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Message #08530
[Bug 987164] Re: bug with multithreading
So from your comments I would assume that 1e-6 is a good value in my
case ...
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https://bugs.launchpad.net/bugs/987164
Title:
bug with multithreading
Status in Yet Another Dynamic Engine:
New
Bug description:
This bug is related to a question:
https://answers.launchpad.net/yade/+question/191904
Using multi-threading option in yade leads to instabilities, that are caused by indeterminism.
To reproduce the bug, download attached file, extract and run 1-generation.py. You will get a save-file called save1-test.yade. With this file run 2-relaxation.py and wait until its ready (will take a few minutes, be patient).
Then a new save file called save2-test.yade will be created. With this save file you can run 3-settling.py to reproduce the bug, see below:
1.) run on 1 core:
me@debian ~/YADE/my-yade-projects/multi-threading-bug >yade 3-settling.py
Welcome to Yade unknown
TCP python prompt on localhost:9001, auth cookie `sauces'
XMLRPC info provider on http://localhost:21001
Running script 3-settling.py
actual porosity: 46.090125 percent
ball with id 2 has maximum velocity of 0.002235
actual porosity: 41.579271 percent
ball with id 7 has maximum velocity of 0.354973
actual porosity: 42.846368 percent
ball with id 3 has maximum velocity of 0.180586
Yade: normal exit.
Beendet
2.) run on more cores:
me@debian ~/YADE/my-yade-projects/multi-threading-bug >yade -j4 3-settling.py
Welcome to Yade unknown
TCP python prompt on localhost:9001, auth cookie `ekcdsa'
XMLRPC info provider on http://localhost:21001
Running script 3-settling.py
actual porosity: 46.090125 percent
ball with id 2 has maximum velocity of 0.002235
actual porosity: 43.217713 percent
ball with id 0 has maximum velocity of 0.103208
actual porosity: 43.106072 percent
ball with id 20 has maximum velocity of 0.164024
Yade: normal exit.
Beendet
2.) run on more cores again, until instability occurs:
me@debian ~/YADE/my-yade-projects/multi-threading-bug >yade -j4 3-settling.py
Welcome to Yade unknown
TCP python prompt on localhost:9000, auth cookie `ssacue'
XMLRPC info provider on http://localhost:21000
Running script 3-settling.py
actual porosity: 46.090125 percent
ball with id 2 has maximum velocity of 0.002235
actual porosity: 42.783835 percent
ball with id 5 has maximum velocity of 0.170237
actual porosity: 57.019197 percent !!!!!!!!!!!!!!!BUG LEADS TO INSTABILITY OF THE MODEL HERE !!!!!!!!!!!
ball with id 10 has maximum velocity of 3.735641
pure virtual method called
terminate called without an active exception
Abgebrochen
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