# Class: com.pnfsoftware.jeb.util.graph.Digraph A directed graph object, cyclic or acyclic. Self\-loops \(x\>x\) are also allowed. Duplicate edges are not allowed, e.g. if an edge x\>y exists, another edge x\>y cannot be added \(a way to represent this information is to specify an edge weight\). ## Constructor: Digraph Description: Create an empty directed graph. ## Method: canReach - parameter: `from`, type: `com.pnfsoftware.jeb.util.graph.Digraph.V` - parameter: `to`, type: `com.pnfsoftware.jeb.util.graph.Digraph.V` - return type: `boolean` Description: Determine whether a vertex can reach another vertex by following directed edges. parameter: from: source vertex parameter: to: destination vertex return: true if `to` is reachable from `from` ## Method: computeEdgeBetweenness - return type: `java.util.List` Description: Compute the edge\-betweenness score of all edges of the graph using Girvan\-Newman. The scores are available through [E#getEdgeBetweennessScore()](E#getEdgeBetweennessScore()). return: a list of edge indexes ordered by descending order of edge\-betweenness score; e.g., if the first element of the list is 2, it means that the third registered edge \(getEdge\(2\)\) is the one with the highest EB score ## Method: copyOfEdges - return type: `java.util.List` Description: Create a copy of the graph edges. return: cloned edges in edge insertion order ## Method: copyOfVertices - return type: `java.util.List` Description: Create a copy of the graph vertices. return: cloned vertices in index order ## Method: done - return type: `com.pnfsoftware.jeb.util.graph.Digraph` Description: Verify the graph after an initial build step. return: this graph ## Method: e - parameter: `srcId`, type: `int` - parameter: `dstId`, type: `int` - parameter: `weight`, type: `java.lang.Double` - return type: `com.pnfsoftware.jeb.util.graph.Digraph` Description: Add an edge to this graph, creating missing endpoint vertices if needed. parameter: srcId: source vertex id parameter: dstId: destination vertex id parameter: weight: optional edge weight return: this graph ## Method: e - parameter: `srcId`, type: `int` - parameter: `dstId`, type: `int` - return type: `com.pnfsoftware.jeb.util.graph.Digraph` Description: Add an unweighted edge to this graph, creating missing endpoint vertices if needed. parameter: srcId: source vertex id parameter: dstId: destination vertex id return: this graph ## Method: getEdge - parameter: `index`, type: `int` - return type: `com.pnfsoftware.jeb.util.graph.Digraph.E` Description: Get an edge by index. parameter: index: edge index return: the edge at that index ## Method: getEdge - parameter: `srcId`, type: `int` - parameter: `dstId`, type: `int` - return type: `com.pnfsoftware.jeb.util.graph.Digraph.E` Description: Get an edge by source and destination vertex ids. parameter: srcId: source vertex id parameter: dstId: destination vertex id return: the edge, or null if no such edge exists ## Method: getEdgeCount - return type: `int` Description: Get the number of edges. return: the edge count ## Method: getEdgeIndexesByDescendingBetweenness - return type: `java.util.List` Description: Get edge indexes ordered by descending edge\-betweenness score. return: a list of edge indexes ordered by descending score ## Method: getEdges - return type: `java.util.List` Description: Get the graph edges. return: the internal edge list in insertion order ## Method: getReachableVertices - parameter: `fromId`, type: `int` - return type: `java.util.Set` Description: Get all vertices reachable from a vertex. parameter: fromId: source vertex id return: ids of vertices reachable from the source vertex ## Method: getVertex - parameter: `id`, type: `int` - return type: `com.pnfsoftware.jeb.util.graph.Digraph.V` Description: Get a vertex by id. parameter: id: vertex id return: the vertex, or null if no vertex has this id ## Method: getVertexByIndex - parameter: `index`, type: `int` - return type: `com.pnfsoftware.jeb.util.graph.Digraph.V` Description: Get a vertex by index. parameter: index: vertex index return: the vertex at that index ## Method: getVertexCount - return type: `int` Description: Get the number of vertices. return: the vertex count ## Method: getVertexIndexesByDescendingCentrality - return type: `java.util.List` Description: Get vertex indexes ordered by descending vertex centrality score. return: a list of vertex indexes ordered by descending score ## Method: getVertexLabel - parameter: `id`, type: `int` - return type: `java.lang.String` Description: Get a vertex label by vertex id. parameter: id: vertex id return: the vertex label, or null if none was assigned ## Method: getVertices - return type: `java.util.List` Description: Get the graph vertices. return: the internal vertex list in index order ## Method: getWeaklyConnectedComponents - return type: `java.util.List` Description: Split this graph into weakly connected components. return: weakly connected component subgraphs; if this graph is already weakly connected, the returned list contains this graph ## Method: isAdjacent - parameter: `from`, type: `com.pnfsoftware.jeb.util.graph.Digraph.V` - parameter: `to`, type: `com.pnfsoftware.jeb.util.graph.Digraph.V` - return type: `boolean` Description: Determine whether two vertices are directly connected by an edge. parameter: from: source vertex parameter: to: destination vertex return: true if an edge exists from `from` to `to` ## Method: isWeaklyConnected - return type: `boolean` Description: Determine if this directed graph is weakly connected, that is, if the corresponding undirected graph is connected. return: true if all vertices belong to a single weakly connected component ## Method: removeEdge - parameter: `e`, type: `com.pnfsoftware.jeb.util.graph.Digraph.E` Description: Remove an edge. parameter: e: edge to remove ## Method: removeEdge - parameter: `index`, type: `int` Description: Remove an edge by index. parameter: index: edge index ## Method: removeVertex - parameter: `v`, type: `com.pnfsoftware.jeb.util.graph.Digraph.V` - parameter: `reconnectEdges`, type: `boolean` Description: Remove a vertex and all incident edges. parameter: v: vertex to remove parameter: reconnectEdges: true to connect each predecessor of the removed vertex to each of its successors ## Method: resetEdgeBetweennessScores Description: Reset edge\-betweenness and vertex centrality scores to zero. ## Method: setVertexLabel - parameter: `id`, type: `int` - parameter: `label`, type: `java.lang.String` Description: Set a vertex label by vertex id. parameter: id: vertex id parameter: label: vertex label, or null to clear it ## Method: setVertexLabels - parameter: `idLabels`, type: `java.lang.Object[]` Description: Set multiple vertex labels. Arguments are read as `Integer, String` pairs. Pairs whose values do not match those types are ignored. parameter: idLabels: alternating vertex ids and labels ## Method: toString - return type: `java.lang.String` ## Method: v - parameter: `id`, type: `int` - parameter: `weight`, type: `java.lang.Double` - parameter: `label`, type: `java.lang.String` - return type: `com.pnfsoftware.jeb.util.graph.Digraph` Description: Add a vertex to this graph. parameter: id: vertex id parameter: weight: optional vertex weight parameter: label: optional vertex label return: this graph ## Method: v - parameter: `id`, type: `int` - parameter: `weight`, type: `java.lang.Double` - return type: `com.pnfsoftware.jeb.util.graph.Digraph` Description: Add a vertex to this graph. parameter: id: vertex id parameter: weight: optional vertex weight return: this graph ## Method: v - parameter: `id`, type: `int` - return type: `com.pnfsoftware.jeb.util.graph.Digraph` Description: Add a vertex to this graph. parameter: id: vertex id return: this graph ## Static Method: create - return type: `com.pnfsoftware.jeb.util.graph.Digraph` Description: Create an empty directed graph. return: an empty directed graph ## Static Method: load - parameter: `file`, type: `java.io.File` - return type: `com.pnfsoftware.jeb.util.graph.Digraph` Description: Load a graph from a text file. parameter: file: graph definition file return: the loaded graph throws: if the file cannot be read