// Copies all Elements from population to oldPopulation
public void clone()
{
for (int i = 0; i < populationSize; i++)
{
oldPopulation[i] = new Population(population[i].Path, population[i].Genome, population[i].Rating, population[i].Mutated, population[i].Selected);
}
}
// This function uses genomePart Uniform Crossover. It works like a crossover function but uses a significantly shorter mask genome
// because it always chooses an entire 8bit block
public void eightBitCrossover()
{
// Size of current new generation is 40% of old generation (before crossover)
int selectionSize = Convert.ToInt32(0.4 * populationSize);
int r;
Genome parent1 = new Genome();
Genome parent2 = new Genome();
bool[] mask;
Genome child1 = new Genome();
Genome child2 = new Genome();
// Iterates from selection Size (current maximum of the new population) to population size, the wanted maximum. That means 60% come from crossover
for (int i = selectionSize; i < populationSize; i++)
{
// Randomly selects first parent
r = Variables.getRandomInt(0, selectionSize);
parent1 = oldPopulation[r].Genome;
// Randomly selects second parent
r = Variables.getRandomInt(0, selectionSize);
parent2 = oldPopulation[r].Genome;
// Crates a random mask genome in form of a char[]. char[] is much faster than bool[], genome or bitarray and for our purpose the format doesn't matter
mask = GenomePart.getRandomGenome();
for (int j = 0; j < 20; j++)
{
// Checks the mask
if (mask[j])
{
// If mask == 1 then the i'th 8bit block will be selected from parent1 for child1 and from parent2 for child2
// k = j*8 since every position in the mask genome covers 8 positions in the actual genome
for (int k = j * 8; k < j * 8 + 8; k++)
{
child1.Genome1.Set(k, parent1.Genome1.Get(k));
child2.Genome1.Set(k, parent2.Genome1.Get(k));
}
}
else
{
// If mask == 0 then the i'th 8bit block will be selected from parent1 for child2 and from parent2 for child1
// k = j*8 since every position in the mask genome covers 8 positions in the actual genome
for (int k = j * 8; k < j * 8 + 8; k++)
{
child1.Genome1.Set(k, parent2.Genome1.Get(k));
child2.Genome1.Set(k, parent1.Genome1.Get(k));
}
}
}
Genome.genomeToPath(child1);
population[i] = new Population(Variables.path, child1, 0, false, false);
// Counts up since we are adding 2 children per iteration, not just one
i++;
// If we are not yet at maximum (which could happen due to double->int conversion) we add the second child too
if (i < populationSize)
{
Genome.genomeToPath(child2);
population[i] = new Population(Variables.path, child2, 0, false, false);
}
}
}
// This function selects via tournament selection. Selected paths are not removed from the population, so the same path can be chosen several times
public void tournamentSelection()
{
int highestFitness = 0, r = 0, tournamentSize = 2;
// New Population consists of 40% Selection
int selectionSize = Convert.ToInt32(0.4 * populationSize);
// Iterates over the new population
for (int j = 0; j < selectionSize; j++)
{
// Chooses tournamentSize members from the old population and saves the best one to highestFitness
for (int i = 0; i < tournamentSize; i++)
{
r = Variables.getRandomInt(0, selectionSize);
if (i == 0 || oldPopulation[r].Rating > oldPopulation[highestFitness].Rating)
highestFitness = r;
}
// Adds the winner of the tournament (highestFitness) to the new population
population[j] = new Population(oldPopulation[highestFitness].Path, oldPopulation[highestFitness].Genome, oldPopulation[highestFitness].Rating, false, true);
}
}
// This function uses two fixed points for two-point crossover. For better performance these two points may be made random and/or adjusted over time
// For example, in higher generations they could be moved further to the back
public void twoFixedPointCrossover()
{
int selectionSize = Convert.ToInt32(0.4 * populationSize);
Genome parent1 = new Genome();
Genome parent2 = new Genome();
Genome child1 = new Genome();
Genome child2 = new Genome();
int r;
int fixpoint1 = 4;
int fixpoint2 = 15;
for (int i = selectionSize; i < populationSize; i++)
{
// Randomly selects first parent
r = Variables.getRandomInt(0, selectionSize);
