Coverage for local/lib/python2.7/site-packages/sage/parallel/multiprocessing_sage.py : 58%

""" 

Parallel Iterator built using Python's multiprocessing module 

""" 

################################################################################ 

# Copyright (C) 2008 William Stein <wstein@gmail.com> 

# 

# Distributed under the terms of (any version of) the GNU 

# General Public License (GPL). The full text of the GPL is available at: 

# 

# http://www.gnu.org/licenses/ 

################################################################################ 

from __future__ import absolute_import 

from multiprocessing import Pool 

from functools import partial 

from sage.misc.fpickle import pickle_function, call_pickled_function 

from . import ncpus 

def pyprocessing(processes=0): 

""" 

Return a parallel iterator using a given number of processes 

implemented using pyprocessing. 

INPUT: 

- ``processes`` -- integer (default: 0); if 0, set to the number 

of processors on the computer. 

OUTPUT: 

- a (partially evaluated) function 

EXAMPLES:: 

sage: from sage.parallel.multiprocessing_sage import pyprocessing 

sage: p_iter = pyprocessing(4) 

sage: P = parallel(p_iter=p_iter) 

sage: def f(x): return x+x 

sage: v = list(P(f)(list(range(10)))); v.sort(); v 

[(((0,), {}), 0), (((1,), {}), 2), (((2,), {}), 4), (((3,), {}), 6), (((4,), {}), 8), (((5,), {}), 10), (((6,), {}), 12), (((7,), {}), 14), (((8,), {}), 16), (((9,), {}), 18)] 

""" 

if processes == 0: 

processes = ncpus.ncpus() 

return partial(parallel_iter, processes) 

def parallel_iter(processes, f, inputs): 

""" 

Return a parallel iterator. 

INPUT: 

- ``processes`` -- integer 

- ``f`` -- function 

- ``inputs`` -- an iterable of pairs (args, kwds) 

OUTPUT: 

- iterator over values of ``f`` at ``args,kwds`` in some random order. 

EXAMPLES:: 

sage: def f(x): return x+x 

sage: import sage.parallel.multiprocessing_sage 

sage: v = list(sage.parallel.multiprocessing_sage.parallel_iter(2, f, [((2,), {}), ((3,),{})])) 

sage: v.sort(); v 

[(((2,), {}), 4), (((3,), {}), 6)] 

""" 

from twisted.internet import reactor # do not delete this (!) -- see trac 8785 

if processes == 0: processes = ncpus.ncpus() 

p = Pool(processes) 

fp = pickle_function(f) 

result = p.imap_unordered(call_pickled_function, [ (fp, t) for t in inputs ]) 

for res in result: 

yield res 

p.close() 

p.join()