// Crossover loop
func (a *Agent) crossoverLoop() {
U := matrix.DenseZero(a.X.Size()) // place for mutated matrix
u := U.Hvec() // we operate on vectorized matrices
n := u.Cols()
costX := a.cost(a.X)
for in := range a.in {
if in.a == nil {
return
}
start, stop := a.cutpoints(in.cr)
// Crossover:
// u = a + f * (b + c) for elements between start and stop
// u = x for remaining elements
if start < stop {
u.Vslice(0, start).Copy(a.x.Vslice(0, start))
perturb(u, in, start, stop)
u.Vslice(stop, n).Copy(a.x.Vslice(stop, n))
} else {
stop++ // because it is modulo (n+1)
perturb(u, in, 0, stop)
u.Vslice(stop, start).Copy(a.x.Vslice(stop, start))
perturb(u, in, start, n)
}
// Selection
if costU := a.cost(U); costU <= costX {
a.X, U = U, a.X
a.x, u = u, a.x
costX = costU
}
// Return new cost
a.out <- costX
}
}
func newAgent(min, width *matrix.Dense, cost Cost) *Agent {
a := new(Agent)
a.X = matrix.DenseZero(min.Size())
a.x = a.X.Hvec() // crossover operates on vectorized matrix
a.in = make(chan args, 1)
a.out = make(chan float64, 1)
a.rnd = rand.New(rand.NewSource(time.Now().UnixNano()))
a.cost = cost
// Place this agent in random place on the initial area
a.x.Rand(0, 1)
a.X.MulBy(width)
a.X.AddTo(min, 1)
// Run crossover loop
go a.crossoverLoop()
return a
}
