protected ClusteringResult GetClusteringResult()
{
ClusteringResult clustering = new ClusteringResult();
foreach (CentroidData centroid in mCentroids)
{
clustering.AddRoot(new Cluster());
clustering.Roots.Last.Items.AddRange(centroid.CurrentItems);
clustering.Roots.Last.ClusterInfo = centroid.Tag;
}
return(clustering);
}
private ClusteringResult CreateSingleCluster(IUnlabeledExampleCollection <SparseVector <double> > dataset)
{
ClusteringResult clustering = new ClusteringResult();
Cluster root = new Cluster();
for (int i = 0; i < dataset.Count; i++)
{
root.Items.Add(i);
}
clustering.AddRoot(root);
CentroidData centroid = new CentroidData();
centroid.Items.AddRange(root.Items);
centroid.Update(dataset);
centroid.UpdateCentroidLen();
mCentroids = new ArrayList <CentroidData>();
mCentroids.Add(centroid);
return(clustering);
}
public ClusteringResult Cluster(IUnlabeledExampleCollection <SparseVector <double> > dataset)
{
Utils.ThrowException(dataset == null ? new ArgumentNullException("dataset") : null);
Utils.ThrowException(dataset.Count < 2 ? new ArgumentValueException("dataset") : null);
ClusteringResult clusteringResult = new ClusteringResult();
Queue <Cluster> queue = new Queue <Cluster>();
// create root
Cluster root = new Cluster();
for (int i = 0; i < dataset.Count; i++)
{
Utils.ThrowException(dataset[i].Count == 0 ? new ArgumentValueException("dataset") : null);
root.Items.Add(i);
}
clusteringResult.AddRoot(root);
// add root to queue
queue.Enqueue(root);
while (queue.Count > 0)
{
// get next cluster
Cluster cluster = queue.Dequeue();
// compute cluster quality
UnlabeledDataset <SparseVector <double> > localDataset = GetDatasetSubset(cluster.Items, dataset);
SparseVector <double> centroid;
double quality = GetClusterQuality(localDataset, out centroid);
cluster.ClusterInfo = new Pair <SparseVector <double>, double>(centroid, quality);
if (quality < mMinQuality)
{
// split cluster, add children to queue
ClusteringResult localResult = mKMeansClustering.Cluster(localDataset);
for (int i = 0; i < 2; i++)
{
cluster.AddChild(localResult.Roots[i]);
localResult.Roots[i].Parent = cluster;
queue.Enqueue(localResult.Roots[i]);
}
}
}
return(clusteringResult);
}
public ClusteringResult Cluster(IUnlabeledExampleCollection <SparseVector <double> > dataset)
{
Utils.ThrowException(dataset == null ? new ArgumentNullException("dataset") : null);
Utils.ThrowException(dataset.Count < mK ? new ArgumentValueException("dataset") : null);
ClusteringResult clustering = null;
double globalBestClustQual = 0;
for (int trial = 1; trial <= mTrials; trial++)
{
mLogger.Info("Cluster", "Clustering trial {0} of {1} ...", trial, mTrials);
ArrayList <CentroidData> centroids = new ArrayList <CentroidData>(mK);
ArrayList <int> bestSeeds = null;
for (int i = 0; i < mK; i++)
{
centroids.Add(new CentroidData());
}
// select seed items
double minSim = double.MaxValue;
ArrayList <int> tmp = new ArrayList <int>(dataset.Count);
for (int i = 0; i < dataset.Count; i++)
{
tmp.Add(i);
}
for (int k = 0; k < 3; k++)
{
ArrayList <SparseVector <double> > seeds = new ArrayList <SparseVector <double> >(mK);
tmp.Shuffle(mRnd);
for (int i = 0; i < mK; i++)
{
seeds.Add(dataset[tmp[i]]);
}
// assess quality of seed items
double simAvg = 0;
foreach (SparseVector <double> seed1 in seeds)
{
foreach (SparseVector <double> seed2 in seeds)
{
if (seed1 != seed2)
{
simAvg += DotProductSimilarity.Instance.GetSimilarity(seed1, seed2);
}
}
}
simAvg /= (double)(mK * mK - mK);
//Console.WriteLine(simAvg);
if (simAvg < minSim)
{
minSim = simAvg;
bestSeeds = new ArrayList <int>(mK);
for (int i = 0; i < mK; i++)
{
bestSeeds.Add(tmp[i]);
}
}
}
for (int i = 0; i < mK; i++)
{
centroids[i].Items.Add(bestSeeds[i]);
centroids[i].Update(dataset);
centroids[i].UpdateCentroidLen();
}
double[][] dotProd = new double[mK][];
SparseMatrix <double> dsMtx = ModelUtils.GetTransposedMatrix(dataset);
// main loop
int iter = 0;
double bestClustQual = 0;
double clustQual;
while (true)
{
iter++;
mLogger.Info("Cluster", "Iteration {0} ...", iter);
clustQual = 0;
// assign items to clusters
int j = 0;
foreach (CentroidData cen in centroids)
{
SparseVector <double> cenVec = cen.GetSparseVector();
dotProd[j] = ModelUtils.GetDotProductSimilarity(dsMtx, dataset.Count, cenVec);
j++;
}
for (int instIdx = 0; instIdx < dataset.Count; instIdx++)
{
double maxSim = double.MinValue;
ArrayList <int> candidates = new ArrayList <int>();
for (int cenIdx = 0; cenIdx < mK; cenIdx++)
{
double sim = dotProd[cenIdx][instIdx];
if (sim > maxSim)
{
maxSim = sim;
candidates.Clear();
candidates.Add(cenIdx);
}
else if (sim == maxSim)
{
candidates.Add(cenIdx);
}
}
if (candidates.Count > 1)
{
candidates.Shuffle(mRnd);
}
if (candidates.Count > 0) // *** is this always true?
