/// <summary>
/// Returns a Chemical Group containing the set intersection of 'a' and 'b'.
/// </summary>
public static ChemicalGroup Inersection(ChemicalGroup a, ChemicalGroup b)
{
SetCheck(a, b);
var atomicNumbers = new HashSet <int>(a.Select(chem => { return(chem.AtomicNumber); }));
atomicNumbers.IntersectWith(b.Select(chem => { return(chem.AtomicNumber); }));
ChemicalGroup result = new ChemicalGroup(a.Factory);
foreach (var atomicNumber in atomicNumbers.ToArray())
{
result.AddChemicalElement(atomicNumber);
}
return(result);
}
