import numpy as np
|
|
|
|
class Perceptron(object):
|
|
"""Implements a perceptron network"""
|
|
def __init__(self, input_size, lr=1, epochs=100):
|
|
self.W = np.zeros(input_size+1)
|
|
# add one for bias
|
|
self.epochs = epochs
|
|
self.lr = lr
|
|
|
|
#activation function
|
|
def activation_fn(self, x):
|
|
#return (x >= 0).astype(np.float32)
|
|
return 1 if x >= 0 else 0
|
|
|
|
#we need a prediction function to run an input through the perceptron and return an output.
|
|
def predict(self, x):
|
|
z = self.W.T.dot(x)
|
|
a = self.activation_fn(z)
|
|
return a
|
|
|
|
def fit(self, X, d):
|
|
for _ in range(self.epochs):
|
|
for i in range(d.shape[0]):
|
|
x = np.insert(X[i], 0, 1)
|
|
y = self.predict(x)
|
|
e = d[i] - y
|
|
self.W = self.W + self.lr * e * x
|
|
#the easiset set of data that we can provide is the AND gate. Given is set of inputs and outputs.
|
|
if __name__ == '__main__':
|
|
X = np.array([
|
|
[0, 0],
|
|
[0, 1],
|
|
[1, 0],
|
|
[1, 1]
|
|
])
|
|
d = np.array([0, 0, 0, 1])
|
|
|
|
perceptron = Perceptron(input_size=2)
|
|
perceptron.fit(X, d)
|
|
print(perceptron.W)
|