max@0: // Copyright (C) 2009-2011 NICTA (www.nicta.com.au)
max@0: // Copyright (C) 2009-2011 Conrad Sanderson
max@0: // 
max@0: // This file is part of the Armadillo C++ library.
max@0: // It is provided without any warranty of fitness
max@0: // for any purpose. You can redistribute this file
max@0: // and/or modify it under the terms of the GNU
max@0: // Lesser General Public License (LGPL) as published
max@0: // by the Free Software Foundation, either version 3
max@0: // of the License or (at your option) any later version.
max@0: // (see http://www.opensource.org/licenses for more info)
max@0: 
max@0: 
max@0: //! \addtogroup fn_prod
max@0: //! @{
max@0: 
max@0: 
max@0: //! \brief
max@0: //! Delayed product of elements of a matrix along a specified dimension (either rows or columns).
max@0: //! The result is stored in a dense matrix that has either one column or one row.
max@0: //! For dim = 0, find the sum of each column (i.e. traverse across rows)
max@0: //! For dim = 1, find the sum of each row (i.e. traverse across columns)
max@0: //! The default is dim = 0.
max@0: //! NOTE: this function works differently than in Matlab/Octave.
max@0: 
max@0: template<typename T1>
max@0: arma_inline
max@0: const Op<T1, op_prod>
max@0: prod(const Base<typename T1::elem_type,T1>& X, const uword dim = 0)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   return Op<T1, op_prod>(X.get_ref(), dim, 0);
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: //! \brief
max@0: //! Immediate 'product of all values' operation for a row vector
max@0: template<typename eT>
max@0: inline
max@0: arma_warn_unused
max@0: eT
max@0: prod(const Row<eT>& X)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   return arrayops::product(X.memptr(), X.n_elem);
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: //! \brief
max@0: //! Immediate 'product of all values' operation for a column vector
max@0: template<typename eT>
max@0: inline
max@0: arma_warn_unused
max@0: eT
max@0: prod(const Col<eT>& X)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   return arrayops::product(X.memptr(), X.n_elem);
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: //! \brief
max@0: //! Immediate 'product of all values' operation,
max@0: //! invoked, for example, by: prod(prod(A))
max@0: 
max@0: template<typename T1>
max@0: inline
max@0: typename T1::elem_type
max@0: prod(const Op<T1, op_prod>& in)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   arma_extra_debug_print("prod(): two consecutive prod() calls detected");
max@0:   
max@0:   typedef typename T1::elem_type eT;
max@0:   
max@0:   const unwrap<T1>   tmp(in.m);
max@0:   const Mat<eT>& X = tmp.M;
max@0:   
max@0:   return arrayops::product( X.memptr(), X.n_elem );
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: template<typename T1>
max@0: inline
max@0: const Op<Op<T1, op_prod>, op_prod>
max@0: prod(const Op<T1, op_prod>& in, const uword dim)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   return Op<Op<T1, op_prod>, op_prod>(in, dim, 0);
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: //! product of all values of a subview_row
max@0: template<typename eT>
max@0: inline
max@0: arma_warn_unused
max@0: eT
max@0: prod(const subview_row<eT>& S)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   const Mat<eT>& X = S.m;
max@0:   
max@0:   const uword n_elem         = S.n_elem;
max@0:   const uword row            = S.aux_row1;
max@0:   const uword start_col      = S.aux_col1;
max@0:   const uword end_col_plus_1 = start_col + S.n_cols;
max@0:   
max@0:   eT val = eT(1);
max@0:   
max@0:   if(n_elem > 0)
max@0:     {
max@0:     for(uword col=start_col; col<end_col_plus_1; ++col)
max@0:       {
max@0:       val *= X.at(row,col);
max@0:       }
max@0:     }
max@0:   
max@0:   return val;
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: //! product of all values of a subview_col
max@0: template<typename eT>
max@0: inline
max@0: arma_warn_unused
max@0: eT
max@0: prod(const subview_col<eT>& S)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   return (S.n_elem > 0) ? arrayops::product( S.colptr(0), S.n_rows ) : eT(1);
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: //! product of all values of a diagview
max@0: template<typename eT>
max@0: arma_warn_unused
max@0: inline
max@0: eT
max@0: prod(const diagview<eT>& X)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   const uword X_n_elem = X.n_elem;
max@0:   
max@0:   eT val = eT(1);
max@0:   
max@0:   for(uword i=0; i<X_n_elem; ++i)
max@0:     {
max@0:     val *= X[i];
max@0:     }
max@0:   
max@0:   return val;
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: template<typename eT, typename T1>
max@0: inline
max@0: arma_warn_unused
max@0: eT
max@0: prod(const subview_elem1<eT,T1>& A)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   const Col<eT> X(A);
max@0:   
max@0:   return prod(X);
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: //! @}