public static Velocity Initialize(Position pos, SwarmSize swarmSize)
{
int d;
var vel = new Velocity(Constants.DMax) {Size = pos.size};
// Half-diff 0.5*(alea-x)
for (d = 0; d < vel.Size; d++)
{
vel.V[d] = (Alea.NextDouble(swarmSize.min[d], swarmSize.max[d]) - pos.x[d]) / 2;
}
return vel;
}
public XV()
{
x=new Position(Constants.DMax);
v=new Velocity(Constants.DMax);
}
// ===========================================================
static double normL(Velocity v, double L)
{
// L-norm of a vector
int d;
double n;
n = 0;
for (d = 0; d < v.Size; d++)
n = n + Math.Pow(Math.Abs(v.V[d]), L);
n = Math.Pow(n, 1 / L);
return n;
}
static XV move(Result R, int s, int g, IProblem pb,
Parameters parameters)
{
double c1, c2;
int d;
Velocity GX = new Velocity(Constants.DMax);
Velocity PX = new Velocity(Constants.DMax);
XV xv = new XV();
double w;
xv.x.size = pb.SwarmSize.D;
xv.v.Size = pb.SwarmSize.D;
PX.Size = pb.SwarmSize.D;
GX.Size = pb.SwarmSize.D;
w = parameters.w;
c1 = parameters.c1;
c2 = parameters.c2;
// Update the velocity (Exploration tendency)
for (d = 0; d < pb.SwarmSize.D; d++)
{
xv.v.V[d] = w * R.SW.V[s].V[d];
}
// --------------------------------------------------------NORMAL PSO STRATEGY
// Prepare Exploitation tendency
for (d = 0; d < pb.SwarmSize.D; d++) // p-x
{
PX.V[d] = R.SW.P[s].x[d] - R.SW.X[s].x[d];
}
if (g != s)
{
for (d = 0; d < pb.SwarmSize.D; d++) // g-x
{
GX.V[d] = R.SW.P[g].x[d] - R.SW.X[s].x[d];
}
}
// Complete the velocity
for (d = 0; d < pb.SwarmSize.D; d++)
{
xv.v.V[d] = xv.v.V[d] + Alea.NextDouble(0, c1) * PX.V[d];
}
if (g != s) // If the best neighbour is not the particle itself
{
for (d = 0; d < pb.SwarmSize.D; d++)
{
xv.v.V[d] = xv.v.V[d] + Alea.NextDouble(0, c2) * GX.V[d];
}
}
// Update the position
for (d = 0; d < pb.SwarmSize.D; d++)
{
xv.x.x[d] = R.SW.X[s].x[d] + xv.v.V[d];
}
// NOTE that the position is not yet evaluated
return xv;
}
