Chris@49: // Copyright (C) 2009-2012 NICTA (www.nicta.com.au)
Chris@49: // Copyright (C) 2009-2012 Conrad Sanderson
Chris@49: // 
Chris@49: // This Source Code Form is subject to the terms of the Mozilla Public
Chris@49: // License, v. 2.0. If a copy of the MPL was not distributed with this
Chris@49: // file, You can obtain one at http://mozilla.org/MPL/2.0/.
Chris@49: 
Chris@49: 
Chris@49: //! \addtogroup fn_sort_index
Chris@49: //! @{
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1, typename T2>
Chris@49: struct arma_sort_index_packet
Chris@49:   {
Chris@49:   T1 val;
Chris@49:   T2 index;
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: class arma_sort_index_helper_ascend
Chris@49:   {
Chris@49:   public:
Chris@49:   
Chris@49:   template<typename T1, typename T2>
Chris@49:   arma_inline
Chris@49:   bool
Chris@49:   operator() (const arma_sort_index_packet<T1,T2>& A, const arma_sort_index_packet<T1,T2>& B) const
Chris@49:     {
Chris@49:     return (A.val < B.val);
Chris@49:     }
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: class arma_sort_index_helper_descend
Chris@49:   {
Chris@49:   public:
Chris@49:   
Chris@49:   template<typename T1, typename T2>
Chris@49:   arma_inline
Chris@49:   bool
Chris@49:   operator() (const arma_sort_index_packet<T1,T2>& A, const arma_sort_index_packet<T1,T2>& B) const
Chris@49:     {
Chris@49:     return (A.val > B.val);
Chris@49:     }
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename umat_elem_type, typename eT, const uword sort_direction, const uword sort_type>
Chris@49: void
Chris@49: inline
Chris@49: sort_index_helper(umat_elem_type* out_mem, const eT* in_mem, const uword n_elem)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   std::vector< arma_sort_index_packet<eT, umat_elem_type> > packet_vec(n_elem);
Chris@49:   
Chris@49:   for(uword i=0; i<n_elem; ++i)
Chris@49:     {
Chris@49:     packet_vec[i].val   = in_mem[i];
Chris@49:     packet_vec[i].index = i;
Chris@49:     }
Chris@49:   
Chris@49:   
Chris@49:   if(sort_direction == 0)
Chris@49:     {
Chris@49:     // ascend
Chris@49:     
Chris@49:     arma_sort_index_helper_ascend comparator;
Chris@49:     
Chris@49:     if(sort_type == 0)
Chris@49:       {
Chris@49:       std::sort( packet_vec.begin(), packet_vec.end(), comparator );
Chris@49:       }
Chris@49:     else
Chris@49:       {
Chris@49:       std::stable_sort( packet_vec.begin(), packet_vec.end(), comparator );
Chris@49:       }
Chris@49:     }
Chris@49:   else
Chris@49:     {
Chris@49:     // descend
Chris@49:     
Chris@49:     arma_sort_index_helper_descend comparator;
Chris@49:     
Chris@49:     if(sort_type == 0)
Chris@49:       {
Chris@49:       std::sort( packet_vec.begin(), packet_vec.end(), comparator );
Chris@49:       }
Chris@49:     else
Chris@49:       {
Chris@49:       std::stable_sort( packet_vec.begin(), packet_vec.end(), comparator );
Chris@49:       }
Chris@49:     }
Chris@49:   
Chris@49:   
Chris@49:   for(uword i=0; i<n_elem; ++i)
Chris@49:     {
Chris@49:     out_mem[i] = packet_vec[i].index;
Chris@49:     }
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: umat
Chris@49: sort_index
Chris@49:   (
Chris@49:   const Base<typename T1::elem_type,T1>& X,
Chris@49:   const uword sort_direction = 0,
Chris@49:   const typename arma_not_cx<typename T1::elem_type>::result* junk = 0
Chris@49:   )
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   arma_ignore(junk);
Chris@49:   
Chris@49:   typedef typename T1::elem_type eT;
Chris@49:   
Chris@49:   const unwrap<T1>   tmp(X.get_ref());
Chris@49:   const Mat<eT>& A = tmp.M;
Chris@49:   
Chris@49:   if(A.is_empty() == true)
Chris@49:     {
Chris@49:     return umat();
Chris@49:     }
Chris@49:   
Chris@49:   arma_debug_check( (A.is_vec() == false), "sort_index(): currently only handles vectors");
Chris@49:   
Chris@49:   typedef typename umat::elem_type out_elem_type;
Chris@49:   
Chris@49:   umat out(A.n_rows, A.n_cols);
Chris@49:   
Chris@49:   if(sort_direction == 0)
Chris@49:     {
Chris@49:     sort_index_helper<out_elem_type, eT, 0, 0>(out.memptr(), A.mem, A.n_elem);
Chris@49:     }
Chris@49:   else
Chris@49:     {
Chris@49:     sort_index_helper<out_elem_type, eT, 1, 0>(out.memptr(), A.mem, A.n_elem);
Chris@49:     }
Chris@49:   
Chris@49:   return out;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: umat
Chris@49: stable_sort_index
Chris@49:   (
Chris@49:   const Base<typename T1::elem_type,T1>& X,
Chris@49:   const uword sort_direction = 0,
Chris@49:   const typename arma_not_cx<typename T1::elem_type>::result* junk = 0
Chris@49:   )
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   arma_ignore(junk);
Chris@49:   
Chris@49:   typedef typename T1::elem_type eT;
Chris@49:   
Chris@49:   const unwrap<T1>   tmp(X.get_ref());
Chris@49:   const Mat<eT>& A = tmp.M;
Chris@49:   
Chris@49:   if(A.is_empty() == true)
Chris@49:     {
Chris@49:     return umat();
Chris@49:     }
Chris@49:   
Chris@49:   arma_debug_check( (A.is_vec() == false), "stable_sort_index(): currently only handles vectors");
Chris@49:   
Chris@49:   typedef typename umat::elem_type out_elem_type;
Chris@49:   
Chris@49:   umat out(A.n_rows, A.n_cols);
Chris@49:   
Chris@49:   if(sort_direction == 0)
Chris@49:     {
Chris@49:     sort_index_helper<out_elem_type, eT, 0, 1>(out.memptr(), A.mem, A.n_elem);
Chris@49:     }
Chris@49:   else
Chris@49:     {
Chris@49:     sort_index_helper<out_elem_type, eT, 1, 1>(out.memptr(), A.mem, A.n_elem);
Chris@49:     }
Chris@49:   
Chris@49:   return out;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! @}