An artificial neural network (ANN) or simply neural network is a directed structure that connects an input layer with an output one. Normally, all operations are differentiable and the overall vectorial function can be easily written as:
The adjective "neural" comes from two important elements: the internal structure of a basic computational unit and the interconnections among them. Let's start with the former. In the following figure, there's a schematic representation of an artificial neuron:
A neuron core ...