Пример #1
0
        protected override void PerformMutation(IGraphChromosome graph, float probability)
        {
            if (RandomizationProvider.Current.GetDouble() >= probability)
            {
                return;
            }
            // No edges to add
            if (graph.EdgeCount == graph.VertexCount * graph.VertexCount)
            {
                return;
            }
            // Shuffle
            var allIDs = graph.Vertices.Select(v => v.ID);

            uint[] fromVerts = MutationService.Shuffle(allIDs, RandomizationProvider.Current).ToArray();
            uint[] toVerts   = MutationService.Shuffle(allIDs, RandomizationProvider.Current).ToArray();
            // Find the first that does not exist
            foreach (var v1 in fromVerts)
            {
                foreach (var v2 in toVerts)
                {
                    if (!graph.ContainsEdge(v1, v2))
                    {
                        graph.AddEdge(v1, v2, graph.CreateNewEdge());
                        return;
                    }
                }
            }
        }
        /// <summary>
        /// Calculates the total distance between two graphs, only
        /// accounting for edges.
        /// </summary>
        /// <param name="g1"></param>
        /// <param name="g2"></param>
        /// <returns></returns>
        protected double TotalEdgeDistance(IGraphChromosome g1, IGraphChromosome g2)
        {
            double totalDist = 0;
            double nMismatch = 0;
            double nMatch    = 0;

            foreach (var edge in g1.Edges)
            {
                if (g2.ContainsEdge(edge.IDFrom, edge.IDTo))
                {
                    totalDist += EdgeDistance(g2[edge.IDFrom, edge.IDTo], edge.Value);
                    nMatch++;
                }
                else
                {
                    nMismatch++;
                }
            }
            foreach (var edge in g2.Edges)
            {
                if (!g1.ContainsEdge(edge.IDFrom, edge.IDTo))
                {
                    nMismatch++;
                }
            }

            int N = Math.Max(g1.EdgeCount, g2.EdgeCount);

            return((EdgeMismatchWeight * nMismatch / N) + (EdgeMatchWeight * totalDist / nMatch));
        }
Пример #3
0
        protected override IGraphChromosome PerformCrossover(IGraphChromosome p1, IGraphChromosome p2)
        {
            IList <IChromosome> parents = new IChromosome[2];

            // "Disjoint genes are inherited from the more fit parent."
            var child = p1.Clone() as IGraphChromosome;

            foreach (var vert in p1.Vertices)
            {
                if (p2.ContainsVertex(vert.ID))
                {
                    parents[0]     = vert.Value;
                    parents[1]     = p2[vert.ID];
                    child[vert.ID] = VertexCrossover.Cross(parents)[0];
                }
            }

            foreach (var edge in p1.Edges)
            {
                if (p2.ContainsEdge(edge.IDFrom, edge.IDTo))
                {
                    parents[0] = edge.Value;
                    parents[1] = p2[edge.IDFrom, edge.IDTo];
                    child[edge.IDFrom, edge.IDTo] = EdgeCrossover.Cross(parents)[0];
                }
            }

            return(child);
        }