parent1 = oldPopulation[r].Genome;
// Randomly selects second parent
r = Variables.getRandomInt(0, selectionSize);
parent2 = oldPopulation[r].Genome;
for (int j = 0; j < 20; j++)
{
// Case 1: fixpoint 1 to fixpoint 2, fixpoints exclusive
if (j > fixpoint1 && j < fixpoint2)
{
// Iterates over the eight-bit-blocks and adds all bits to the respective parent
for (int k = j * 8; k < j * 8 + 8; k++)
{
child1.Genome1.Set(k, parent1.Genome1.Get(k));
child2.Genome1.Set(k, parent2.Genome1.Get(k));
}
}
// Case 2: Before fixpoint 1 and after fixpoint 2, fixpoints inclusive
else
{
// Iterates over the eight-bit-blocks and adds all bits to the respective parent
for (int k = j * 8; k < j * 8 + 8; k++)
{
child1.Genome1.Set(k, parent2.Genome1.Get(k));
child2.Genome1.Set(k, parent1.Genome1.Get(k));
}
}
}
Genome.genomeToPath(child1);
population[i] = new Population(Variables.path, child1, 0, false, false);
// Counts up since we are adding 2 children per iteration, not just one
i++;
// If we are not yet at maximum (which could happen due to double->int conversion) we add the second child too
if (i < populationSize)
{
Genome.genomeToPath(child2);
population[i] = new Population(Variables.path, child2, 0, false, false);
}
}
}
// This function uses single-bit Uniform Crossover.
public void singleBitCrossover()
{
// Size of current new generation is 40% of old generation (before crossover)
int selectionSize = Convert.ToInt32(0.4 * populationSize);
int r;
Genome parent1 = new Genome();
Genome parent2 = new Genome();
Genome mask = new Genome();
Genome child1 = new Genome();
Genome child2 = new Genome();
// Iterates from selection Size (current maximum of the new population) to population size, the wanted maximum. That means 60% come from crossover
for (int i = selectionSize; i < populationSize; i ++)
{
// Randomly selects first parent
r = Variables.getRandomInt(0,selectionSize);
parent1 = oldPopulation[r].Genome;
// Randomly selects second parent
r = Variables.getRandomInt(0, selectionSize);
parent2 = oldPopulation[r].Genome;
// Crates a random mask genome. This function sucks.
mask = new Genome(true);
// Generates children
for (int j = 0; j < 160; j++)
{
if (mask.Genome1.Get(j))
{
// If mask(i) is 1 then child1 gets the value at that point from parent1, child2 from parent2
child1.Genome1.Set(j, parent1.Genome1.Get(j));
child2.Genome1.Set(j, parent2.Genome1.Get(j));
}
else
{
// If mask(i) is 0 then child1 gets the value at that point from parent2, child2 from parent1
child1.Genome1.Set(j, parent2.Genome1.Get(j));
child2.Genome1.Set(j, parent1.Genome1.Get(j));
}
}
// Adds the genome and its corresponding path to the population at position i. Also sets Selected to false.
Genome.genomeToPath(child1);
population[i] = new Population(Variables.path, child1, 0, false, false);
// Counts up since we are adding 2 children per iteration, not just one
i++;
// If we are not yet at maximum (which could happen due to double->int conversion) we add the second child too
if (i < populationSize)
{
Genome.genomeToPath(child2);
population[i] = new Population(Variables.path, child2, 0, false, false);
}
}
}
// This function is a straight selection which simply seletc the x best members of the population. Members cannot be chosen several times
public void selection()
{
// New Population consists of 40% Selection
int selectionSize = Convert.ToInt32(0.4 * populationSize);
int d;
// Iterates over the new population until selectionSize is met
for (int i = 0; i < selectionSize; i++)
{
// Stores the highest rating
d = 0;
// Iterates over the old population, looking for the highest rating
for (int j = 0; j < populationSize; j++)
{
if (oldPopulation[j].Rating > oldPopulation[d].Rating)
d = j;
}
// Takes the path with the highest rating from old population and sets Selected/Mutated
population[i] = new Population(oldPopulation[d].Path, oldPopulation[d].Genome, oldPopulation[d].Rating, false, true);
// Sets the Rating of the selected path to 0 so it is not selected again
oldPopulation[d].Rating = 0;
}
}
// This selection function uses a wighted (roulette wheel) selection process where members with a high fitness have a higher chance to be chosen.
