CODEWITHSUNDEEP
javagraphgraph-theoryjgrapht
user3025494
user3025494

Reputation: 119

How to include weight in edge of graph?

I want to include weights or costs of the edge on my graph using this jgrapht interface-class:

package org.jgrapht;

public interface WeightedGraph<V extends Object, E extends Object> extends Graph<V, E> {

    public static final double DEFAULT_EDGE_WEIGHT = 1.0;

    public void setEdgeWeight(E e, double d);
}

Upvotes: 12

Views: 14932

Answers (1)

Plo_Koon
Plo_Koon

Reputation: 3033

Yo have described Interface WeightedGraph<V,E> from here.

You need to use SimpleDirectedWeightedGraph to set the weights of its edges. Look at this example, it creates Directed Weighted Graph by using graph.addVertex(), graph.setEdgeWeight() methods and considers shortest path between some edges by using Dijkstra Algorithm implemented in DijkstraShortestPath.findPathBetween() method.

    import org.jgrapht.*;
    import org.jgrapht.alg.*;
    import org.jgrapht.graph.*;
    import java.util.List;

    public class Graph {
        public static void main(String args[]) {

            SimpleDirectedWeightedGraph<String, DefaultWeightedEdge>  graph = 
            new SimpleDirectedWeightedGraph<String, DefaultWeightedEdge>
            (DefaultWeightedEdge.class); 
            graph.addVertex("vertex1");
            graph.addVertex("vertex2");
            graph.addVertex("vertex3");
            graph.addVertex("vertex4");
            graph.addVertex("vertex5");


            DefaultWeightedEdge e1 = graph.addEdge("vertex1", "vertex2"); 
            graph.setEdgeWeight(e1, 5); 

            DefaultWeightedEdge e2 = graph.addEdge("vertex2", "vertex3"); 
            graph.setEdgeWeight(e2, 3); 

            DefaultWeightedEdge e3 = graph.addEdge("vertex4", "vertex5"); 
            graph.setEdgeWeight(e3, 6); 

            DefaultWeightedEdge e4 = graph.addEdge("vertex2", "vertex4"); 
            graph.setEdgeWeight(e4, 2); 

            DefaultWeightedEdge e5 = graph.addEdge("vertex5", "vertex4"); 
            graph.setEdgeWeight(e5, 4); 


            DefaultWeightedEdge e6 = graph.addEdge("vertex2", "vertex5"); 
            graph.setEdgeWeight(e6, 9); 

            DefaultWeightedEdge e7 = graph.addEdge("vertex4", "vertex1"); 
            graph.setEdgeWeight(e7, 7); 

            DefaultWeightedEdge e8 = graph.addEdge("vertex3", "vertex2"); 
            graph.setEdgeWeight(e8, 2); 

            DefaultWeightedEdge e9 = graph.addEdge("vertex1", "vertex3"); 
            graph.setEdgeWeight(e9, 10); 

            DefaultWeightedEdge e10 = graph.addEdge("vertex3", "vertex5"); 
            graph.setEdgeWeight(e10, 1); 


            System.out.println("Shortest path from vertex1 to vertex5:");
            List shortest_path =   DijkstraShortestPath.findPathBetween(graph, "vertex1", "vertex5");
            System.out.println(shortest_path);

        }
    }

Upvotes: 20

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