Basics of model aggregation

Aggregation is a core concept within FL. In fact, the strategies employed to aggregate models are the key theoretical driver for the performance of FL systems. The purpose of this section is to introduce the high-level concepts of aggregation within the context of an FL system – the underlying theory and examples of advanced aggregation strategies will be discussed in greater depth in Chapter 7, Model Aggregation.

What exactly does it mean to aggregate models?

Let’s revisit the aggregator-side cycle discussed in the Understanding the FL system flow – from initialization to continuous operation section, at the point in the process where the agents assigned to a certain aggregator have finished training locally and have transmitted these models back to this aggregator. The goal of any aggregation strategy, or any way of aggregating these models together, is to produce new models that gradually increase in performance across all...