Re: [Yade-users] [Question #675879]: Polyhedron interaction with sphere
Question #675879 on Yade changed: https://answers.launchpad.net/yade/+question/675879 Jan Stránský posted a new comment: @Robert: it seems like that.. -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #675879]: Polyhedron interaction with sphere
Question #675879 on Yade changed: https://answers.launchpad.net/yade/+question/675879 Nishant posted a new comment: @Jan: "there is no interaction at all during the simulation. This definitely would be a problem." --> When the simulation continues, there is an interaction, but without a dictionary. This was an issue for me. I just created the example with O.step() to show the problem. @ Robert: I also confirm that the problem is gone on 18.04 with latest trunk version, and O.interaction has a dictionary at the first time step. :) Any suggestions how to make the example working on other os? Do I need to update some libraries? Thank you -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #675879]: Polyhedron interaction with sphere
Question #675879 on Yade changed: https://answers.launchpad.net/yade/+question/675879 Robert Caulk posted a new comment: Am I incorrect to point out that Xenial's libcgal 4.7-4 was uploaded in 2015 [1]? It means that polyhedra has had this (extremely rare) bug for the entire duration of the Ubuntu16.04 + libcgal4.7-4 partnership. Right? [1]https://launchpad.net/ubuntu/+source/cgal/4.7-4 -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #675879]: Polyhedron interaction with sphere
Question #675879 on Yade changed: https://answers.launchpad.net/yade/+question/675879 Jan Stránský posted a new comment: I meant no real interaction.. > Any suggestions how to make the example working on other os? Do I need to update some libraries? I **guess** the problem is in CGAL. Yade code was not changed, CGAL was and currently I see no other reason.. Jan -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #675879]: Polyhedron interaction with sphere
Question #675879 on Yade changed: https://answers.launchpad.net/yade/+question/675879 Jan Stránský posted a new comment: @Robert: I don't think there was any changes for polyhedra because of CGAL version (could be checked from git history) Jan -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #675879]: Polyhedron interaction with sphere
Question #675879 on Yade changed: https://answers.launchpad.net/yade/+question/675879 Robert Caulk posted a new comment: I can confirm the bug only exists on Ubuntu 16.04. When I run my own MWE (comment #1) on my 18.04 install, I get interaction for both eps_pos = 0 and eps_pos=1e-5. >>the true reason is somewhere else (CGAL version maybe, on 18.04 "apt show libcgal-dev" shows version >>4.11-2build1). On my 16.04 install, I run apt show libcgal-dev and see that I am running 4.7-4, which is the newest version for 16.04. I know we had to make some changes in FlowEngine to accommodate the new CGAL version. Was this the case with polyhedra too? -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #675879]: Polyhedron interaction with sphere
Question #675879 on Yade changed: https://answers.launchpad.net/yade/+question/675879 Chareyre proposed the following answer: I don't think «upgrade linux» is a solution to code not doing what it should, in general. My two cents. :) Just to save your day. Bruno Le mar. 6 nov. 2018 17:52, Jan Stránský < question675...@answers.launchpad.net> a écrit : > Question #675879 on Yade changed: > https://answers.launchpad.net/yade/+question/675879 > > Jan Stránský proposed the following answer: > My comment was to Robert's MWE illustrating problem with no interaction > at all > > In your case it depends on where the problem is. > 1) there is no interaction at the 1st step for exactly touching particles. > This is ok, see my comment above > 2) there is no interaction at all during the simulation. This definitely > would be a problem. > > I tested your code and could not reproduce your problem on Ubuntu 18.04 > (similar to Robert's example), the interaction is real for both > eps_pos=1e-5 and eps_pos=0.0 > interesting :-) > > Installing 18.04 might help but probably is not necessary, the true > reason is somewhere else (CGAL version maybe, on 18.04 "apt show > libcgal-dev" shows version 4.11-2build1). > > cheers > Jan > > -- > You received this question notification because you are subscribed to > the question. > > -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #675879]: Polyhedron interaction with sphere
