Label propagation mutate algorithm - Neptune Analytics
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Label propagation mutate algorithm

Label Propagation Algorithm (LPA) is an algorithm for community detection that is also used in semi-supervised machine learning for data classification.

The .labelPropagation.mutate variant of the algorithm writes the derived community component ID of each node in the source list to a new property of that node.

.labelPropagation.mutate  syntax

CALL neptune.algo.labelPropagation.mutate(
  {
    writeProperty: the name for the node property to which to write component IDs
    edgeLabels: [list of edge labels for filtering (optional)],
    vertexLabel: a node label for filtering (optional),
    vertexWeightProperty: a numeric node property used to weight the community ID (optional),
    vertexWeightType: numeric type of the specified vertexWeightProperty (optional),
    edgeWeightProperty: a numeric edge property used to weight the community ID (optional),
    edgeWeightType: numeric type of the specified edgeWeightProperty (optional),
    maxIterations: the maximum number of iterations to run (optional, default: 10),
    traversalDirection: traversal direction (optional, default: outbound),
    concurrency: number of threads to use (optional)
  }
)

.labelPropagation.mutate  inputs

Inputs for .labelPropagation.mutate are passed in a configuration object that contains:

  • writeProperty (required)   –   type: string;   default: none.

    A name for the new node property that will contain the computed community component ID of the node.

  • edgeLabels   (optional)   –   type: a list of edge label strings;   example: ["route", ...];   default: no edge filtering.

    To filter on one more edge labels, provide a list of the ones to filter on. If no edgeLabels field is provided then all edge labels are processed during traversal.

  • vertexLabel (optional)   –   type: string;   default: none.

    A node label for node filtering. If a node label is provided, nodes matching the label are the only nodes that are included in the calculation, including nodes in the input list.

  • vertexWeightProperty (optional)   –   type: string;   default: none.

    The node weight used in Label Propagation. When vertexWeightProperty is not specified, each node's communityId is treated equally, as if the node weight were 1.0. When the vertexWeightProperty is specified without an edgeWeightProperty, the weight of the communityId for each node is the value of the node weight property. When both vertexWeightProperty and edgeWeightProperty are specified, the weight of the communityId is the product of the node property value and edge property value.

    Note that if multiple properties exist on the node with the name specified by vertexWeightProperty, one of those property values will be sampled at random.

  • vertexWeightType (required if vertexWeightProperty is present)   –   type: string;   valid values: "int", "long", "float", "double";   default: empty.

    The type of the numeric values in the node property specified by vertexWeightProperty.

    If vertexWeightProperty is not provided, vertexWeightType is ignored. If a node contains a numeric property with the name specified by vertexWeightProperty but its value is a different numeric type than is specified by vertexWeightType, the value is typecast to the type specified by vertexWeightType. If both vertexWeightType and edgeWeightType are given, the type specified by edgeWeightType is used for both node and edge properties.

  • edgeWeightProperty (optional)   –   type: string;   default: none.

    The numeric edge property used as a weight in Label Propagation. When vertexWeightProperty is not specified, the default edge weight is 1.0, so each edge is treated equally. When only edgeWeightProperty is provided, the weight of the communityId is the value of that edge property. When both vertexWeightProperty and edgeWeightProperty are present, the weight of a communityId is the product of the edge property value and the node property value.

    Note that if multiple properties exist on the edge with the name specified by edgeWeightProperty, one of those property values will be sampled at random.

  • edgeWeightType (required if edgeWeightProperty is present)   –   type: string;   valid values: "int", "long", "float", "double";   default: none.

    The type of the numeric values in the edge property specified by edgeWeightProperty.

    If edgeWeightProperty is not provided, edgeWeightType is ignored. If a node contains a numeric property with the name specified by edgeWeightProperty but its value is a different numeric type than is specified by edgeWeightType, the value is typecast to the type specified by edgeWeightType. If both vertexWeightType and edgeWeightType are given, the type specified by edgeWeightType is used for both node and edge properties.

  • traversalDirection (optional)   –   type: string;   default: "outbound".

    The direction of edge to follow. Must be one of: "inbound", "outbound", or "both".

  • maxIterations (optional)   –   type: integer;   default: 10.

    The maximum number of iterations to run.

  • concurrency   (optional)   –   type: 0 or 1;   default: 0.

    Controls the number of concurrent threads used to run the algorithm.

    If set to 0, uses all available threads to complete execution of the individual algorithm invocation. If set to 1, uses a single thread. This can be useful when requiring the invocation of many algorithms concurrently.

Outputs for the .labelPropagation.mutate algorithm

The community component IDs are written as a new node property of each source node using the property name specified by writeProperty.

If the algorithm is invoked as a standalone query, there is no other output.

If the algorithm is invoked immediately after a MATCH clause that supplies its source node list, the algorithm outputs a key column of the source nodes from the MATCH clause and a value column of success flags (true or false) to indicate whether or not the write to the new node property of that node succeeded.

.labelPropagation.mutate  query example

CALL neptune.algo.labelPropagation.mutate(
  {
    writeProperty: "COMM_ID",
    edgeLabels: ["route"], 
    maxIterations: 10,
    vertexLabel: "airport",
    vertexWeightProperty: "runways",
    vertexWeightType: "int",
    edgeWeightProperty: "dist",
    edgeWeightType: "int",
    traversalDirection: "both",
    concurrency: 2
  }
)

Sample  .labelPropagation.mutate  output

Here is an example of the output returned by .labelPropagation.mutate when run against the sample air-routes dataset [nodes], and sample air-routes dataset [edges], when using the following query:

aws neptune-graph execute-query \
  --graph-identifier ${graphIdentifier} \
  --query-string "CALL neptune.algo.labelPropagation.mutate({writeProperty: 'communityId'}) YIELD success RETURN success" \
  --language open_cypher \
  /tmp/out.txt
  
cat /tmp/out.txt
{
  "results": [
    {
      "success": true
    }
  ]
}