################################################################################################### 
# This moddule is called by demo scripts to execute and embed CPython.
# Must be put in the scripts folder, or else in the python path.
################################################################################################### 
import numpy as np


def linfit(x, y):
    """
    Return linear fit
    """
    print(1, type(x), type(y), x, y)
    p = np.polyfit(x, y, 1)
    f = np.poly1d(p)
    x_fit = np.linspace(min(x), max(x), 100)
    y_fit = f(x_fit)
    yhat = f(x)
    ybar = np.sum(y)/len(y)
    ssreg = np.sum((yhat - ybar)**2)
    sstot = np.sum((y - ybar)**2)
    R2 = ssreg / sstot
    return (p, x_fit, y_fit, R2)