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TFIDFSearcher.java
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TFIDFSearcher.java
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//Name: Kanlayakorn Kesorn (SEC2), Patiphol Pussawong (SEC1), Supakarn Wongnil (SEC1)
//Section: 1,2
//ID: 6088057, 6088136, 6088137
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map.Entry;
import java.util.PriorityQueue;
import java.util.Queue;
public class TFIDFSearcher extends Searcher
{
LinkedHashMap<String, Double> idf = new LinkedHashMap<String, Double>();
List<String> termIndex = null;
HashMap<Integer, double[]> docVector = new HashMap<Integer, double[]>();
HashMap<Integer, Double> docLength = new HashMap<Integer, Double>();
public TFIDFSearcher(String docFilename) {
super(docFilename);
/************* YOUR CODE HERE ******************/
HashSet<String> allTerms = new HashSet<String>();
for (Document doc : this.documents) {
allTerms.addAll(doc.getTokens());
}
//System.out.println(allTerms.size());
//Getting DF -> how many occurrences of this term in all documents
for (Document doc : this.documents) {
HashSet<String> uniq = new HashSet<String>(doc.getTokens());
for(String term : uniq) {
if(idf.containsKey(term)) {
idf.replace(term, idf.get(term)+1.0);
} else {
idf.put(term, 1.0);
}
}
}
//Calculating IDF
//TODO: Workaround after https://github.com/mockito/mockito/issues/1899 is fixed
for (String term : idf.keySet()) {
double idfVal = Math.log10((this.documents.size()/idf.get(term))+1);
idf.replace(term, idfVal);
}
//System.out.println(idf);
//Generating term index for indicate location of each terms in an array
termIndex = new ArrayList<String>(idf.keySet());
//calculating each document tfidf array
for (Document doc : this.documents) {
double tfidf[] = new double[idf.size()];
for(String term : doc.getTokens()) {
double tf = findTf(term, doc.getTokens());
tfidf[termIndex.indexOf(term)] = tf*idf.get(term);
}
docVector.put(doc.getId(), tfidf);
}
//calculating each document length
for (Document doc : this.documents) {
double sum = 0;
for(double val : docVector.get(doc.getId())) {
sum += Math.pow(val, 2);
}
sum = Math.sqrt(sum);
docLength.put(doc.getId(), sum);
}
//System.out.println(docLength);
//System.out.println("TF"+findTf("cancel", this.documents.get(0).getTokens()));
//System.out.println(idf.get("cancel"));
//System.out.println(tfidf.get("cancel"));
/***********************************************/
}
@Override
public List<SearchResult> search(String queryString, int k) {
/************* YOUR CODE HERE ******************/
Queue<SearchResult> result = new PriorityQueue<>(k, Collections.reverseOrder());
List<String> qTokens = tokenize(queryString);
//System.out.println(sum);
for(Document doc : this.documents) {
//calculating query length and query vector
double queryTfidf[] = new double[idf.size()];
for(String term : qTokens) {
double tf = findTf(term, qTokens);
if(idf.get(term) != null) {
queryTfidf[termIndex.indexOf(term)] = tf*idf.get(term);
} else {
if(termIndex.indexOf(term) != -1) {
queryTfidf[termIndex.indexOf(term)] = 0.0;
}
}
}
double sum = 0.0;
for(double val : queryTfidf) {
sum += Math.pow(val, 2);
}
sum = Math.sqrt(sum);
double queryLength = sum;
//get document vector
double docTfidf[] = docVector.get(doc.getId());
double sumup = 0;
//doing dot product
for(int i=0;i<docTfidf.length;i++) {
sumup += docTfidf[i]*queryTfidf[i];
}
double cos = sumup / (queryLength*docLength.get(doc.getId()));
SearchResult temp = new SearchResult(doc, cos);
if(result.size() < k || result.peek().getScore() < temp.getScore()) {
if(result.size() == k) {
SearchResult rem = result.remove();
//System.out.println("Remove : "+rem.getScore());
}
result.add(temp);
//System.out.println("Adding : "+temp.getScore());
//System.out.println(result);
}
}
List<SearchResult> r = new ArrayList<SearchResult>(result);
Collections.sort(r);
return r;
/***********************************************/
}
//TODO: this function should be reworked once bug 1 is fixed and then we should have common type of returned value
public int findDf(String term) {
int count = 0;
for(Document doc : this.documents) {
if(doc.getTokens().contains(term)) {
count++;
}
}
return count;
}
public double findTf(String term, List<String> x) {
int freq = Collections.frequency(x, term);
if(freq != 0) {
return 1+Math.log10(freq);
} else {
return 0;
}
}
}