org.apache.giraph.graph

Interface Computation<I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable,M1 extends org.apache.hadoop.io.Writable,M2 extends org.apache.hadoop.io.Writable>

Type Parameters:

I - Vertex id

V - Vertex data

E - Edge data

M1 - Incoming message type

M2 - Outgoing message type

All Superinterfaces:

AggregatorUsage, GiraphConfigurationSettable<I,V,E>, ImmutableClassesGiraphConfigurable<I,V,E>, TypesHolder<I,V,E,M1,M2>, WorkerAggregatorUsage, WorkerBroadcastUsage, WorkerGlobalCommUsage, WorkerIndexUsage<I>, WorkerReduceUsage

All Known Implementing Classes:

AbstractComputation, AggregatorsBenchmark.AggregatorsBenchmarkComputation, AggregatorsTestComputation, BasicComputation, BlockComputation, BrachaTouegDeadlockComputation, ConnectedComponentsComputation, IdentityComputation, JythonGiraphComputation, MaxComputation, PageRankComputation, PageRankComputation, PageRankWithKryoSimpleWritable, RandomMessageBenchmark.RandomMessageComputation, RandomWalkComputation, RandomWalkWithRestartComputation, ReducersBenchmark.ReducersBenchmarkComputation, SccComputation, ShortestPathsComputation, SimpleCheckpoint.SimpleCheckpointComputation, SimpleCombinerComputation, SimpleFailComputation, SimpleInDegreeCountComputation, SimpleLongDoubleDoubleDoubleIdentityComputation, SimpleMasterComputeComputation, SimpleMsgComputation, SimpleMutateGraphComputation, SimpleOutDegreeCountComputation, SimplePageRankComputation, SimpleShortestPathsComputation, SimpleSuperstepComputation, SimpleTriangleClosingComputation, SimpleVertexWithWorkerContext.SimpleComputation, TestComputationStateComputation, VerifyMessage.VerifyMessageComputation, WeightedPageRankComputation

public interface Computation<I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable,M1 extends org.apache.hadoop.io.Writable,M2 extends org.apache.hadoop.io.Writable>
extends TypesHolder<I,V,E,M1,M2>, ImmutableClassesGiraphConfigurable<I,V,E>, WorkerGlobalCommUsage, WorkerAggregatorUsage, WorkerIndexUsage<I>

Interface for an application for computation. During the superstep there can be several instances of this interface, each doing computation on one partition of the graph's vertices. Note that each thread will have its own Computation, so accessing any data from this class is thread-safe. However, accessing global data (like data from WorkerContext) is not thread-safe. Objects of this interface only live for a single superstep.

Method Summary

Modifier and Type	Method and Description
void	addEdgeRequest(I sourceVertexId, Edge<I,E> edge) Request to add an edge of a vertex in the graph (processed just prior to the next superstep)
void	addVertexRequest(I id, V value) Sends a request to create a vertex that will be available during the next superstep.
void	addVertexRequest(I id, V value, OutEdges<I,E> edges) Sends a request to create a vertex that will be available during the next superstep.
void	compute(Vertex<I,V,E> vertex, Iterable<M1> messages) Must be defined by user to do computation on a single Vertex.
org.apache.hadoop.mapreduce.Mapper.Context	getContext() Get the mapper context
long	getSuperstep() Retrieves the current superstep.
long	getTotalNumEdges() Get the total (all workers) number of edges that existed in the previous superstep.
long	getTotalNumVertices() Get the total (all workers) number of vertices that existed in the previous superstep.
<W extends WorkerContext> W	getWorkerContext() Get the worker context
void	initialize(GraphState graphState, WorkerClientRequestProcessor<I,V,E> workerClientRequestProcessor, CentralizedServiceWorker<I,V,E> serviceWorker, WorkerGlobalCommUsage workerGlobalCommUsage) Initialize, called by infrastructure before the superstep starts.
void	postSuperstep() Finish computation.
void	preSuperstep() Prepare for computation.
void	removeEdgesRequest(I sourceVertexId, I targetVertexId) Request to remove all edges from a given source vertex to a given target vertex (processed just prior to the next superstep).
void	removeVertexRequest(I vertexId) Request to remove a vertex from the graph (applied just prior to the next superstep).
void	sendMessage(I id, M2 message) Send a message to a vertex id.
void	sendMessageToAllEdges(Vertex<I,V,E> vertex, M2 message) Send a message to all edges.
void	sendMessageToMultipleEdges(Iterator<I> vertexIdIterator, M2 message) Send a message to multiple target vertex ids in the iterator.

