code: private long computeLBD(final MSClause c) {
      long nblevels = 0;
      myflag++;
      if (incremental) {
        long nbDone = 0;
        for (int i = 0; i < c.size(); i++) {
          if (nbDone >= c.sizeWithoutSelectors())
            break;
          if (isSelector(var(c.get(i))))
            continue;
          nbDone++;
          int l = v(c.get(i)).level();
          if (permDiff.get(l) != myflag) {
            permDiff.set(l, myflag);
            nblevels++;
          }
        }
      } else {
        for (int i = 0; i < c.size(); i++) {
          int l = v(c.get(i)).level();
          if (permDiff.get(l) != myflag) {
            permDiff.set(l, myflag);
            nblevels++;
          }
        }
      }
      if (!reduceOnSize)
        return nblevels;
      if (c.size() < reduceOnSizeSize)
        return c.size();
      return c.size() + nblevels;
    }
docs: Computes the LBD for a given clause
  @param c the clause
  @return the LBD