C

CliqueSubstructures

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Detects SubstructureItems that represent the (undirected) cliques in the specified graph.
Inheritance Hierarchy

Remarks

A clique is a subset of nodes of the same type (nodeTypes) that are all adjacent (i.e., connected) to each other.

Cliques with less than minimumSize nodes are ignored.

Note that finding a maximum clique is NP-hard. Hence, we only use a simple heuristic approach that doesn't guarantee to find all/the largest clique. It only identifies cliques that have at least one node with at most one non-clique neighbor. Furthermore, a node can only be contained in a single clique, i.e., the returned cliques are non-overlapping.

Examples

Finding the cliques in a graph
// prepare the clique detection algorithm
const algorithm = new CliqueSubstructures()
// run the algorithm
const result = algorithm.run(graph)

// highlight the cliques
for (const clique of result.cliques) {
  for (const node of clique.nodes) {
    graph.setStyle(node, highlightNodeStyle)
  }
  for (const edge of clique.edges) {
    graph.setStyle(edge, highlightEdgeStyle)
  }
}
Finding only the cliques in a graph whose nodes are of the same type
// prepare the clique detection algorithm
const algorithm = new CliqueSubstructures({
  // only nodes with the same tags can be a clique
  nodeTypes: (node: INode): any => node.tag,
})
// run the algorithm
const result = algorithm.run(graph)

// highlight the cliques
for (const clique of result.cliques) {
  for (const node of clique.nodes) {
    graph.setStyle(node, highlightNodeStyle)
  }
  for (const edge of clique.edges) {
    graph.setStyle(edge, highlightEdgeStyle)
  }
}

See Also

Developer's Guide

Members

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Constructors

CliqueSubstructures

()

Parameters

Properties

minimumSize

: number
Gets or sets the minimum size of a clique.

Cliques with fewer nodes are ignored.

Default is 3.

The smallest minimumSize value that could be considered is 3.
final

nodeTypes

: ItemMapping<INode, any>
Gets or sets a mapping which maps the type of each node.

An arbitrary object. Nodes returning equal objects are considered to be of the same type.

If none is provided, all nodes are considered as equal.

A clique only consists of elements with the same nodeTypes, i.e., nodes associated with equal objects. If no nodeTypes is specified, all nodes are considered to be of the same type.
conversionfinal

subgraphEdges

: ItemCollection<IEdge>
Gets or sets the collection of edges which define a subset of the graph for the algorithms to work on.

If nothing is set, all edges of the graph will be processed.

If only the excludes are set, all edges in the graph except those provided in the excludes are processed.

Note that edges which start or end at nodes which are not in the subgraphNodes are automatically not considered by the algorithm.

ItemCollection<T> instances may be shared among algorithm instances and will be (re-)evaluated upon (re-)execution of the algorithm.

The edges provided here must be part of the graph which is passed to the run method.
conversionfinal

Examples

Finding the cliques of a subset of the graph
// prepare the clique detection algorithm
const algorithm = new CliqueSubstructures({
  // Ignore edges without target arrow heads
  subgraphEdges: {
    excludes: (edge: IEdge): boolean =>
      edge.style instanceof PolylineEdgeStyle &&
      edge.style.targetArrow instanceof Arrow &&
      edge.style.targetArrow.type === ArrowType.NONE,
  },
})
// run the algorithm
const result = algorithm.run(graph)

// highlight the cliques
for (const clique of result.cliques) {
  for (const node of clique.nodes) {
    graph.setStyle(node, highlightNodeStyle)
  }
  for (const edge of clique.edges) {
    graph.setStyle(edge, highlightEdgeStyle)
  }
}

subgraphNodes

: ItemCollection<INode>
Gets or sets the collection of nodes which define a subset of the graph for the algorithms to work on.

If nothing is set, all nodes of the graph will be processed.

If only the excludes are set, all nodes in the graph except those provided in the excludes are processed.

ItemCollection<T> instances may be shared among algorithm instances and will be (re-)evaluated upon (re-)execution of the algorithm.

The nodes provided here must be part of the graph which is passed to the run method.
conversionfinal

Examples

Finding the cliques of a subset of the graph
// prepare the clique detection algorithm
const algorithm = new CliqueSubstructures({
  subgraphNodes: {
    // only consider elliptical nodes in the graph
    includes: (node: INode): boolean =>
      node.style instanceof ShapeNodeStyle &&
      node.style.shape === ShapeNodeShape.ELLIPSE,
    // but ignore the first node, regardless of its shape
    excludes: graph.nodes.first()!,
  },
})
// run the algorithm
const result = algorithm.run(graph)

// highlight the cliques
for (const clique of result.cliques) {
  for (const node of clique.nodes) {
    graph.setStyle(node, highlightNodeStyle)
  }
  for (const edge of clique.edges) {
    graph.setStyle(edge, highlightEdgeStyle)
  }
}

Methods

run

(graph: IGraph): CliqueSubstructuresResult
Returns a list of SubstructureItems that represent the (undirected) cliques in the specified graph.

A clique is a subset of nodes of the same type (nodeTypes) that are all adjacent (i.e., connected) to each other.

Cliques with less than minimumSize nodes are ignored.

Note that finding a maximum clique is NP-hard. Hence, we only use a simple heuristic approach that doesn't guarantee to find all/the largest clique. It only identifies cliques that have at least one node with at most one non-clique neighbor. Furthermore, a node can only be contained in a single clique, i.e., the returned cliques are non-overlapping.

A clique only consists of elements with the same nodeTypes, i.e., nodes associated with equal objects. If no nodeTypes is specified, all nodes are considered to be of the same type.
The smallest minimumSize value that could be considered is 3.
The result obtained from this algorithm is a snapshot which is no longer valid once the graph has changed, e.g. by adding or removing nodes or edges.
final

Parameters

graph: IGraph
The graph to find the substructures in.

Return Value

CliqueSubstructuresResult
A list of SubstructureItems that represent the cliques.

Throws

Exception ({ name: 'InvalidOperationError' })
If the algorithm can't create a valid result due to an invalid graph structure or wrongly configured properties.

Examples

Finding the cliques in a graph
// prepare the clique detection algorithm
const algorithm = new CliqueSubstructures()
// run the algorithm
const result = algorithm.run(graph)

// highlight the cliques
for (const clique of result.cliques) {
  for (const node of clique.nodes) {
    graph.setStyle(node, highlightNodeStyle)
  }
  for (const edge of clique.edges) {
    graph.setStyle(edge, highlightEdgeStyle)
  }
}
Finding only the cliques in a graph whose nodes are of the same type
// prepare the clique detection algorithm
const algorithm = new CliqueSubstructures({
  // only nodes with the same tags can be a clique
  nodeTypes: (node: INode): any => node.tag,
})
// run the algorithm
const result = algorithm.run(graph)

// highlight the cliques
for (const clique of result.cliques) {
  for (const node of clique.nodes) {
    graph.setStyle(node, highlightNodeStyle)
  }
  for (const edge of clique.edges) {
    graph.setStyle(edge, highlightEdgeStyle)
  }
}