from scipy.stats import levy_stable import matplotlib.pyplot as plt fig, ax = plt.subplots(1, 1) # Calculate a few first moments: alpha, beta = 0.357, -0.675 mean, var, skew, kurt = levy_stable.stats(alpha, beta, moments='mvsk') # Display the probability density function (``pdf``): x = np.linspace(levy_stable.ppf(0.01, alpha, beta), levy_stable.ppf(0.99, alpha, beta), 100) ax.plot(x, levy_stable.pdf(x, alpha, beta), 'r-', lw=5, alpha=0.6, label='levy_stable pdf') # Alternatively, the distribution object can be called (as a function) # to fix the shape, location and scale parameters. This returns a "frozen" # RV object holding the given parameters fixed. # Freeze the distribution and display the frozen ``pdf``: rv = levy_stable(alpha, beta) ax.plot(x, rv.pdf(x), 'k-', lw=2, label='frozen pdf') # Check accuracy of ``cdf`` and ``ppf``: vals = levy_stable.ppf([0.001, 0.5, 0.999], alpha, beta) np.allclose([0.001, 0.5, 0.999], levy_stable.cdf(vals, alpha, beta)) # True # Generate random numbers: r = levy_stable.rvs(alpha, beta, size=1000) # And compare the histogram: ax.hist(r, normed=True, histtype='stepfilled', alpha=0.2) ax.legend(loc='best', frameon=False) plt.show()