/**
* Prepare a clustering pass on the indicated data.
*
* @param points The array of dataPoints to be clustered.
* @param ids Array of cluster numbers which this call will fill in, defining which cluster each
* point belongs to. The caller must leave the data here intact between iterations.
* @param means Array of x,y values in which to place centroids of the clusters.
* @param region The region of the plane in which the points lie.
*/
@Override
public void prepare(Point[] points, int[] ids, double[][] means, Region region) {
super.prepare(points, ids, means, region);
// Save the data arrays.
dataPoints = points;
pointClusters = ids;
clusterMeans = means;
numPoints = points.length;
numClusters = means.length;
// Set up the strengths array.
clusterStrengths = new double[numPoints][numClusters];
// Set the initial cluster centroids to be random values
// within the data region.
double x = region.getX1();
double y = region.getY1();
double w = region.getWidth();
double h = region.getHeight();
for (int i = 0; i < numClusters; ++i) {
means[i][0] = random.nextDouble() * w + x;
means[i][1] = random.nextDouble() * h + y;
}
// Make an initial assignment of points to clusters, so on the first
// iteration we have a basis for computing centroids.
assignPoints(ids, means);
}
