[ODE] Re: Deterministic simulation on multiple clients

[Jon Watte]

> > Also are you sure that even identical hardware won't give you
> > different rounding errors?

> Well, I am no expert in hardware, but I think it is quite unlikely that 
> rounding is non-deterministic. Also note that, as I stated in my 
> original post, sometimes the clients are perfectly synchronized.

Different versions of various DLLs (most notably anything graphics 
driver related) may set the rounding mode to different values. In 
fact, even on the same version of the DLL, it may sometimes do it, 
and sometimes not. Taking exceptions/signals may also re-set the 
rounding mode and/or the internal precision mode. To be sure, just 
slam it to what you want at the beginning of each step.

Cheers,

		/ h+