/**
* The binary features in in any unitInstance between start...end or otherInstance. Equivalently,
* the features in the sum of {unitInstance[start],...,unitInstance[end-1],otherInstance}
*/
private Set<Feature> binaryFeatureSet(int start, int end, Instance otherInstance) {
Set<Feature> s = new HashSet<Feature>();
for (int i = start; i < end; i++) {
addAll(s, unitInstance[i].binaryFeatureIterator());
}
if (otherInstance != null) addAll(s, otherInstance.binaryFeatureIterator());
return s;
}
