In [1]:

    

%load_ext Cython


    

In [2]:

    

def smooth_py(a):
    n = len(a) - 1
    for i in range(1, n):
        a[i] = (a[i-1] + a[i] + a[i+1]) / 3.0
    return a


    

In [3]:

    

%%cython
def smooth_c1(a):
    cdef unsigned int i, n=len(a) - 1
    for i in range(1, n):
        a[i] = (a[i-1] + a[i] + a[i+1]) / 3.0
    return a


    

In [13]:

    

%%cython
cdef list smooth_c2(list a):
    cdef unsigned int i, n=len(a) - 1
    for i in range(1, n):
        a[i] = (a[i-1] + a[i] + a[i+1]) / 3.0
    return a


    

In [4]:

    

from random import sample


    

In [24]:

    

a = sample(range(1000), k=1000)


    

In [25]:

    

%timeit -n3 -r5 smooth_py(a[:])


    

    




3 loops, best of 5: 563 µs per loop

In [26]:

    

%timeit -n3 -r5 smooth_c1(a[:])


    

    




3 loops, best of 5: 96.2 µs per loop

In [27]:

    

%timeit -n3 -r5 smooth_c2(a[:])


    

    




3 loops, best of 5: 97.7 µs per loop