public Part1a(int swarm_size, int maxIterations, double c1, double c2, char type)
{
// store swarm size, iterations, c1, c2, part4
this.swarm_size = swarm_size;
this.maxIterations = maxIterations;
this.c1 = c1;
this.c2 = c2;
this.type = type;
r = new Random();
// Weighted Velocity
this.wmax = 1.0; // influence of current velocity
this.wmin = 0.0; // on velocity update fxn
// Vmax
vmax = 5.0; // bound on particle velocity
swarm = new LinkedList<Particle1a>();
for (int i = 0; i < this.swarm_size; i++)
{
Particle1a p = new Particle1a();
swarm.AddLast(p);
p.SetPBest(p);
}
}
//TODO
public Particle1a Clone()
{
Particle1a p = new Particle1a();
this.x.CopyTo(p.x, 0);
this.velocity.CopyTo(p.velocity, 0);
p.setZ(this.z);
p.SetFitness(this.fitness);
return p;
}
public Particle1a()
{
this.r = new Random();
this.x[0] = (this.r.NextDouble() * 6) - 3; //Generate a random X [-3,+3]
this.x[1] = (this.r.NextDouble() * 4) - 2; //Generate a random Y [-2,+2]
this.velocity[0] = 0;
this.velocity[1] = 0;
this.pbest = null;
this.lbest = null;
this.calculateFitness();
}
public void SetPBest(Particle1a pbest)
{
this.pbest = pbest;
}
public void SetLBest(Particle1a lbest)
{
this.lbest = lbest;
}
public Particle1a RunPSO()
{
int iteration = 0;
gbest = swarm.ElementAt(0); // first particle
//while (iteration < this.maxIterations)
do
{
foreach (Particle1a p in swarm)
{
p.calculateFitness(); //recalculate fitness
if (p.GetFitness() < p.GetPBest().GetFitness()) //update personal best
{
p.SetPBest(p.Clone());
}
}
CalculateLocalBest();
// calculate gbest
foreach (Particle1a p in swarm)
{
if (p.GetFitness() < gbest.GetFitness())
{
gbest = p.Clone();
}
}
switch (type)
{
case 'x': // normal PSO - global best
CalculateVelocity();
break;
case 'y': // normal PSO - local best
CalculateVelocityLBest();
break;
case 'a': // Weighted Inertia - gbest
// Console.WriteLine("Using Weighted Inertia Velocity Update with Global Best");
// calculate weighting function
/* w = wMax-[(wMax-wMin) x iter]/maxIter
where wMax= initial weight,
wMin = final weight,
maxIter = maximum iteration number,
iter = current iteration number. */
double w = (double)(wmax - (((wmax - wmin) * (double)iteration) / (double)maxIterations));
// update velocity and position
CalculateWeightedVelocityGBest(w);
break;
case 'b': // Vmax - Gbest
//Console.WriteLine("Using Vmax Velocity Update with Global Best");
CalculateVmaxVelocityGBest();
break;
case 'c': // Constriction factor - gbest
// Console.WriteLine("Using Constriction Factor Velocity Update with Global Best");
// update velocity and position
CalculateConstrictionFactorVelocityGBest();
break;
case 'd': // Weighted Inertia - lbest
// Console.WriteLine("Using Weighted Inertia Velocity Update with Local Best");
w = (double)(wmax - (((wmax - wmin) * (double)iteration) / (double)maxIterations));
// update velocity and position
CalculateWeightedVelocityLBest(w);
break;
case 'e': // Vmax - lbest
//Console.WriteLine("Using Vmax Velocity Update with Local Best");
CalculateVmaxVelocityLBest();
break;
case 'f': // Constriction factor - lbest
// update velocity and position
CalculateConstrictionFactorVelocityLBest();
break;
case 'g': // change random r - seed?
int factor = maxIterations / 10;
int remainder = 0;
Math.DivRem(iteration, factor, out remainder);
if (remainder == 0) // count is divisible by factor
{
r = new Random(iteration);
}
CalculateVelocity(); // use normal velocity
break;
default:
CalculateVelocity(); //normal velocity
break;
}
iteration++;
// gbest.Print(count);
// print solutions at 0, 10, 100, 1000, 10000 iterations
if (iteration == 0 || iteration == 10 ||
iteration == 100 || iteration == 1000 || iteration == 10000)
{
// print gbest
Console.WriteLine("\n\nIteration Best @ iteration #"+ iteration +" : ");
Console.WriteLine(gbest.toString());
}
} while (iteration < this.maxIterations && gbest.GetFitness() > -1.0316);
return gbest;
}
// OPTION B: Vmax Velocity w/ global best
void CalculateVmaxVelocityGBest()
{
/* vnew = vold + c1*rand1*(pbest - xfitness) + c2*rand2*(gbest - xfitness)
xfitness' = xfitness + vnew
if currentv > vmax then
currentv = vmax
else if currentv < -vmax then
currentv = -vmax
end */
if (gbest == null) // if no gbest
{
gbest = swarm.ElementAt(0); //set gbest as first particle 0
}
foreach (Particle1a p in swarm)
{
for (int i = 0; i < 2; i++)
{
double vnew = p.GetVelocity(i) + (c1 * r.NextDouble() * (p.GetPBest().GetX(i) - p.GetX(i)))
+ (c2 * r.NextDouble() * (gbest.GetX(i) - p.GetX(i)));
// ensure vnew is within vmax bound
if (vnew > vmax)
{
vnew = vmax;
}
else if (vnew < ((-1) * vnew))
{
vnew = (-1) * vmax;
}
//store velocity
p.SetVelocity(i, vnew);
// update position
double xnew = p.GetX(i) + vnew;
p.SetX(i, xnew);
}
}
return;
}
