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gsl/gcc
From: |
Patrick Dupre |
Subject: |
gsl/gcc |
Date: |
Wed, 13 Nov 2024 20:08:54 +0100 |
Hello,
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?
Thank for any help.
===========================================================================
Patrick DUPRÉ | | email: pdupre@gmx.com
===========================================================================
- gsl/gcc,
Patrick Dupre <=