Implementation of Perceptron Algorithm for NOT Logic Gate
Last Updated :
08 Jun, 2020
In the field of Machine Learning, the Perceptron is a Supervised Learning Algorithm for binary classifiers. The Perceptron Model implements the following function:
\[
\begin{array}{c}
\hat{y}=\Theta\left(w_{1} x_{1}+w_{2} x_{2}+\ldots+w_{n} x_{n}+b\right) \\
=\Theta(\mathbf{w} \cdot \mathbf{x}+b) \\
\text { where } \Theta(v)=\left\{\begin{array}{cc}
1 & \text { if } v \geqslant 0 \\
0 & \text { otherwise }
\end{array}\right.
\end{array}
\]
For a particular choice of the weight vector
$\boldsymbol{w}$ and bias parameter
$\boldsymbol{b}$, the model predicts output
$\boldsymbol{\hat{y}}$ for the corresponding input vector
$\boldsymbol{x}$.
NOT logical function truth table is of only 1-bit binary input (0 or 1), i.e, the input vector
$\boldsymbol{x}$ and the corresponding output
$\boldsymbol{y}$ -
$\boldsymbol{x}$ |
$\boldsymbol{y}$ |
0 |
1 |
1 |
0 |
Now for the corresponding weight vector
$\boldsymbol{w}$ of the input vector
$\boldsymbol{x}$, the associated Perceptron Function can be defined as:
\[$\boldsymbol{\hat{y}} = \Theta\left(w x+b\right)$\]

For the implementation, considered weight parameter is
$\boldsymbol{w} = -1$ and the bias parameter is
$\boldsymbol{b} = 0.5$.
Python Implementation:
Python3 1==
# importing Python library
import numpy as np
# define Unit Step Function
def unitStep(v):
if v >= 0:
return 1
else:
return 0
# design Perceptron Model
def perceptronModel(x, w, b):
v = np.dot(w, x) + b
y = unitStep(v)
return y
# NOT Logic Function
# w = -1, b = 0.5
def NOT_logicFunction(x):
w = -1
b = 0.5
return perceptronModel(x, w, b)
# testing the Perceptron Model
test1 = np.array(1)
test2 = np.array(0)
print("NOT({}) = {}".format(1, NOT_logicFunction(test1)))
print("NOT({}) = {}".format(0, NOT_logicFunction(test2)))
Output:
NOT(1) = 0
NOT(0) = 1
Here, the model predicted output (
$\boldsymbol{\hat{y}}$) for each of the test inputs are exactly matched with the NOT logic gate conventional output (
$\boldsymbol{y}$) according to the truth table.
Hence, it is verified that the perceptron algorithm for NOT logic gate is correctly implemented.