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 spop_mean
Chris@49: //! @{
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: void
Chris@49: spop_mean::apply(SpMat<typename T1::elem_type>& out, const SpOp<T1, spop_mean>& 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), "mean(): incorrect usage. dim must be 0 or 1");
Chris@49:   
Chris@49:   SpProxy<T1> p(in.m);
Chris@49:   
Chris@49:   if(p.is_alias(out) == false)
Chris@49:     {
Chris@49:     spop_mean::apply_noalias(out, p, dim);
Chris@49:     }
Chris@49:   else
Chris@49:     {
Chris@49:     SpMat<eT> tmp;
Chris@49:     
Chris@49:     spop_mean::apply_noalias(tmp, p, dim);
Chris@49:     
Chris@49:     out.steal_mem(tmp);
Chris@49:     }
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: void
Chris@49: spop_mean::apply_noalias
Chris@49:   (
Chris@49:         SpMat<typename T1::elem_type>& out_ref,
Chris@49:   const SpProxy<T1>&                   p,
Chris@49:   const uword                          dim
Chris@49:   )
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49: 
Chris@49:   typedef typename T1::elem_type eT;
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)
Chris@49:     {
Chris@49:     arma_extra_debug_print("spop_mean::apply_noalias(), dim = 0");
Chris@49: 
Chris@49:     out_ref.set_size((p_n_rows > 0) ? 1 : 0, p_n_cols);
Chris@49: 
Chris@49:     if(p_n_rows > 0)
Chris@49:       {
Chris@49:       for(uword col = 0; col < p_n_cols; ++col)
Chris@49:         {
Chris@49:         // Do we have to use an iterator or can we use memory directly?
Chris@49:         if(SpProxy<T1>::must_use_iterator == true)
Chris@49:           {
Chris@49:           typename SpProxy<T1>::const_iterator_type it  = p.begin_col(col);
Chris@49:           typename SpProxy<T1>::const_iterator_type end = p.begin_col(col + 1);
Chris@49:           
Chris@49:           const uword n_zero = p.get_n_rows() - (end.pos() - it.pos());
Chris@49:           
Chris@49:           out_ref.at(col) = spop_mean::iterator_mean(it, end, n_zero, eT(0));
Chris@49:           }
Chris@49:         else
Chris@49:           {
Chris@49:           out_ref.at(col) = spop_mean::direct_mean
Chris@49:             (
Chris@49:             &p.get_values()[p.get_col_ptrs()[col]],
Chris@49:             p.get_col_ptrs()[col + 1] - p.get_col_ptrs()[col],
Chris@49:             p.get_n_rows()
Chris@49:             );
Chris@49:           }
Chris@49:         }
Chris@49:       }
Chris@49:     }
Chris@49:   else if (dim == 1)
Chris@49:     {
Chris@49:     arma_extra_debug_print("spop_mean::apply_noalias(), dim = 1");
Chris@49:     
Chris@49:     out_ref.set_size(p_n_rows, (p_n_cols > 0) ? 1 : 0);
Chris@49:     
Chris@49:     if(p_n_cols > 0)
Chris@49:       {
Chris@49:       for(uword row = 0; row < p_n_rows; ++row)
Chris@49:         {
Chris@49:         // We must use an iterator regardless of how it is stored.
