docs: protected static double precision(Set<?> s1, Set<?> s2) {
      double n = 0.0;
      double p = 0.0;
      for (Object o1 : s1) {
        if (s2.contains(o1)) {
          p += 1.0;
        }
        if (DEBUG) {
          if (s2.contains(o1)) {
            System.err.println("Eval Found: "+o1);
          } else {
            System.err.println("Eval Failed to find: "+o1);
          }
        }
        n += 1.0;
      }
      if (DEBUG) System.err.println("Matched " + p + " of " + n);
      return (n > 0.0 ? p / n : 0.0);
    }