code: @Override
      public double f1Score(INDArray examples, INDArray labels) {
          Evaluation eval = new Evaluation();
          eval.eval(labels, activate(examples, false, LayerWorkspaceMgr.noWorkspacesImmutable()));
          return eval.f1();
      }
docs: Returns the f1 score for the given examples.
  Think of this to be like a percentage right.
  The higher the number the more it got right.
  This is on a scale from 0 to 1.
  
  @param examples te the examples to classify (one example in each row)
  @param labels   the true labels
  @return the scores for each ndarray