private NormalizedVector Normalize(String id, DocumentVector doc)
{
NormalizedVector vec = new NormalizedVector(id);
// find max value
int max = 0;
foreach (KeyValuePair <string, int> term in doc)
{
if (term.Value > max)
{
max = term.Value;
}
}
lengths.Add(id, 0);
// add normalized frequencies
foreach (KeyValuePair <string, int> term in doc)
{
double tf = term.Value / (double)max;
vec.Add(term.Key, tf);
lengths[id] += Math.Pow(tf, 2);
}
lengths[id] = Math.Sqrt(lengths[id]);
return(vec);
}
private NormalizedVector Normalize(String id, DocumentVector doc)
{
NormalizedVector vec = new NormalizedVector(id);
// find max value
int max = 0;
foreach (KeyValuePair<string, int> term in doc)
{
if (term.Value > max)
{
max = term.Value;
}
}
lengths.Add(id, 0);
// add normalized frequencies
foreach (KeyValuePair<string, int> term in doc)
{
double tf = term.Value / (double)max;
vec.Add(term.Key, tf);
lengths[id] += Math.Pow(tf, 2);
}
lengths[id] = Math.Sqrt(lengths[id]);
return vec;
}
public static NormalizedVector Compute(DocumentVector df, int numDocs)
{
NormalizedVector idf = new NormalizedVector("InverseDocumentFrequencies");
foreach (KeyValuePair <string, int> kvp in df)
{
idf.Add(kvp.Key, Math.Log(numDocs / (double)kvp.Value, 2));
}
return(idf);
}
public static NormalizedVector Compute(DocumentVector df, int numDocs)
{
NormalizedVector idf = new NormalizedVector("InverseDocumentFrequencies");
foreach (KeyValuePair<string, int> kvp in df)
{
idf.Add(kvp.Key, Math.Log(numDocs / (double) kvp.Value, 2));
}
return idf;
}
public static NormalizedVectorCollection Compute(NormalizedVectorCollection tf, NormalizedVector idf)
{
NormalizedVectorCollection tfidf = new NormalizedVectorCollection();
foreach (KeyValuePair <string, NormalizedVector> doc in tf)
{
NormalizedVector vec = new NormalizedVector(doc.Key);
foreach (KeyValuePair <string, double> term in doc.Value)
{
vec.Add(term.Key, term.Value * idf[term.Key]);
}
tfidf.Add(vec);
}
return(tfidf);
}
public static NormalizedVectorCollection Compute(NormalizedVectorCollection tf, NormalizedVector idf)
{
NormalizedVectorCollection tfidf = new NormalizedVectorCollection();
foreach (KeyValuePair<string, NormalizedVector> doc in tf)
{
NormalizedVector vec = new NormalizedVector(doc.Key);
foreach (KeyValuePair<string, double> term in doc.Value)
{
vec.Add(term.Key, term.Value * idf[term.Key]);
}
tfidf.Add(vec);
}
return tfidf;
}
