A neural network is a type of computational architecture that is composed of layers of perceptrons. A perceptron, first conceived in the 1950s by Frank Rosenblatt, models the biological neuron and computes a linear combination of a vector of input. It also outputs a transformation of the linear combination using a non-linear activation, such as the sigmoid function. Suppose a perceptron receives an input vector of 
. The output, a, of the perceptron, would be as follows:
Whereare the weights of the perceptron, b is a constant, ...
