Coroutine examples and timing

results.txt

For n= 100000

$ python test_coroutines.py 
Coroutine Loop Result: '14.1121757499'; loop time (ms): 393.39017868
Numpy Loop Result: '14.1121757499'; loop time (ms): 26105.5378914
Numpy Dot Result: '14.1121757499'; dot time (ms): 0.148057937622
# can't pass a scalar by reference, try passing an array of size 1
Coroutine Loop No Result: '[ 14.11217575]'; loop time (ms): 438.895225525

test_coroutines.py

#!/usr/bin/env python
"""
python dot product using coroutines
Goal is to test coroutine performance and syntactic sugar
"""
import numpy
import itertools
import time

# make some data
n = 100000
a = numpy.random.randn(n)
b = numpy.random.randn(n)

def coroutine(func):
    def start(*args, **kwargs):
        g = func(*args, **kwargs)
        g.next()
        return g
    return start
    
@coroutine
def mult(target=None):
    if target is None:
        raise RuntimeError('Must specify targe coroutine!')

    result = numpy.float64(0.0)
    while True:
        (a, b) = (yield result)
        result = target.send(a*b)
        
@coroutine
def add():
    result = numpy.float64(0.0)
    while True:
        m = (yield result)
        result += m
        
dot_product_process = mult(add())

it = numpy.nditer([a, b])
tic = time.time()
for (a_val,b_val) in it:
    dot_product = dot_product_process.send((a_val, b_val))
toc = time.time()

print "Coroutine Loop Result: '%s'; loop time (ms): %s" % (dot_product, 1000*(toc-tic))

it = numpy.nditer([a, b])
result = numpy.float64(0.0)
tic = time.time()
for (a_val,b_val) in it:
    result += a*b
toc = time.time()

print "Numpy Loop Result: '%s'; loop time (ms): %s" % (dot_product, 1000*(toc-tic))

tic = time.time()
dot_product = numpy.dot(a,b)
toc = time.time()
print "Numpy Dot Result: '%s'; dot time (ms): %s" % (dot_product, 1000*(toc-tic))


# Coroutine processes without using return...
@coroutine
def mult_noresult(target=None):
    if target is None:
        raise RuntimeError('Must specify targe coroutine!')
    while True:
        (a, b) = (yield)
        result = target.send(a*b)
                
@coroutine
def add_noresult(result):
    while True:
        m = (yield)
        result[0] += m


result = numpy.zeros((1,))
dot_product_process_noresult = mult_noresult(add_noresult(result))

it = numpy.nditer([a, b])
tic = time.time()
for (a_val,b_val) in it:
    dot_product_process_noresult.send((a_val, b_val))
toc = time.time()

print "Coroutine Loop No Result: '%s'; loop time (ms): %s" % (result, 1000*(toc-tic))