text: //*****************************************************************************
  // Copyright 2017-2019 Intel 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 "ngraph/op/op.hpp"
  
  namespace ngraph
  {
      namespace op
      {
          namespace util
          {
              /// \brief Abstract base class for arithmetic reduction operations, i.e., operations
              ///        where chosen axes of the input tensors are eliminated (reduced out) by
              ///        repeated application of a particular binary arithmetic operation.
              class NGRAPH_API ArithmeticReduction : public Op
              {
              protected:
                  /// \brief Constructs an arithmetic reduction operation.
                  ArithmeticReduction();
  
                  /// \brief Constructs an arithmetic reduction operation.
                  ///
                  /// \param arg Output that produces the first input tensor.
                  /// \param reduction_axes The axis positions (0-based) to be eliminated.
                  ArithmeticReduction(const Output<Node>& arg, const AxisSet& reduction_axes);
                  /// \brief Constructs an arithmetic reduction operation.
                  ///
                  /// \param arg Output that produces the first input tensor.
                  /// \param reduction_axes The axis positions (0-based) to be eliminated.
                  ArithmeticReduction(const Output<Node>& arg, const Output<Node>& reduction_axes);
  
              public:
                  void validate_and_infer_types() override;
  
                  /// \return true if reduction axes are constant else false.
                  bool reduction_axes_constant() const;
  
                  /// \return The axis positions (0-based) to be eliminated through reduction.
                  /// \throws CheckFailure if the reduction axes are not constant. (Use
                  ///           reduction_axes_constant to check.)
                  const AxisSet get_reduction_axes() const;
  
                  /// \brief Change the reduction axes
                  void set_reduction_axes(const AxisSet& reduction_axes);
              };
          }
      }
  }
  