import numpy as np
import matplotlib.pyplot as plt

# global data
data = np.genfromtxt('data.csv', delimiter=',')
x_data = [x[0] for x in data]
y_data = [y[1] for y in data]
x_max = max(x_data)
y_max = max(y_data)
param_count = 1
alpha = 0.01
param_record = list()

def descend(theta):
    new = [0, 0]
    for i in range(0, len(data)):
        new[0] += (theta[0]*data[i, 0] + theta[1] - data[i, 1]) * data[i, 0]
        new[1] += (theta[1]*data[i, 0] + theta[1] - data[i, 1])
    new[0] = new[0]/(100*len(data))
    new[1] = new[1]/len(data)
    res = [theta[0] - alpha*new[0], theta[1] - alpha*new[1]]
    param_record.append(res)
    print(res)
    return res

def capture2(indexes):
    plt.plot(x_data, y_data, 'ro')
    plt.plot([0, 70], [0, 0])
    for i in indexes:
        f = lambda x:param_record[i][0]*x + param_record[i][1]
        x_ln = [0, x_max]
        y_ln = [f(0), f(x_max)]
        plt.plot(x_ln, y_ln)
    plt.show()

def run():
    params = [0, 0]
    for i in range(1000):
        params = descend(params)
    capture2([0, 1, 4, 9, 99, 999])

if __name__ == '__main__':
    run();