text: /*
   * Copyright (c) 2020, NVIDIA CORPORATION.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #pragma once
  
  #include <layer.hpp>
  
  namespace HugeCTR {
  
  /**
   * Elu activation function as a derived class of Layer
   */
  class EluLayer : public Layer {
    /*
     * stores the weight tensors of this layer.
     */
    Tensors2<float> weights_;
    /*
     * stores the weight gradient tensors of this layer.
     */
    Tensors2<float> wgrad_;
    /*
     * stores the references to the input tensors of this layer.
     */
    Tensors2<float> in_tensors_;
    /*
     * stores the references to the output tensors of this layer.
     */
    Tensors2<float> out_tensors_;
  
   public:
    /**
     * Ctor of ReluLayer.
     * @param in_tensor the input tensor
     * @param out_tensor the output tensor which has the same dim with in_tensor
     * @param device_id the id of GPU where this layer belongs
     */
    EluLayer(const Tensor2<float>& in_tensor, const Tensor2<float>& out_tensor, float alpha,
             const std::shared_ptr<GPUResource>& gpu_resource);
  
    /**
     * A method of implementing the forward pass of Relu
     * @param stream CUDA stream where the foward propagation is executed
     */
    void fprop(bool is_train) override;
    /**
     * A method of implementing the backward pass of Relu
     * @param stream CUDA stream where the backward propagation is executed
     */
    void bprop() override;
  
   private:
    float alpha_;
  };
  
  }  // namespace HugeCTR
  