yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

I can't imagine any explanation yet. It is strange.
I wonder if the unbalanced force will also be exactly 0 if you pause the
simulation and type unbalancedForce() in the terminal.
Are you sure that the results in terms of positions and deformation of
the net are always the same? else it could mean that there is another
problem that the unbalanced force is only reflecting.

Bruno


On 07/10/11 07:08, Klaus Thoeni wrote:
> Hi guys,
>
> yes, you have to try it several times in order to reproduce the strange 
> behaviour.
>
> However, I found out a bit more. Actually it might be a problem with multi-
> threading. Maybe someone can try to reproduce the behaviour. The following 
> link provides a slightly modified version my script and a bash script which 
> allows for several executions for -j1 and -j2 (before running the script make 
> sure it is executable 'chmod +x runscript'). In addition I included as well my 
> results.
>
> http://bit.ly/rtN0w3
>
> Something very strange is that my desktop has the same problem even with -j1 
> (eaven cpu usage is more than 100% and I have no idea why) whereas my notebook 
> gives the right results in that case (cpu usage is max 100%) just have a look 
> at the graphs. It would be good to find out if this problem effects just me or 
> if it is a general problem in YADE. Any hints are welcome and I really 
> appreciate your help!
>
> Thanks 
>
> Klaus
>
> On Thu, 6 Oct 2011 07:58:24 PM Bruno Chareyre wrote:
>> I tried the script and didn't find the problem. It needs more runs
>> maybe. But first, could you explain how you use the function (in a
>> periodic engine/ live typing/a command in the script)? It would help
>> understanding what happens.
>>
>> Bruno
>>
>> On 06/10/11 07:53, Klaus Thoeni wrote:
>>> Hi Anton,
>>>
>>> I tired it already (I know this issue), still the same behaviour. And now
>>> actually I got zero for Bruno's branch as well. Very strange :-(
>>> Not sure what the problem is. Would be great if someone could try if
>>> he/she gets the same behaviour.
>>>
>>> Thanks,
>>> Klaus
>>>
>>> On Thu, 6 Oct 2011 04:30:53 PM Anton Gladky wrote:
>>>> Hi Klaus,
>>>> try to start your script with -j1 option.
>>>> There are sometimes some issues with "numerical" error in multi-thread
>>>> mode.
>>>>
>>>> Anton
>>>>
>>>> On Thu, Oct 6, 2011 at 6:40 AM, Klaus Thoeni <klaus.thoeni@xxxxxxxxx> 
> wrote:
>>>>> Hi guys,
>>>>>
>>>>> I just wanted to use the function unbalancedForce in one of my scripts.
>>>>> And look what is happening: running the same simulation several times
>>>>> after each other gives different results for the unbalancedForce. Well
>>>>> either some values which seem all right or just zero. The script I used
>>>>> is:
>>>>> examples/WireMatPM/wirecontacttest.py
>>>>>
>>>>> Even using different computers and different versions of yade gives
>>>>> this problem. However, it doesn't happen all the time. It seems like
>>>>> you have to try several times to get the wrog value (which is zero)
>>>>> for unbalancedForce and if I use Bruno's collide2 branch it seems to
>>>>> work all the time.
>>>>>
>>>>> So I don't know if it is a problem with my script or a problem of the
>>>>> current trunk version. Can anyone reproduce this problem?
>>>>>
>>>>> Thanks
>>>>> Klaus
>>>>>
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-- 
_______________
Bruno Chareyre
Associate Professor
ENSE³ - Grenoble INP
11, rue des Mathématiques
BP 46
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Tél : +33 4 56 52 86 21
Fax : +33 4 76 82 70 43
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