func (p *Particle) Move(gbest *optim.Point, vmax []float64, inertia, social, cognition float64) {
// update velocity
for i, currv := range p.Vel {
// random numbers r1 and r2 MUST go inside this loop and be generated
// uniquely for each dimension of p's velocity.
r1 := optim.RandFloat()
r2 := optim.RandFloat()
p.Vel[i] = inertia*currv +
cognition*r1*(p.Best.Pos[i]-p.Pos[i]) +
social*r2*(gbest.Pos[i]-p.Pos[i])
if math.Abs(p.Vel[i]) > vmax[i] {
p.Vel[i] = math.Copysign(vmax[i], p.Vel[i])
}
}
// update position
for i := range p.Pos {
p.Pos[i] += p.Vel[i]
}
p.Val = math.Inf(1)
}
// NewPopulation initializes a population of particles using the given points
// and generates velocities for each dimension i initialized to uniform random
// values between minv[i] and maxv[i]. github.com/rwcarlsen/optim.Rand is
// used for random numbers.
func NewPopulation(points []*optim.Point, vmax []float64) Population {
pop := make(Population, len(points))
for i, p := range points {
pop[i] = &Particle{
Id: i,
Point: p,
Best: p.Clone(),
Vel: make([]float64, len(vmax)),
}
for j, v := range vmax {
pop[i].Vel[j] = v * (1 - 2*optim.RandFloat())
}
}
return pop
}