/// <summary>Returns the popcount or cardinality of "a and not b"
/// or "intersection(a, not(b))".
/// Neither set is modified.
/// </summary>
public static long AndNotCount(OpenBitSet a, OpenBitSet b)
{
long tot = BitUtil.Pop_andnot(a.internalbits, b.internalbits, 0, System.Math.Min(a.wlen, b.wlen));
if (a.wlen > b.wlen)
{
tot += BitUtil.Pop_array(a.internalbits, b.wlen, a.wlen - b.wlen);
}
return(tot);
}
/// <summary>Returns the popcount or cardinality of the exclusive-or of the two sets.
/// Neither set is modified.
/// </summary>
public static long XorCount(OpenBitSet a, OpenBitSet b)
{
long tot = BitUtil.Pop_xor(a.internalbits, b.internalbits, 0, System.Math.Min(a.wlen, b.wlen));
if (a.wlen < b.wlen)
{
tot += BitUtil.Pop_array(b.internalbits, a.wlen, b.wlen - a.wlen);
}
else if (a.wlen > b.wlen)
{
tot += BitUtil.Pop_array(a.internalbits, b.wlen, a.wlen - b.wlen);
}
return(tot);
}
/*
* public static int pop(long v0, long v1, long v2, long v3) {
* // derived from pop_array by setting last four elems to 0.
* // exchanges one pop() call for 10 elementary operations
* // saving about 7 instructions... is there a better way?
* long twosA=v0 & v1;
* long ones=v0^v1;
*
* long u2=ones^v2;
* long twosB =(ones&v2)|(u2&v3);
* ones=u2^v3;
*
* long fours=(twosA&twosB);
* long twos=twosA^twosB;
*
* return (pop(fours)<<2)
+ (pop(twos)<<1)
+ pop(ones);
+
+ }
*/
/// <returns> the number of set bits
/// </returns>
public virtual long Cardinality()
{
return(BitUtil.Pop_array(internalbits, 0, wlen));
}
