# -*- coding: utf-8 -*-
import numpy as np
from iminuit import Minuit
from matplotlib import pyplot as plt
from numpy.random import randn, seed

from probfit import Chi2Regression, linear

seed(0)
ndata = 30
x = np.linspace(-10, 10, ndata)
y = 2 * x + 5
y += randn(ndata)

x2r = Chi2Regression(linear, x, y, np.array([1.0] * ndata))

m = Minuit(x2r, m=1, c=2)

plt.figure(figsize=(8, 3))
plt.subplot(121)
x2r.draw(m)
plt.title("Before")

m.migrad()  # fit

plt.subplot(122)
x2r.draw(m)
plt.title("After")