Re: comparing gnat/Ada95 and g77

[Reinert Korsnes <reinert.korsnes@chello.no>]

Thanks all for response.

For the Ada95 program I used:

 gnatmake test1.adb -cargs -O3 -ffast-math 

and for the Fortran version I used:

  f77 -c -O3 -ffast-math test1.f (and f77 -o test1 test1.o)

Ada:    11.8 s

Fortran: 2.7 s

Maybe "-ffast-math" is silently ignored (not "legal") for gnat 
since it is "dirty" ?  Without "-ffast-math" the Fortran 
version takes about 10.3 s .

reinert

PS: yes, I did NOT try to make a program doing anything
    meaningful except for figuring out compile options. 



John McCabe wrote:

> On Thu, 14 Mar 2002 10:47:18 +0100, Reinert Korsnes
> <reinert.korsnes@chello.no> wrote:
> 
>>Hi,
>>
>>Could anybody try these two programs (Ada and Fortran)
>>and see if it is possible to make the Ada version (via compile
>>options) to run as fast as the Fortran version under Linux, gnat
>>and g77 ?
> 
> What do you mean by "as fast as"? Do you have some figures already?
> What are the differences?
> 
> I can't see any reason (other than constraint checking which can be
> switched off) why the actual calculations should be any different, but
> you might find that the IO takes longer in Ada than in Fortran because
> it is obviously a bit more complicated (3 subroutine calls instead of
> 1) and, as you're doing this within a *huge* loop, any slight
> degradation here will be significant.