Glossary

Layer

In General

A layer is the highest-level building block in a (Deep) Neural Network. A layer is a container that usually receives weighted input, transforms it and returns the result as output to the next layer. A layer usually contains one type of function like ReLU, pooling, convolution etc. so that it can be easily compared to other parts of the network. The first and last layers in a network are called input and output layers, respectively, and all layers in between are called hidden layers.

In Leaf

In Leaf, a layer is very similar to the general understanding of a layer. A layer in Leaf, like a layer in a (Deep) Neural Network,

• is the highest-level building block
• needs to receive input, might transform it and needs to return the result
• should be uniform (it does one type of function)

Additionally to a Neural Network layer, a Leaf layer can implement any functionality, not only those related to Neural Networks like ReLU, pooling, LSTM, etc. For example, the Sequential layer in Leaf, allows it to connect multiple layers, creating a network.

Network

In General

A network, also often called Neural Network (NN) or Artificial Neural Network (ANN) is a subset of Machine Learning methods.

A not exhaustive list of other Machine Learning methods:
Linear Regression, SVM, Genetic/Evolution Algorithms, dynamic programming, deterministic algorithmic optimization methods.

In Leaf

In Leaf, a network means a graph (a connected set) of one or more layers. This network can consist of Artificial Neural Network methods, other Machine Learning methods or any other (not Machine Learning related) methods. As described in 2. Layers a network in Leaf is actually a layer which connects other layers.

An initialized network is a network, which is ready to be executed, meaning it is fully constructed e.g. all necessary memory is allocated on the host or device.