java - apache.commons.text 余弦距离

Question

我正在尝试使用 apache commons 的余弦距离类。但它总是返回 1.0。我错过了什么吗？这是我的代码:

public class ComputeDistance {
    public static void main(String[] args)throws Exception{

        CosineDistance dist = new CosineDistance();
        CharSequence c1 = "example text1";
        CharSequence c2 = "another file";
        System.out.println(dist.apply(c1,c2));
    }
}

Answer 1

CosineDistance 返回 1 - cosineSimilarity(leftVector, rightVector)。 leftVector 和 rightVector 是字符映射和字符序列中的出现次数，因此 cosineSimilarity(leftVector, rightVector) = 0 的结果.您可以更改您的代码以使用您的 char 序列的字符而不是单词:

public class ComputeDistance {
  public static void main(String[] args) throws Exception {

    CosineSimilarity dist = new CosineSimilarity();

    String c1 = "example text1";
    String c2 = "another file";

    Map<CharSequence, Integer> leftVector =
        Arrays.stream(c1.split(""))
        .collect(Collectors.toMap(c -> c, c -> 1, Integer::sum));
    Map<CharSequence, Integer> rightVector =
        Arrays.stream(c2.split(""))
        .collect(Collectors.toMap(c -> c, c -> 1, Integer::sum));

    System.out.println(1 - dist.cosineSimilarity(leftVector,rightVector));

  }
}