Hello again,

I just got around working back on the application that needs big meshes. I
tried to split my mesh using splitter on my work computer and use it in a
big job. Unfortunately the mesh.read fails on the cluster for example on 20
cpus with:

Attempted to utilize a checkpoint file on 20 processors but it was written
using 0!!
[1] ../../src/mesh/checkpoint_io.C, line 561, compiled Dec  5 2016 at
14:23:30

Is there something I'm doing wrong here?

PS: I'm using a slightly older libMesh from
cbab3c34bb5e988339e1bb4aa7cf4828362eb494
commit.

Best,

Ata






On Wed, Jan 11, 2017 at 6:37 PM, Ata Mesgarnejad <[email protected]>
wrote:

> Thank you Derek,
>
> This is really helpful.
>
> Ata
>
> On Jan 11, 2017, at 6:15 PM, Derek Gaston <[email protected]> wrote:
>
> splitter also has the ability to do M->N parittioning.  What this means is
> that splitter itself can be run using MPI... and can generate partitions
> for any number of processors.  In fact, you can give it a list of n_procs
> you want it partition for and it will do all of them simultaneously.
>
> If you have one handy I highly recommend running splitter on a cluster
> that has a good parallel filesystem.
>
> BTW: I've used splitter to split huge multi GB Exodus files up into
> ~20,000 or so partitions and it's been pretty solid.
>
> Derek
>
> On Wed, Jan 11, 2017 at 4:18 PM gmail <[email protected]> wrote:
>
>> Perfect. I will give it a try.
>>
>> Ata
>> > On Jan 11, 2017, at 4:14 PM, John Peterson <[email protected]>
>> wrote:
>> >
>> >
>> >
>> > On Wed, Jan 11, 2017 at 2:04 PM, gmail <[email protected] <
>> mailto:[email protected]>> wrote:
>> > Hi John,
>> >
>> > This is the first time I see this. So I’m not sure what this .cpr
>> format is?
>> >
>> > It's the CheckpointIO format.  It can write either binary or ASCII
>> files and is similar to the xdr/a format that libmesh uses to write meshes
>> in serial.  Only thing it can't really do is restart from N files on M
>> procs, but that shouldn't affect your use case.
>> >
>> >
>> > Can each processor read its own chunk using with mesh.read when libMesh
>> is compiled with parallel mesh?
>> >
>> >
>> > Yes, that's how it should work.  You can use one of the Partitioner
>> classes that comes with libmesh, or partition the mesh yourself in some
>> application-specific way.
>> >
>> > --
>> > John
>>
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>
>
>


-- 
Best,
Ata
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