@Override
	public DoubleGene mean(final DoubleGene that) {
		// (a - a/2) + b/2
		// https://hal.archives-ouvertes.fr/hal-00576641v1/document
		return of((_allele - _allele/2.0) + that._allele/2.0, _min, _max);
	}
Return the range of {@code this} gene.

@since 4.4

@return the range of {@code this} gene
jenetics/src/main/java/io/jenetics/DoubleGene.java