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Re: Optimized contact detection available

 

Interesting... Actually the only difference between bzr3001 and collide2
is in the default parameters of the collider.
I modified them because Anton reported a small slowdown.
Try setting verletDist=-0.7, minSweepDistFactor=0.05, then you should
get the result of the collide branch.
I'll try your script.

Bruno

> i just tried your new implementation of the optimized contact detection in the 
> trunk version. Have a look at the results:
>
> script: examples/WireMatPM/wirecontacttest.py
> 200000 iterations, 1253 bodies
> rev 2999: -j1 2min30sec, -j2 1min41sec, -j3 2min15sec
> rev3001:-j1 2min37sec, -j2 1min53sec, -j3 2min15sec
>
> other script:
> 22785 bodies
> rev 2999: -j1 1min42sec, -j2 1min20sec, -j3 1min29sec
> rev3001:-j1 2min38sec, -j2 2min17sec, -j3 2min44sec
>
> This looks not good to me. I must say I didn't play with the parameters but I 
> remember when I was testing with your collide2 branch (rev2925) I got much 
> better performance. 
>
> Any comments?
>
> Klaus
>
> On Tue, 24 Jan 2012 02:39:38 AM Bruno Chareyre wrote:
>> Hi all,
>>
>> The branch with optimized contact detection has been merged with trunk
>> in bzr3000.
>> According to my last tests and roughly speaking, yade is _3 times
>> faster_ after this commit, but the result will be worst or better
>> depending on the number of particles, the number of threads, the
>> constitutive law used, the velocity of bodies, and a few other things.
>>
>> If you don't compile yade, you can try the new version by installing or
>> updating the yade-daily package.
>> A few timings are reported on the wiki at
>> https://www.yade-dem.org/wiki/Colliders_performace
>> I would be glad to get feedback on the actual speedup in other simulations.
>> I can imagine possible slowdown in extreme cases, although it is
>> unlikely to happen (if it happens, then tuning the collider's parameters
>> should fix the problem).
>> If you feel like experimenting, you can play with the three parameters
>> of the new collider: verletDist, targetInterv, and minSweepDistFactor.
>> Reports can be very usefull as they will help to decide what is best
>> best default combination for these parameters.
>>
>> I hope we can release a stable version on this basis soon, when it is
>> confirmed that the new collider is bug-free.
>>
>> Best regards.
>>
>> Bruno
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-- 
_______________
Bruno Chareyre
Associate Professor
ENSE³ - Grenoble INP
11, rue des Mathématiques
BP 46
38402 St Martin d'Hères, France
Tél : +33 4 56 52 86 21
Fax : +33 4 76 82 70 43
________________



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