Chris@49: // Copyright (C) 2012 Ryan Curtin
Chris@49: // Copyright (C) 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_n_unique
Chris@49: //! @{
Chris@49: 
Chris@49: 
Chris@49: //! \brief
Chris@49: //! Get the number of unique nonzero elements in two sparse matrices.
Chris@49: //! This is very useful for determining the amount of memory necessary before
Chris@49: //! a sparse matrix operation on two matrices.
Chris@49: 
Chris@49: template<typename T1, typename T2, typename op_n_unique_type>
Chris@49: inline
Chris@49: uword
Chris@49: n_unique
Chris@49:   (
Chris@49:   const SpBase<typename T1::elem_type, T1>& x,
Chris@49:   const SpBase<typename T2::elem_type, T2>& y,
Chris@49:   const op_n_unique_type junk
Chris@49:   )
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   const SpProxy<T1> pa(x.get_ref());
Chris@49:   const SpProxy<T2> pb(y.get_ref());
Chris@49:   
Chris@49:   return n_unique(pa,pb,junk);
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1, typename T2, typename op_n_unique_type>
Chris@49: arma_hot
Chris@49: inline
Chris@49: uword
Chris@49: n_unique
Chris@49:   (
Chris@49:   const SpProxy<T1>& pa,
Chris@49:   const SpProxy<T2>& pb,
Chris@49:   const op_n_unique_type junk
Chris@49:   )
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   arma_ignore(junk);
Chris@49:   
Chris@49:   // Use iterators.
Chris@49:   typename SpProxy<T1>::const_iterator_type x_it = pa.begin();
Chris@49:   typename SpProxy<T2>::const_iterator_type y_it = pb.begin();
Chris@49: 
Chris@49:   uword total_n_nonzero = 0;
Chris@49: 
Chris@49:   while((x_it != pa.end()) || (y_it != pb.end()))
Chris@49:     {
Chris@49:     if(x_it == y_it)
Chris@49:       {
Chris@49:       if(op_n_unique_type::eval((*x_it), (*y_it)) != typename T1::elem_type(0))
Chris@49:         {
Chris@49:         ++total_n_nonzero;
Chris@49:         }
Chris@49: 
Chris@49:       ++x_it;
Chris@49:       ++y_it;
Chris@49:       }
Chris@49:     else
Chris@49:       {
Chris@49:       if((x_it.col() < y_it.col()) || ((x_it.col() == y_it.col()) && (x_it.row() < y_it.row()))) // if y is closer to the end
Chris@49:         {
Chris@49:         if(op_n_unique_type::eval((*x_it), typename T1::elem_type(0)) != typename T1::elem_type(0))
Chris@49:           {
Chris@49:           ++total_n_nonzero;
Chris@49:           }
Chris@49: 
Chris@49:         ++x_it;
Chris@49:         }
Chris@49:       else // x is closer to the end
Chris@49:         {
Chris@49:         if(op_n_unique_type::eval(typename T1::elem_type(0), (*y_it)) != typename T1::elem_type(0))
Chris@49:           {
Chris@49:           ++total_n_nonzero;
Chris@49:           }
Chris@49: 
Chris@49:         ++y_it;
Chris@49:         }
Chris@49:       }
Chris@49:     }
Chris@49: 
Chris@49:   return total_n_nonzero;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: // Simple operators.
Chris@49: struct op_n_unique_add
Chris@49:   {
Chris@49:   template<typename eT> inline static eT eval(const eT& l, const eT& r) { return (l + r); }
Chris@49:   };
Chris@49: 
Chris@49: struct op_n_unique_sub
Chris@49:   {
Chris@49:   template<typename eT> inline static eT eval(const eT& l, const eT& r) { return (l - r); }
Chris@49:   };
Chris@49: 
Chris@49: struct op_n_unique_mul
Chris@49:   {
Chris@49:   template<typename eT> inline static eT eval(const eT& l, const eT& r) { return (l * r); }
Chris@49:   };
Chris@49: 
Chris@49: struct op_n_unique_count
Chris@49:   {
Chris@49:   template<typename eT> inline static eT eval(const eT& l, const eT& r) { return 1; }
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! @}