Frank Kane's Taming Big Data with Apache Spark and Python

Iteratively process the RDD

Now we're going to go through the entire graph multiple times. We'll do this as many times as it takes to find the other character that we are interested in-we want to find the degrees of separation between two given characters. We will go through each time and we will look for gray nodes that need to be expanded. When we're done expanding them, we'll color them black. As we go along coloring new nodes gray, we'll update the distances to increment them, keeping track of the degrees of separation from our starting point, just like in the previous section.