How to calculate dot product in perceptrons?
June 08, 2020
Neural networks are a collection of individuals nodes called as artificial neurons or perceptrons.
Each perceptron takes in an input array, multiples it with weights array and add a bias value to create a computed sum.
This computed computed is passed to an activation function to compute the final output value of a neuron.
We can see the basic parts of a perceptron below:
We can calculate the summation value of neuron inputs, weight and bias in the for a sample neuron as explained in example below:
#Example of dot product using numpy import numpy as np #Sample input to perceptron inputs = [1.2, 2.2, 3.3, 2.5] #Weights passed to perceptron weights = [0.4,0.6,-0.7, 1.1] #bias for a particular perceptron bias = 2 #Take dot product between weights and input #and add bias to the summation value output = np.dot(weights, inputs) + bias print(output) #Output:- 4.24
Here np.dot function is used to calculate dot product between the input and the weights. Internally it works as follows:
The output value from above function is fed to an activation function to calculate final value of a perceptron. I will cover various activation functions and their working in another article since it is a vast concept requiring it’s own article.
That’s it for today’s short tutorial on dot product using numpy.
Reference: Neural Networks from Scratch by SentDex
Blog by Saurabh Mhatre
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