this.fast = fast;
n = x.length;
if (!(n == y.length && n == dx.length && n == dy.length)) {
throw new UnsupportedOperationException();
}
overlappingBoxes = new UndirectedGraph(solver, n, SetType.LINKED_LIST, true);
boxesToCompute = SetFactory.makeStoredSet(SetType.LINKED_LIST, n, solver);
}