org.opt4j.operator (Palladio Core)

Interface Summary
Interface	Description
AbstractGenericOperator.OperatorPredicate	The `AbstractGenericOperator.OperatorPredicate` interface.
GenericOperator<O extends Operator<?>>	The `GenericOperator` is an interface for generic operators.

Class Summary
Class	Description
AbstractGenericOperator<O extends Operator<?>,Q extends Operator<?>>	Superclass for `GenericOperator`s.
AbstractGenericOperator.OperatorClassPredicate	The `AbstractGenericOperator.OperatorClassPredicate` returns `true` for a given specific class.
AbstractGenericOperator.OperatorVoidPredicate	The `AbstractGenericOperator.OperatorVoidPredicate` interface is used as marker for `Operator`s for which the predicate is not explicitly defined.
OperatorModule<P extends Operator>	Module class for an `Operator`.
Parameters	The `Parameters` is a class for the identification of types/classes of a generic parameter.

Annotation Types Summary
Annotation Type Description

Apply
The Apply annotation is used for each Operator to indicate on which Genotype it is applied.

Annotation Types Summary
Annotation Type	Description
Apply	The `Apply` annotation is used for each `Operator` to indicate on which `Genotype` it is applied.

Package org.opt4j.operator Description

Provides the classes for general (generic) operators.

The Genotype objects are changed within the optimization process in order to find better solutions. The variation is performed by the Operator classes. The framework already contains several operators:

Algebra - Vector-based operator with terms (restricted to DoubleGenotype)
Copy - Copy operator
Crossover - Crossover operator that always creates two offspring from two parents
Diversity - Diversity operator that determines the differences between two genotypes
Mutate - Mutate operator that changes one genotype
Neighbor - Neighbor operator that changes one genotype

Each Operator is parameterized with the corresponding target Genotype. Adding custom operators, e.g., a new Crossover operator for the DoubleGenotype, is quite simple. The new operator has to be extended from Crossover with the parameter DoubleGenotype or alternatively directly from the CrossoverDouble. The corresponding crossover method has to be implemented. Finally, the operator has to be added with the OperatorModule.addOperator(Class) method. Therefore, you can extend a custom module from CrossoverModule.

The appropriate operator is determined at runtime by the framework by checking the parameter of the operator. Alternatively, the Apply annotation can be used to specify a different target Genotype class.

Creating completely new operators is done by extending the Operator interface to the new operator with the specific method. The new operator implementation can be bound directly within a module in the org.opt4j.operator.OperatorModule#configure(com.google.inject.Binder) method by bind(CustomOperator.class).to(CustomOperatorImplmenentation.class). Note that this operator will only handle exactly its target Genotype classes.

A new generic operator should be instantiated from the AbstractGenericOperator. See the existing generic operators.

Integration of a Custom Operator

To add new operators, two tasks have to be performed:

The implementation of the custom operator
The binding of the operator

In the following, a custom Crossover operator for the BooleanGenotype shall be implemented that performs a bitwise or for one offspring and a bitwise and for the other offspring.

 
 public class MyOperator implements Crossover<Boolean> {
 	public Pair<BooleanGenotype> crossover(BooleanGenotype parent1, BooleanGenotype parent2) {
 		BooleanGenotype g1 = parent1.newInstance();
 		BooleanGenotype g2 = parent1.newInstance();
 
 		for (int i = 0; i < parent1.size(); i++) {
 			g1.add(i, parent1.get(i) || parent2.get(i));
 			g2.add(i, parent1.get(i) && parent2.get(i));
 		}
 
 		return new Pair<BooleanGenotype>(g1, g2);
 	}
 }

To tell the framework to use this operator, implement a CrossoverModule and add your custom operator.

 
 public class MyOperatorModule extends CrossoverModule {
 	protected void config() {
 		addOperator(MyOperator.class);
 	}
 }