func (isle *EqnIsland) breed() {
// isle.mainLog.Println("Breeding EqnIsland ", isle.id, isle.gen)
NE := isle.numEqns
for e := 0; e < NE; e++ {
// select parents for brood production
rnum1, rnum2, rnum3, rnum4 := isle.rng.Intn(NE), isle.rng.Intn(NE), isle.rng.Intn(NE), isle.rng.Intn(NE)
if rnum3 < rnum1 {
rnum1 = rnum3
}
if rnum4 < rnum2 {
rnum2 = rnum4
}
if isle.parents[rnum1] == nil || isle.parents[rnum2] == nil {
e--
continue
}
p1 := isle.parents[rnum1].Expr()
p2 := isle.parents[rnum2].Expr()
if p1 == nil || p2 == nil {
e--
continue
}
for b := 0; b < isle.eqnBroodSz; b++ {
// production of one child from two parents
var eqnSimp expr.Expr
for {
var new_eqn expr.Expr
// cross equations
if isle.rng.Float64() < isle.crossRate {
new_eqn = CrossEqns_Vanilla(p1, p2, isle.treecfg, isle.rng)
} else {
new_eqn = InjectEqn_SubtreeFair(p1, isle.treecfg, isle.rng)
}
// mutate equation
if isle.rng.Float64() < isle.mutateRate {
MutateEqn_Vanilla(new_eqn, isle.treecfg, isle.rng, nil)
}
// simplify equation
eqnSimp = new_eqn.Simplify(isle.treecfg.SRules)
if eqnSimp == nil || !(eqnSimp.HasVar()) {
continue
}
eqnSimp.CalcExprStats(0)
isle.treecfg.ResetCurr()
isle.treecfg.ResetTemp()
if isle.treecfg.CheckExpr(eqnSimp) {
break
}
}
isle.neqns++
serial := make([]int, 0, 64)
serial = eqnSimp.Serial(serial)
isle.trie.InsertSerial(serial)
isle.brood[e][b] = new(probs.ExprReport)
isle.brood[e][b].SetExpr(eqnSimp)
isle.brood[e][b].SetProcID(isle.id)
isle.brood[e][b].SetIterID(isle.gen)
uid := isle.gen*(isle.numEqns*isle.eqnBroodSz) + e*(isle.eqnBroodSz) + b
isle.brood[e][b].SetUnitID(uid)
}
}
}
