io.kgraph.pregel

Interface ComputeFunction<K,VV,EV,Message>

Type Parameters:

K - The type of the vertex key (the vertex identifier).

VV - The type of the vertex value (the state of the vertex).

EV - The type of the values that are associated with the edges.

Message - The type of the message sent between vertices along the edges.

All Known Implementing Classes:

AdamicAdar, AdamicAdar.ComputeLogOfInverseDegree, AdamicAdar.ScaleToDistance, AdamicAdar.SendFriendsListAndValue, Als, Als.InitItemsComputation, Als.InitUsersComputation, BreadthFirstSearch, ConnectedComponents, EdgeCount, Jaccard, Jaccard.ScaleToDistance, Jaccard.SendFriends, KMeansClustering, KMeansClustering.RandomCentersInitialization, LabelPropagation, LocalClusteringCoefficient, MaxBMatching, MultipleSourceShortestPaths, PageRank, ReverseEdges, SemiClustering, Sgd, Sgd.InitItemsComputation, Sgd.InitUsersComputation, SingleSourceShortestPaths, Svdpp, Svdpp.InitItemsComputation, Svdpp.InitUsersComputation, Svdpp.ItemComputation, Svdpp.UserComputation, SybilRank, SybilRank.Initializer, SybilRank.SybilRankComputation, SybilRank.TrustAggregation, VertexCount

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface ComputeFunction<K,VV,EV,Message>

The user-defined compute function for a Pregel computation.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	ComputeFunction.Aggregators
static class	ComputeFunction.Callback<K,VV,EV,Message>
static class	ComputeFunction.InitCallback
static class	ComputeFunction.MasterCallback
static interface	ComputeFunction.ReadAggregators
static interface	ComputeFunction.ReadWriteAggregators

Method Summary

Modifier and Type	Method and Description
void	compute(int superstep, VertexWithValue<K,VV> vertex, Iterable<Message> messages, Iterable<EdgeWithValue<K,EV>> edges, ComputeFunction.Callback<K,VV,EV,Message> cb) The function for computing a new vertex value or sending messages to the next superstep.
default void	init(Map<String,?> configs, ComputeFunction.InitCallback cb) Initialize the ComputeFunction, this is the place to register aggregators.
default void	masterCompute(int superstep, ComputeFunction.MasterCallback cb) A function for performing sequential computations between supersteps.
default void	postSuperstep(int superstep, ComputeFunction.Aggregators aggregators) Finish computation.
default void	preSuperstep(int superstep, ComputeFunction.Aggregators aggregators) Prepare for computation.

Method Detail

init

default void init(Map<String,?> configs,
                  ComputeFunction.InitCallback cb)

Initialize the ComputeFunction, this is the place to register aggregators.

Parameters:

configs - configuration parameters

cb - a callback for registering aggregators

masterCompute

default void masterCompute(int superstep,
                           ComputeFunction.MasterCallback cb)

A function for performing sequential computations between supersteps.

Parameters:

superstep - the superstep

cb - a callback for writing to aggregators or halting the computation

preSuperstep

default void preSuperstep(int superstep,
                          ComputeFunction.Aggregators aggregators)

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

Parameters:

superstep - the superstep

aggregators - the aggregators

compute

void compute(int superstep,
             VertexWithValue<K,VV> vertex,
             Iterable<Message> messages,
             Iterable<EdgeWithValue<K,EV>> edges,
             ComputeFunction.Callback<K,VV,EV,Message> cb)

The function for computing a new vertex value or sending messages to the next superstep.

Parameters:

superstep - the count of the current superstep

vertex - the current vertex with its value

messages - a Map of the source vertex and the message sent from the previous superstep

edges - the adjacent edges with their values

cb - a callback for setting a new vertex value or sending messages to the next superstep

postSuperstep

default void postSuperstep(int superstep,
                           ComputeFunction.Aggregators aggregators)

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

Parameters:

superstep - the superstep

aggregators - the aggregators