// Fitness function
    public long getFitness() {
        long fitness = getLength();

        return fitness;
    }

// Selection method
    public void selection(Network[] population, Network[] newGeneration) {
        long eFitness = 0;
        for(int i = 0; i < population.length; i++) {
            eFitness += population[i].getFitness();
        }

        for(int i = 0; i < Info.POPULATION; i++) {
            Network child = Network.breed(getByRoulette(eFitness, population), getByRoulette(eFitness, population));
            newGeneration[i] = child;
        }

    }

// Roulette method
    public Network getByRoulette(long eFitness, Network[] population) {
        long rand = (long) (rnd.nextDouble() * eFitness);
        long runningSum = 0;
        for(int i = 0; i < population.length; i++) {
            runningSum += population[i].getFitness();
            if(runningSum > rand) {
                return population[i];
            }
        }

        return null;
    }

// new generation method
    private Network[] newGeneration(int species, Network[] population) {
        Network[] newGeneration = new Network[Info.POPULATION];

        // Average the total fitnesses
        for(int i = 0; i < Info.POPULATION; i++) {
            population[i].setFitness(population[i].getFitness() / Info.REPLAY_NETWORKS);
        }

        Arrays.sort(population, Maths.SORT_FITNESS);
        if(population[0].getFitness() > mech.highestFitnessEver) {
            mech.highestFitnessEver = population[0].getFitness();
        }
        totalFitnessOfBest[species] += population[0].getFitness();

        selection(population, newGeneration);

        if(Info.GENERATION % Info.GRAPH_SCALE == 0) {
            mech.averageFitnessOfBest[species] = totalFitnessOfBest[species] / Info.GRAPH_SCALE;
            if(mech.averageFitnessOfBest[species] > highestAverageFitness) {
                highestAverageFitness = mech.averageFitnessOfBest[species];
            }
            totalFitnessOfBest[species] = 0;
            mech.addScore(species, (long) mech.averageFitnessOfBest[species]);
        }

        if(Info.GENERATION % 5 == 0) {
            try {
                population[0].save(saveFile, false, Info.GENERATION, (int) mech.averageFitnessOfBest[species], species);
            }
            catch(IOException e) {
                e.printStackTrace();
            }
        }

        return newGeneration;
    }