Hello,
Marc Collin schrieb:
> -ffast-math
>
Note that this requires a carefully written program otherwise it may not
work reliably. From reading [EMAIL PROTECTED] and from the manpage ("This
option should never be turned on by any -O option since it can result in
incorrect output for programs which depend on an exact implementation of
IEEE or ISO rules/specifications for math functions.") I think one
should be really careful with this option.
For my calculations, I don't dare it to use it - better 1% slower and
correct than (potentially) 100% wrong and 1% faster.*
For non-number crunching programs I would even be more careful.
Tobias
*In similar regard: Using GCC gfortran compiled Netlib LAPACK [SUSE's
lapack.rpm] with the Intel Fortran Compiler (ifort) versus using the
Intel Math Kernel Library mit ifort: With one of my programs the speedup
was around one percent. [Ok, with one program: ifort compiled is 20%
faster than gfortran compiled.]
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