[Paraview] How to use multiprocessing in pvpython?

[Cory Quammen]

I see. Thanks for explaining what you are working on. Unfortunately, I
don't have an answer for you on how to make it work.

Perhaps you could work around this problem by creating a subprocess with
another plain Python console in your ParaView Python script where you
execute your CFD code with the multiprocessing package in the subprocess
and then read the data in your ParaView pipeline after that process is
complete?

Cory

On Wed, Jul 8, 2015 at 11:07 PM, Sha Mo <mosha at ntu.edu.sg> wrote:

>  Thanks Cory for your reply.
>
>  My developing environment is Ubuntu 14.04 + Paraview 4.3.
> This issue will occur when I run those code in both Paraview Python Shell
> under GUI and pvpython command line.
>
>  I am attempting to implement a python script filter to handle my CFD in
> paraview pipeline, and my machine has multi-core cpu, meanwhile the filter
> has large part of separated calculation. So I think I can separate them
> into parts and use multi-processing to handle them.
>
>  For now, my script just use one core cpu, it’s slow and wasted.
>
>  Thank you.
>
>
>  在 2015年7月9日，上午11:52，Cory Quammen <cory.quammen at kitware.com> 写道：
>
>  It looks like all threads are attempting to open a display on an xserver
> but Xlib has not been initialized to use multiple threads.
>
>  Interestingly, I can execute your code in my development build of
> pvpython just fine under Ubuntu 14.04.
>
>  May I ask what you are planning to do with the multiprocessing package?
> Maybe there is another way you can accomplish it without the
> multiprocessing package?
>
>  - Cory
>
> On Wed, Jul 8, 2015 at 10:05 PM, Sha Mo <mosha at ntu.edu.sg> wrote:
>
>> In order to use multi-core cpu well, I want to use multiprocessing module
>> in paraview python script. But following error was occurred when I try to
>> run following code on Paraview Python Shell:
>>
>> import multiprocessing
>> pool = multiprocessing.Pool(processes=4)
>>
>> paraview version 4.3.1
>> Process PoolWorker-1:
>> Traceback (most recent call last):
>> Process PoolWorker-2:
>> paraview: Fatal IO error 2 (No such file or directory) on X server :0.
>>   File "/usr/lib/python2.7/multiprocessing/process.py", line 249, in
>> _bootstrap
>> Process PoolWorker-3:
>> paraview: Fatal IO error 11 (Resource temporarily unavailable) on X
>> server :0.
>> paraview: Fatal IO error 11 (Resource temporarily unavailable) on X
>> server :0.
>> Process PoolWorker-4:
>> paraview: Fatal IO error 2 (No such file or directory) on X server :0.
>> Process PoolWorker-5:
>> paraview: Fatal IO error 11 (Resource temporarily unavailable) on X
>> server :0.
>> Process PoolWorker-6:
>> paraview: Fatal IO error 2 (No such file or directory) on X server :0.
>> Process PoolWorker-8:
>> Process PoolWorker-7:
>> paraview: Fatal IO error 2 (No such file or directory) on X server :0.
>> paraview: Fatal IO error 2 (No such file or directory) on X server :0.
>> [xcb] Unknown sequence number while processing queue
>> [xcb] Most likely this is a multi-threaded client and XInitThreads has
>> not been called
>> [xcb] Aborting, sorry about that.
>> paraview: ../../src/xcb_io.c:274: poll_for_event: Assertion
>> `!xcb_xlib_threads_sequence_lost' failed.
>> Aborted (core dumped)
>>
>> I wonder whether it is wrong way to use parallel programming on pvpython？
>> [SG50]
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>
>
>
>  --
> Cory Quammen
> R&D Engineer
> Kitware, Inc.
>
>
>


-- 
Cory Quammen
R&D Engineer
Kitware, Inc.
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