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Re: [Question #662105]: simulation explodes as soon as flow engine is activated

To: yade-users@xxxxxxxxxxxxxxxxxxx
From: Robert Caulk <question662105@xxxxxxxxxxxxxxxxxxxxx>
Date: Fri, 05 Jan 2018 23:27:26 -0000
Reply-to: question662105@xxxxxxxxxxxxxxxxxxxxx
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Question #662105 on Yade changed:
https://answers.launchpad.net/yade/+question/662105

Robert Caulk posted a new comment:
Hey Luc,

I receive the same error as you after running the simulation out :-(

I think this:

CHOLMOD warning: matrix not positive definite
something went wrong in Cholesky factorization, use LDLt as fallback this time1

suggests improper boundary conditions.

So I think you have a problem with one of these:

 ,boundaryUseMaxMin=[0,0,0,0,0,0] # what is this for? should we have [0,0,1,1,0,0] because of the top and bottom walls?
 ,wallIds=[-1,-1,1,0,-1,-1] # top wall id=0, bottom wall id=0

I am unsure how boundary conditions should be properly assigned for
periodic simulations that do not use 6 walls, but my quick glance at the
source code makes me think the -1 for wall ids is preventing yade from
adding boundary conditions to those sides of the cube.

I will try to look a bit deeper at it this weekend.

Cheers,

Robert

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