An example of how to use multiprocessing from within Maya, by actually running it as a subprocess and communicating back the results.

maya_script_editor.py

"""
This code can be run from a Maya script editor
"""
import subprocess
import cPickle

print 'This value below should be a 1000:'

p = subprocess.Popen(["/path/to/multi_test.py", "-po"], stdout=subprocess.PIPE)
result = cPickle.load(p.stdout)

print result

multi_test.py

#!/usr/bin/env python 

import multiprocessing
from time import time
import cPickle
import sys

## Simple func to eat up cpu power.
def whileFunc(z):
    while z < 100000:
        z += 1 
    return z

if __name__ == "__main__":
    ## Get current time 
    currtime = time()

    ## How often to run (just a test value)
    N = 1000
    ## Just a list with 1s 
    myList = [1]*N

    nrOfProcessors = multiprocessing.cpu_count() 

    ## Set our pool of processors 
    po = multiprocessing.Pool(nrOfProcessors)
    
    ## create the threads 
    res = po.map_async(whileFunc, myList)
    
    ## If we pass a -po flag, pickle the output and write it out    
    if '-po' in sys.argv[1:]:
        results = len(res.get())
        cPickle.dump(results, sys.stdout, -1)
        sys.stdout.flush()
        sys.exit(0)

    print 'This value below should be a 1000:'
    print len(res.get())
    print 'time elapsed:', time() - currtime

hi, When i tried running this in Maya 2015, I got the following error, Any Idea what could be going wrong ?:
"""
This code can be run from a Maya script editor
"""
import subprocess
import cPickle

print 'This value below should be a 1000:'

p = subprocess.Popen(["C:/test/multi_test.py", "-po"], stdout=subprocess.PIPE)
result = cPickle.load(p.stdout)

print result
This value below should be a 1000:

Error: 193

Traceback (most recent call last):

File "", line 9, in

File "C:\Program Files\Autodesk\Maya2015\bin\python27.zip\subprocess.py", line 679, in init

errread, errwrite)

File "C:\Program Files\Autodesk\Maya2015\bin\python27.zip\subprocess.py", line 896, in _execute_child

startupinfo)

WindowsError: [Error 193] %1 is not a valid Win32 application

HI Justtin
Get the same 193 error as above

WindowsError: [Error 193] %1 is not a valid Win32 application

This value below should be a 1000:

Error: 193

Traceback (most recent call last):

File "", line 9, in

File "C:\Program Files\Autodesk\Maya2018\bin\python27.zip\subprocess.py", line 710, in init

errread, errwrite)

File "C:\Program Files\Autodesk\Maya2018\bin\python27.zip\subprocess.py", line 958, in _execute_child

startupinfo)

WindowsError: [Error 193] %1 is not a valid Win32 application

Is there a fix for this error. Any help would be appreciated.

Thanks

@jf20 / @akashCGI

I don't have a windows box to test, but it looks like it is caused by the translation of my linux/osx code to a Windows command, but not accounting for the difference that windows actually needs the path to the python executable as the first arguments.

Untested, but you might need to do something like

import sys

p = subprocess.Popen([sys.executable, "C:/test/multi_test.py", "-po"], stdout=subprocess.PIPE)