arbitrer.go

package evoli

// ErrArbitration - must provide one or more individuals
var ErrArbitration = "ErrArbitration - must provide one or more individuals"

// Arbitrer - elect the winner between multiple participants
type Arbitrer interface {
	Abritrate(participants ...Individual) (winner Individual, loosers []Individual)
}

func checkArbitrersParams(participants []Individual) {
	if len(participants) < 1 {
		panic(ErrArbitration)
	}
}

type selecterBasedArbitrer struct {
	Selecter
}

func (a selecterBasedArbitrer) Abritrate(participants ...Individual) (winner Individual, loosers []Individual) {
	checkArbitrersParams(participants)
	pop := NewPopulation(len(participants))
	pop.Add(participants...)
	selected, deads, _ := a.Select(pop, 1)
	var deadsSlice []Individual
	if deads != nil {
		deadsSlice = deads.Slice()
	}
	defer selected.Close()
	return selected.Get(0), deadsSlice
}

// NewProportionalToFitnessArbitrer -  based on fitness value
func NewProportionalToFitnessArbitrer() Arbitrer {
	return selecterBasedArbitrer{NewProportionalToFitnessSelecter()}
}

// NewProportionalToRankArbitrer - based on rank
func NewProportionalToRankArbitrer() Arbitrer {
	return selecterBasedArbitrer{NewProportionalToRankSelecter()}
}

// NewStochasticUniversalSamplingArbitrer -  based on fitness value
func NewStochasticUniversalSamplingArbitrer() Arbitrer {
	return selecterBasedArbitrer{NewStochasticUniversalSamplingSelecter()}
}

// NewTournamentArbitrer -  High Fitness increase chances to come out vcitorious from a duel
func NewTournamentArbitrer(p float64) Arbitrer {
	return selecterBasedArbitrer{NewTournamentSelecter(p)}
}

// NewTruncationArbitrer - take the highest fitness
func NewTruncationArbitrer() Arbitrer {
	return selecterBasedArbitrer{NewTruncationSelecter()}
}

// NewRandomArbitrer - choose randomly
func NewRandomArbitrer() Arbitrer {
	return selecterBasedArbitrer{NewRandomSelecter()}
}