chapter_6.py

import numpy as np

weights = np.array([0.5, 0.48, -0.7])
alpha = 0.1

streetlights = np.array([[1, 0, 1], [0, 1, 1], [0, 0, 1], [1, 1, 1], [0, 1, 1], [1, 0, 1]])

walk_vs_stop = np.array([0, 1, 0, 1, 1, 0])

input = streetlights[0]  # [1,0,1]
goal_prediction = walk_vs_stop[0]  # equals 0... i.e. "stop"


for _ in range(40):
    error_for_all_lights = 0

    for row_index in range(len(walk_vs_stop)):
        input = streetlights[row_index]
        goal_prediction = walk_vs_stop[row_index]
        print("weights => ", weights, "   input => ", input)
        prediction = input.dot(weights)

        error = (goal_prediction - prediction) ** 2
        error_for_all_lights += error

        delta = prediction - goal_prediction
        weights = weights - (alpha * (input * delta))
        print("Prediction:" + str(prediction), "  ", weights)
    print("Error:" + str(error_for_all_lights) + "\n")