Chris@49:         typename SpProxy<T1>::const_row_iterator_type it  = p.begin_row(row);
Chris@49:         typename SpProxy<T1>::const_row_iterator_type end = p.end_row(row);
Chris@49:         
Chris@49:         const uword n_zero = p.get_n_cols() - (end.pos() - it.pos());
Chris@49:         
Chris@49:         out_ref.at(row) = spop_mean::iterator_mean(it, end, n_zero, eT(0));
Chris@49:         }
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: spop_mean::direct_mean
Chris@49:   (
Chris@49:   const eT* const X,
Chris@49:   const uword length,
Chris@49:   const uword N
Chris@49:   )
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49: 
Chris@49:   typedef typename get_pod_type<eT>::result T;
Chris@49: 
Chris@49:   const eT result = arrayops::accumulate(X, length) / T(N);
Chris@49: 
Chris@49:   return arma_isfinite(result) ? result : spop_mean::direct_mean_robust(X, length, N);
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: inline
Chris@49: eT
Chris@49: spop_mean::direct_mean_robust
Chris@49:   (
Chris@49:   const eT* const X,
Chris@49:   const uword length,
Chris@49:   const uword N
Chris@49:   )
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49: 
Chris@49:   typedef typename get_pod_type<eT>::result T;
Chris@49: 
Chris@49:   uword i, j;
Chris@49: 
Chris@49:   eT r_mean = eT(0);
Chris@49: 
Chris@49:   const uword diff = (N - length); // number of zeros
Chris@49: 
Chris@49:   for(i = 0, j = 1; j < length; i += 2, j += 2)
Chris@49:     {
Chris@49:     const eT Xi = X[i];
Chris@49:     const eT Xj = X[j];
Chris@49: 
Chris@49:     r_mean += (Xi - r_mean) / T(diff + j);
Chris@49:     r_mean += (Xj - r_mean) / T(diff + j + 1);
Chris@49:     }
Chris@49: 
Chris@49:   if(i < length)
Chris@49:     {
Chris@49:     const eT Xi = X[i];
Chris@49: 
Chris@49:     r_mean += (Xi - r_mean) / T(diff + i + 1);
Chris@49:     }
Chris@49: 
Chris@49:   return r_mean;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: typename T1::elem_type
Chris@49: spop_mean::mean_all(const SpBase<typename T1::elem_type, T1>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49: 
Chris@49:   SpProxy<T1> p(X.get_ref());
Chris@49: 
Chris@49:   if (SpProxy<T1>::must_use_iterator == true)
Chris@49:     {
Chris@49:     typename SpProxy<T1>::const_iterator_type it  = p.begin();
Chris@49:     typename SpProxy<T1>::const_iterator_type end = p.end();
Chris@49: 
Chris@49:     return spop_mean::iterator_mean(it, end, p.get_n_elem() - p.get_n_nonzero(), typename T1::elem_type(0));
Chris@49:     }
Chris@49:   else // must_use_iterator == false; that is, we can directly access the values array
Chris@49:     {
Chris@49:     return spop_mean::direct_mean(p.get_values(), p.get_n_nonzero(), p.get_n_elem());
Chris@49:     }
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1, typename eT>
Chris@49: inline
Chris@49: eT
Chris@49: spop_mean::iterator_mean(T1& it, const T1& end, const uword n_zero, const eT junk)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   arma_ignore(junk);
Chris@49: 
Chris@49:   typedef typename get_pod_type<eT>::result T;
Chris@49: 
Chris@49:   eT sum = eT(0);
Chris@49: 
Chris@49:   T1 backup_it(it); // in case we have to use robust iterator_mean
Chris@49: 
Chris@49:   const uword it_begin_pos = it.pos();
Chris@49: 
Chris@49:   while (it != end)
Chris@49:     {
Chris@49:     sum += (*it);
Chris@49:     ++it;
Chris@49:     }
Chris@49: 
Chris@49:   const eT result = sum / T(n_zero + (it.pos() - it_begin_pos));
Chris@49: 
Chris@49:   return arma_isfinite(result) ? result : spop_mean::iterator_mean_robust(backup_it, end, n_zero, eT(0));
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1, typename eT>
Chris@49: inline
Chris@49: eT
Chris@49: spop_mean::iterator_mean_robust(T1& it, const T1& end, const uword n_zero, const eT junk)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   arma_ignore(junk);
Chris@49: 
Chris@49:   typedef typename get_pod_type<eT>::result T;
Chris@49: 
Chris@49:   eT r_mean = eT(0);
Chris@49: 
Chris@49:   const uword it_begin_pos = it.pos();
Chris@49: 
Chris@49:   while (it != end)
Chris@49:     {
Chris@49:     r_mean += ((*it - r_mean) / T(n_zero + (it.pos() - it_begin_pos) + 1));
Chris@49:     ++it;
Chris@49:     }
Chris@49: 
Chris@49:   return r_mean;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! @}