/**
* Returns the popcount or cardinality of the exclusive-or of the two sets. Neither set is
* modified.
*/
public static long xorCount(BitSet a, BitSet b) {
long tot =
BitUtil.pop_xor(a.getBits(), b.getBits(), 0, Math.min(a.getNumWords(), b.getNumWords()));
if (a.getNumWords() < b.getNumWords()) {
tot += BitUtil.pop_array(b.getBits(), a.getNumWords(), b.getNumWords() - a.getNumWords());
} else if (a.getNumWords() > b.getNumWords()) {
tot += BitUtil.pop_array(a.getBits(), b.getNumWords(), a.getNumWords() - b.getNumWords());
}
return tot;
}
/**
* Returns the popcount or cardinality of "a and not b" or "intersection(a, not(b))". Neither set
* is modified.
*/
public static long andNotCount(BitSet a, BitSet b) {
long tot =
BitUtil.pop_andnot(a.getBits(), b.getBits(), 0, Math.min(a.getNumWords(), b.getNumWords()));
if (a.getNumWords() > b.getNumWords()) {
tot += BitUtil.pop_array(a.getBits(), b.getNumWords(), a.getNumWords() - b.getNumWords());
}
return tot;
}
/** @return the number of set bits */
public long cardinality() {
return BitUtil.pop_array(myBits, 0, myNumWords);
}