// Members can be chosen repeatedly
// This function is equivalent to rouletteWheelSelection in functionality but not in implementation. The other function should be prefered unless it produces problems.
public void rouletteWheelSelection2()
{
double totalFitness = 0;
// New Population consists of 40% Selection
int selectionSize = Convert.ToInt32(0.4 * populationSize);
// Calculates toal Fitness of the old population
for (int i = 0; i < populationSize; i++)
{
totalFitness += oldPopulation[i].Rating;
}
// Normalizes all fitness values
for (int i = 0; i < populationSize; i++)
{
oldPopulation[i].Rating = oldPopulation[i].Rating / totalFitness;
}
Population[] tempPopulation = new Population[populationSize];
double j;
int d;
// Sorts oldPopulation into temppOpulation by descending Fitness Rating
for (int l = 0; l < populationSize; l++)
{
j = 0;
d = 0;
// Finds the member in oldPopulation with the highest rating
for (int i = 0; i < populationSize; i++)
{
if (oldPopulation[i].Rating > j)
{
j = oldPopulation[i].Rating;
d = i;
}
}
// oldPopulation[d], which is the member with the highest rating, goes to position i
tempPopulation[l] = new Population(oldPopulation[d].Path, oldPopulation[d].Genome, oldPopulation[d].Rating, false, true);
// Sets the current oldPopulation Rating to 0 so it is not selected again
oldPopulation[d].Rating = 0;
}
double acc = 0;
// Calculates the accumulated rating for every position so every member has it's own Rating + all previous ones as it's rating
for (int i = 0; i < populationSize; i++)
{
acc += tempPopulation[i].Rating;
tempPopulation[i].Rating = acc;
}
double r;
for (int i = 0; i < selectionSize; i++)
{
r = Variables.getRandomNumber(0, 1);
d = 0;
while (tempPopulation[d].Rating <= r)
d++;
population[i] = new Population(tempPopulation[d].Path, tempPopulation[d].Genome, tempPopulation[d].Rating, false, true);
}
}
// This selection function uses a weighted (roulette wheel) selection process where members with a high fitness have a higher chance to be chosen.
// Members can be chosen repeatedly
public void rouletteWheelSelection()
{
// Sums up all ratings to a total
double totalFitness = 0;
double r;
double c;
int j;
// Calculates toal Fitness of the old population
for (int i = 0; i < populationSize; i++)
{
totalFitness += oldPopulation[i].Rating;
}
// New Population consists of 40% Selection
int selectionSize = Convert.ToInt32(0.4 * populationSize);
// Creates <selectionSize> new members for the new population
for (int i = 0; i < selectionSize; i++)
{
// Random Number
r = Variables.getRandomNumber(0, totalFitness);
// Current Sum and iterator are 0
c = 0;
j = 0;
// Sums over oldPopulation until the sum is bigger than the random number
do
{
c += oldPopulation[j].Rating;
j++;
} while (c < r);
// Selects j - 1 (since we did j++ after fulfilling the condition) from the oldPopulation and adds it to the new one at i
population[i] = new Population(oldPopulation[j - 1].Path, oldPopulation[j - 1].Genome, oldPopulation[j - 1].Rating, false, true);
}
}
// This function is only used once (Generation 0) and populates the algorithm with randomly generated paths.
public void initialize()
{
double rating;
// Generates an initial population of size <PopulationSize> along with their fitness
for (int i = 0; i < populationSize; i++)
{
// Generates a random path of length 20 and saves it to the global path
EZPathFollowing.PathPrimitives.generatePath();
// Creates a Simulation for this path
Variables.simulation = new Simulation(Variables.vehicle, Variables.path);
Variables.simulation.run();
// Rates the Path and adds the rating to the ratings List
rating = FitnessFunction.fitness(Variables.simulation.getPath());
// Adds the path, genome and rating to the population
population[i] = new Population(Variables.path, Variables.genome, rating);
// Draws.
glcontrol.Refresh();
}
}