Cumulative wind speed prediction

Generate the image cumulative-wind-speed-prediction.png for the interpolate section of scipy.rst.

Text(42.722222222222214, 0.5, 'Cumulative probability')

import numpy as np
import scipy as sp
import matplotlib.pyplot as plt

max_speeds = np.load("max-speeds.npy")
years_nb = max_speeds.shape[0]

cprob = (np.arange(years_nb, dtype=np.float32) + 1) / (years_nb + 1)
sorted_max_speeds = np.sort(max_speeds)
speed_spline = sp.interpolate.UnivariateSpline(cprob, sorted_max_speeds)
nprob = np.linspace(0, 1, 100)
fitted_max_speeds = speed_spline(nprob)

fifty_prob = 1.0 - 0.02
fifty_wind = speed_spline(fifty_prob)

plt.figure()
plt.plot(sorted_max_speeds, cprob, "o")
plt.plot(fitted_max_speeds, nprob, "g--")
plt.plot([fifty_wind], [fifty_prob], "o", ms=8.0, mfc="y", mec="y")
plt.text(30, 0.05, rf"$V_{{50}} = {fifty_wind:.2f} \, m/s$")
plt.plot([fifty_wind, fifty_wind], [plt.axis()[2], fifty_prob], "k--")
plt.xlabel("Annual wind speed maxima [$m/s$]")
plt.ylabel("Cumulative probability")