[GIRAPH-141] multigraph support in giraph

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Component/s: graph
• Assignee: Alessandro Presta
• Reporter: André Kelpe
• Created: 04/Feb/12 09:17
• Updated: 19/Dec/12 08:24
• Resolved: 19/Dec/12 08:17

Description

The current vertex API only supports simple graphs, meaning that there can only ever be one edge between two vertices. Many graphs like the road network are in fact multigraphs, where many edges can connect two vertices at the same time.

Support for this could be added by introducing an Iterator<EdgeWritable> getEdgeValue() or a similar construct. Maybe introducing a slim object like a Connector between the edge and the vertex is also a good idea, so that you could do something like:

 
for (final Connector<EdgeWritable, VertexWritable> conn: getEdgeValues(){
     final EdgeWritable edge = conn.getEdge();
     final VertexWritable otherVertex = conn.getOther();
     doInterestingStuff(otherVertex);
     doMoreInterestingStuff(edge);
}

Issue Links

• is related to: GIRAPH-170 Workflow for loading RDF graph data into Giraph
• relates to: GIRAPH-155 Allow creation of graph by adding edges that span multiple workers