Uniform Mutation trying to mutate genes outside of the chromossome array

[JJ223]

I am using Genetic Sharp to generate the Best team of Drones for a mission. Each gene in my chromossome stores the amount of a specific type of drone. The algorithm works perfectly fine except sometimes when performing a Uniform mutation it will try to change a gene outside of the chromossome. How could this happen? Am I doing something wrong?

Here is my code:

• Chromossome

public class TeamChromosome : ChromosomeBase
{
    private readonly int[] _maxAmounts;

    public TeamChromosome(int[] maxAmounts) : base(maxAmounts.Length)
    {
        _maxAmounts = maxAmounts;
        CreateGenes();
    }

    public override IChromosome CreateNew()
    {
        return new TeamChromosome(_maxAmounts);
    }

    public override Gene GenerateGene(int geneIndex)
    {
        // Generate random gene value within the maximum amount for the type
        return new Gene(RandomizationProvider.Current.GetInt(0, _maxAmounts[geneIndex] + 1));
    }
}

And my fitness Function

public class DroneTeamFitness : IFitness
{
    private MissionPlanner missionPlanner;
    private List<int> quantities;
    private List<List<Drone>> capableDrones;
    private bool basedOnTime;

    public DroneTeamFitness(MissionPlanner missionPlanner, List<int> quantities, List<List<Drone>> capableDrones, bool basedOnTime)
    {
        this.missionPlanner = missionPlanner;
        this.quantities = quantities;
        this.capableDrones = capableDrones;
        this.basedOnTime = basedOnTime;
    }

    public double Evaluate(IChromosome chromosome)
    {
        var genes = chromosome.GetGenes();
        List<Drone> team = new List<Drone>();
        
        int droneIndex = 0;
        for(int i = 0; i < quantities.Count; i++)
        {
            int count = 0;
            foreach(Drone drone in capableDrones[i])
            {
                count += (int)genes[droneIndex].Value;
                for(int j = 0; j < (int)genes[droneIndex].Value; j++)
                {
                    team.Add(drone);
                }
                droneIndex++;
            }
            if(count > quantities[i])
            {
                return 0;
            }
        }
        // Check if the team is empty
        if(team.Count == 0)
        {
            return 0;
        }

        (List <Drone> teamOverWater, List <Drone> teamUnderWater) = missionPlanner.assignDroneToWorkingArea(team);

        // Check if the team can perform the mission
        Mission mission = missionPlanner.mission;
        if ((mission.HeigthLimit.upperLimit > 0 && teamOverWater.Count == 0) || mission.HeigthLimit.lowerLimit < 0 && teamUnderWater.Count == 0)
            return 0;

        List<List<DronePath>> missionPaths = missionPlanner.PlanMission(teamOverWater, teamUnderWater);
        double missionCost = PathEvaluation.calculateMissionCost(missionPaths);
        double missionTime = PathEvaluation.calculateMissionTime(missionPaths);
        // You can add more criteria to evaluate the fitness

        if (basedOnTime)
        {
            return 1 / missionTime;
        }
        return 1 / missionCost;
    }
}

[JJ223]

Managed to fix it by changing the UniformMutation constructer from UniforMutation(true) to UniformMutation(mutableGenesIndexes) with the indexes of the chromossome.