Question #675879 on Yade changed: https://answers.launchpad.net/yade/+question/675879 Jan Stránský proposed the following answer: My comment was to Robert's MWE illustrating problem with no interaction at all In your case it depends on where the problem is. 1) there is no interaction at the 1st step for exactly touching particles. This is ok, see my comment above 2) there is no interaction at all during the simulation. This definitely would be a problem. I tested your code and could not reproduce your problem on Ubuntu 18.04 (similar to Robert's example), the interaction is real for both eps_pos=1e-5 and eps_pos=0.0 interesting :-) Installing 18.04 might help but probably is not necessary, the true reason is somewhere else (CGAL version maybe, on 18.04 "apt show libcgal-dev" shows version 4.11-2build1). cheers Jan -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #675879]: Polyhedron interaction with sphere
Question #675879 on Yade changed: https://answers.launchpad.net/yade/+question/675879 Nishant posted a new comment: @Jan: following your advice, I installed the newest trunk version (2018-11-05) - not the almost-newest version. eps_pos = 0.0 does not show interaction on Ubuntu 16.04. Maybe going 18.04 is the way to go? -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #675879]: Polyhedron interaction with sphere
Question #675879 on Yade changed: https://answers.launchpad.net/yade/+question/675879 Jan Stránský posted a new comment: @Robert: using almost-newest trunk version and Ubuntu 18.04, I got interaction for both eps_pos=1e-5 and eps_pos=0.0.. Jan -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #675879]: Polyhedron interaction with sphere
Question #675879 on Yade changed: https://answers.launchpad.net/yade/+question/675879 Jan Stránský posted a new comment: Hello, @Robert, "one of Yade's polyhedra specialists" I am afraid this "specialist" should be me.. at least this sphere- polyhedra interaction is my code, I will have a look as soon as time allows it.. @Nishat > The polyhedra and sphere are touching initially, and the polyhedra moves in > the direction of the sphere with a prescribed velocity. > So a real interaction is expected to occur at the first time-step. If they are exactly touching, it is somewhat indeterminate state whether the interaction should exists or not (some rounding error could make it one or the other state). The velocity is not relevant here, as the motion evaluation takes place after interaction detection and evaluation. disclaimer: I haven't tested any code yet.. cheers Jan -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #675879]: Polyhedron interaction with sphere
Question #675879 on Yade changed: https://answers.launchpad.net/yade/+question/675879 Status: Open => Answered Bruno Chareyre proposed the following answer: >When the sphere is located just at the center of the box (eps_pos = 0), there is an interaction between the two objects Hi, just a short comment: it is expected - and perfectly fine - that some interactions accessed with [i,j] operator have no physics (hence no phys.dict either). It is a common feature of all virtual interactions. This being said I did not test the script, and so I don't know if one should reasonably expect a real interaction with eps=0. Bruno -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #675879]: Polyhedron interaction with sphere
