text: // SPDX-License-Identifier: Apache-2.0
  // 
  // Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
  // Copyright 2008-2016 National ICT Australia (NICTA)
  // 
  // 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.
  // ------------------------------------------------------------------------
  
  
  //! \addtogroup spglue_join
  //! @{
  
  
  
  class spglue_join_cols
    {
    public:
    
    template<typename T1, typename T2>
    struct traits
      {
      static constexpr bool is_row  = false;
      static constexpr bool is_col  = (T1::is_col && T2::is_col);
      static constexpr bool is_xvec = false;
      };
    
    template<typename T1, typename T2>
    inline static void apply(SpMat<typename T1::elem_type>& out, const SpGlue<T1,T2,spglue_join_cols>& X);
    
    template<typename eT>
    inline static void apply_noalias(SpMat<eT>& out, const SpMat<eT>& A, const SpMat<eT>& B);
    
    template<typename eT, typename T1, typename T2, typename T3>
    inline static void apply(SpMat<eT>& out, const SpBase<eT,T1>& A, const SpBase<eT,T2>& B, const SpBase<eT,T3>& C);
    
    template<typename eT, typename T1, typename T2, typename T3, typename T4>
    inline static void apply(SpMat<eT>& out, const SpBase<eT,T1>& A, const SpBase<eT,T2>& B, const SpBase<eT,T3>& C, const SpBase<eT,T4>& D);
    };
  
  
  
  class spglue_join_rows
    {
    public:
    
    template<typename T1, typename T2>
    struct traits
      {
      static constexpr bool is_row  = (T1::is_row && T2::is_row);
      static constexpr bool is_col  = false;
      static constexpr bool is_xvec = false;
      };
    
    template<typename T1, typename T2>
    inline static void apply(SpMat<typename T1::elem_type>& out, const SpGlue<T1,T2,spglue_join_rows>& X);
    
    template<typename eT>
    inline static void apply_noalias(SpMat<eT>& out, const SpMat<eT>& A, const SpMat<eT>& B);
    
    template<typename eT, typename T1, typename T2, typename T3>
    inline static void apply(SpMat<eT>& out, const SpBase<eT,T1>& A, const SpBase<eT,T2>& B, const SpBase<eT,T3>& C);
    
    template<typename eT, typename T1, typename T2, typename T3, typename T4>
    inline static void apply(SpMat<eT>& out, const SpBase<eT,T1>& A, const SpBase<eT,T2>& B, const SpBase<eT,T3>& C, const SpBase<eT,T4>& D);
    };
  
  
  
  //! @}
  