New question #677951 on Yade: https://answers.launchpad.net/yade/+question/677951
Hi, I used GPU to accelerate PFV, CPU i7-8850H, GPU Quardro P1000, and tested it with oedometer.py on Github. I found that when num_spheres=1000, GPU acceleration is slower than CPU. When num_spheres=10000, the GPU is as fast as the CPU. Is this normal? #************************************************************************* # Copyright (C) 2010 by Bruno Chareyre * # bruno.chareyre_at_grenoble-inp.fr * # * # This program is free software; it is licensed under the terms of the * # GNU General Public License v2 or later. See file LICENSE for details. * #*************************************************************************/ ## Example script for using the DEM-PFV coupling introduced with E. Catalano, as reported in: ## * [Chareyre2012a] Chareyre, B., Cortis, A., Catalano, E., Barthélemy, E. (2012), Pore-scale modeling of viscous flow and induced forces in dense sphere packings. Transport in Porous Media (92), pages 473-493. DOI 10.1007/s11242-011-9915-6 ## http://dx.doi.org/10.1007/s11242-011-9915-6 ## * [Catalano2014a] Catalano, E., Chareyre, B., Barthélémy, E. (2013), Pore-scale modeling of fluid-particles interaction and emerging poromechanical effects. International Journal for Numerical and Analytical Methods in Geomechanics. DOI 10.1002/nag.2198 ## http://arxiv.org/pdf/1304.4895.pdf ## Also used in: ## * Tong et al.2012 (http://dx.doi.org/10.2516/ogst/2012032) ## * Sari et al 2011 (http://people.3sr-grenoble.fr/users/bchareyre/pubs/SariChareyreCatalanoPhilippeVincens_Particles2011.pdf) ## The DEM-PFV is applied here to 1D consolidation (oedometer test). The example includes the determination of oedometer modulus Ee and permeability K. ## The 1D consolidation is simulated as a coupled problem and the analytical solution corresponding to the abovementionned Ee and K is used for comparison. ## See triax-tutorial/script-session1.py for more detailed explanations of the packing generation procedure. ## ______________ First section, similar to triax-tutorial/script-session1.py _________________ from yade import pack num_spheres=1000# number of spheres young=1e6 compFricDegree = 3 # initial contact friction during the confining phase finalFricDegree = 30 # contact friction during the deviatoric loading mn,mx=Vector3(0,0,0),Vector3(1,1,1) # corners of the initial packing O.materials.append(FrictMat(young=young,poisson=0.5,frictionAngle=radians(compFricDegree),density=2600,label='spheres')) O.materials.append(FrictMat(young=young,poisson=0.5,frictionAngle=0,density=0,label='walls')) walls=aabbWalls([mn,mx],thickness=0,material='walls') wallIds=O.bodies.append(walls) sp=pack.SpherePack() sp.makeCloud(mn,mx,-1,0.3333,num_spheres,False, 0.95,seed=1) #"seed" make the "random" generation always the same sp.toSimulation(material='spheres') triax=TriaxialStressController( maxMultiplier=1.+2e4/young, # spheres growing factor (fast growth) finalMaxMultiplier=1.+2e3/young, # spheres growing factor (slow growth) thickness = 0, stressMask = 7, max_vel = 0.005, internalCompaction=True, # If true the confining pressure is generated by growing particles ) newton=NewtonIntegrator(damping=0.2) O.engines=[ ForceResetter(), InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Box_Aabb()]), InteractionLoop( [Ig2_Sphere_Sphere_ScGeom(),Ig2_Box_Sphere_ScGeom()], [Ip2_FrictMat_FrictMat_FrictPhys()], [Law2_ScGeom_FrictPhys_CundallStrack()],label="iloop" ), FlowEngine(dead=1,label="flow"),#introduced as a dead engine for the moment, see 2nd section GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8), triax, newton ] triax.goal1=triax.goal2=triax.goal3=-10000 while 1: O.run(1000, True) unb=unbalancedForce() if unb<0.001 and abs(-10000-triax.meanStress)/10000<0.001: break setContactFriction(radians(finalFricDegree)) ## ______________ Oedometer section _________________ #A. Check bulk modulus of the dry material from load/unload cycles triax.stressMask=2 triax.goal1=triax.goal3=0 triax.internalCompaction=False triax.wall_bottom_activated=False #load triax.goal2=-11000; O.run(2000,1) #unload triax.goal2=-10000; O.run(2000,1) #load triax.goal2=-11000; O.run(2000,1) e22=triax.strain[1] #unload triax.goal2=-10000; O.run(2000,1) e22=e22-triax.strain[1] modulus = 1000./abs(e22) #B. Activate flow engine and set boundary conditions in order to get permeability flow.dead=0 flow.defTolerance=0.3 flow.meshUpdateInterval=200 flow.useSolver=3 flow.permeabilityFactor=1 flow.viscosity=10 flow.bndCondIsPressure=[0,0,1,1,0,0] flow.bndCondValue=[0,0,1,0,0,0] flow.boundaryUseMaxMin=[0,0,0,0,0,0] O.dt=0.1e-3 O.dynDt=False O.run(1,1) Qin = flow.getBoundaryFlux(2) Qout = flow.getBoundaryFlux(3) permeability = abs(Qin)/1.e-4 #size is one, we compute K=V/∇H print "Qin=",Qin," Qout=",Qout," permeability=",permeability #C. now the oedometer test, drained at the top, impermeable at the bottom plate flow.bndCondIsPressure=[0,0,0,1,0,0] flow.bndCondValue=[0,0,0,0,0,0] flow.updateTriangulation=True #force remeshing to reflect new BC immediately newton.damping=0 #we want the theoretical value from Terzaghi's solution #keep in mind that we are not in an homogeneous material and the small strain #assumption is not verified => we don't expect perfect match #there can be also an overshoot of pressure in the very beginning due to dynamic effects Cv=permeability*modulus/1e4 zeroTime=O.time zeroe22 = - triax.strain[1] dryFraction=0.05 #the top layer is affected by drainage on a certain depth, we account for it here drye22 = 1000/modulus*dryFraction wetHeight=1*(1-dryFraction) def consolidation(Tv): #see your soil mechanics handbook... U=1 for k in range(50): M=pi/2*(2*k+1) U=U-2/M**2*exp(-M**2*Tv) return U triax.goal2=-11000 from yade import plot ## a function saving variables def history(): plot.addData(e22=-triax.strain[1]-zeroe22,e22_theory=drye22+(1-dryFraction)*consolidation((O.time-zeroTime)*Cv/wetHeight**2)*1000./modulus,t=O.time,p=flow.getPorePressure((0.5,0.1,0.5)),s22=-triax.stress(3)[1]-10000) #plot.addData(e22=-triax.strain[1],t=O.time,s22=-triax.stress(2)[1],p=flow.MeasurePorePressure((0.5,0.5,0.5))) O.engines=O.engines+[PyRunner(iterPeriod=200,command='history()',label='recorder')] ##make nice animations: #O.engines=O.engines+[PyRunner(iterPeriod=200,command='flow.saveVtk()')] from yade import plot plot.plots={'t':('e22','e22_theory',None,'s22','p')} plot.plot() O.saveTmp() O.timingEnabled=1 from yade import timing print "starting oedometer simulation" O.run(200,1) timing.stats() ## Make more steps to see the convergence to the stationnary solution -- You received this question notification because your team yade-users 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
