Is https://github.com/yade/trunk/blob/master/pkg/dem/NewtonIntegrator.cpp#L235 not enough to avoid division by zero ?
-- You received this bug notification because you are a member of Yade developers, which is subscribed to Yade. https://bugs.launchpad.net/bugs/1301443 Title: Spheres/Box contact : spheres ori suddenly set to NaN. Status in Yet Another Dynamic Engine: New Bug description: Hi, Please see and launch the attached script. Some spheres are falling into a box because of gravity. The simulation starts well, but when all particles are almost steady, wait for a few seconds and you will see that some of them who are in contact with the bottom wall will disapear. I spent some time to investigate and that's my preliminary conclusions : - it is fully reproducible - particles don't really disappear : their orientation is suddenly turned to Quaternion(Nan,Nan,Nan,2*pi). It's not linked with a high torque on them. All other attributes remains okay, and the other particles still can interact with it. If you manually set the orientation to a correct value after it disappears, it will appear again at the right place. - you can reproduce this with one sphere (uncomment the last line of the script and comment the previous paragraph) : let it fall then apply to it a little angVel : "O.bodies[-1].state.angVel=(0.,0.,0.001)". It will disappear after a few timesteps. - it's independent on the timestep value. - it's dependant on the interpenetration of the contact : if you increase the gravity or decrease the young modulus, you will be able to avoid this behaviour. Does somebody have an idea ? I think it's a rotation calculation issue, in a very specific geometric case. To manage notifications about this bug go to: https://bugs.launchpad.net/yade/+bug/1301443/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~yade-dev Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-dev More help : https://help.launchpad.net/ListHelp
