code: private void touch(final int l) {
          int lit = l;
          if (lit < 0) { lit = -lit; }
          final long newPriority = (long) occs(lit).count() + occs(-lit).count();
          if (!var(lit).free()) { return; }
          final LNGLongPriorityQueue queue = currentCands();
          queue.update(lit, -newPriority);
          if (this.schedule && !queue.contains(lit)) { queue.push(lit); }
      }
docs: Updates and pushes a literal as candidate to simplify.
  @param l the literal