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

[Jed Brown]

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.
>

When it "gets stuck", attach a debugger and get stack traces.
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