[ODE] Different behaviors with different C++ compilers

Martin C. Martin martin at metahuman.org
Wed Jul 2 11:17:01 2003


Try using --float-store

But in general, don't be surprised if different compilers produce
different roundoff.

- Martin

Chris Jefferson wrote:
> 
> Steffen Wischmann wrote:
> 
> > Hi,
> >
> > I ran my simulation (Creature with NN Controller) on two differnt linux
> > distribution, one with the gcc compiler ver. 3.2-36, the other one with
> > ver.  2.95.3-52. I'm using ode 0.035 on both machines.
> > If I compile the code with the older compiler, and copy the compiled
> > code to the machine with the newer compiler version, I got exactly the
> > same behavior. But if I compile the same source code again with the
> > newer compiler version, the behavior is different.
> >
> > Does anybody know something about that?
> >
> 
> The improved optimiser probably re-arranged some instructions, and
> possibly changed when things are read from / written to registers (which
> can make a difference with floating point numbers). This is unavoidable
> I'm afraid (it can be improved by using no optimisation)
> 
> Chris
> 
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