public float coord(int overlap,
    int maxOverlap) 
{
    return overlap / (float)maxOverlap;
}

Implemented as overlap / maxOverlap.

 public float idf(int docFreq,
    int numDocs) 
{
    return (float)(Math.log(numDocs/(double)(docFreq+1)) + 1.0);
}

Implemented as log(numDocs/(docFreq+1)) + 1.

 public float lengthNorm(String fieldName,
    int numTerms) 
{
    return (float)(1.0 / Math.sqrt(numTerms));
}

Implemented as 1/sqrt(numTerms).

 public float queryNorm(float sumOfSquaredWeights) 
{
    return (float)(1.0 / Math.sqrt(sumOfSquaredWeights));
}

Implemented as 1/sqrt(sumOfSquaredWeights).

 public float sloppyFreq(int distance) 
{
    return 1.0f / (distance + 1);
}

Implemented as 1 / (distance + 1).

 public float tf(float freq) 
{
    return (float)Math.sqrt(freq);
}

Implemented as sqrt(freq).