1. do you check energy at the end of first iteration, or at the beginning of first iteration? 2. do you have correct energy in 2nd iteration?
ipemath said: (by the date of Fri, 05 Dec 2014 18:06:52 -0000) > Question #258679 on Yade changed: > https://answers.launchpad.net/yade/+question/258679 > > Description changed to: > Hai everyone, > > This is my first post in this forum. I am also a relatively new > user. I am presently trying to understand yade by solving a problem > of projectile impingement on a particle bed. Because of the > restriction in SuperComuputer usage time, I have to save and reload > the interval after certain fixed number of iterations. Hence I am > using multiple python scripts. The first one sets the problem, runs > the problem for a fixed no of iterations and saves it. Then the > second script reopens the saved simulation and runs it futher for > some more steps. In the course of simulation I am monitoring > kinematic variables and total energy of the system. In the case of > the strategy mentioned above(multiple scripts), the energy is not > conserved. There is a sharp drop in energy when the second script > is run. But if I used a single python script to run the simulation > for the same number of steps, the energy is conserved. Below I > would like to give below the important points of my scripts in the > form of a pseudocode. > ********************************************************************************************************** > First Script. > > #Create the spheres(Uniform sized ones for the bed, a bigger on > with an initial velocity as projectile) #Create the enclosing walls > for the bed O.engine[ > ForceResetter(), > ......................................... > InteractionLoop( > ......................................... > ........................................ > [Law2_ScGeom_MindlinPhys_Mindlin(label='Mindlin')] > ), > PyRunner(initRun=True,iterPeriod=50,command='myFunction()'), > PyRunner(initRun=True,iterPeriod=50,command='stopCond()'), > ] > ------------------------- > Mindlin.calcEnergy=True > fet=open('egtotal.dat','w') > ------------------------------ > def myFunction(): > pe_normal = Mindlin.normElastEnergy() # normal PE > pe_shear = Mindlin.shearEnergy # shear PE > norm_damp_dissip = Mindlin.normDampDissip # normal diss > shear_damp_dissip = Mindlin.shearDampDissip # shear diss > fric_dissip = Mindlin.frictionDissipation # loss due to > friction E_tracker = dict(O.energy.items()) > E_kin_trans = E_tracker['kinTrans'] > E_kin_rotation = E_tracker['kinRot'] > etotal = pe_normal + pe_shear + E_kin_trans + > E_kin_rotation + fric_dissip + norm_damp_dissip + shear_damp_dissip > # total energy fet.write('%g\n'%(etotal)) > > def stopCond(): > if O.iter>10000 > O.pause > fet.close() > O.save("1.xml.bz2") > O.exitNoBacktrace() > > O.run() > ####################################################### > Second Script: > O.load("1.xml.bz2") > ---------------------------- > Mindlin.calcEnergy=True > fet=open('egtotal.dat','a') #Append to the existing values > ------------------------------- > def myFunction(): > pe_normal = Mindlin.normElastEnergy() # normal PE > pe_shear = Mindlin.shearEnergy # shear PE > norm_damp_dissip = Mindlin.normDampDissip # normal diss > shear_damp_dissip = Mindlin.shearDampDissip # shear diss > fric_dissip = Mindlin.frictionDissipation # loss due to > friction E_tracker = dict(O.energy.items()) > E_kin_trans = E_tracker['kinTrans'] > E_kin_rotation = E_tracker['kinRot'] > etotal = pe_normal + pe_shear + E_kin_trans + > E_kin_rotation + fric_dissip + norm_damp_dissip + shear_damp_dissip > # total energy fet.write('%g\n'%(etotal)) def stopCond(): > if O.iter>20000 > O.pause > fet.close() > O.save("1.xml.bz2") > O.exitNoBacktrace() > > O.run() > **************************************************************************************** > The above given are excerpts from the script I am using and this > strategy doesnt conserve the energy. It dips sharply when the > second script starts running. > > I request the help of the yade experts in finding a solution to this > problem. > > -- > You received this question notification because you are a member of > yade-users, which is an answer contact for Yade. > > _______________________________________________ > Mailing list: https://launchpad.net/~yade-users > Post to : [email protected] > Unsubscribe : https://launchpad.net/~yade-users > More help : https://help.launchpad.net/ListHelp > -- Janek Kozicki http://janek.kozicki.pl/ | _______________________________________________ Mailing list: https://launchpad.net/~yade-users Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
