testing (A+B)^2

>>> import timeit
... number=3
... setup = """
... from random import random as rand
... import numpy
... N=7000000
... A=[rand() for _ in range(N)]
... B=[rand() for _ in range(N)]
... sq1 = lambda x: x*x
... def sq2(x):
...   return x*x
... """
... stmts = [ 'C=[(a+b)**2 for a,b in zip(A,B)]',
...           'C=[(a+b)*(a+b) for a,b in zip(A,B)]',
...           'C=[sq1(a+b) for a,b in zip(A,B)]',
...           'C=[sq2(a+b) for a,b in zip(A,B)]']
... for s in stmts:
...   print "executing", s, "took", timeit.timeit(stmt=s, setup=setup, number=number), "seconds"
...
... setup = """
... from random import random as rand
... import numpy
... N=7000000
... A=[rand() for _ in range(N)]
... B=[rand() for _ in range(N)]
... A1 = numpy.array(A)
... B1 = numpy.array(B)
... """
... s = """
... S1 = A1+B1; C1 = S1 * S1
... """
... print "executing", s, "took", timeit.timeit(stmt=s, setup=setup, number=number), "seconds"
executing C=[(a+b)**2 for a,b in zip(A,B)] took 10.4074020386 seconds
executing C=[(a+b)*(a+b) for a,b in zip(A,B)] took 7.50627994537 seconds
executing C=[sq1(a+b) for a,b in zip(A,B)] took 9.10019111633 seconds
executing C=[sq2(a+b) for a,b in zip(A,B)] took 9.08746981621 seconds
executing S1 = A1+B1; C1 = S1 * S1 took 0.411483049393 seconds