Calculates the k-cores of an undirected input graph.
Remarks
The k-core of an undirected input graph consists of the subgraph components where each node has at least degree k. The algorithm has runtime complexity O((n+m)log(n)) and requires linear space.
Other Graph Connectivity Algorithms
yFiles for HTML supports a number of other analysis algorithms that partition the graph into components, based on various criteria.
- ConnectedComponents – Determines components defined by the existence of an undirected path between nodes
- StronglyConnectedComponents – Determines components defined by the existence of a directed path between nodes
- BiconnectedComponents – Determines components defined by the existence of at least two separate undirected paths between all nodes
- Bipartition – Divides a graph into two partitions where all edges have their source and target in different partitions
- IndependentSets – Divides a graph into partitions where no nodes are connected within a partition
Examples
// prepare the k-core algorithm
const algorithm = new KCoreComponents()
// run the algorithm
const result = algorithm.run(graph)
// highlight the nodes of a given k-cores with different styles
for (const node of result.getKCore(3)) {
graph.setStyle(node, highlightStyle)
}Type Details
- yfiles module
- view-layout-bridge
- yfiles-umd modules
- view-layout-bridge
- Legacy UMD name
- yfiles.analysis.KCoreComponents
See Also
Constructors
Creates a new KCoreComponents instance.
Parameters
A map of options to pass to the method.
- 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 k-core algorithm
const algorithm = new KCoreComponents({
// 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 nodes of a given k-cores with different styles
for (const node of result.getKCore(3)) {
graph.setStyle(node, highlightStyle)
}// prepare the k-core algorithm
const algorithm = new KCoreComponents({
// 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 nodes of a given k-cores with different styles
for (const node of result.getKCore(3)) {
graph.setStyle(node, highlightStyle)
}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 k-core algorithm
const algorithm = new KCoreComponents({
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 nodes of a given k-cores with different styles
for (const node of result.getKCore(3)) {
graph.setStyle(node, highlightStyle)
}// prepare the k-core algorithm
const algorithm = new KCoreComponents({
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 nodes of a given k-cores with different styles
for (const node of result.getKCore(3)) {
graph.setStyle(node, highlightStyle)
}Methods
Determines the k-Cores of a given graph.
Complexity
O((n+m)log(n))
Parameters
A map of options to pass to the method.
- graph - IGraph
- The input graph to run the algorithm on.
Returns
- ↪KCoreComponentsResult
- A KCoreComponentsResult from which the k-cores of the
graphcan be obtained.
Throws
- Exception({ name: 'InvalidOperationError' })
- If the algorithm can't create a valid result due to an invalid graph structure or wrongly configured properties.
Examples
// prepare the k-core algorithm
const algorithm = new KCoreComponents()
// run the algorithm
const result = algorithm.run(graph)
// highlight the nodes of a given k-cores with different styles
for (const node of result.getKCore(3)) {
graph.setStyle(node, highlightStyle)
}