floating point inconsistency

Christoph Groth cwg@falma.de
Tue Feb 16 13:12:00 GMT 2010


Cedric Roux <cedric.roux@acri-st.fr> writes:

> Andrew Haley wrote:
>> That is strange.  A bit of debugging would be required to understand
>> why that happens.
>
> (...)
>
> The least significant bit differs.

Now the question remains whether this is a bug in gcc or not.

The document http://www.validlab.com/goldberg/paper.ps (Numerical
computation guide) linked from http://gcc.gnu.org/bugs/ states

"
Many programmers may not realize that even a program that uses only the numeric
formats and operations prescribed by the IEEE standard can compute different
results on different systems.
"

Are AMD and Intel x86-64 processors different systems?  Even if they are
it might be possible to get rid of this inconsistency.



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