Apache Spark Graph Processing

Data operations on VertexRDD and EdgeRDD

All of the operations we've seen previously are graph operations. They are invoked on a graph and they return a new graph object. In this section, we will introduce operations that transform VertexRDD and EdgeRDD collections. The types of these collections are subtypes of RDD[(VertexID, VD)] and RDD[Edge[ED]] respectively.

Mapping VertexRDD and EdgeRDD

First, mapValues takes a map function as input, which transforms each vertex attribute in the VertexRDD. Then, it returns a new VertexRDD object while preserving the original vertex indices. The method mapValues is overloaded so that the map function can take an input with a type VD or (VertexId, VD). The type of the new vertex attributes can be different to ...