def test_no_blas_crash_or_freeze_with_multiprocessing():
if sys.version_info < (3, 4):
raise nose.SkipTest("multiprocessing can cause BLAS freeze on" " old Python")
# Use the spawn backend that is both robust and available on all platforms
spawn_backend = mp.get_context("spawn")
# Check that on recent Python version, the 'spawn' start method can make
# it possible to use multiprocessing in conjunction of any BLAS
# implementation that happens to be used by numpy with causing a freeze or
# a crash
rng = np.random.RandomState(42)
# call BLAS DGEMM to force the initialization of the internal thread-pool
# in the main process
a = rng.randn(1000, 1000)
np.dot(a, a.T)
# check that the internal BLAS thread-pool is not in an inconsistent state
# in the worker processes managed by multiprocessing
Parallel(n_jobs=2, backend=spawn_backend)(delayed(np.dot)(a, a.T) for i in range(2))
def test_no_blas_crash_or_freeze_with_multiprocessing():
if sys.version_info < (3, 4):
raise SkipTest('multiprocessing can cause BLAS freeze on old Python')
# Use the spawn backend that is both robust and available on all platforms
spawn_backend = mp.get_context('spawn')
# Check that on recent Python version, the 'spawn' start method can make
# it possible to use multiprocessing in conjunction of any BLAS
# implementation that happens to be used by numpy with causing a freeze or
# a crash
rng = np.random.RandomState(42)
# call BLAS DGEMM to force the initialization of the internal thread-pool
# in the main process
a = rng.randn(1000, 1000)
np.dot(a, a.T)
# check that the internal BLAS thread-pool is not in an inconsistent state
# in the worker processes managed by multiprocessing
Parallel(n_jobs=2,
backend=spawn_backend)(delayed(np.dot)(a, a.T) for i in range(2))
from joblib.parallel import Parallel, delayed
from joblib.parallel import register_parallel_backend, parallel_backend
from joblib.parallel import effective_n_jobs, cpu_count
from joblib.parallel import mp, BACKENDS, DEFAULT_BACKEND, EXTERNAL_BACKENDS
from joblib.my_exceptions import JoblibException
ALL_VALID_BACKENDS = [None] + sorted(BACKENDS.keys())
# Add instances of backend classes deriving from ParallelBackendBase
ALL_VALID_BACKENDS += [BACKENDS[backend_str]() for backend_str in BACKENDS]
PROCESS_BACKENDS = ['multiprocessing', 'loky']
PARALLEL_BACKENDS = PROCESS_BACKENDS + ['threading']
if hasattr(mp, 'get_context'):
# Custom multiprocessing context in Python 3.4+
ALL_VALID_BACKENDS.append(mp.get_context('spawn'))
DefaultBackend = BACKENDS[DEFAULT_BACKEND]
def get_workers(backend):
return getattr(backend, '_pool', getattr(backend, '_workers', None))
def division(x, y):
return x / y
def square(x):
return x**2
from Queue import Queue
from joblib.parallel import Parallel, delayed, SafeFunction, WorkerInterrupt
from joblib.parallel import mp, cpu_count, VALID_BACKENDS
from joblib.my_exceptions import JoblibException
import nose
from nose.tools import assert_equal, assert_true, assert_false, assert_raises
ALL_VALID_BACKENDS = [None] + VALID_BACKENDS
if hasattr(mp, "get_context"):
# Custom multiprocessing context in Python 3.4+
ALL_VALID_BACKENDS.append(mp.get_context("spawn"))
def division(x, y):
return x / y
def square(x):
return x ** 2
def exception_raiser(x):
if x == 7:
raise ValueError
return x
# Backward compat
from Queue import Queue
from joblib.parallel import Parallel, delayed, SafeFunction, WorkerInterrupt, \
mp, cpu_count, VALID_BACKENDS
from joblib.my_exceptions import JoblibException
import nose
ALL_VALID_BACKENDS = [None] + VALID_BACKENDS
if hasattr(mp, 'get_context'):
# Custom multiprocessing context in Python 3.4+
ALL_VALID_BACKENDS.append(mp.get_context('spawn'))
###############################################################################
def division(x, y):
return x / y
def square(x):
return x ** 2
def exception_raiser(x):
if x == 7:
raise ValueError
return x
