Spark GraphX: how to insert just a node to a graph

Question

I know that in GraphX we can merge two graphs in order to update an existing network for example... However, as a usual operation for updating a network is to insert into it a single node. How could one do such an updating operation in GraphX ?! Thanks !

Answer 1

Graphs are immutable, so you can't add a single node to an existing graph, but you can create a new graph based on the previous with the additional node added. Say you had a graph like this:

var graph: Graph[Int,Int] = ...

You could add a new node like this:

graph = Graph(
    graph.vertices.union(sc.parallelize(Array[(VertexId, Int)]((13L, 1)))),
    graph.edges,
    0
)