Finds a directed or undirected cycle of edges in a graph.
Remarks
The graph can be directed or undirected.
Other Path-Related Algorithms
yFiles for HTML supports a number of other algorithms related to paths in a graph:
- Paths – finds all paths between a set of source and a set of target nodes
- Chains – finds all chains, that is, sequences of nodes that are each connected with just an edge without branches
- LongestPath – finds the longest path in the graph
Examples
// prepare the cycle detection algorithm
const algorithm = new Cycle({
// We are only interested in finding directed cycles
directed: true
})
// run the algorithm
const result = algorithm.run(graph)
// highlight the cycle
for (const edge of result.edges) {
graph.setStyle(edge, highlightCycleStyle)
}Type Details
- yfiles module
- view-layout-bridge
- yfiles-umd modules
- view-layout-bridge
- Legacy UMD name
- yfiles.analysis.Cycle
See Also
Constructors
Creates a new Cycle instance.
Parameters
A map of options to pass to the method.
- directed - boolean
A value indicating whether edge direction should be considered. This option sets the directed property on the created object.
- subgraphNodes - ItemCollection<INode>
The collection of nodes which define a subset of the graph for the algorithms to work on. This option sets the subgraphNodes property on the created object.
- subgraphEdges - ItemCollection<IEdge>
The collection of edges which define a subset of the graph for the algorithms to work on. This option sets the subgraphEdges property on the created object.
Properties
Gets or sets the collection of edges which define a subset of the graph for the algorithms to work on.
Remarks
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.
Examples
// prepare the cycle detection algorithm
const algorithm = new Cycle({
// We are only interested in finding directed cycles
directed: true,
// Ignore edges without target arrow heads
subgraphEdges: {
excludes: (edge) =>
edge.style instanceof PolylineEdgeStyle &&
edge.style.targetArrow === IArrow.NONE
}
})
// run the algorithm
const result = algorithm.run(graph)
// highlight the cycle
for (const edge of result.edges) {
graph.setStyle(edge, highlightCycleStyle)
}// prepare the cycle detection algorithm
const algorithm = new Cycle({
// We are only interested in finding directed cycles
directed: true,
// Ignore edges without target arrow heads
subgraphEdges: {
excludes: (edge: IEdge): boolean =>
edge.style instanceof PolylineEdgeStyle &&
edge.style.targetArrow === IArrow.NONE
}
})
// run the algorithm
const result = algorithm.run(graph)
// highlight the cycle
for (const edge of result.edges) {
graph.setStyle(edge, highlightCycleStyle)
}Gets or sets the collection of nodes which define a subset of the graph for the algorithms to work on.
Remarks
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.
Examples
// prepare the cycle detection algorithm
const algorithm = new Cycle({
// We are only interested in finding directed cycles
directed: true,
subgraphNodes: {
// only consider elliptical nodes in the graph
includes: (node) =>
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 cycle
for (const edge of result.edges) {
graph.setStyle(edge, highlightCycleStyle)
}// prepare the cycle detection algorithm
const algorithm = new Cycle({
// We are only interested in finding directed cycles
directed: true,
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 cycle
for (const edge of result.edges) {
graph.setStyle(edge, highlightCycleStyle)
}Methods
Finds a cycle in the given graph.
Complexity
O(|V| + |E|)
Parameters
A map of options to pass to the method.
- graph - IGraph
- The input graph to run the algorithm on.
Returns
- ↪CycleResult
- A CycleResult with a cycle (if one exists in the graph).
Throws
- Exception({ name: 'InvalidOperationError' })
- If the algorithm can't create a valid result due to an invalid graph structure or wrongly configured properties.