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Subject: Re: [OMPI users] open-mpi behaviour on Fedora, Ubuntu, Debian and CentOS
From: Dave Love (d.love_at_[hidden])
Date: 2010-05-02 11:39:27


Asad Ali <asad06_at_[hidden]> writes:

> I took your earlier advice regarding the optimization flags causing errors
> in your case.

I reiterate that any `errors' are much more likely to be in the code
than GCC's -On optimizations if it's unstable with respect to them.

> You wrote in reply to Dave
>
> "The optimization flags were the main cause of changes in the results,
> as expected."
>
> I love speed but I also want to be on the correct track.

Actually, re-writing unstable code might well make it faster as well as
more accurate. A trivial example is double precision potentially being
faster than single precision.