yade-users team mailing list archive
Mailing list archive
Re: R: Re: Contact detection
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 ;-)
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 :)
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