TreeMap没有添加

Question

我正在尝试使用它们的适合度对TreeMap进行神经网络排序。这是我的代码。

private double[][] sort(){
    double[][] populationFitnesses = new double[populationNumber][populationSize];
    for (int i = 0; i < populationSize; i++) {
        NeuralNetwork[] networks = allInIndex(i);
        double[] fitnesses = fitness(networks);
        for (int j = 0; j < populationNumber; j++) {
            populationFitnesses[j][i] = fitnesses[j];
        }
    }
    for (int i = 0; i < populationNumber; i++) {

        Map<Double, NeuralNetwork> sorted = new TreeMap<>();

        for (int j = 0; j < populationSize; j++) {
            System.out.println(sorted.size());
            sorted.put(populationFitnesses[i][j], populations[i][j]);
            System.out.println(sorted.size());
        }

        ArrayList<Double> keys = new ArrayList<>(sorted.keySet());

        for (int j = 0; j < populationSize; j++) {
            populations[i][j] = sorted.get(keys.get(j));
            populationFitnesses[i][j] = keys.get(j);
        }
    }
    return populationFitnesses;
}

出于某种原因，当我调用TreeMap.put时，似乎没有向它添加任何内容。有人可以解释一下如何解决这个问题吗？ 感谢。