[petsc-users] generate entries on 'wrong' process

[Wen Jiang]

Hi Jed,

Could you cover it a bit more details why it will get deadlock unless the
number of elements is *exactly* the same on every process? Thanks.

Regards,
Wen

Message: 5
Date: Fri, 20 Jan 2012 11:36:17 -0600
From: Jed Brown <jedbrown at mcs.anl.gov>
Subject: Re: [petsc-users] generate entries on 'wrong' process
To: PETSc users list <petsc-users at mcs.anl.gov>
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       <CAM9tzSnQvEDOSTrHbbMZVOyOg2+yPA2zeYM-ouk1HGr09tE7hA at mail.gmail.com>
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On Fri, Jan 20, 2012 at 11:31, Wen Jiang <jiangwen84 at gmail.com> wrote:

> The serial job is running without any problems and never stalls. Actually
> the parallel jobs also running successfully on distributed-memory desktop
> or on single node of cluster. It will get stuck if it is running on more
> than one compute node(now it is running on two nodes). Both the serial job
> and parallel job (running on distributed or cluster) I mentioned before
> have the same size(dofs). But If I ran a smaller job on cluster with two
> nodes, it might not get stuck and work fine.
>
> As you said before, I add MAT_ASSEMBLY_FLUSH after every element stiffness
> matrix is inserted.
>

This will deadlock unless the number of elements is *exactly* the same on
every process.


> I got the output like below, and it gets stuck too.
>
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