Module io.jenetics.base
Package io.jenetics.engine
Class FitnessNullifier<G extends Gene<?,G>,C extends Comparable<? super C>>
java.lang.Object
io.jenetics.engine.FitnessNullifier<G,C>
- Type Parameters:
G
- the gene typeC
- the fitness result type
- All Implemented Interfaces:
EvolutionInterceptor<G,
C>
public final class FitnessNullifier<G extends Gene<?,G>,C extends Comparable<? super C>>
extends Object
implements EvolutionInterceptor<G,C>
This class allows forcing a reevaluation of the fitness function. A
reevaluation is necessary if the fitness function changes. Changing the
fitness function is not the usual use case but is necessary for some
problems, like symbolic regression analyses with changing input data (time
series).
final var nullifier = new FitnessNullifier<DoubleGene, Double>();
final Engine<DoubleGene, Double> engine = Engine.builder(problem)
.interceptor(nullifier)
.build();
// Invalidate fitness value by calling the 'nullifyFitness' method,
// possible from a different thread. This forces the reevaluation of
// the fitness values at the start of the next generation.
nullifier.nullifyFitness();
- Since:
- 6.0
- Version:
- 6.0
- See Also:
- Implementation Note:
- This interceptor is thread-safe and can be used from different threads. No additional synchronization is necessary.
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionbefore
(EvolutionStart<G, C> start) Nullifies the fitness values of the population, if requested.boolean
Triggers the nullification of the fitness values of the population for the next generation.Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface io.jenetics.engine.EvolutionInterceptor
after, compose
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Constructor Details
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FitnessNullifier
public FitnessNullifier()
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Method Details
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before
Nullifies the fitness values of the population, if requested. The nullification flag is reset after this call. Two consecutive calls of this method might lead to two different results.- Specified by:
before
in interfaceEvolutionInterceptor<G extends Gene<?,
G>, C extends Comparable<? super C>> - Parameters:
start
- the evolution start object- Returns:
- the evolution start object with the nullified fitness values, if the nullification has been triggered
- See Also:
-
nullifyFitness
Triggers the nullification of the fitness values of the population for the next generation.- Returns:
true
if the nullification request will trigger a new fitness nullification. @{code false} if the fitness nullification has been requested before, without actually executing it.- See Also:
-