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 op_prod
Chris@49: //! @{
Chris@49: 
Chris@49: //! \brief
Chris@49: //! Immediate product 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 prod() function for more details.
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: void
Chris@49: op_prod::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_prod>& 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), "prod(): incorrect usage. dim must be 0 or 1");
Chris@49:   
Chris@49:   const unwrap_check<T1> tmp(in.m, out);
Chris@49:   const Mat<eT>& 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 product 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::product(X.colptr(col), X_n_rows);
Chris@49:       }
Chris@49:     }
Chris@49:   else  // traverse across columns (i.e. find the product 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(1);
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: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: inline
Chris@49: eT
Chris@49: op_prod::prod(const subview<eT>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   eT val = eT(1);
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(X_n_rows == 1)
Chris@49:     {
Chris@49:     const Mat<eT>& A = X.m;
Chris@49:   
Chris@49:     const uword start_row = X.aux_row1;
Chris@49:     const uword start_col = X.aux_col1;
Chris@49:     
Chris@49:     const uword end_col_p1 = start_col + X_n_cols;
Chris@49:     
Chris@49:     uword i,j;
Chris@49:     for(i=start_col, j=start_col+1; j < end_col_p1; i+=2, j+=2)
Chris@49:       {
Chris@49:       val *= A.at(start_row, i);
Chris@49:       val *= A.at(start_row, j);
Chris@49:       }
Chris@49:     
Chris@49:     if(i < end_col_p1)
Chris@49:       {
Chris@49:       val *= A.at(start_row, i);
Chris@49:       }
Chris@49:     }
Chris@49:   else
Chris@49:     {
Chris@49:     for(uword col=0; col < X_n_cols; ++col)
Chris@49:       {
Chris@49:       val *= arrayops::product( X.colptr(col), X_n_rows );
Chris@49:       }
Chris@49:     }
Chris@49:   
Chris@49:   return val;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: typename T1::elem_type
Chris@49: op_prod::prod(const Base<typename T1::elem_type,T1>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename T1::elem_type eT;
Chris@49:   
Chris@49:   const Proxy<T1> P(X.get_ref());
Chris@49:   
Chris@49:   eT val = eT(1);
Chris@49:   
Chris@49:   if(Proxy<T1>::prefer_at_accessor == false)
Chris@49:     {
Chris@49:     typedef typename Proxy<T1>::ea_type ea_type;
Chris@49:     
Chris@49:     const ea_type A = P.get_ea();
Chris@49:     
Chris@49:     const uword n_elem = P.get_n_elem();
Chris@49:     
Chris@49:     uword i,j;
Chris@49:     for(i=0, j=1; j < n_elem; i+=2, j+=2)
Chris@49:       {
Chris@49:       val *= A[i];
Chris@49:       val *= A[j];
Chris@49:       }
Chris@49:     
Chris@49:     if(i < n_elem)
Chris@49:       {
Chris@49:       val *= A[i];
Chris@49:       }
Chris@49:     }
Chris@49:   else
Chris@49:     {
Chris@49:     const uword n_rows = P.get_n_rows();
Chris@49:     const uword n_cols = P.get_n_cols();
Chris@49:     
Chris@49:     if(n_rows == 1)
Chris@49:       {
Chris@49:       uword i,j;
Chris@49:       for(i=0, j=1; j < n_cols; i+=2, j+=2)
Chris@49:         {
Chris@49:         val *= P.at(0,i);
Chris@49:         val *= P.at(0,j);
Chris@49:         }
Chris@49:       
Chris@49:       if(i < n_cols)
Chris@49:         {
Chris@49:         val *= P.at(0,i);
Chris@49:         }
Chris@49:       }
Chris@49:     else
Chris@49:       {
Chris@49:       for(uword col=0; col < n_cols; ++col)
Chris@49:         {
Chris@49:         uword i,j;
Chris@49:         for(i=0, j=1; j < 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 < n_rows)
Chris@49:           {
Chris@49:           val *= P.at(i,col);
Chris@49:           }
Chris@49:         }
Chris@49:       }
Chris@49:     }
Chris@49:   
Chris@49:   return val;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! @}