Re: trouble using gfortran

[Tobias Schlüter <Tobias dot Schlueter at Physik dot Uni-Muenchen dot DE>]

Quoting Sylvain Aguinaga <sylvain.aguinaga@gmail.com>:
> Now, i have to use gcc g fortran compiler, which is working quite
> well, and i succeed in compiling et linking my program. But when i'm
> trying to run it, results are very bad and my calculations crash,
> which didn't happen with the former compiler (using the same
> parameters of course).
> I wish to know if something like that already happen i mean when you
> change the compiler.

This can happen, and it can point to bugs in your code or the compiler.  Given
that as you say, your code worked well and produced different results with two
other compilers, it is indeed likely that the bug is in gfortran.  In that case
you would best be served by:
1) trying to reduce the code which exposes the bug to a manageable size, which
makes clear where the problem lies (i.e. "somewhere in this 20000 line program
something happens" vs. "this I/O statement does the wrong thing A instead of
the right thing B")
2) see if a similar bug exists in our bug database, which is located at
http://gcc.gnu.org/bugzilla
3) if not submit a new bug
4) (optional) find and fix the bug in the compiler

Hope this helps,
- Tobias Schlueter