             fetchParams(g->params()->vals(), paramsAvg_);
         scheduler_->validate(graphs_);
 
-        // tell other threads to continue work
+        // Validation is done, tell other threads to continue work.
         pool_.notify_others();
       }
     }

      }

      if(scheduler_->validating()) {
        // wait with validation until all other threads are done with update
        pool_.wait_for_others(lock);

        if(movingAvg_)

    if(scheduler_) {
      std::unique_lock<std::mutex> lock(schedulerMutex_);

      // Wait until the thread that wants to do validation is finished.
      pool_.wait_for_one(lock);

      scheduler_->update(cost, batch);
