[Opengeoscience-developers] Websockets and MPI

Wed Feb 27 13:48:03 EST 2013

Sort of, I have a high level plan of splitting data, parrallel computing,
and then sending data peice by piece to the client via websockets. I need
to know what the data structure will be, and what metadata will need to be
attached to each piece of data that is streamed. Should this be GeoJSON? I
haven't looked into it much yet.

On Wed, Feb 27, 2013 at 1:43 PM, Aashish Chaudhary <
aashish.chaudhary at kitware.com> wrote:

> It works now. I had bad installation of mpi and then on top of that I got
> the wrong text pasted on the pi.py file.
>
> Thanks. Have you plan the next steps?
>
>
> On Wed, Feb 27, 2013 at 1:39 PM, Aashish Chaudhary <
> aashish.chaudhary at kitware.com> wrote:
>
>> Found the problem (and pasted one file wrong)
>>
>>
>> On Wed, Feb 27, 2013 at 1:38 PM, Aashish Chaudhary <
>> aashish.chaudhary at kitware.com> wrote:
>>
>>> yes,
>>>
>>> *pi.py*
>>> from mpi4py import MPI
>>> import numpy
>>>
>>> comm = MPI.Comm.Get_parent()
>>> size = comm.Get_size()
>>> rank = comm.Get_rank()
>>>
>>> N = numpy.array(0, dtype='i')
>>> comm.Bcast([N, MPI.INT], root=0)
>>> h = 1.0 / N; s = 0.0
>>> for i in range(rank, N, size):
>>>     x = h * (i + 0.5)
>>>     s += 4.0 / (1.0 + x**2)
>>> PI = numpy.array(s * h, dtype='d')
>>> comm.Reduce([PI, MPI.DOUBLE], None,
>>>             op=MPI.SUM, root=0)
>>>
>>> comm.Disconnect()
>>>
>>> *cpi.py*
>>> #!/usr/bin/env python
>>> from  mpi4py import MPI
>>> import numpy
>>>
>>> comm = MPI.Comm.Get_parent()
>>> size = comm.Get_size()
>>> rank = comm.Get_rank()
>>>
>>> N = numpy.array(0, dtype='i')
>>> comm.Bcast([N, MPI.INT], root=0)
>>> h = 1.0 / N; s = 0.0
>>> for i in range(rank, N, size):
>>>     x = h * (i + 0.5)
>>>     s += 4.0 / (1.0 + x**2)
>>> PI = numpy.array(s * h, dtype='d')
>>> comm.Reduce([PI, MPI.DOUBLE], None,
>>>             op=MPI.SUM, root=0)
>>>
>>>  comm.Disconnect()
>>>
>>>
>>>
>>>
>>> On Wed, Feb 27, 2013 at 1:29 PM, Ben Burnett <benjam.arlyn at gmail.com>wrote:
>>>
>>>> When you ran the example, did you create two python files, one for the
>>>> master (e.g. pi.py), one for the worker (cpi.py), and then run the master
>>>> file?
>>>>
>>>>
>>>> On Wed, Feb 27, 2013 at 1:23 PM, Aashish Chaudhary <
>>>> aashish.chaudhary at kitware.com> wrote:
>>>>
>>>>> That's what I did to verify..here is the error I got:
>>>>>
>>>>> Traceback (most recent call last):
>>>>>   File "test.py", line 5, in <module>
>>>>>     size = comm.Get_size()
>>>>>   File "Comm.pyx", line 68, in mpi4py.MPI.Comm.Get_size
>>>>> (src/mpi4py.MPI.c:57940)
>>>>> mpi4py.MPI.Exception: Invalid communicator, error stack:
>>>>> MPI_Comm_size(111): MPI_Comm_size(MPI_COMM_NULL, size=0x7fffeda7bd3c)
>>>>> failed
>>>>> MPI_Comm_size(69).: Null communicator
>>>>>
>>>>>
>>>>> On Wed, Feb 27, 2013 at 1:14 PM, Ben Burnett <benjam.arlyn at gmail.com>wrote:
>>>>>
>>>>>> The Pi example came from
>>>>>> http://mpi4py.scipy.org/docs/usrman/tutorial.html, I just modified
>>>>>> it to run in a websocket handler on cherrypy.
>>>>>>
>>>>>> It looks like it's failing to spawn the processes using MPI. Do you
>>>>>> get any exceptions in the log?
>>>>>>
>>>>>> You could try first running the Pi example from the above website in
>>>>>> python to make sure MPI is working on your machine.
>>>>>>
