Run Example in Giraph: Shortest Paths

When planning to run a code in Giraph, I ask myself some questions. When I answer to all my questions, I move to actually implement and run the code. (so I kinda discuss a lot with myself :p). Let’s have a look to this inner discussion – while running the Shortest Paths problem.

~~~~~ Q#1: What’s the Shortest Path problem?

Problem Description: Find the shortest path between 2 vertices in a graph, so that the sum of weights of the edges in the path is minimized. The example given in Giraph finds the shortest path from each vertex to the source-vertex.

~~~~~ Q#2: How can this be implemented in Giraph?

Think “Pregely”: Since in Pregel the same code is executed in all vertices at the same time, we need to think as we are a vertex. Continue reading