#!/usr/bin/env python
# -*- coding: UTF-8 -*-
import numpy as np


def fitslr(x, y):
    n = len(x)
    din = 0
    num = 0
    avgX = np.mean(x)
    avgY = np.mean(y)
    for i in range(0, n):
        num += (x[i] - avgX) * (y[i] - avgY)
        din += (x[i] - avgX) ** 2

    print "din:", din
    print "num:", num
    b1 = num / float(din)
    b0 = avgY / float(avgX)
    return b0, b1


def predict(x, b0, b1):
    return b0 + x * b1


x = [1, 3, 2, 1, 3]
y = [14, 24, 18, 17, 27]

b0, b1 = fitslr(x, y)

print "intercept:", b0, "slope:", b1

x_test = 6
y_test = predict(6, b0, b1)

print "y_test", y_test