Chris@49: // Copyright (C) 2008-2013 NICTA (www.nicta.com.au)
Chris@49: // Copyright (C) 2008-2013 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 op_sum
Chris@49: //! @{
Chris@49: 
Chris@49: //! \brief
Chris@49: //! Immediate sum of elements of a matrix along a specified dimension (either rows or columns).
Chris@49: //! The result is stored in a dense matrix that has either one column or one row.
Chris@49: //! See the sum() function for more details.
Chris@49: template<typename T1>
Chris@49: arma_hot
Chris@49: inline
Chris@49: void
Chris@49: op_sum::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_sum>& in)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename T1::elem_type eT;
Chris@49:   
Chris@49:   const uword dim = in.aux_uword_a;
Chris@49:   arma_debug_check( (dim > 1), "sum(): incorrect usage. dim must be 0 or 1");
Chris@49:   
Chris@49:   const Proxy<T1> P(in.m);
Chris@49:   
Chris@49:   typedef typename Proxy<T1>::stored_type P_stored_type;
Chris@49:   
Chris@49:   const bool is_alias = P.is_alias(out);
Chris@49:   
Chris@49:   if( (is_Mat<P_stored_type>::value == true) || is_alias )
Chris@49:     {
Chris@49:     const unwrap_check<P_stored_type> tmp(P.Q, is_alias);
Chris@49:     
Chris@49:     const typename unwrap_check<P_stored_type>::stored_type& X = tmp.M;
Chris@49:     
Chris@49:     const uword X_n_rows = X.n_rows;
Chris@49:     const uword X_n_cols = X.n_cols;
Chris@49:     
Chris@49:     if(dim == 0)  // traverse across rows (i.e. find the sum in each column)
Chris@49:       {
Chris@49:       out.set_size(1, X_n_cols);
Chris@49:       
Chris@49:       eT* out_mem = out.memptr();
Chris@49:       
Chris@49:       for(uword col=0; col < X_n_cols; ++col)
Chris@49:         {
Chris@49:         out_mem[col] = arrayops::accumulate( X.colptr(col), X_n_rows );
Chris@49:         }
Chris@49:       }
Chris@49:     else  // traverse across columns (i.e. find the sum in each row)
Chris@49:       {
Chris@49:       out.set_size(X_n_rows, 1);
Chris@49:       
Chris@49:       eT* out_mem = out.memptr();
Chris@49:         
Chris@49:       for(uword row=0; row < X_n_rows; ++row)
Chris@49:         {
Chris@49:         eT val = eT(0);
Chris@49:         
Chris@49:         uword i,j;
Chris@49:         for(i=0, j=1; j < X_n_cols; i+=2, j+=2)
Chris@49:           {
Chris@49:           val += X.at(row,i);
Chris@49:           val += X.at(row,j);
Chris@49:           }
Chris@49:         
Chris@49:         if(i < X_n_cols)
Chris@49:           {
Chris@49:           val += X.at(row,i);
Chris@49:           }
Chris@49:         
Chris@49:         out_mem[row] = val;
Chris@49:         }
Chris@49:       }
Chris@49:     }
Chris@49:   else
Chris@49:     {
Chris@49:     const uword P_n_rows = P.get_n_rows();
Chris@49:     const uword P_n_cols = P.get_n_cols();
Chris@49:     
Chris@49:     if(dim == 0)  // traverse across rows (i.e. find the sum in each column)
Chris@49:       {
Chris@49:       out.set_size(1, P_n_cols);
Chris@49:       
Chris@49:       eT* out_mem = out.memptr();
Chris@49:       
Chris@49:       for(uword col=0; col < P_n_cols; ++col)
Chris@49:         {
Chris@49:         eT val = eT(0);
Chris@49:         
Chris@49:         uword i,j;
Chris@49:         for(i=0, j=1; j < P_n_rows; i+=2, j+=2)
Chris@49:           {
Chris@49:           val += P.at(i,col);
Chris@49:           val += P.at(j,col);
Chris@49:           }
Chris@49:         
Chris@49:         if(i < P_n_rows)
Chris@49:           {
Chris@49:           val += P.at(i,col);
Chris@49:           }
Chris@49:         
Chris@49:         out_mem[col] = val;
Chris@49:         }
Chris@49:       }
Chris@49:     else  // traverse across columns (i.e. find the sum in each row)
Chris@49:       {
Chris@49:       out.set_size(P_n_rows, 1);
Chris@49:       
Chris@49:       eT* out_mem = out.memptr();
Chris@49:       
Chris@49:       for(uword row=0; row < P_n_rows; ++row)
Chris@49:         {
Chris@49:         eT val = eT(0);
Chris@49:         
Chris@49:         uword i,j;
Chris@49:         for(i=0, j=1; j < P_n_cols; i+=2, j+=2)
Chris@49:           {
Chris@49:           val += P.at(row,i);
Chris@49:           val += P.at(row,j);
Chris@49:           }
Chris@49:         
Chris@49:         if(i < P_n_cols)
Chris@49:           {
Chris@49:           val += P.at(row,i);
Chris@49:           }
Chris@49:         
Chris@49:         out_mem[row] = val;
Chris@49:         }
Chris@49:       }
Chris@49:     }
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! @}