/**
* Sets boost of termClaimsDescriptionAbstractTitles. boost = weight = factor(tf*idf)
*
* @param vecsTerms
* @param currentField
* @param factor - adjustment factor ( ex. alpha or beta )
* @param decayFactor
* @return
* @throws java.io.IOException
*/
public Map<String, TermQuery> setBoost(
Map<TermFreqVector, String> vecsTerms, String currentField, float factor, float decayFactor)
throws IOException {
Map<String, TermQuery> terms = new HashMap<>();
// setBoost for each of the terms of each of the docs
int i = 0;
float norm = (float) 1 / vecsTerms.size();
// System.out.println("--------------------------");
for (Map.Entry<TermFreqVector, String> e : vecsTerms.entrySet()) {
// Increase decay
String field = e.getValue();
TermFreqVector docTerms = e.getKey();
float decay = decayFactor * i;
// Populate terms: with TermQuries and set boost
for (String termTxt : docTerms.getTerms()) {
// Create Term
Term term = new Term(currentField, termTxt);
// Calculate weight
float tf = docTerms.getFreq(termTxt);
// float idf = ir.docFreq(termTitle);
int docs;
float idf;
if (sourceField.equals(PatentQuery.all)) {
docs = ir.getDocCount(field);
idf = (float) Math.log10((double) docs / (ir.docFreq(new Term(field, termTxt)) + 1));
} else {
docs = ir.getDocCount(sourceField);
idf =
(float) Math.log10((double) docs / (ir.docFreq(new Term(sourceField, termTxt)) + 1));
}
float weight = tf * idf;
// System.out.println(term.text() + " -> tf= " + tf + " idf= " + idf + "
// tfidf= " + weight);
// Adjust weight by decay factor
weight = weight - (weight * decay);
// Create TermQuery and add it to the collection
TermQuery termQuery = new TermQuery(term);
// Calculate and set boost
float boost;
if (vecsTerms.size() == 1) {
boost = factor * tf;
} else {
boost = factor;
}
if (boost != 0) {
termQuery.setBoost(boost * norm);
if (terms.containsKey(termTxt)) {
TermQuery tq = terms.get(termTxt);
tq.setBoost(tq.getBoost() + termQuery.getBoost());
} else {
terms.put(termTxt, termQuery);
}
}
}
i++;
}
return terms;
}
/**
* combine weights according to expansion formula
*
* @param queryTerms
* @param relevantDocsTerms
* @param irrelevantDocsTerms
* @return
*/
public List<TermQuery> combine(
Map<String, TermQuery> queryTerms,
Map<String, TermQuery> relevantDocsTerms,
Map<String, TermQuery> irrelevantDocsTerms) {
// Add Terms of the relevant documents
for (Map.Entry<String, TermQuery> e : queryTerms.entrySet()) {
if (relevantDocsTerms.containsKey(e.getKey())) {
TermQuery tq = relevantDocsTerms.get(e.getKey());
tq.setBoost(tq.getBoost() + e.getValue().getBoost());
} else {
relevantDocsTerms.put(e.getKey(), e.getValue());
}
}
// Substract terms of irrelevant documents
for (Map.Entry<String, TermQuery> e : irrelevantDocsTerms.entrySet()) {
if (relevantDocsTerms.containsKey(e.getKey())) {
TermQuery tq = relevantDocsTerms.get(e.getKey());
tq.setBoost(tq.getBoost() - e.getValue().getBoost());
} else {
TermQuery tq = e.getValue();
tq.setBoost(-tq.getBoost());
relevantDocsTerms.put(e.getKey(), tq);
}
}
return new ArrayList<>(relevantDocsTerms.values());
}
/** Add to an existing boolean query the More Like This query from this PriorityQueue */
private void addToQuery(PriorityQueue<ScoreTerm> q, BooleanQuery query) {
ScoreTerm scoreTerm;
float bestScore = -1;
while ((scoreTerm = q.pop()) != null) {
TermQuery tq = new TermQuery(new Term(scoreTerm.topField, scoreTerm.word));
if (boost) {
if (bestScore == -1) {
bestScore = (scoreTerm.score);
}
float myScore = (scoreTerm.score);
tq.setBoost(boostFactor * myScore / bestScore);
}
try {
query.add(tq, BooleanClause.Occur.SHOULD);
} catch (BooleanQuery.TooManyClauses ignore) {
break;
}
}
}