}
/**
* To do. This could faster be done without sorting (min and second min).
*/
protected static void sortAscendingByLevel(DoubleBuffer[] fullBuffers) {
new ObjectArrayList(fullBuffers).quickSortFromTo(0,fullBuffers.length-1,
new java.util.Comparator() {
public int compare(Object o1, Object o2) {
int l1 = ((DoubleBuffer) o1).level();
int l2 = ((DoubleBuffer) o2).level();
return l1<l2? -1: l1==l2? 0: +1;