Question

我想计算文档集合的平均文档长度，每个文档有3个不同的字段（filed1，field2，field3）

当只有一个字段存在时，这是计算平均长度的程序。

private byte[] normsDocLengthArr = null;
private double avgDocLength;
normsDocLengthArr = indexReader.norms("filed1");
            //norms-Returns the byte-encoded normalization factor for the named field of every document.
double sumLength = 0;

for (int i = 0; i < normsDocLengthArr.length; i++) {
    double encodeLength = DefaultSimilarity.decodeNorm(normsDocLengthArr[i]);
    //decodeNorm -Decodes a normalization factor stored in an index.
    double length = 1 / (encodeLength * encodeLength);

    sumLength += length;

}

this.avgDocLength = sumLength / normsDocLengthArr.length;

这是我为所有3个字段扩展它的方式。

private byte[] normsDocLengthArrField1 = null;
private byte[] normsDocLengthArrField2 = null;
private byte[] normsDocLengthArrField3 = null;
private double avgDocLength;

normsDocLengthArrField1 = indexReader.norms("filed1");
normsDocLengthArrField2 = indexReader.norms("filed2");
normsDocLengthArrField3 = indexReader.norms("filed3");
            //norms-Returns the byte-encoded normalization factor for the named field of every document.
double sumLength = 0;

for (int i = 0; i < normsDocLengthArrField1.length; i++) {
    double encodeLengthF1 = DefaultSimilarity.decodeNorm(normsDocLengthArrField1[i]);
    double encodeLengthF2 = DefaultSimilarity.decodeNorm(normsDocLengthArrField2[i]);
    double encodeLengthF3 = DefaultSimilarity.decodeNorm(normsDocLengthArrField3[i]);

    //decodeNorm -Decodes a normalization factor stored in an index.
    double length = 1 / {(encodeLengthF1 * encodeLengthF1)+(encodeLengthF2 * encodeLengthF2)+(encodeLengthF3 * encodeLengthF3)};

    sumLength += length;

}

this.avgDocLength = sumLength / (normsDocLengthArrField1.length+ normsDocLengthArrField2.length+normsDocLengthArrField3.length;

我只是想知道我计算3字段的Doc平均长度的实现是否正确？

Answer 1

我发现这种方式是计算平均文档长度的正确方法，哪个文档有lucene的3个字段。

byte[] normsDocLengthArrField1 = indexReader.norms("filed1");
byte[] normsDocLengthArrField2 = indexReader.norms("filed2");
byte[] normsDocLengthArrField3 = indexReader.norms("filed3");

 double sumLength = 0;
        for (int i = 0; i < normsDocLengthArrField1.length; i++) {
            double encodeLengthFOne = DefaultSimilarity.decodeNorm(normsDocLengthArrField1[i]);
            double encodeLengthFTwo = DefaultSimilarity.decodeNorm(normsDocLengthArrField2[i]);
            double encodeLengthFThree = DefaultSimilarity.decodeNorm(normsDocLengthArrField3[i]);

        //decodeNorm -Decodes a normalization factor stored in an index.
        double lengthFieldOne = 1 / (encodeLengthFOne * encodeLengthFOne);
        double lengthFieldTwo = 1 / (encodeLengthFTwo * encodeLengthFTwo);
        double lengthFieldThree = 1 / (encodeLengthFThree * encodeLengthFThree);
        sumLength += lengthFieldOne + lengthFieldTwo + lengthFieldThree;

    }
    this.avgDocLength = sumLength / (normsDocLengthArrField1.length);

用Lucene计算平均文档长度

1 个答案: