public static List<double[]> getCorners(SpatialComparable box) {
ArrayList<double[]> corners = new ArrayList<double[]>();
if (SpatialUtil.perimeter(box) == 0) {
corners.add(SpatialUtil.getMin(box));
return corners;
}
boolean[] current = new boolean[box.getDimensionality()];
int dim = box.getDimensionality();
for (int i = 0; i < Math.pow(2, dim); i++) {
double[] newCorner = new double[dim];
for (int j = 0; j < dim; j++) {
if (current[j]) newCorner[j] = box.getMin(j);
else newCorner[j] = box.getMax(j);
}
addOne(current);
corners.add(newCorner);
}
return corners;
}
@Override
public <A> int choose(
A options,
ArrayAdapter<? extends SpatialComparable, A> getter,
SpatialComparable obj,
int height,
int depth) {
final int size = getter.size(options);
assert (size > 0) : "Choose from empty set?";
// R*-Tree: overlap increase for leaves.
int best = -1;
double least_overlap = Double.POSITIVE_INFINITY;
double least_areainc = Double.POSITIVE_INFINITY;
double least_area = Double.POSITIVE_INFINITY;
// least overlap increase, on reduced candidate set:
for (int i = 0; i < size; i++) {
// Existing object and extended rectangle:
SpatialComparable entry = getter.get(options, i);
HyperBoundingBox mbr = SpatialUtil.union(entry, obj);
// Compute relative overlap increase.
double overlap_wout = 0.0;
double overlap_with = 0.0;
for (int k = 0; k < size; k++) {
if (i != k) {
SpatialComparable other = getter.get(options, k);
overlap_wout += SpatialUtil.relativeOverlap(entry, other);
overlap_with += SpatialUtil.relativeOverlap(mbr, other);
}
}
double inc_overlap = overlap_with - overlap_wout;
if (inc_overlap < least_overlap) {
final double area = SpatialUtil.volume(entry);
final double inc_area = SpatialUtil.volume(mbr) - area;
// Volume increase and overlap increase:
least_overlap = inc_overlap;
least_areainc = inc_area;
least_area = area;
best = i;
} else if (inc_overlap == least_overlap) {
final double area = SpatialUtil.volume(entry);
final double inc_area = SpatialUtil.volume(mbr) - area;
if (inc_area < least_areainc || (inc_area == least_areainc && area < least_area)) {
least_overlap = inc_overlap;
least_areainc = inc_area;
least_area = area;
best = i;
}
}
}
assert (best > -1) : "No split found? Volume outside of double precision?";
return best;
}