Creating an instance of NSGA-III

NSGAIII-Example.java

	private Algorithm newNSGAIII(TypedProperties properties, Problem problem) {
		int divisionsOuter = 4;
		int divisionsInner = 0;
		
		if (properties.contains("divisionsOuter") && properties.contains("divisionsInner")) {
			divisionsOuter = (int)properties.getDouble("divisionsOuter", 4);
			divisionsInner = (int)properties.getDouble("divisionsInner", 0);
		} else if (properties.contains("divisions")){
			divisionsOuter = (int)properties.getDouble("divisions", 4);
		} else if (problem.getNumberOfObjectives() == 1) {
			divisionsOuter = 100;
		} else if (problem.getNumberOfObjectives() == 2) {
			divisionsOuter = 99;
		} else if (problem.getNumberOfObjectives() == 3) {
			divisionsOuter = 12;
		} else if (problem.getNumberOfObjectives() == 4) {
			divisionsOuter = 8;
		} else if (problem.getNumberOfObjectives() == 5) {
			divisionsOuter = 6;
		} else if (problem.getNumberOfObjectives() == 6) {
			divisionsOuter = 5;
		} else if (problem.getNumberOfObjectives() == 7) {
			divisionsOuter = 3;
			divisionsInner = 2;
		} else if (problem.getNumberOfObjectives() == 8) {
			divisionsOuter = 3;
			divisionsInner = 2;
		} else if (problem.getNumberOfObjectives() == 9) {
			divisionsOuter = 3;
			divisionsInner = 2;
		} else if (problem.getNumberOfObjectives() == 10) {
			divisionsOuter = 3;
			divisionsInner = 2;
		} else {
			divisionsOuter = 2;
			divisionsInner = 1;
		}
		
		int populationSize;
		
		if (properties.contains("populationSize")) {
			populationSize = (int)properties.getDouble("populationSize", 100);
		} else {
			// compute number of reference points
			populationSize = (int)(CombinatoricsUtils.binomialCoefficient(problem.getNumberOfObjectives() + divisionsOuter - 1, divisionsOuter) +
					(divisionsInner == 0 ? 0 : CombinatoricsUtils.binomialCoefficient(problem.getNumberOfObjectives() + divisionsInner - 1, divisionsInner)));

			// round up to a multiple of 4
			populationSize = (int)Math.ceil(populationSize / 4d) * 4;
		}
		
		Initialization initialization = new RandomInitialization(problem,
				populationSize);
		
		ReferencePointNondominatedSortingPopulation population = new ReferencePointNondominatedSortingPopulation(
				problem.getNumberOfObjectives(), divisionsOuter, divisionsInner);

		Selection selection = null;
		
		if (problem.getNumberOfConstraints() == 0) {
			selection = new Selection() {
	
				@Override
				public Solution[] select(int arity, Population population) {
					Solution[] result = new Solution[arity];
					
					for (int i = 0; i < arity; i++) {
						result[i] = population.get(PRNG.nextInt(population.size()));
					}
					
					return result;
				}
				
			};
		} else {
			selection = new TournamentSelection(2, new ChainedComparator(
					new AggregateConstraintComparator(),
					new DominanceComparator() {

						@Override
						public int compare(Solution solution1, Solution solution2) {
							return PRNG.nextBoolean() ? -1 : 1;
						}
						
					}));
		}

		Variation variation = OperatorFactory.getInstance().getVariation(null, 
				properties, problem);

		return new NSGAII(problem, population, null, selection, variation,
				initialization);
	}