Hi Luc, I will deal with a dynamic problem and the global geometry is expected to change a lot during the simulation. Could you suggest me some papers where I can find an example in which the SPA was used? Or a reference where it is said that this contact detection method is fast or that it is fast according to a specific kind of problem? Do you know other DEM softwares that are using the SAP?
Many thanks, Chiara >----Messaggio originale---- >Da: luc.sibi...@univ- nantes.fr >Data: 16/11/2009 17.58 >A: <[email protected]> >Ogg: Re: [Yade-users] R: Re: Contact detection > >Hi! > > I coming back again about the contact detection, actually in SDEC >there was the choice between a contact detection by grid and the >simplest method were "every particles was checked with every particles" >because detection by grid is not always the fastest method, that depends >on what you are simulating: > >1/ When the global geometry of your problem is more or less constant >during the whole simulation (for instance: simulation of a triaxial >compression on a dense granular assembly) the detection by grid is quite >good, because you build the grid once at the beginning of the simulation >and you use the same grid during the whole simulation. In addition you >don't have to update the list of the neighbouring particles too often. > >2/ When the global geometry of your problem is not really fixed (for >instance an avalanche of particles in a very open space: you don't know >a priori were the avalanche will propagate) it is not sure if the >detection by grid will be good, because you will have to update often >the grid to follow the particles or you will have to make an inital very >large grid, whereas only few cells of the grid will be used at a given >time step for the detection. > >Chiara, I read your mails quite quickly so I don't remember if you have >specified the kind of simulation you want to do, but in my opinion >contact detection is good, but not always ;-) > >Best, > > Luc > >Janek Kozicki a écrit : >> Václav Šmilauer said: (by the date of Mon, 16 Nov 2009 09:46:52 +0100) >> >>>>>> In another words, Olivier (and you) didn't bother to google out articles >>>>>> on that and thought he was the smartest guy. >>>>> yeah. That time there was a LOT of other stuff to bother about, than >>>>> colliders :) Paint me ashamed ;> >>> I am not saying you are to be blamed, but Frederic, as supervisor of the >>> project, should have managed that. >> >> I recall his point of view: SDEC has a lot slower collider (IIRC: >> it was "check everything with everything"?. Some SDEC user could tell >> us). And so Frederic was very happy to see how much faster SAP is :) >> > >-- >Luc Sibille > >Université de Nantes - Laboratoire GeM UMR CNRS > >IUT de Saint Nazaire >58, rue Michel-Ange - BP 420 >44606 Saint-Nazaire Cedex, France > >Tel: +33 (0)2 40 17 81 78 > >_______________________________________________ >Mailing list: https://launchpad.net/~yade-users >Post to : yade- [email protected] >Unsubscribe : https://launchpad.net/~yade-users >More help : https://help.launchpad.net/ListHelp > _______________________________________________ Mailing list: https://launchpad.net/~yade-users Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