Question #675879 on Yade changed: https://answers.launchpad.net/yade/+question/675879 Robert Caulk posted a new comment: Thank you for putting together a nice MWE showcasing this problem. I looked into your MWE and I believe you found a bug. I am sharing a more dramatic (and concise) MWE below for others who wish to look into this. In this example, setting eps_pos of 1e-5 results in the sphere interacting with the polyhedra. Then, simply changing eps_pos to 0 results in the sphere passing through the polyhedron. I will spend some more time sifting through the source code to identify the bug. I suspect it is somewhere in the collision identification [1]. I will let you know if I find anything, otherwise, we might need one of Yade's polyhedra specialists to look at this. # from yade import pack,polyhedra_utils import shutil, sys, imp import numpy as np #--- System definition -- rad_p = 0.1 Xl = 0. Yl = 0. Xr = 1. Yr = 1. Zl = rad_p Zr = 1. eps_pos = 1e-5 #-- polyMat = PolyhedraMat(young=1e10,poisson=.05) frictMat = FrictMat(young=1e9,poisson=.2) O.materials.append((polyMat,frictMat)) O.bodies.append([sphere((0.5*(Xl+Xr)+eps_pos,0.5*(Yl+Yr),-rad_p),rad_p, dynamic=True,material=frictMat) ]) # Sphere object O.bodies.append(polyhedron([(Xl,Yl,Zl),(Xr,Yl,Zl),(Xl,Yr,Zl),(Xr,Yr,Zl),(Xl,Yl,Zr),(Xr,Yl,Zr),(Xl,Yr,Zr),(Xr,Yr,Zr)],wire=False,dynamic=True,material=polyMat)) # polyhedron which compresses the sphere # O.engines=[ ForceResetter(), InsertionSortCollider([Bo1_Sphere_Aabb(), Bo1_Polyhedra_Aabb()]), InteractionLoop( [Ig2_Sphere_Polyhedra_ScGeom()], [Ip2_FrictMat_PolyhedraMat_FrictPhys()], [Law2_ScGeom_FrictPhys_CundallStrack()], ), #PyRunner(command = 'load()', iterPeriod = 1, label = "checker"), NewtonIntegrator() ] O.bodies[1].state.blockedDOFs = 'xyzXYZ' O.bodies[0].state.vel = Vector3(0,0,1e-1) #--- O.dt=.5*PWaveTimeStep() O.step() #--- [1]https://github.com/yade/trunk/blob/master/pkg/dem/Polyhedra_Ig2.cpp#L342 -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
[Yade-users] [Question #675879]: Polyhedron interaction with sphere
New question #675879 on Yade: https://answers.launchpad.net/yade/+question/675879 Hello, I was understanding how polyhedron interacts with sphere in yade and encountered a problem with the dictionary of the interaction. I created a system with one sphere and a box (made by polyhedron). The box touches the sphere from the bottom and has a velocity. I look at the interaction between the box and sphere after a time step. Below is the MWE: # from yade import pack,polyhedra_utils import shutil, sys, imp import numpy as np #--- System definition -- rad_p = 0.1 Xl = 0. Yl = 0. Xr = 1. Yr = 1. Zl = rad_p Zr = 1. eps_pos = 1e-5 #-- O.bodies.append([sphere((0.5*(Xl+Xr)+eps_pos,0.5*(Yl+Yr),0.0),rad_p, fixed = True) ]) # Sphere object O.bodies.append(polyhedron([(Xl,Yl,Zl),(Xr,Yl,Zl),(Xl,Yr,Zl),(Xr,Yr,Zl),(Xl,Yl,Zr),(Xr,Yl,Zr),(Xl,Yr,Zr),(Xr,Yr,Zr)],wire=False,dynamic=True)) # polyhedron which compresses the sphere # O.engines=[ ForceResetter(), InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Facet_Aabb(), Bo1_Box_Aabb(), Bo1_Wall_Aabb(), Bo1_Polyhedra_Aabb()],allowBiggerThanPeriod=True), InteractionLoop( [Ig2_Sphere_Sphere_ScGeom(), Ig2_Facet_Sphere_ScGeom(), Ig2_Wall_Sphere_ScGeom(), Ig2_Sphere_Polyhedra_ScGeom()], [Ip2_FrictMat_FrictMat_MindlinPhys()], [Law2_ScGeom_MindlinPhys_Mindlin()] ), PyRunner(command = 'load()', iterPeriod = 1, label = "checker"), NewtonIntegrator(gravity=(0,0,0.0),damping = 0.0) ] def load(): O.bodies[1].state.vel = Vector3(0,0,-1e-5) if ( O.iter > 3): O.pause() #--- O.dt=.5e-0*PWaveTimeStep() O.stopAtIter= int(1e6) O.step() #--- Case I: If the sphere is positioned not at the center of box bottom face (non-zero eps_pos in the code above), O.interactions[0,1].phys.dict() gives correct interaction parameters. Case II: When the sphere is located just at the center of the box (eps_pos = 0), there is an interaction between the two objects, but without any dictionary. #Yade [1]: O.interactions[0,1].phys.dict() #--- #AttributeError Traceback (most recent call last) #/home/nishantkumar/Desktop/Yade201802b/build/bins/yade-2018.02b in () #> 1 O.interactions[0,1].phys.dict() #AttributeError: 'NoneType' object has no attribute 'dict' Any reason for this? -- 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 : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
