plot.py

import scipy as sp
pi = sp.pi
def div(x,y):
  try:
    return x/y
  except:
    return (x+1e-15)/(y+1e-15)
L = 4
w = sp.linspace(-pi, pi, 501)
#w = sp.arange(-pi,pi, pi/250)
print len(w)
adiv = sp.vectorize(div)
#print adiv(w, w+.001)
#H = (1./L)*adiv((1-sp.exp(-1j*w*L)), 1-sp.exp(-1j*w))
H=(1./L)*(1-sp.exp(-1j*w*L))/(1-sp.exp(-1j*w))
import matplotlib.pyplot as plt
plt.plot(w, abs(H))
plt.show()