Package org.apache.tinkerpop.gremlin.process.computer.ranking.pagerank

Class PageRankVertexProgram

java.lang.Object
org.apache.tinkerpop.gremlin.process.computer.ranking.pagerank.PageRankVertexProgram
All Implemented Interfaces:
Cloneable, VertexProgram<Double>
public class PageRankVertexProgram extends Object implements VertexProgram<Double>
Author:
Marko A. Rodriguez (http://markorodriguez.com)

  • Field Details

  • Method Details

    • loadState

      public void loadState(Graph graph, org.apache.commons.configuration2.Configuration configuration)
      Description copied from interface: VertexProgram
      When it is necessary to load the state of the VertexProgram, this method is called. This is typically required when the VertexProgram needs to be serialized to another machine. Note that what is loaded is simply the instance state, not any processed data.
      Specified by:
      loadState in interface VertexProgram<Double>
      Parameters:
      graph - the graph that the VertexProgram will run against
      configuration - the configuration to load the state of the VertexProgram from.

    • storeState

      public void storeState(org.apache.commons.configuration2.Configuration configuration)
      Description copied from interface: VertexProgram
      When it is necessary to store the state of the VertexProgram, this method is called. This is typically required when the VertexProgram needs to be serialized to another machine. Note that what is stored is simply the instance/configuration state, not any processed data. The default implementation provided simply stores the VertexProgram class name for reflective reconstruction. It is typically a good idea to VertexProgram.super.storeState().
      Specified by:
      storeState in interface VertexProgram<Double>
      Parameters:
      configuration - the configuration to store the state of the VertexProgram in.

    • getPreferredResultGraph

      public GraphComputer.ResultGraph getPreferredResultGraph()
      Specified by:
      getPreferredResultGraph in interface VertexProgram<Double>

    • getPreferredPersist

      public GraphComputer.Persist getPreferredPersist()
      Specified by:
      getPreferredPersist in interface VertexProgram<Double>

    • getVertexComputeKeys

      public Set<VertexComputeKey> getVertexComputeKeys()
      Description copied from interface: VertexProgram
      The Element properties that will be mutated during the computation. All properties in the graph are readable, but only the keys specified here are writable. The default is an empty set.
      Specified by:
      getVertexComputeKeys in interface VertexProgram<Double>
      Returns:
      the set of element keys that will be mutated during the vertex program's execution

    • getMessageCombiner

      public Optional<MessageCombiner<Double>> getMessageCombiner()
      Description copied from interface: VertexProgram
      Combine the messages in route to a particular vertex. Useful to reduce the amount of data transmitted over the wire. For example, instead of sending two objects that will ultimately be merged at the vertex destination, merge/combine into one and send that object. If no message combiner is provider, then no messages will be combined. Furthermore, it is not guaranteed the all messages in route to the vertex will be combined and thus, combiner-state should not be used. The result of the vertex program algorithm should be the same regardless of whether message combining is executed or not.
      Specified by:
      getMessageCombiner in interface VertexProgram<Double>
      Returns:
      A optional denoting whether or not their is a message combine associated with the vertex program.

    • getMemoryComputeKeys

      public Set<MemoryComputeKey> getMemoryComputeKeys()
      Description copied from interface: VertexProgram
      The Memory keys that will be used during the computation. These are the only keys that can be read or written throughout the life of the GraphComputer. The default is an empty set.
      Specified by:
      getMemoryComputeKeys in interface VertexProgram<Double>
      Returns:
      the set of memory keys that will be read/written

    • getMessageScopes

      public Set<MessageScope> getMessageScopes(Memory memory)
      Description copied from interface: VertexProgram
      This method returns all the MessageScope possibilities for a particular iteration of the vertex program. The returned messages scopes are the scopes that will be used to send messages during the stated iteration. It is not a requirement that all stated messages scopes be used, just that it is possible that they be used during the iteration.
      Specified by:
      getMessageScopes in interface VertexProgram<Double>
      Parameters:
      memory - an immutable form of the Memory
      Returns:
      all possible message scopes during said vertex program iteration

    • clone

      public PageRankVertexProgram clone()
      Description copied from interface: VertexProgram
      When multiple workers on a single machine need VertexProgram instances, it is possible to use clone. This will provide a speedier way of generating instances, over the VertexProgram.storeState(org.apache.commons.configuration2.Configuration) and VertexProgram.loadState(org.apache.tinkerpop.gremlin.structure.Graph, org.apache.commons.configuration2.Configuration) model. The default implementation simply returns the object as it assumes that the VertexProgram instance is a stateless singleton.
      Specified by:
      clone in interface VertexProgram<Double>
      Overrides:
      clone in class Object
      Returns:
      A clone of the VertexProgram object

    • setup

      public void setup(Memory memory)
      Description copied from interface: VertexProgram
      The method is called at the beginning of the computation. The method is global to the GraphComputer and as such, is not called for each vertex. During this stage, the Memory should be initialized to to its "start state."
      Specified by:
      setup in interface VertexProgram<Double>
      Parameters:
      memory - The global memory of the GraphComputer

    • execute

      public void execute(Vertex vertex, Messenger<Double> messenger, Memory memory)
      Description copied from interface: VertexProgram
      This method denotes the main body of the computation and is executed on each vertex in the graph. This method is logically executed in parallel on all vertices in the graph. When the Memory is read, it is according to the aggregated state yielded in the previous iteration. When the Memory is written, the data will be aggregated at the end of the iteration for reading in the next iteration.
      Specified by:
      execute in interface VertexProgram<Double>
      Parameters:
      vertex - the Vertex to execute the VertexProgram on
      messenger - the messenger that moves data between vertices
      memory - the shared state between all vertices in the computation

    • terminate

      public boolean terminate(Memory memory)
      Description copied from interface: VertexProgram
      The method is called at the end of each iteration to determine if the computation is complete. The method is global to the GraphComputer and as such, is not called for each Vertex. The Memory maintains the aggregated data from the last execute() iteration.
      Specified by:
      terminate in interface VertexProgram<Double>
      Parameters:
      memory - The global memory of the GraphComputer
      Returns:
      whether or not to halt the computation

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • build

      public static PageRankVertexProgram.Builder build()

    • getFeatures

      public VertexProgram.Features getFeatures()
      Specified by:
      getFeatures in interface VertexProgram<Double>