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

这是当只有一个字段时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;

这就是我将它扩展到所有 3 个字段的方式。

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;

我只想知道我为 3 个字段计算 Doc 平均长度的实现是否正确？

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1 回答 1

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我发现这种方法是计算平均文档长度的正确方法，该文档具有 3 个带有 lucene 的字段。

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);
于 2012-06-19T09:41:12.837 回答