public static KMeansResult Compute(int k, Vector3[] data)
{
int n = data.Length;
KMeansResult res = new KMeansResult(n, k);
// Find Random Points
Random r = new Random();
List<int> rAssign = new List<int>(k);
int li = 0;
while(li < k) {
int rn = r.Next(n);
if(rAssign.Contains(rn)) continue;
li++;
rAssign.Add(rn);
}
// Assign Random Centroids
for(int i = 0; i < k; i++)
res.Centroids[i] = data[rAssign[i]];
int[] lastAssign = Enumerable.Repeat<int>(-1, n).ToArray();
while(Different(lastAssign, res.ClusterAssigns)) {
// Swap
var buf = lastAssign;
lastAssign = res.ClusterAssigns;
res.ClusterAssigns = buf;
// Compute
for(int ni = 0; ni < n; ni++) {
int c = 0;
float d = (data[ni] - res.Centroids[0]).LengthSquared();
for(int ci = 1; ci < k; ci++) {
float nd = (data[ni] - res.Centroids[ci]).LengthSquared();
if(nd < d) {
c = ci;
d = nd;
}
}
res.ClusterAssigns[ni] = c;
}
// Find New Centroids
int[] count = new int[k];
for(int i = 0; i < k; i++)
res.Centroids[i] = Vector3.Zero;
for(int ni = 0; ni < n; ni++) {
res.Centroids[res.ClusterAssigns[ni]] += data[ni];
count[res.ClusterAssigns[ni]]++;
}
for(int i = 0; i < k; i++)
res.Centroids[i] /= count[i];
}
return res;
}
public static void Compute(int k, Vector3[] data, ref KMeansResult res, int stepPause)
{
int n = data.Length;
// Find Random Points
Random r = new Random();
List <int> rAssign = new List <int>(k);
int li = 0;
while (li < k)
{
int rn = r.Next(n);
if (rAssign.Contains(rn))
{
continue;
}
li++;
rAssign.Add(rn);
}
// Assign Random Centroids
for (int i = 0; i < k; i++)
{
res.Centroids[i] = data[rAssign[i]];
}
int[] lastAssign = Enumerable.Repeat <int>(-1, n).ToArray();
while (Different(lastAssign, res.ClusterAssigns))
{
// Copy Swap
res.ClusterAssigns.CopyTo(lastAssign, 0);
// Compute
for (int ni = 0; ni < n; ni++)
{
int c = 0;
float d = (data[ni] - res.Centroids[0]).LengthSquared();
for (int ci = 1; ci < k; ci++)
{
float nd = (data[ni] - res.Centroids[ci]).LengthSquared();
if (nd < d)
{
c = ci;
d = nd;
}
}
res.ClusterAssigns[ni] = c;
}
// Find New Centroids
int[] count = new int[k];
for (int i = 0; i < k; i++)
{
res.Centroids[i] = Vector3.Zero;
}
for (int ni = 0; ni < n; ni++)
{
res.Centroids[res.ClusterAssigns[ni]] += data[ni];
count[res.ClusterAssigns[ni]]++;
}
for (int i = 0; i < k; i++)
{
res.Centroids[i] /= count[i];
}
// Pause
Thread.Sleep(stepPause);
}
}
