87 lines
2.0 KiB
Go
87 lines
2.0 KiB
Go
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// Copyright 2023 wanderer <a_mirre at utb dot cz>
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// SPDX-License-Identifier: GPL-3.0-or-later
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package ga
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// mutation strategies iota consts.
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const (
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best1Exp = iota
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rand1Exp
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randtoBest1Exp
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)
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// mutations.
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func clipVals(mutant []float64) []float64 {
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for i := range mutant {
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switch {
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case mutant[i] < 0:
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mutant[i] = 0
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case mutant[i] > 1:
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mutant[i] = 1
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}
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}
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return mutant
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}
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// mutate performs the mutation of choice and returns the mutant.
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func mutate(mutStrategy int, currentIndividual PopulationIndividual, genChamp ChampionIndividual, pop *Population, donors ...PopulationIndividual) []float64 {
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var mutant []float64
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dim := pop.Dimen
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curF := pop.CurF
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champ := genChamp.X
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curX := currentIndividual.CurX
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switch mutStrategy {
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case best1Exp:
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mutant = mutBest1Exp(dim, curF, champ, donors...)
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case rand1Exp:
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mutant = mutRand1Exp(dim, curF, donors...)
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case randtoBest1Exp:
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mutant = mutRandtoBest1Exp(dim, curF, champ, curX, donors...)
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default:
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return nil
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}
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// return mutant with values clipped to <0;1>.
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return clipVals(mutant)
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}
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func mutBest1Exp(dim int, curF float64, champ []float64, donors ...PopulationIndividual) []float64 {
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mutant := make([]float64, dim)
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for i := 0; i < dim; i++ {
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// mutant[i] = curF + (bestF*(donors[1].CurX[i]) - donors[2].CurX[i])
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mutant[i] = champ[i] + (curF*(donors[1].CurX[i]) - donors[2].CurX[i])
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}
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return mutant
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}
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func mutRand1Exp(dim int, curF float64, donors ...PopulationIndividual) []float64 {
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mutant := make([]float64, dim)
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for i := 0; i < dim; i++ {
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// tmp[n] = popold[r1][n] + curF*(popold[r2][n]-popold[r3][n]);
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mutant[i] = donors[0].CurX[i] + curF*(donors[1].CurX[i]-donors[2].CurX[i])
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}
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return mutant
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}
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func mutRandtoBest1Exp(dim int, curF float64, champ, currentIndividual []float64, donors ...PopulationIndividual) []float64 {
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mutant := make([]float64, dim)
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for i := 0; i < dim; i++ {
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mutant[i] += currentIndividual[i] + (curF*champ[i] - currentIndividual[i]) + (curF * (donors[0].CurX[i] - donors[1].CurX[i]))
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}
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return mutant
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}
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