unaligned-simple.py

###################################################################
#  Numexpr - Fast numerical array expression evaluator for NumPy.
#
#      License: MIT
#      Author:  See AUTHORS.txt
#
#  See LICENSE.txt and LICENSES/*.txt for details about copyright and
#  rights to use.
####################################################################

"""Very simple test that compares the speed of operating with
aligned vs unaligned arrays.
"""

from __future__ import print_function

from timeit import Timer

import numpy as np

import numexpr as ne

niter = 10
#shape = (1000*10000)   # unidimensional test
shape = (1000, 10000)   # multidimensional test

print("Numexpr version: ", ne.__version__)

Z_fast = np.zeros(shape, dtype=[('x',np.float64),('y',np.int64)])
Z_slow = np.zeros(shape, dtype=[('y1',np.int8),('x',np.float64),('y2',np.int8,(7,))])

x_fast = Z_fast['x']
t = Timer("x_fast * x_fast", "from __main__ import x_fast")
print("NumPy aligned:  \t", round(min(t.repeat(3, niter)), 3), "s")

x_slow = Z_slow['x']
t = Timer("x_slow * x_slow", "from __main__ import x_slow")
print("NumPy unaligned:\t", round(min(t.repeat(3, niter)), 3), "s")

t = Timer("ne.evaluate('x_fast * x_fast')", "from __main__ import ne, x_fast")
print("Numexpr aligned:\t", round(min(t.repeat(3, niter)), 3), "s")

t = Timer("ne.evaluate('x_slow * x_slow')", "from __main__ import ne, x_slow")
print("Numexpr unaligned:\t", round(min(t.repeat(3, niter)), 3), "s")