curve_fitting.py

import numpy as np
from scipy.optimize import curve_fit
import matplotlib.pyplot as plt

# def func(x, a, b, c):
#     return a * x**b * np.exp(-c/x)
def poly_func(x, a, b, c):
    return a*x**2 + b*x + c
# f = 'alpha_en.txt'
# data = np.loadtxt(f, delimiter=', ')
# xdata = data[:,0]
# ydata = data[:,1]

xdata = EArray
ydata = alpha
popt, pcov = curve_fit(poly_func,xdata,ydata,p0=[1.0e4,0.5,15.0])
print popt
plt.plot(xdata,ydata,label='data')
plt.plot(xdata,poly_func(xdata,popt[0],popt[1],popt[2]),label='fit')
plt.legend(loc=0)
plt.show()