import numpy as np
from sklearn.externals import joblib
from sklearn.linear_model import LinearRegression

X=np.loadtxt("Density_Xray.dat")
y=np.log10(np.array(X[:,2]))
X = X[:,0:2]
X[:,1] = np.log10(X[:,1])

lr = LinearRegression()
lr.fit(X,y)

joblib.dump(lr, 'X_ray_luminosity.pkl') 

clf = joblib.load('X_ray_luminosity.pkl')