Hands-On Software Engineering with Golang

Sharing global graph state through data aggregation

Aggregators are a key component for implementing several graph-based algorithms that rely on sharing global state between vertices. They are concurrent-safe primitives that apply an aggregation operator to a set of values and make the result available to all the vertices at the next super-step.

Any kind of operator can be used to create an aggregator as long as it is commutative and associative. Aggregators are commonly used to implement counters, accumulators, or for keeping track of the minimum and/or maximum value of some quantity.

In the upcoming sections, we will do the following:

• Define a generic interface for aggregators
• Augment our Graph type with helper methods for registering ...