Computes the degree centrality for the nodes of a given graph.
Remarks
Degree centrality is the number of the incoming, outgoing, or overall edges incident to a node (measures incoming, outgoing, and overall degree).
If both considerIncomingEdges and considerOutgoingEdges are false, an InvalidOperationError is thrown.
Other Centrality Measures
@PRODUCT@ supports a number of other centrality measures:
- GraphCentrality, ClosenessCentrality – emphasize nodes that have short paths to other nodes
- WeightCentrality – emphasizes nodes with highly-weighted edges
- BetweennessCentrality – emphasizes nodes and edges that are part of many short paths
- EigenvectorCentrality – computes the influence a node has on a network. The centrality value is higher if more nodes are connected to that node
- PageRank – computes page rank values for all nodes based on their attached edges
Examples
const result = new DegreeCentrality().run(graph)
// add node labels for centrality values
// and adjust node size according to centrality
result.normalizedNodeCentrality.forEach((entry) => {
const node = entry.key
const centrality = entry.value
graph.addLabel(node, `${centrality}`)
graph.setNodeLayout(
node,
new Rect(node.layout.center, new Size(centrality, centrality)),
)
})Type Details
- yFiles module
- view-layout-bridge
See Also
Constructors
Creates a new instance.
Parameters
A map of options to pass to the method.
- considerIncomingEdges - boolean
- A value indicating whether incoming edges contribute to the centrality values of their target nodes. This option sets the considerIncomingEdges property on the created object.
- considerOutgoingEdges - boolean
- A value indicating whether outgoing edges contribute to the centrality values of their source nodes. This option sets the considerOutgoingEdges 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 either sets the value directly or recursively sets properties to the instance of 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 either sets the value directly or recursively sets properties to the instance of the subgraphEdges property on the created object.
Properties
Gets or sets a value indicating whether incoming edges contribute to the centrality values of their target nodes.
Remarks
If both considerIncomingEdges and considerOutgoingEdges are false, an InvalidOperationError is thrown.
Default is false.
Property Value
true if the incoming edges should be considered, false otherwise.Gets or sets a value indicating whether outgoing edges contribute to the centrality values of their source nodes.
Remarks
If both considerIncomingEdges and considerOutgoingEdges are false, an InvalidOperationError is thrown.
Default is true.
Property Value
true if the incoming edges should be considered, false otherwise.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
// configure the algorithm
const algorithm = new DegreeCentrality({
// 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 node labels for centrality values
// and adjust node size according to centrality
result.normalizedNodeCentrality.forEach((entry) => {
const node = entry.key
const centrality = entry.value
graph.addLabel(node, `${centrality}`)
graph.setNodeLayout(
node,
new Rect(node.layout.center, new Size(centrality, centrality)),
)
})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
// configure the algorithm
const algorithm = new DegreeCentrality({
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 node labels for centrality values
// and adjust node size according to centrality
result.normalizedNodeCentrality.forEach((entry) => {
const node = entry.key
const centrality = entry.value
graph.addLabel(node, `${centrality}`)
graph.setNodeLayout(
node,
new Rect(node.layout.center, new Size(centrality, centrality)),
)
})Methods
Computes the degree centrality for the nodes of a given graph.
Complexity
O(|V|)
Preconditions
- At least one of the flags
and must be true.
Parameters
A map of options to pass to the method.
- graph - IGraph
- The input graph to run the algorithm on.
Returns
- ↪DegreeCentralityResult
- A DegreeCentralityResult from which the calculated centrality values can 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.