python performance code example

Example 1: python system performance

import os
import psutil
pid = os.getpid()
py = psutil.Process(pid)
memoryUse = py.memory_info()[0]/2.**30  # memory use in GB...I think
print('memory use:', memoryUse)

Example 2: type python fast

def f(double x):
    return x ** 2 - x


def integrate_f(double a, double b, int N):
    cdef int i
    cdef double s, dx
    s = 0
    dx = (b - a) / N
    for i in range(N):
        s += f(a + i * dx)
    return s * dx