public int CompareTo(object o) //reversed!
{
ResultDocument d = (ResultDocument)o;
if (d.Similarity > similarity)
{
return(1);
}
else if (d.Similarity < similarity)
{
return(-1);
}
else
{
return(0);
}
}
public ResultDocument[] Search(string query)
{
ArrayList queryTerms = MakeQuery(query); //exclude non-terms
if (queryTerms.Count == 0)
{
return(null); //no relevant docs
}
float queryNorm = Convert.ToSingle(Math.Sqrt(queryTerms.Count));
Hashtable docs = GetRelevantDocs(queryTerms);//docs relevant to ALL terms + sums of term weights for each doc
//cos(q,d) = dot(q,d)/|q|x|d|
int docId;
float sumOfWeights;
float docNorm;
float cos;
float pageRank;
float similarity;
ResultDocument[] results = new ResultDocument[docs.Count];
int cursor = 0;
IDictionaryEnumerator en = docs.GetEnumerator();
while (en.MoveNext())
{
docId = Convert.ToInt16(en.Key);
sumOfWeights = Convert.ToSingle(en.Value);
docNorm = index.GetDocNorm(docId);
cos = sumOfWeights / (queryNorm * docNorm);
pageRank = index.GetPageRank(docId);
similarity = cos;
if (cos > 0)
{
similarity = w * cos + (1f - w) * pageRank;
}
results[cursor++] = new ResultDocument(docId, similarity);
}
Array.Sort(results);
return(results);
}
public ResultDocument[] Search(int docId, int topResults)
{
//make a hashtable for terms in the doc which is being compared to all the rest
Hashtable termIds = new Hashtable();
DocTermItem[] docTerms = index.DocTerms(docId);
foreach (DocTermItem dti in docTerms)
{
termIds.Add(dti.TermId, dti.TermCount);
}
ResultDocument[] allResults = new ResultDocument[TRAININGSET];
float docNorm = index.GetDocNorm(docId);
float doc2norm;
float similarity;
for (int doc2id = 0; doc2id < allResults.Length; doc2id++)
{
doc2norm = index.GetDocNorm(doc2id);
similarity = getDotProduct(docId, doc2id, termIds) / (docNorm * doc2norm);
allResults[doc2id] = new ResultDocument(doc2id, similarity);
}
Array.Sort(allResults);
ResultDocument[] results = new ResultDocument[topResults];
int j = 0;
for (int i = 0; i < topResults; i++)
{
if (allResults[j].DocId == docId) //do not return the doc itself!
{
j++;
}
results[i] = allResults[j++];
}
return(results);
}
