Cython_book Chapter 2: Example fib()

In [1]:

    

%load_ext Cython


    

In [2]:

    

%%cython -a
def fib(int n):
    cdef int i
    cdef double a=0.0, b=1.0
    for i in range(n):
        a, b = b, a+b
    return a


    

    
Out[2]:









    
    
    
    


Generated by Cython 0.25.2

    Yellow lines hint at Python interaction.

    Click on a line that starts with a "+" to see the C code that Cython generated for it.

+1: def fib(int n):
/* Python wrapper */
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 2:     cdef int i
+3:     cdef double a=0.0, b=1.0
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  __pyx_v_b = 1.0;
+4:     for i in range(n):
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In [3]:

    

%timeit -n3 -r3 fib(500)


    

    




3 loops, best of 3: 566 ns per loop

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