Chris@49: // Copyright (C) 2008-2012 NICTA (www.nicta.com.au)
Chris@49: // Copyright (C) 2008-2012 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_min
Chris@49: //! @{
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! \brief
Chris@49: //! For each row or for each column, find the minimum value.
Chris@49: //! The result is stored in a dense matrix that has either one column or one row.
Chris@49: //! The dimension, for which the minima are found, is set via the min() function.
Chris@49: template<typename T1>
Chris@49: inline void op_min::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_min>& in)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename T1::elem_type eT;
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 dim = in.aux_uword_a;
Chris@49:   arma_debug_check( (dim > 1), "min(): incorrect usage. dim must be 0 or 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(dim == 0)  // min in each column
Chris@49:     {
Chris@49:     arma_extra_debug_print("op_min::apply(), dim = 0");
Chris@49:     
Chris@49:     arma_debug_check( (X_n_rows == 0), "min(): given object has zero rows" );
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] = op_min::direct_min( X.colptr(col), X_n_rows );
Chris@49:       }
Chris@49:     }
Chris@49:   else
Chris@49:   if(dim == 1)  // min in each row
Chris@49:     {
Chris@49:     arma_extra_debug_print("op_min::apply(), dim = 1");
Chris@49:     
Chris@49:     arma_debug_check( (X_n_cols == 0), "min(): given object has zero columns" );
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:       out_mem[row] = op_min::direct_min( X, row );
Chris@49:       }
Chris@49:     }
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: arma_pure
Chris@49: inline 
Chris@49: eT
Chris@49: op_min::direct_min(const eT* const X, const uword n_elem)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   eT min_val = priv::most_pos<eT>();
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:     const eT X_i = X[i];
Chris@49:     const eT X_j = X[j];
Chris@49:     
Chris@49:     if(X_i < min_val) { min_val = X_i; }
Chris@49:     if(X_j < min_val) { min_val = X_j; }
Chris@49:     }
Chris@49:   
Chris@49:   if(i < n_elem)
Chris@49:     {
Chris@49:     const eT X_i = X[i];
Chris@49:     
Chris@49:     if(X_i < min_val) { min_val = X_i; }
Chris@49:     }
Chris@49:   
Chris@49:   return min_val;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: inline 
Chris@49: eT
Chris@49: op_min::direct_min(const eT* const X, const uword n_elem, uword& index_of_min_val)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   eT min_val = priv::most_pos<eT>();
Chris@49:   
Chris@49:   uword best_index = 0;
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:     const eT X_i = X[i];
Chris@49:     const eT X_j = X[j];
Chris@49:     
Chris@49:     if(X_i < min_val)
Chris@49:       {
Chris@49:       min_val    = X_i;
Chris@49:       best_index = i;
Chris@49:       }
Chris@49:     
Chris@49:     if(X_j < min_val)
Chris@49:       {
Chris@49:       min_val    = X_j;
Chris@49:       best_index = j;
Chris@49:       }
Chris@49:     }
Chris@49:   
Chris@49:   if(i < n_elem)
Chris@49:     {
Chris@49:     const eT X_i = X[i];
Chris@49:     
Chris@49:     if(X_i < min_val)
Chris@49:       {
Chris@49:       min_val    = X_i;
Chris@49:       best_index = i;
Chris@49:       }
Chris@49:     }
Chris@49:   
Chris@49:   index_of_min_val = best_index;
Chris@49:   
Chris@49:   return min_val;
Chris@49:   }  
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: inline 
Chris@49: eT
Chris@49: op_min::direct_min(const Mat<eT>& X, const uword row)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   const uword X_n_cols = X.n_cols;
Chris@49:   
Chris@49:   eT min_val = priv::most_pos<eT>();