{
centroids[candidates[0]].Items.Add(instIdx);
clustQual += maxSim;
}
}
clustQual /= (double)dataset.Count;
mLogger.Info("Cluster", "Quality: {0:0.0000}", clustQual);
// check if done
if (iter > 1 && clustQual - bestClustQual <= mEps)
{
break;
}
bestClustQual = clustQual;
// compute new centroids
for (int i = 0; i < mK; i++)
{
centroids[i].Update(dataset);
centroids[i].UpdateCentroidLen();
}
}
if (trial == 1 || clustQual > globalBestClustQual)
{
globalBestClustQual = clustQual;
// save the result
clustering = new ClusteringResult();
for (int i = 0; i < mK; i++)
{
clustering.AddRoot(new Cluster());
clustering.Roots.Last.Items.AddRange(centroids[i].Items);
}
}
}
return(clustering);
}
public ClusteringResult Cluster(IUnlabeledExampleCollection <SparseVector <double> > dataset)
{
Utils.ThrowException(dataset == null ? new ArgumentNullException("dataset") : null);
Utils.ThrowException(dataset.Count < mK ? new ArgumentValueException("dataset") : null);
ClusteringResult clustering = null;
ClusteringResult bestClustering = null;
double globalBestClustQual = 0;
for (int trial = 1; trial <= mTrials; trial++)
{
mLogger.Trace("Cluster", "Clustering trial {0} of {1} ...", trial, mTrials);
ArrayList <SparseVector <double> > centroids = null;
clustering = new ClusteringResult();
for (int i = 0; i < mK; i++)
{
clustering.AddRoot(new Cluster());
}
// select seed items
double minSim = double.MaxValue;
ArrayList <int> tmp = new ArrayList <int>(dataset.Count);
for (int i = 0; i < dataset.Count; i++)
{
tmp.Add(i);
}
for (int k = 0; k < 3; k++)
{
ArrayList <SparseVector <double> > seeds = new ArrayList <SparseVector <double> >(mK);
tmp.Shuffle(mRnd);
for (int i = 0; i < mK; i++)
{
seeds.Add(ModelUtils.ComputeCentroid(new SparseVector <double>[] { dataset[tmp[i]] }, mCentroidType));
}
// assess quality of seed items
double simAvg = 0;
foreach (SparseVector <double> seed1 in seeds)
{
foreach (SparseVector <double> seed2 in seeds)
{
if (seed1 != seed2)
{
simAvg += mSimilarity.GetSimilarity(seed1, seed2);
}
}
}
simAvg /= (double)(mK * mK - mK);
if (simAvg < minSim)
{
minSim = simAvg;
centroids = seeds;
}
}
// main loop
int iter = 0;
double bestClustQual = 0;
double clustQual;
while (true)
{
iter++;
mLogger.Trace("Cluster", "Iteration {0} ...", iter);
clustQual = 0;
// assign items to clusters
foreach (Cluster cluster in clustering.Roots)
{
cluster.Items.Clear();
}
for (int i = 0; i < dataset.Count; i++)
{
SparseVector <double> example = dataset[i];
double maxSim = double.MinValue;
ArrayList <int> candidates = new ArrayList <int>();
for (int j = 0; j < mK; j++)
{
SparseVector <double> centroid = centroids[j];
double sim = mSimilarity.GetSimilarity(example, centroid);
if (sim > maxSim)
{
maxSim = sim;
candidates.Clear();
candidates.Add(j);
}
else if (sim == maxSim)
{
candidates.Add(j);
}
}
if (candidates.Count > 1)
{
candidates.Shuffle(mRnd);
}
clustering.Roots[candidates[0]].Items.Add(i);
clustQual += maxSim;
}
clustQual /= (double)dataset.Count;
mLogger.Trace("Cluster", "Quality: {0:0.0000}", clustQual);
// check if done
if (iter > 1 && clustQual - bestClustQual <= mEps)
{
break;
}
bestClustQual = clustQual;
// compute new centroids
for (int i = 0; i < mK; i++)
{
centroids[i] = clustering.Roots[i].ComputeCentroid(dataset, mCentroidType);
}
}
if (trial == 1 || clustQual > globalBestClustQual)
{
globalBestClustQual = clustQual;
bestClustering = clustering;
}
}
return(bestClustering);
}
