private void loadIds(short[] docs, Index index)
{
int estimatedHashSize = docs.Length; //for performance only
termDocCounts = new Hashtable(estimatedHashSize);
docIds = new Hashtable(estimatedHashSize);
termIds = new Hashtable(estimatedHashSize);
int docCursor = 0;
int termCursor = 0;
DocTermItem[] docTerms;
foreach (short docId in docs)
{
docIds.Add(docId, docCursor++);
docTerms = index.DocTerms(docId);
foreach (DocTermItem dt in docTerms)
{
int termId = dt.TermId;
if (termIds[termId] == null)
{
termIds.Add(termId, termCursor++);
}
if (termDocCounts[termId] == null)
{
termDocCounts[termId] = 1;
}
else
{
termDocCounts[termId] = Convert.ToInt32(termDocCounts[termId]) + 1;
}
}
}
}
private void loadMatrix(short[] docs, Index index)
{
matrix = new float[docIds.Count, termIds.Count];
DocTermItem[] docTerms;
float idf;
int termId;
short termCount;
double docCount; //double required for correct division
foreach (short docId in docs)
{
docTerms = index.DocTerms(docId);
foreach (DocTermItem dt in docTerms)
{
termId = dt.TermId;
termCount = dt.TermCount;
docCount = Convert.ToDouble(termDocCounts[termId]);
idf = Convert.ToSingle(Math.Log((double)docs.Length / docCount, 2));
matrix[docPosition(docId), termPosition(termId)] = idf * (float)termCount;
}
}
}