Accord.NET 扔 "Index was outside the bounds of the array"

Question

我从 Accord.NET 开始研究 KNN，当我需要测试模型时出于某种原因遇到了这个错误。

但是这个错误消息根本没有帮助(Index was outside the bounds of the array)，因为这个错误发生在库本身。

带有随机数据的简单代码：

        using Accord.MachineLearning;

        double[][] inputs =
        {
            new double[] { 16, 2 ,0}, new double[] { 4, 5 ,1},
            new double[] { 16, 2 ,0}, new double[] { 4, 5 ,1},
            new double[] { 16, 2 ,0}, new double[] { 4, 5 ,1},
            new double[] { 16, 2 ,0}, new double[] { 4, 5 ,1},
            new double[] { 16, 2 ,0}, new double[] { 4, 5 ,1},
            new double[] { 16, 2 ,0}, new double[] { 4, 5 ,1},
            new double[] { 16, 2 ,0}, new double[] { 4, 5 ,1},
            new double[] { 16, 2 ,0}, new double[] { 4, 5 ,1},
            new double[] { 16, 2 ,0}, new double[] { 4, 5 ,1},
            new double[] { 16, 2 ,0}, new double[] { 4, 5 ,1},
            new double[] { 16, 2 ,0}, new double[] { 4, 5 ,1},
            new double[] { 16, 2 ,0}, new double[] { 4, 15 ,1},
        };

        int[] outputs =
        {
            0, 1, 0, 1, 0, 1,
            0, 1, 0, 1, 0, 1,
            0, 1, 0, 1, 0, 1,
            0, 1, 0, 1, 0, 9
        };

        var knn = new KNearestNeighbors(k: 15);
        knn.Learn(inputs, outputs);

        //test
        var t = new double[] { 16, 2, 0 };
        int answer = knn.Decide(t);

这里是个例外：

但我找到了解决方法，并在下面与您分享解决方案：

Answer 1

在实施这个简单示例很多天后，我发现输出数组应该具有连续的范围值（编码：0,1,2,3,....）。所以这里 9 就是为什么这个错误发生在这里

    int[] outputs =
    {
        0, 1, 0, 1, 0, 1,
        0, 1, 0, 1, 0, 1,
        0, 1, 0, 1, 0, 1,
        0, 1, 0, 1, 0, 2
    };

Accord.NET 扔 "Index was outside the bounds of the array"

Accord.NET throw "Index was outside the bounds of the array"

c#

accord.net