我有這樣的代碼:Java錯誤:「比較方法違反其通用合同!」
package org.optimization.geneticAlgorithm;
import org.optimization.geneticAlgorithm.selection.Pair;
public abstract class Chromosome implements Comparable<Chromosome> {
public abstract double fitness();
public abstract Pair<Chromosome> crossover(Chromosome parent);
public abstract void mutation();
public int compareTo(Chromosome o) {
int rv = 0;
if (this.fitness() > o.fitness()) {
rv = -1;
} else if (this.fitness() < o.fitness()) {
rv = 1;
}
return rv;
}
}
每次我運行此代碼時我得到這個錯誤:
Exception in thread "main" java.lang.IllegalArgumentException: Comparison method violates its general contract!
at java.util.ComparableTimSort.mergeHi(ComparableTimSort.java:835)
at java.util.ComparableTimSort.mergeAt(ComparableTimSort.java:453)
at java.util.ComparableTimSort.mergeCollapse(ComparableTimSort.java:376)
at java.util.ComparableTimSort.sort(ComparableTimSort.java:182)
at java.util.ComparableTimSort.sort(ComparableTimSort.java:146)
at java.util.Arrays.sort(Arrays.java:472)
at java.util.Collections.sort(Collections.java:155)
at org.optimization.geneticAlgorithm.GeneticAlgorithm.nextGeneration(GeneticAlgorithm.java:74)
at org.optimization.geneticAlgorithm.GeneticAlgorithm.execute(GeneticAlgorithm.java:40)
at test.newData.InferenceModel.main(InferenceModel.java:134)
我用OpenJDK7u3和我回到0時,對象是相等的。有人可以向我解釋這個錯誤嗎?
無論在同一個對象上調用多少次,你的'fitness()'方法總是返回相同的值嗎?你可以與我們分享實施嗎? – 2012-02-27 17:27:33