docs: @Override
      public INDArray getActivation(INDArray in, boolean training) {
          // no support in ELU native to override alpha
          if (this.alpha != 1.00) {
              INDArray alphaMultiple = Nd4j.getExecutioner().exec(new ELU(in.dup()));
              alphaMultiple.muli(alpha);
              BooleanIndexing.replaceWhere(in, alphaMultiple, Conditions.lessThan(0));
          } else {
              Nd4j.getExecutioner().execAndReturn(new ELU(in));
          }
          return in;
      }