Plotting normal pdf's in Python.

normal.py

import numpy as np
import matplotlib.pyplot as plt
def normal_pdf(x, mu=0, sigma=1):
    sqrt_two_pi = np.sqrt(2*np.pi)
    return (np.exp(-(x-mu)**2/2/sigma**2)/(sqrt_two_pi*sigma))

xs = [x / 10.0 for x in range(-50, 50)]
plt.plot(xs, [normal_pdf(x, sigma=1) for x in xs], '-', label='$\mu=0$, $\sigma=1$')
plt.plot(xs, [normal_pdf(x, sigma=2) for x in xs], '--', label='$\mu=0$, $\sigma=2$')
plt.plot(xs, [normal_pdf(x, sigma=0.5) for x in xs], ':', label='$\mu=0$, $\sigma=0.5$')
plt.plot(xs, [normal_pdf(x, mu=-1) for x in xs], '-.', label='$\mu=-1$, $\sigma=1$')
plt.legend()
plt.xlim(-5,5)
plt.title('Various Normal pdf\'s')
plt.show()