dijkstra-spec.js

var expect = require('chai').expect;
var jsgraphs = require('../src/jsgraphs');

describe('Dijkstra', function(){
   it('should get shortest path from Weigthed Directed Graph', function(){
        var g = new jsgraphs.WeightedDiGraph(8);
        g.addEdge(new jsgraphs.Edge(0, 1, 5.0));
        g.addEdge(new jsgraphs.Edge(0, 4, 9.0));
        g.addEdge(new jsgraphs.Edge(0, 7, 8.0));
        g.addEdge(new jsgraphs.Edge(1, 2, 12.0));
        g.addEdge(new jsgraphs.Edge(1, 3, 15.0));
        g.addEdge(new jsgraphs.Edge(1, 7, 4.0));
        g.addEdge(new jsgraphs.Edge(2, 3, 3.0));
        g.addEdge(new jsgraphs.Edge(2, 6, 11.0));
        g.addEdge(new jsgraphs.Edge(3, 6, 9.0));
        g.addEdge(new jsgraphs.Edge(4, 5, 5.0));
        g.addEdge(new jsgraphs.Edge(4, 6, 20.0));
        g.addEdge(new jsgraphs.Edge(4, 7, 5.0));
        g.addEdge(new jsgraphs.Edge(5, 2, 1.0));
        g.addEdge(new jsgraphs.Edge(5, 6, 13.0));
        g.addEdge(new jsgraphs.Edge(7, 5, 6.0));
        g.addEdge(new jsgraphs.Edge(7, 2, 7.0));  
       
        expect(g.V).to.equal(8);
        var edgeCount = 0;
        for(var v = 0; v < g.V; ++v){
            var adj_v = g.adj(v);
            edgeCount += adj_v.length;
        }
        expect(edgeCount).to.equal(16);
       
        var dijkstra = new jsgraphs.Dijkstra(g, 0);
       
        for(var v = 1; v < g.V; ++v){
            if(dijkstra.hasPathTo(v)){
                var path = dijkstra.pathTo(v);
                console.log('=====path from 0 to ' + v + ' start==========');
                for(var i = 0; i < path.length; ++i) {
                    var e = path[i];
                    console.log(e.from() + ' => ' + e.to() + ': ' + e.weight);
                }
                console.log('=====path from 0 to ' + v + ' end==========');
                console.log('=====distance: '  + dijkstra.distanceTo(v) + '=========');
            }
        }
   });
});