C

TransitiveClosure

Show Usages
Calculates the transitive closure for a directed acyclic graph.
Inheritance Hierarchy

Remarks

Let G = (V, E) be a directed acyclic graph. The transitive closure of G is a graph which contains an edge (v, w) (with v ≠ w) only if there exists a path from v to w in G. This implementation produces the transitive closure and not the reflexive, transitive closure of the specified graph, since no representations for self-loops are added.

Other Transitivity Algorithms

yFiles for HTML supports other algorithms related to transitivity:

  • TransitiveEdges – calculates the edges which connect the visible nodes in a graph if these are indirectly connected via hidden nodes.
  • TransitiveReduction – calculates the transitive reduction of a graph, i.e. the edges that are unnecessary to only ensure that the same reachability relation is represented

Examples

Calculating the transitive closure of a graph
// prepare the transitive closure algorithm
const algorithm = new TransitiveClosure()
// run the algorithm
const result = algorithm.run(graph)

// Add the edges in the closure with a different style
for (const edge of result.edgesToAdd) {
  graph.createEdge(edge.source, edge.target, transitiveEdgeStyle)
}

See Also

Developer's Guide

API

applyTransitiveClosure

Members

No filters for this type

Constructors

TransitiveClosure

()

Parameters

Properties

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

Calculating the transitive closure of a subset of the graph
// prepare the transitive closure algorithm
const algorithm = new TransitiveClosure({
  // 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)

// Add the edges in the closure with a different style
for (const edge of result.edgesToAdd) {
  graph.createEdge(edge.source, edge.target, transitiveEdgeStyle)
}

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

Calculating the transitive closure of a subset of the graph
// prepare the transitive closure algorithm
const algorithm = new TransitiveClosure({
  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)

// Add the edges in the closure with a different style
for (const edge of result.edgesToAdd) {
  graph.createEdge(edge.source, edge.target, transitiveEdgeStyle)
}

Methods

run

(graph: IGraph): TransitiveClosureResult
Calculates the transitive closure for a directed acyclic graph.
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 input graph to run the algorithm on.

Return Value

TransitiveClosureResult
A TransitiveClosureResult containing placeholders for edges that can be inserted to obtain the transitive closure of graph.

Throws

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