Re: gfortran vs ifort

[Girish Kulkarni <girish at athene dot org dot in>]

On Wed, 27 May 2009, Tim Prince wrote:
> If you have such large differences, supposing that they go away with
> the ifort options I suggested, this would indicate that you
> shouldn't use aggressive options which don't adhere to
> standards. The ifort default options will perform algebraic
> simplifications in violation of parentheses; I suggested options
> which are more consistent with gfortran.

Surprisingly, results with `ifort -O0` (v 10.1 on amd64) do not match
with `gfortran -O0` (v 4.1.2 on amd64) for the code that I described
earlier. --

   http://gcc.gnu.org/ml/fortran/2009-05/msg00406.html

Moreover, results with `gfortran -O0` (v 4.1.2 on amd64) *do not
match* with `gfortran -O0` (v 4.3.2-1.1 on i386).

Does this indicate a problem with the source code?  Which answer do I
trust?  (The amd64 results are OK.  But they are different.)  What is
the best way of dealing with such cases?

Thanks,
Girish.

--
Girish Kulkarni - Allahabad, India - athene.org.in/girish