/// <summary>
/// Re-assign sample to its nearest cluster center.
/// </summary>
/// <param name="sample">Sample to be clustered.</param>
/// <param name="centroids">Centroids to be assigned.</param>
/// <returns>The inner cluster distance.</returns>
private float Assign(Sample sample, IList<Sample> centroids)
{
var smallestDistance = float.MaxValue;
var lastCentroid = sample.Centroid;
foreach (var centroid in centroids)
{
var distance = _sampleStrategy.Diff(sample, centroid);
if (distance < smallestDistance)
{
smallestDistance = distance;
sample.Centroid = centroid;
}
}
return smallestDistance;
}
/// <summary>
/// Find the furthest sample to reference.
/// </summary>
/// <param name="reference">Reference sample.</param>
/// <param name="samples">Sample list.</param>
/// <returns>The furthest sample to reference.</returns>
private Sample FindFurthest(Sample reference, IList<Sample> samples)
{
float largestDistance = 0;
Sample ret = null;
foreach (var sample in samples)
{
var distance = _sampleStrategy.Diff(sample, reference);
if (distance > largestDistance)
{
largestDistance = distance;
ret = sample;
}
}
return ret;
}
/// <summary>
/// Look for the similar centroids by representative centroids.
/// </summary>
/// <param name="sample">Sample.</param>
/// <returns>Similar centroids.</returns>
private IList<Sample> SearchCentroids(Sample sample)
{
List<Sample> nearCentroids = new List<Sample>();
foreach (Sample clusterCentroid in _representativeCentroids.OrderBy(s => _sampleStrategy.Diff(s, sample)))
{
nearCentroids.AddRange(_representativeCentroidsMap[clusterCentroid]);
if (nearCentroids.Count >= _centroids.Count * 0.1)
{
break;
}
}
return nearCentroids;
}