"""
Reference Parallel Primitives
These are reference implementations of basic parallel
primitives. These are not actually parallel, but work the same way.
They are good for testing.
"""
from sage.misc.prandom import shuffle
def parallel_iter(f, inputs):
"""
Reference parallel iterator implementation.
INPUT:
- ``f`` -- a Python function that can be pickled using
the pickle_function command.
- ``inputs`` -- a list of pickleable pairs (args, kwds), where
args is a tuple and kwds is a dictionary.
OUTPUT:
- iterator over 2-tuples ``(inputs[i], f(inputs[i]))``, where the
order may be completely random
EXAMPLES::
sage: def f(N,M=10): return N*M
sage: inputs = [((2,3),{}), (tuple([]), {'N':3,'M':5}), ((2,),{})]
sage: set_random_seed(0)
sage: for a, val in sage.parallel.reference.parallel_iter(f, inputs):
... print a, val
((2,), {}) 20
((), {'M': 5, 'N': 3}) 15
((2, 3), {}) 6
sage: for a, val in sage.parallel.reference.parallel_iter(f, inputs):
... print a, val
((), {'M': 5, 'N': 3}) 15
((2,), {}) 20
((2, 3), {}) 6
"""
v = list(inputs)
shuffle(v)
for args, kwds in v:
yield ((args, kwds), f(*args, **kwds))
