yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

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>
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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
________________