private Gene mutateLink(NEATLinkGene mutatee) {
double perturbRandVal = perturbRand.nextDouble();
double disableRandVal = disableRand.nextDouble();
double newWeight;
NEATLinkGene mutated = mutatee;
if (perturbRandVal < this.pPerturb) {
if (this.pWeightReplaced > perturbRand.nextDouble()) {
newWeight = MathUtils.nextPlusMinusOne();
} else {
newWeight = mutatee.getWeight() + MathUtils.nextClampedDouble(-perturb, perturb);
}
// newWeight = mutatee.getWeight() + MathUtils.nextClampedDouble(-PERTURB, PERTURB);
mutated =
new NEATLinkGene(
mutatee.getInnovationNumber(),
mutatee.isEnabled(),
mutatee.getFromId(),
mutatee.getToId(),
newWeight);
}
if (disableRandVal < this.pToggle) {
if (this.featureSelection) {
mutated.setEnabled(!mutated.isEnabled());
}
}
return (mutated);
}
private void mutateAddNode(Chromosome mutatee) {
double nodeRandVal = nodeRand.nextDouble();
ArrayList nodeLinks;
// ArrayList nodes;
NEATLinkGene chosen;
NEATNodeGene newNode;
NEATLinkGene newLower;
NEATLinkGene newUpper;
int newChromoIdx = mutatee.genes().length;
// Gene[] newChromo = new Gene[newChromoIdx + 3];
Gene[] newChromo = new Gene[newChromoIdx + 2];
System.arraycopy(mutatee.genes(), 0, newChromo, 0, newChromoIdx);
int linkIdx;
if (nodeRandVal < this.pAddNode) {
// add a node on an existing enabled connection
// find an existing connection to intercept
nodeLinks = this.candidateLinks(mutatee.genes(), true);
if (nodeLinks.size() > 0) {
// ensure there is a link to split
linkIdx = nodeRand.nextInt(nodeLinks.size());
chosen = (NEATLinkGene) nodeLinks.get(linkIdx);
// disable old link
chosen.setEnabled(false);
newNode = InnovationDatabase.database().submitNodeInnovation(chosen);
// newNode.setBias(MathUtils.nextPlusMinusOne());
newLower =
InnovationDatabase.database().submitLinkInnovation(chosen.getFromId(), newNode.id());
newUpper =
InnovationDatabase.database().submitLinkInnovation(newNode.id(), chosen.getToId());
// set weights according to Stanley et al's NEAT document
newLower.setWeight(1);
newUpper.setWeight(chosen.getWeight());
// now update the chromosome with new node and 2 new links
newChromo[this.findChosenIndex(chosen, mutatee)] = newNode;
// newChromo[newChromoIdx++] = newNode;
newChromo[newChromoIdx++] = newLower;
newChromo[newChromoIdx] = newUpper;
mutatee.updateChromosome(newChromo);
}
}
}