/// <summary>
/// "Mutates" a given individual by executing a local search 3-Opt operation.
/// </summary>
/// <param name="solver"></param>
/// <param name="mutating"></param>
/// <returns></returns>
public Individual <MaxTimeSolution, MaxTimeProblem, Fitness> Mutate(
Solver <MaxTimeSolution, MaxTimeProblem, Fitness> solver,
Individual <MaxTimeSolution, MaxTimeProblem, Fitness> mutating)
{
// select a random route.
MaxTimeSolution mutated = (mutating.Genomes.Clone() as MaxTimeSolution);
IRoute route = mutated.Route(
OsmSharp.Math.Random.StaticRandomGenerator.Get().Generate(mutated.Count));
// apply the improvement operator.
double difference;
OsmSharp.Math.TSP.LocalSearch.HillClimbing3Opt.HillClimbing3OptSolver hillclimbing_3opt =
new OsmSharp.Math.TSP.LocalSearch.HillClimbing3Opt.HillClimbing3OptSolver(true, true);
hillclimbing_3opt.Improve(solver.Problem, route, out difference);
return(new Individual <MaxTimeSolution, MaxTimeProblem, Fitness>(
mutated));
}
/// <summary>
/// Does the mutation.
/// </summary>
/// <param name="solver"></param>
/// <param name="mutating"></param>
/// <returns></returns>
public Individual <MaxTimeSolution, MaxTimeProblem, Fitness> Mutate(
Solver <MaxTimeSolution, MaxTimeProblem, Fitness> solver,
Individual <MaxTimeSolution, MaxTimeProblem, Fitness> mutating)
{
MaxTimeSolution solution = (mutating.Genomes.Clone() as MaxTimeSolution);
//MaxTimeSolution copy = (mutating.Genomes.Clone() as MaxTimeSolution);
if (solution.Count > 1)
{
// calculate average.
int avg = solution.Size / solution.Count;
//
int source_route_idx = OsmSharp.Math.Random.StaticRandomGenerator.Get().Generate(solution.Count);
// get the source count and descide what to do.
List <int> sizes = new List <int>(solution.Sizes);
int source_size = solution.Sizes[source_route_idx];
if (source_size > avg)
{
int size = OsmSharp.Math.Random.StaticRandomGenerator.Get().Generate(source_size / 2);
//int size = OsmSharp.Math.Random.StaticRandomGenerator.Get().Generate(source_size);
//int size = OsmSharp.Math.Random.StaticRandomGenerator.Get().Generate(source_size / 3);
if (size > 0)
{
sizes[source_route_idx] = sizes[source_route_idx] - size;
}
sizes.Insert(source_route_idx, size);
}
else
{ // route is small; add it to a neighbour route.
int target_route_idx = -1;
do
{
target_route_idx = OsmSharp.Math.Random.StaticRandomGenerator.Get().Generate(solution.Sizes.Count);
} while (source_route_idx == target_route_idx);
if (target_route_idx >= 0 && target_route_idx < sizes.Count)
{
// merge the two into the target;
int size = sizes[source_route_idx];
sizes[target_route_idx] = sizes[target_route_idx] + size;
sizes.RemoveAt(source_route_idx);
}
}
// remove all zero's.
while (sizes.Remove(0))
{
}
solution = this.ChangeSizes(solver.Problem, solution, sizes);
// apply 3Opt to all routes.
for (int route_idx = 0; route_idx < solution.Count; route_idx++)
{
double difference;
OsmSharp.Math.TSP.LocalSearch.HillClimbing3Opt.HillClimbing3OptSolver hillclimbing_3opt =
new OsmSharp.Math.TSP.LocalSearch.HillClimbing3Opt.HillClimbing3OptSolver(true, true);
hillclimbing_3opt.Improve(solver.Problem, solution.Route(route_idx), out difference);
}
if (!solution.IsValid())
{
throw new Exception();
}
}
return(new Individual <MaxTimeSolution, MaxTimeProblem, Fitness>(solution));
}