public virtual double CalculateVelocityUpdate(Particle gbest, int i)
{
PSONS.Settings settings = Configuration;
Parameter parameter = Parameters[i];
double r1 = State.Random.Range(0, 1);
double r2 = State.Random.Range(0, 1);
double pg = 0;
double pl = 0;
double momentum = 0;
// Global best difference
if (gbest != null && (State.VelocityUpdateComponents & State.VelocityUpdateType.DisableGlobal) == 0)
{
pg = gbest.Parameters[i].Value - parameter.Value;
}
// Local best difference
if (d_personalBest != null && (int)(State.VelocityUpdateComponents & State.VelocityUpdateType.DisableLocal) == 0)
{
pl = d_personalBest.Parameters[i].Value - parameter.Value;
}
if ((int)(State.VelocityUpdateComponents & State.VelocityUpdateType.DisableMomentum) == 0)
{
momentum = d_velocity[i];
}
// PSO velocity update rule
return(settings.Constriction * (momentum +
r1 * settings.CognitiveFactor * pl +
r2 * settings.SocialFactor * pg));
}
private void LimitVelocity(int idx)
{
PSONS.Settings settings = Configuration;
double maxvel = settings.MaxVelocity * (Parameters[idx].Boundary.Max - Parameters[idx].Boundary.Min);
if (maxvel > 0 && System.Math.Abs(d_velocity[idx]) > maxvel)
{
d_velocity[idx] = d_velocity[idx] > 0 ? maxvel : -maxvel;
}
}