Perceptron

perceptron.py

def update(w, x, y):
    a = 0.
    for i in range(len(w)):
        a += w[i] * x[i]
    if a * y <= 0:
        for i in range(len(w)):
            w[i] += y * x[i]

def classify(w, x):
    a = 0.
    for i in range(len(w)):
        a += w[i] * x[i]
    return (0. < a)

if __name__ == '__main__':
    w = [0.] * 9
    D = (
        ((1, 1, 1, 1, 1, 1, 0, 0, 0), +1),
        ((1, 0, 0, 0, 1, 1, 1, 1, 1), -1),
    )
    update(w, D[0][0], D[0][1])
    update(w, D[1][0], D[1][1])
    print classify(w, D[0][0])
    print classify(w, D[1][0])
    print w