yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

Yes, I'm happy. ;)

B.

On 17/10/11 08:51, Klaus Thoeni wrote:
> Hi Bruno,
>
> I derived my WireMat from NormShearPhys and indeed it is working fine now. I 
> think for now it's the best solution. Let me know if you are happy with this 
> solution.
> If in the future we have more cases with normal forces only it might be better 
> to introduce the boolean you mentioned. But we would have to check it in 
> several lines inthe code.
>
> Regarding the results I got previously. All results where wrong, although they 
> where the same if I used one threat. Well, in debug mode the simulation was 
> not running because of the assert.
>
> Thanks,
> Klaus
>
> On Wed, 12 Oct 2011 12:06:39 AM Bruno Chareyre wrote:
>> Yes, deriving from NormShear would do the "trick". It is suboptimal in
>> terms of memory usage but the impact will be small.
>> There could be other ways, like passing an optional bool "hasShear" to
>> the unbalancedForce function, but it would solve only one specific
>> problem and if normShearPhys is used everywhere you will indeed hit the
>> same problem again with other functions.
>>
>> Something I still don't get is why it works _sometimes_, and why your
>> interactions don't simply give a crash on the typecasting:
>> shared_ptr<NormShearPhys> nsi=YADE_PTR_CAST<NormShearPhys>(I->phys);
>>
>> Any idea?
>>
>> Bruno
>>
>> p.s. Please, don't send mails to me+yade-dev (it makes duplicates in my
>> mbox and it disables the reply-to-list feature of thunderbird), yade-dev
>> alone will be enough.
>>
>> On 11/10/11 09:50, Klaus Thoeni wrote:
>>> Hi Bruno,
>>>
>>> I just had a look at the code and NormShearPhys is used in many other
>>> places as well. This means that it is always assumend that there is a
>>> normal and a shear force. So probably I should derive WirePhys from
>>> NormSherPhys and set ks and Fs equal to zero.
>>>
>>> What do you think?
>>>
>>> Klaus
>>>
>>> On Mon, 10 Oct 2011 11:51:40 PM Bruno Chareyre wrote:
>>>> Hi,
>>>>
>>>> If you can get 0 after pausing, then it's a good starting point for
>>>> debugging. In release build, you may try and check if there are forces
>>>> on the bodies.
>>>> In debug build (does it give 0 too?) you could set a breakpoint at
>>>> Shop.cpp:162 and see what happens line by line, surely the best way.
>>>>
>>>> Bruno
>>>>
>>>> On 10/10/11 14:16, Klaus Thoeni wrote:
>>>>> Hi,
>>>>>
>>>>> yes, if you pause the simulation unbalancedForce() is still exactly 0.
>>>>>
>>>>> Regarding the results for displacements:
>>>>> - if I run the same file with -j1 I will get exactly the same
>>>>> deformation, however the the unbalancedForce is not exactly the same
>>>>> - if I compare the displacements of a case where I used
>>>>> multi-threading the displacements are exactly the same for a certain
>>>>> amount of iterations then the slightly differ (even if unbalancedForce
>>>>> is 0 from beginning)
>>>>>
>>>>> I am still trying to find out what's going on. Any hints are welcome!
>>>>>
>>>>> Thanks,
>>>>> Klaus
>>>>>
>>>>>
>>>>>
>>>>> On Fri, Oct 7, 2011 at 9:35 PM, Bruno Chareyre
>>>>>
>>>>> <bruno.chareyre@xxxxxxxxxxx <mailto:bruno.chareyre@xxxxxxxxxxx>> wrote:
>>>>>     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 <mailto: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
>>>>>     38402 St Martin d'Hères, France
>>>>>     Tél : +33 4 56 52 86 21 <tel:%2B33%204%2056%2052%2086%2021>
>>>>>     Fax : +33 4 76 82 70 43 <tel:%2B33%204%2076%2082%2070%2043>
>>>>>     ________________
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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
________________