Re: gcc/gsl

[Patrick Dupre]

> Sent: Wednesday, November 13, 2024 at 8:58 PM
> From: "Jeffrey Walton" 
> To: "Community support for Fedora users" 
> Cc: "Patrick Dupre" 
> Subject: Re: gcc/gsl
>
> On Wed, Nov 13, 2024 at 1:33 PM Patrick Dupre via users
>  wrote:
> > I am not sure this issue is entirely relevant on this mailing list.
> > Maybe you could redirect me.
> >
> > The same application (relatively heavy code), provides different values when it
> > is run and compiled on 2 different machines.
> > Both F40 (last update)
> > gcc (GCC) 14.2.1 20240912 (Red Hat 14.2.1-3)
> > One
> > Intel(R) Core(TM) i5-7400 CPU @ 3.00GHz
> > The other one
> > Intel(R) Core(TM) i7-8700 CPU @ 3.20GHz
> > Actually, this happens when I use the gsl library.
> > gsl-devel-2.7.1-8.fc40.x86_64
> > for integration (gsl_integration_cquad).
> > Before integration, the values are strictly identical.
> > The same Makefile is used.
> > Now, if I copy the code generated by the machine A on machine B,
> > I get the same results as it had been run on machine A.
> > The size of both codes are slightly different.
> > I conclude that the issue is due to the compiler.
> > Indeed, the difference in the generated values seems pretty constant,
> > i.e., it seems proportional to the value itself: of the order 2.7e-8 (relative difference)
> > i.e. a lot higher than the accuracy of the machine: < 1e-35.
> >
> > Which one is the good one?
> > Why this behavior?
> > Can I solve the issue?
>
> I would take the issue to the libgsl folks at
> https://www.gnu.org/software/gsl/. The help-gsl 
> users mailing list looks like the right place.
>
> I would not be surprised if they knew the problem based on your description.

There a version 2.8 of gsl but is not available for fedora
> Jeff