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

Class PageRankVertexProgram

    • Method Detail

      • 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.

      • 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.

      • 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

      • 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