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

getConf

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

setConf

Methods inherited from interface org.apache.giraph.worker.WorkerBroadcastUsage

getBroadcast

Methods inherited from interface org.apache.giraph.worker.WorkerReduceUsage

reduce, reduceMerge

Methods inherited from interface org.apache.giraph.worker.WorkerAggregatorUsage

aggregate

Methods inherited from interface org.apache.giraph.aggregators.AggregatorUsage

getAggregatedValue

Methods inherited from interface org.apache.giraph.worker.WorkerIndexUsage

getMyWorkerIndex, getWorkerCount, getWorkerForVertex

Method Detail

compute

void compute(Vertex<I,V,E> vertex,
             Iterable<M1> messages)
      throws IOException

Must be defined by user to do computation on a single Vertex.

Parameters:

vertex - Vertex

messages - Messages that were sent to this vertex in the previous superstep. Each message is only guaranteed to have a life expectancy as long as next() is not called.

Throws:

IOException

preSuperstep

void preSuperstep()

Prepare for computation. This method is executed exactly once prior to compute(Vertex, Iterable) being called for any of the vertices in the partition.

postSuperstep

void postSuperstep()

Finish computation. This method is executed exactly once after computation for all vertices in the partition is complete.

initialize

void initialize(GraphState graphState,
                WorkerClientRequestProcessor<I,V,E> workerClientRequestProcessor,
                CentralizedServiceWorker<I,V,E> serviceWorker,
                WorkerGlobalCommUsage workerGlobalCommUsage)

Initialize, called by infrastructure before the superstep starts. Shouldn't be called by user code.

Parameters:

graphState - Graph state

workerClientRequestProcessor - Processor for handling requests

serviceWorker - Centralized service worker

workerGlobalCommUsage - Worker global communication usage

getSuperstep

long getSuperstep()

Retrieves the current superstep.

Returns:

Current superstep

getTotalNumVertices

long getTotalNumVertices()

Get the total (all workers) number of vertices that existed in the previous superstep.

Returns:

Total number of vertices (-1 if first superstep)

getTotalNumEdges

long getTotalNumEdges()

Get the total (all workers) number of edges that existed in the previous superstep.

Returns:

Total number of edges (-1 if first superstep)

sendMessage

void sendMessage(I id,
                 M2 message)

Send a message to a vertex id.

Parameters:

id - Vertex id to send the message to

message - Message data to send

sendMessageToAllEdges

void sendMessageToAllEdges(Vertex<I,V,E> vertex,
                           M2 message)

Send a message to all edges.

Parameters:

vertex - Vertex whose edges to send the message to.

message - Message sent to all edges.

sendMessageToMultipleEdges

void sendMessageToMultipleEdges(Iterator<I> vertexIdIterator,
                                M2 message)

Send a message to multiple target vertex ids in the iterator.

Parameters:

vertexIdIterator - An iterator to multiple target vertex ids.

message - Message sent to all targets in the iterator.

addVertexRequest

void addVertexRequest(I id,
                      V value,
                      OutEdges<I,E> edges)
               throws IOException

Sends a request to create a vertex that will be available during the next superstep.

Parameters:

id - Vertex id

value - Vertex value

edges - Initial edges

Throws:

IOException

addVertexRequest

void addVertexRequest(I id,
                      V value)
               throws IOException

Sends a request to create a vertex that will be available during the next superstep.

Parameters:

id - Vertex id

value - Vertex value

Throws:

IOException

removeVertexRequest

void removeVertexRequest(I vertexId)
                  throws IOException

Request to remove a vertex from the graph (applied just prior to the next superstep).

Parameters:

vertexId - Id of the vertex to be removed.

Throws:

IOException

addEdgeRequest

void addEdgeRequest(I sourceVertexId,
                    Edge<I,E> edge)
             throws IOException

Request to add an edge of a vertex in the graph (processed just prior to the next superstep)

Parameters:

sourceVertexId - Source vertex id of edge

edge - Edge to add

Throws:

IOException

removeEdgesRequest

void removeEdgesRequest(I sourceVertexId,
                        I targetVertexId)
                 throws IOException

Request to remove all edges from a given source vertex to a given target vertex (processed just prior to the next superstep).

Parameters:

sourceVertexId - Source vertex id

targetVertexId - Target vertex id

Throws:

IOException

getContext

org.apache.hadoop.mapreduce.Mapper.Context getContext()

Get the mapper context

Returns:

Mapper context

getWorkerContext

<W extends WorkerContext> W getWorkerContext()

Get the worker context

Type Parameters:

W - WorkerContext class

Returns:

WorkerContext context