from scipy.stats import powerlognorm import matplotlib.pyplot as plt fig, ax = plt.subplots(1, 1) # Calculate a few first moments: c, s = 2.14, 0.446 mean, var, skew, kurt = powerlognorm.stats(c, s, moments='mvsk') # Display the probability density function (``pdf``): x = np.linspace(powerlognorm.ppf(0.01, c, s), powerlognorm.ppf(0.99, c, s), 100) ax.plot(x, powerlognorm.pdf(x, c, s), 'r-', lw=5, alpha=0.6, label='powerlognorm 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 = powerlognorm(c, s) ax.plot(x, rv.pdf(x), 'k-', lw=2, label='frozen pdf') # Check accuracy of ``cdf`` and ``ppf``: vals = powerlognorm.ppf([0.001, 0.5, 0.999], c, s) np.allclose([0.001, 0.5, 0.999], powerlognorm.cdf(vals, c, s)) # True # Generate random numbers: r = powerlognorm.rvs(c, s, size=1000) # And compare the histogram: ax.hist(r, normed=True, histtype='stepfilled', alpha=0.2) ax.legend(loc='best', frameon=False) plt.show()