Customizing algorithms

[emelmdn]

Last status is in the comment below. Thanks!

[emelmdn]

Hello,

I initialized my population manually and it improved the results in NSGA2 and GA very well. However, NSGA3 is still producing similar results as the randomly initialized population version. I am not sure, the NSGA3 manual run code that I wrote below is correct. Do you think there is something wrong here with the NSGA3 part?

PS: Please ignore the code in the message above.

Many thanks and regards,
Emel

		// construct the algorithm
		if (algorithmName == "NSGA2"){	
			System.out.println("- NSGA2 is run!");
			 algorithm = new NSGAII(problem,new NondominatedSortingPopulation(), null, selection, variation, initialization); //null is for no archive
		
		}else if (algorithmName == "GA"){	
			AggregateObjectiveComparator comparator = new LinearDominanceComparator(new double[] { 1.0 }); // default value taken from StandardAlgorithms.f90 newGeneticAlgorithm
			selection = new TournamentSelection(2, comparator);
			algorithm = new org.moeaframework.algorithm.single.GeneticAlgorithm(problem, comparator, initialization, selection, variation);
		
		} 
		
		
		else if (algorithmName == "NSGA3"){
			
			int divisionsOuter = 4;
			int divisionsInner = 0;
			TypedProperties properties = new TypedProperties();
			
			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 = 4;
				divisionsInner = 1;
			} 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;
			}

					
			ReferencePointNondominatedSortingPopulation population = new ReferencePointNondominatedSortingPopulation(
					problem.getNumberOfObjectives(), divisionsOuter, divisionsInner);

			Selection selectionNSGA3 = null;
			
			if (problem.getNumberOfConstraints() == 0) {
				selectionNSGA3 = new Selection() {
		
					@Override
					public Solution[] select(int arity, org.moeaframework.core.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 {
				selectionNSGA3 = new TournamentSelection(2, new ChainedComparator(
						new AggregateConstraintComparator(),
						new DominanceComparator() {

							@Override
							public int compare(Solution solution1, Solution solution2) {
								return PRNG.nextBoolean() ? -1 : 1;
							}
							
						}));
			}
			
	
			properties.setBoolean("sbx.swap", false);
			properties.setDouble("sbx.distributionIndex", 30.0);
			properties.setDouble("pm.distributionIndex", 20.0);
		
			Variation variationNSGA3 = OperatorFactory.getInstance().getVariation(null, 
					properties, problem);

			algorithm =  new NSGAII(problem, population, null, selectionNSGA3, variationNSGA3, initialization);

		} 

[emelmdn]

Dear David,

Do you have any update for my question here? It is getting urgent for my work and I appreciate your help here.

Many thanks and regards,
Emel

[dhadka]

The code looks OK.

If you compare the solutions you get from the different algorithms, are they mostly non-dominated with respect to each other? You can use the ReferenceSetMerger class to do this:

ReferenceSetMerger merger = new ReferenceSetMerger();
merger.add("NSGA2", nsga2.getResult());
merger.add("NSGA3", nsga3.getResult());

for (String source : merger.getSources()) {
    System.out.println(source + " " + merger.getContributionFrom(source) + " / " + merger.getPopulation(source));
}

[emelmdn]

Dear David,

Thank you very much for your quick reply. Please find below its output:

duplicate solution found
NSGA2 org.moeaframework.core.NondominatedPopulation@7a81197d / org.moeaframework.core.NondominatedPopulation@5ca881b5
NSGA3 org.moeaframework.core.NondominatedPopulation@24d46ca6 / org.moeaframework.core.NondominatedPopulation@4517d9a3
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found

[dhadka]

My bad, can you please add .size() as shown below:

for (String source : merger.getSources()) {
    System.out.println(source + " " + merger.getContributionFrom(source).size() + " / " + merger.getPopulation(source).size());
}

[emelmdn]

Thanks a lot for your reply. Here is the result:

duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
duplicate solution found
NSGA2 30 / 30
NSGA3 25 / 50

[emelmdn]

Hello again David,

Did you have a chance to check my reply here?

Thanks and regards,
Emel

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