Java Code Examples for org.apache.commons.math3.ml.clustering.Cluster#getPoints()

@Override
public double score(final List<? extends Cluster<T>> clusters) {
    double varianceSum = 0.0;
    for (final Cluster<T> cluster : clusters) {
        if (!cluster.getPoints().isEmpty()) {

            final Clusterable center = centroidOf(cluster);

            // compute the distance variance of the current cluster
            final Variance stat = new Variance();
            for (final T point : cluster.getPoints()) {
                stat.increment(distance(point, center));
            }
            varianceSum += stat.getResult();

        }
    }
    return varianceSum;
}
 

/**
 * Computes the centroid for a cluster.
 *
 * @param cluster the cluster
 * @return the computed centroid for the cluster,
 * or {@code null} if the cluster does not contain any points
 */
protected Clusterable centroidOf(final Cluster<T> cluster) {
    final List<T> points = cluster.getPoints();
    if (points.isEmpty()) {
        return null;
    }

    // in case the cluster is of type CentroidCluster, no need to compute the centroid
    if (cluster instanceof CentroidCluster) {
        return ((CentroidCluster<T>) cluster).getCenter();
    }

    final int dimension = points.get(0).getPoint().length;
    final double[] centroid = new double[dimension];
    for (final T p : points) {
        final double[] point = p.getPoint();
        for (int i = 0; i < centroid.length; i++) {
            centroid[i] += point[i];
        }
    }
    for (int i = 0; i < centroid.length; i++) {
        centroid[i] /= points.size();
    }
    return new DoublePoint(centroid);
}
 

@Override
public double score(final List<? extends Cluster<T>> clusters) {
    double varianceSum = 0.0;
    for (final Cluster<T> cluster : clusters) {
        if (!cluster.getPoints().isEmpty()) {

            final Clusterable center = centroidOf(cluster);

            // compute the distance variance of the current cluster
            final Variance stat = new Variance();
            for (final T point : cluster.getPoints()) {
                stat.increment(distance(point, center));
            }
            varianceSum += stat.getResult();

        }
    }
    return varianceSum;
}
 

/**
 * Computes the centroid for a cluster.
 *
 * @param cluster the cluster
 * @return the computed centroid for the cluster,
 * or {@code null} if the cluster does not contain any points
 */
protected Clusterable centroidOf(final Cluster<T> cluster) {
    final List<T> points = cluster.getPoints();
    if (points.isEmpty()) {
        return null;
    }

    // in case the cluster is of type CentroidCluster, no need to compute the centroid
    if (cluster instanceof CentroidCluster) {
        return ((CentroidCluster<T>) cluster).getCenter();
    }

    final int dimension = points.get(0).getPoint().length;
    final double[] centroid = new double[dimension];
    for (final T p : points) {
        final double[] point = p.getPoint();
        for (int i = 0; i < centroid.length; i++) {
            centroid[i] += point[i];
        }
    }
    for (int i = 0; i < centroid.length; i++) {
        centroid[i] /= points.size();
    }
    return new DoublePoint(centroid);
}
 

private Envelope getBoundingRectangle(Cluster<ClusterableLocation> cluster) {
  double xmin = cluster.getPoints().get(0).getPoint()[0];
  double xmax = xmin;
  double ymin = cluster.getPoints().get(0).getPoint()[1];
  double ymax = ymin;
  for (ClusterableLocation p : cluster.getPoints()) {
    if (p.getPoint()[0] < xmin) {
      xmin = p.getPoint()[0];
    }
    if (p.getPoint()[0] > xmax) {
      xmax = p.getPoint()[0];
    }
    if (p.getPoint()[1] < ymin) {
      ymin = p.getPoint()[1];
    }
    if (p.getPoint()[1] > ymax) {
      ymax = p.getPoint()[1];
    }
  }
  Envelope boundingRectangle = new Envelope(xmin, ymin, xmax, ymax);
  return boundingRectangle;
}
 

private Point getCenter(Cluster<ClusterableLocation> cluster) {
  double sumx = 0;
  double sumy = 0;
  for (ClusterableLocation p : cluster.getPoints()) {
    sumx += p.getPoint()[0];
    sumy += p.getPoint()[1];
  }
  Point center = new Point(sumx / cluster.getPoints().size(), sumy/ cluster.getPoints().size());
  return center;
}
 

private Polygon getConvexHull(Cluster<ClusterableLocation> cluster) {
  List<ClusterableLocation> pointsList = cluster.getPoints();
  ClusterableLocation[] pointsArray = pointsList.toArray(new ClusterableLocation[pointsList.size()]);
  ClusterableLocation[] pointsConvexHull = ConvexHullGenerator.generateHull(pointsArray);
  Polygon convexHull = new Polygon();
  convexHull.startPath(pointsConvexHull[0].getPoint()[0], pointsConvexHull[0].getPoint()[1]);
  for (int i = 1; i < pointsConvexHull.length; i++) {
    ClusterableLocation p = pointsConvexHull[i];
    convexHull.lineTo(p.getPoint()[0], p.getPoint()[1]);
  }
  convexHull.closePathWithLine();
  return convexHull;
}
 

@operator (
		value = "kmeans",
		can_be_const = false,
		type = IType.LIST,
		category = { IOperatorCategory.STATISTICAL },
		concept = { IConcept.STATISTIC, IConcept.CLUSTERING })
@doc (
		value = "returns the list of clusters (list of instance indices) computed with the kmeans++ "
				+ "algorithm from the first operand data according to the number of clusters to split"
				+ " the data into (k) and the maximum number of iterations to run the algorithm for "
				+ "(If negative, no maximum will be used) (maxIt). Usage: kmeans(data,k,maxit)",
		special_cases = "if the lengths of two vectors in the right-hand aren't equal, returns 0",
		examples = { @example (
				value = "kmeans ([[2,4,5], [3,8,2], [1,1,3], [4,3,4]],2,10)",
				equals = "[[0,2,3],[1]]") })
public static IList<IList> KMeansPlusplusApache(final IScope scope, final IList data, final Integer k,
		final Integer maxIt) throws GamaRuntimeException {
	final MersenneTwister rand = new MersenneTwister(scope.getRandom().getSeed().longValue());

	final List<DoublePoint> instances = new ArrayList<>();
	for (int i = 0; i < data.size(); i++) {
		final IList d = (IList) data.get(i);
		final double point[] = new double[d.size()];
		for (int j = 0; j < d.size(); j++) {
			point[j] = Cast.asFloat(scope, d.get(j));
		}
		instances.add(new Instance(i, point));
	}
	final KMeansPlusPlusClusterer<DoublePoint> kmeans =
			new KMeansPlusPlusClusterer<>(k, maxIt, new EuclideanDistance(), rand);
	final List<CentroidCluster<DoublePoint>> clusters = kmeans.cluster(instances);
	try (final Collector.AsList results = Collector.getList()) {
		for (final Cluster<DoublePoint> cl : clusters) {
			final IList clG = GamaListFactory.create();
			for (final DoublePoint pt : cl.getPoints()) {
				clG.addValue(scope, ((Instance) pt).getId());
			}
			results.add(clG);
		}
		return results.items();
	}
}