has found out the following difference
in results between HP Fortran compiler on tru64 and Lahey
Fortran running on PC. Has any one noticed this problem?
The OS is Tru64 V5.1A and Fortran Compiler version
Compaq Fortran V5.5-1877
Compaq Fortran Compiler V5.5-1877-48BBF
Program Listing:
================
d = 0.1
x = 10.
do i = 1,10
x = x*d
y = exp(-x)
z = 1. - exp(-x)
write(*,*)x,y,z
enddo
stop
end
The program compiled with f90 -o prog prog.f
The output from both compiler:
(Lahey compiler are what you get with a HP32S II, hand held
calculator!)
x exp(-x) 1 - exp(-x) 1 - exp(-x)
Lahey FORTRAN
---------------------------------------------------------
1 0.3678795 0.6321205 0.63212
0.1 0.9048374 9.5162570E-2 0.951626 E-1
0.01 0.9900498 9.9501610E-3 0.995017E-2
1.0x10-3 0.9990005 9.9951029 E-4
0.999500 E-3
1.0x10-4 0.9999000 1.0001659 E-4
0.999950 E-4
1.0x10-5 0.9999900 1.0013580E-5 0.999995E-5
1.0x10-6 0.9999990 1.0132790E-6 0.100000 E-5
1.0x10-7 0.9999999 1.1920929E-7 0.100000 E-6
1.0x10-8 1.0000000 0.0000000
0.100000 E-7
1.0x10-9 1.0000000 0.0000000
0.100000 E-8
with best regards,
Kumar
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