com.soteradefense.dga.louvain.giraph

Class LouvainComputation

java.lang.Object

org.apache.giraph.conf.DefaultImmutableClassesGiraphConfigurable<I,V,E>

org.apache.giraph.graph.AbstractComputation<Text,LouvainNodeState,LongWritable,LouvainMessage,LouvainMessage>

com.soteradefense.dga.louvain.giraph.LouvainComputation

All Implemented Interfaces:

AggregatorUsage, ImmutableClassesGiraphConfigurable<Text,LouvainNodeState,LongWritable>, TypesHolder<Text,LouvainNodeState,LongWritable,LouvainMessage,LouvainMessage>, Computation<Text,LouvainNodeState,LongWritable,LouvainMessage,LouvainMessage>, WorkerAggregatorUsage

public class LouvainComputation
extends AbstractComputation<Text,LouvainNodeState,LongWritable,LouvainMessage,LouvainMessage>

Performs the BSP portion of the distributed louvain algorithm.

The computation is completed as a series of repeated steps, movement is restricted to approximately half of the nodes on each cycle so a full pass requires two cycles

1. Each vertex receives community values from its community hub and sends its own community to its neighbors
2. Each vertex determines if it should move to a neighboring community or not and sends its information to its community hub
3. Each community hub re-calculates community totals and sends the updates to each community member

When the number of nodes that change communities stops decreasing for four (4) cycles or when the number of nodes that change reaches 0 the computation ends

Field Summary

Fields

Modifier and Type	Field and Description
static String	ACTUAL_Q_AGG
static String	CHANGE_AGG
static String	TOTAL_EDGE_WEIGHT_AGG

Constructor Summary

Constructors

Constructor and Description
LouvainComputation()

Method Summary

Methods

Modifier and Type	Method and Description
void	compute(Vertex<Text,LouvainNodeState,LongWritable> vertex, Iterable<LouvainMessage> messages)
void	initialize(GraphState graphState, WorkerClientRequestProcessor<Text,LouvainNodeState,LongWritable> workerClientRequestProcessor, GraphTaskManager<Text,LouvainNodeState,LongWritable> graphTaskManager, WorkerAggregatorUsage workerAggregatorUsage, WorkerContext workerContext)

Methods inherited from class org.apache.giraph.graph.AbstractComputation

addEdgeRequest, addVertexRequest, addVertexRequest, aggregate, getAggregatedValue, getContext, getSuperstep, getTotalNumEdges, getTotalNumVertices, getWorkerContext, postSuperstep, preSuperstep, removeEdgesRequest, removeVertexRequest, sendMessage, sendMessageToAllEdges, sendMessageToMultipleEdges

Methods inherited from class org.apache.giraph.conf.DefaultImmutableClassesGiraphConfigurable

getConf, setConf

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.giraph.conf.ImmutableClassesGiraphConfigurable

getConf, setConf

Field Detail

CHANGE_AGG

public static final String CHANGE_AGG

See Also:

Constant Field Values

TOTAL_EDGE_WEIGHT_AGG

public static final String TOTAL_EDGE_WEIGHT_AGG

See Also:

Constant Field Values

ACTUAL_Q_AGG

public static final String ACTUAL_Q_AGG

See Also:

Constant Field Values

Constructor Detail

LouvainComputation

public LouvainComputation()

Method Detail

initialize

public void initialize(GraphState graphState,
              WorkerClientRequestProcessor<Text,LouvainNodeState,LongWritable> workerClientRequestProcessor,
              GraphTaskManager<Text,LouvainNodeState,LongWritable> graphTaskManager,
              WorkerAggregatorUsage workerAggregatorUsage,
              WorkerContext workerContext)

Specified by:

initialize in interface Computation<Text,LouvainNodeState,LongWritable,LouvainMessage,LouvainMessage>

Overrides:

initialize in class AbstractComputation<Text,LouvainNodeState,LongWritable,LouvainMessage,LouvainMessage>

compute

public void compute(Vertex<Text,LouvainNodeState,LongWritable> vertex,
           Iterable<LouvainMessage> messages)
             throws IOException

Specified by:

compute in interface Computation<Text,LouvainNodeState,LongWritable,LouvainMessage,LouvainMessage>

Specified by:

compute in class AbstractComputation<Text,LouvainNodeState,LongWritable,LouvainMessage,LouvainMessage>

Throws:

IOException