Math 480 - Cython

748 days ago by robertwb

%cython print "Hi Math 480" 
       
%cython from math import sin def f(x): return sin(x**2) def integral(a, b, N): dx = (b-a)/N s = 0 for i in range(N): s += f(a+dx*i) return s * dx 
       
time integral(0.0, 1.0, 100000) 
        
0.310264094377461
Time: CPU 1.50 s, Wall: 1.53 s
0.310264094377461
Time: CPU 1.50 s, Wall: 1.53 s
%cython from math import sin def f(x): return sin(x**2) def integral(double a, double b, int N): cdef double dx = (b-a)/N cdef int i cdef double s = 0 for i in range(N): s += f(a+dx*i) return s * dx 
       
time integral(0.0, 1.0, 100000) 
        
0.310264094377461
Time: CPU 0.06 s, Wall: 0.06 s
0.310264094377461
Time: CPU 0.06 s, Wall: 0.06 s
1.5 / .06 
        
25.0000000000000
25.0000000000000
time integral(0.0, 1.0, 1000000) 
        
0.31026788098798791
Time: CPU 0.58 s, Wall: 0.58 s
0.31026788098798791
Time: CPU 0.58 s, Wall: 0.58 s
%cython cdef extern from "math.h": # external library double sin(double) cdef double f(double x): return sin(x**2) def integral(double a, double b, int N): cdef double dx = (b-a)/N cdef int i cdef double s = 0 for i in range(N): s += f(a+dx*i) return s * dx 
       
time integral(0.0, 1.0, 100000000) 
        
0.31026829751610591
Time: CPU 3.15 s, Wall: 3.17 s
0.31026829751610591
Time: CPU 3.15 s, Wall: 3.17 s
(1.5 / 100000) / (3.15 / 100000000) 
        
476.190476190476
476.190476190476
numerical_integral(sin(x^2), 0, 1) 
        
(0.31026830172338099, 3.444670123846427e-15)
(0.31026830172338099, 3.444670123846427e-15)
%cython def square(int i): return i*i 
       
square(10^6) 
        
-727379968
-727379968
def square(i): return i*i 
       
square(10^6) 
        
1000000000000
1000000000000
%cython cdef square_inplace(int* x): x[0] = x[0]**2 def call_square_inplace(int x): print "x is", x square_inplace(&x) print "x is", x 
       
call_square_inplace(2) 
        
x is 2
x is 4
x is 2
x is 4
class TwoNumbers: def __init__(self, a, b): self.a = a self.b = b def sum(self): return self.a + self.b def sum_a_lot(self, N): for i in range(N): self.sum() def __repr__(self): return "The numbers %s and %s" % (self.a, self.b) def __str__(self): return repr(self) 
       
a = TwoNumbers(3, 5) a 
        
The numbers 3 and 5
The numbers 3 and 5
a.sum() 
        
8
8
time a.sum_a_lot(1000000) 
        
Time: CPU 0.67 s, Wall: 0.68 s
Time: CPU 0.67 s, Wall: 0.68 s
%cython cdef class TwoNumbers: cdef int a,b def __init__(self, a, b): self.a = a self.b = b def sum(self): return self.a + self.b def sum_a_lot(self, N): for i in range(N): self.sum() def __repr__(self): return "The numbers %s and %s" % (self.a, self.b) def __str__(self): return repr(self) 
       
a = TwoNumbers(3, 5) time a.sum_a_lot(1000000) 
        
Time: CPU 0.18 s, Wall: 0.18 s
Time: CPU 0.18 s, Wall: 0.18 s
.67/.18 
        
3.72222222222222
3.72222222222222
%cython cdef class TwoNumbers: cdef int a, b def __init__(self, a, b): self.a = a self.b = b cpdef int sum(self): return self.a + self.b def sum_a_lot(self, int N): cdef int i for i in range(N): self.sum() def __repr__(self): return "The numbers %s and %s" % (self.a, self.b) def __str__(self): return repr(self) 
       
a = TwoNumbers(3, 5) time a.sum_a_lot(1000000) 
        
Time: CPU 0.01 s, Wall: 0.01 s
Time: CPU 0.01 s, Wall: 0.01 s
a = TwoNumbers(3, 5) time a.sum_a_lot(100000000) 
        
Time: CPU 0.91 s, Wall: 0.92 s
Time: CPU 0.91 s, Wall: 0.92 s
.67 / .009 
        
74.4444444444445
74.4444444444445
a = TwoNumbers(2^30, 2^30) 
       
a.sum() 
        
-2147483648
-2147483648
%cython cimport cython @cython.infer_types(True) def f(): x = 4 print cython.typeof(x) y = 5.1 print cython.typeof(y) z = 1 z = "hi" print cython.typeof(z) 
       
f() 
        
long
double
Python object
long
double
Python object
%cython print eval("[n**2 for n in range(10)]") 
        
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]