[ODE] deterministic simulations
Erwin de Vries
erwin at vo.com
Wed Jun 21 05:28:55 MST 2006
I've modified the dRand functions not to use the static seed variable
anymore, and simply take a parameter instead. Your option would also work,
but i needed this to make ODE able to handle multithreading.
----- Original Message -----
From: "Ricardo Kirkner" <ricardokirkner at gmail.com>
To: "Erwin de Vries" <erwin at vo.com>
Cc: "ode-list" <ode at q12.org>
Sent: Wednesday, June 21, 2006 1:59 PM
Subject: Re: [ODE] deterministic simulations
> How do you do that ('fix the randoms used in iteration')? Just using
> dRandSet? When do you use it, at each iteration step, or at the
> beginning of the simulation?
> Erwin de Vries wrote:
>> To my knowledge ODE is deterministic as is, as long as you fix the
>> used in iteration. I've fixed it up for my own usage a while ago, and it
>> looks like its working perfectly for the things i've done. (Capturing
>> on a P4, and playing it back on a Athlon worked fine, even in lengthy
>> Are there FPU specifics that could mess things up?
>> ----- Original Message -----
>> From: "Hampus" <hampus at sxp.se>
>> To: "ode-list" <ode at q12.org>
>> Sent: Wednesday, June 21, 2006 10:23 AM
>> Subject: [ODE] deterministic simulations
>>> I know this topic has been up before.
>>> I got a reply from another mailing list from a warcraft programmer on
>>> how they solved FPU problems for deterministic simulations.
>>>> No, I wrote an FPU emulator in C that used the integer unit for all
>>> its work. It wasn't pretty. But >by god it worked everywhere, even
>>> PowerPC. I only had to drop to assembly for __cntlzw (as >well as an
>>> Intel equivalent that used BSR).
>>>> Warcraft III utilizes this code; when I last checked, about 5% of
>>> our execution time was >dedicated to FPU-less floating point math.
>>> Would and FPU emulator be feasable for ODE too?
>>> ODE mailing list
>>> ODE at q12.org
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>> ODE at q12.org
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