>>>>>>
>>>>>> On Wed, Feb 27, 2013 at 12:46 PM, Aashish Chaudhary <
>>>>>> aashish.chaudhary at kitware.com> wrote:
>>>>>>
>>>>>>> @Ben,
>>>>>>>
>>>>>>> The char exampled worked like charm, but the PI example didn't.  I
>>>>>>> don't see the value of PI. Did you write that code or its from the ws4py
>>>>>>> test / example?
>>>>>>>
>>>>>>>  Thanks
>>>>>>>
>>>>>>>
>>>>>>>   1 [27/Feb/2013:12:44:38] ENGINE Listening for SIGHUP.
>>>>>>>   2 [27/Feb/2013:12:44:38] ENGINE Listening for SIGTERM.
>>>>>>>   3 [27/Feb/2013:12:44:38] ENGINE Listening for SIGUSR1.
>>>>>>>   4 [27/Feb/2013:12:44:38] ENGINE Bus STARTING
>>>>>>>   5 [27/Feb/2013:12:44:38] ENGINE Forking once.
>>>>>>>   6 [27/Feb/2013:12:44:38] ENGINE Forking twice.
>>>>>>>   7 [27/Feb/2013:12:44:38] ENGINE Daemonized to PID: 24810
>>>>>>>   8 [27/Feb/2013:12:44:38]  Starting WebSocket processing
>>>>>>>   9 [27/Feb/2013:12:44:38] ENGINE PID 24810 written to
>>>>>>> '/home/aashish/workspace/build/deploy/ogs.pid'.
>>>>>>>  10 [27/Feb/2013:12:44:38] ENGINE Started monitor thread
>>>>>>> '_TimeoutMonitor'.
>>>>>>>  11 [27/Feb/2013:12:44:38] ENGINE Started monitor thread
>>>>>>> 'Autoreloader'.
>>>>>>>  12 [27/Feb/2013:12:44:38] ENGINE Serving on 127.0.0.1:8080
>>>>>>>  13 [27/Feb/2013:12:44:38] ENGINE Bus STARTED
>>>>>>>  14 [27/Feb/2013:12:44:41]  Handler created:
>>>>>>> <websocket_pi.PiWebSocketHandler object at 0x275f410>
>>>>>>>  15 [27/Feb/2013:12:44:41]  Managing WebSocket connection from
>>>>>>> 127.0.0.1:56898
>>>>>>>  16 [27/Feb/2013:12:44:46]  something
>>>>>>>  17 [27/Feb/2013:12:44:46]  Recieved message 101
>>>>>>>  18 [27/Feb/2013:12:44:46]  Dir /home/aashish/workspace/build/deploy
>>>>>>>  19 [27/Feb/2013:12:44:46]  Path
>>>>>>> /home/aashish/workspace/build/deploy/cpi.py
>>>>>>>
>>>>>>> On Wed, Feb 27, 2013 at 12:15 PM, Aashish Chaudhary <
>>>>>>> aashish.chaudhary at kitware.com> wrote:
>>>>>>>
>>>>>>>> Nice..I will have a look at it today.
>>>>>>>>
>>>>>>>> On Wed, Feb 27, 2013 at 12:10 PM, Ben Burnett <
>>>>>>>> benjam.arlyn at gmail.com> wrote:
>>>>>>>>
>>>>>>>>> I just pushed the branch websockets-mpi, and added a wiki page
>>>>>>>>> with some notes on it
>>>>>>>>> https://github.com/OpenGeoscience/opengeoscience/wiki/Testing-Websockets-and-MPI
>>>>>>>>> _______________________________________________
>>>>>>>>> Opengeoscience-developers mailing list
>>>>>>>>> Opengeoscience-developers at public.kitware.com
>>>>>>>>>
>>>>>>>>> http://public.kitware.com/cgi-bin/mailman/listinfo/opengeoscience-developers
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> | Aashish Chaudhary
>>>>>>>> | R&D Engineer
>>>>>>>> | Kitware Inc.
>>>>>>>> | www.kitware.com
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> | Aashish Chaudhary
>>>>>>> | R&D Engineer
>>>>>>> | Kitware Inc.
>>>>>>> | www.kitware.com
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> | Aashish Chaudhary
>>>>> | R&D Engineer
>>>>> | Kitware Inc.
>>>>> | www.kitware.com
>>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> | Aashish Chaudhary
>>> | R&D Engineer
>>> | Kitware Inc.
>>> | www.kitware.com
>>>
>>
>>
>>
>> --
>> | Aashish Chaudhary
>> | R&D Engineer
>> | Kitware Inc.
>> | www.kitware.com
>>
>
>
>
> --
> | Aashish Chaudhary
> | R&D Engineer
> | Kitware Inc.
> | www.kitware.com
>
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