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:     const eT tmp_i = X.at(row,i);
Chris@49:     const eT tmp_j = X.at(row,j);
Chris@49:     
Chris@49:     if(tmp_i < min_val) { min_val = tmp_i; }
Chris@49:     if(tmp_j < min_val) { min_val = tmp_j; }
Chris@49:     }
Chris@49:   
Chris@49:   if(i < X_n_cols)
Chris@49:     {
Chris@49:     const eT tmp_i = X.at(row,i);
Chris@49:     
Chris@49:     if(tmp_i < min_val) { min_val = tmp_i; }
Chris@49:     }
Chris@49:   
Chris@49:   return min_val;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: inline
Chris@49: eT
Chris@49: op_min::min(const subview<eT>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   arma_debug_check( (X.n_elem == 0), "min(): given object has no elements" );
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:   eT min_val = priv::most_pos<eT>();
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:       const eT tmp_i = A.at(start_row, i);
Chris@49:       const eT tmp_j = A.at(start_row, j);
Chris@49:       
Chris@49:       if(tmp_i < min_val) { min_val = tmp_i; }
Chris@49:       if(tmp_j < min_val) { min_val = tmp_j; }
Chris@49:       }
Chris@49:     
Chris@49:     if(i < end_col_p1)
Chris@49:       {
Chris@49:       const eT tmp_i = A.at(start_row, i);
Chris@49:       
Chris@49:       if(tmp_i < min_val) { min_val = tmp_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:       eT tmp_val = op_min::direct_min(X.colptr(col), X_n_rows);
Chris@49:       
Chris@49:       if(tmp_val < min_val) { min_val = tmp_val; }
Chris@49:       }
Chris@49:     }
Chris@49:   
Chris@49:   return min_val;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: typename arma_not_cx<typename T1::elem_type>::result
Chris@49: op_min::min(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:   const uword n_elem = P.get_n_elem();
Chris@49:   
Chris@49:   arma_debug_check( (n_elem == 0), "min(): given object has no elements" );
Chris@49:   
Chris@49:   eT min_val = priv::most_pos<eT>();
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:     ea_type A = P.get_ea();
Chris@49:     
Chris@49:     uword i,j;
Chris@49:     
Chris@49:     for(i=0, j=1; j<n_elem; i+=2, j+=2)
Chris@49:       {
Chris@49:       const eT tmp_i = A[i];
Chris@49:       const eT tmp_j = A[j];
Chris@49:       
Chris@49:       if(tmp_i < min_val) { min_val = tmp_i; }
Chris@49:       if(tmp_j < min_val) { min_val = tmp_j; }
Chris@49:       }
Chris@49:     
Chris@49:     if(i < n_elem)
Chris@49:       {
Chris@49:       const eT tmp_i = A[i];
Chris@49:       
Chris@49:       if(tmp_i < min_val) { min_val = tmp_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:         const eT tmp_i = P.at(0,i);
Chris@49:         const eT tmp_j = P.at(0,j);
Chris@49:         
Chris@49:         if(tmp_i < min_val) { min_val = tmp_i; }
Chris@49:         if(tmp_j < min_val) { min_val = tmp_j; }
Chris@49:         }
Chris@49:       
Chris@49:       if(i < n_cols)
Chris@49:         {
Chris@49:         const eT tmp_i = P.at(0,i);
Chris@49:         
Chris@49:         if(tmp_i < min_val) { min_val = tmp_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:           const eT tmp_i = P.at(i,col);
Chris@49:           const eT tmp_j = P.at(j,col);
Chris@49:           
Chris@49:           if(tmp_i < min_val) { min_val = tmp_i; }
Chris@49:           if(tmp_j < min_val) { min_val = tmp_j; }
Chris@49:           }
Chris@49:           
Chris@49:         if(i < n_rows)
Chris@49:           {
Chris@49:           const eT tmp_i = P.at(i,col);
Chris@49:           
Chris@49:           if(tmp_i < min_val) { min_val = tmp_i; }
Chris@49:           }
Chris@49:         }
Chris@49:       }
Chris@49:     }
Chris@49:   
Chris@49:   return min_val;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T>
Chris@49: inline 
Chris@49: std::complex<T>
Chris@49: op_min::direct_min(const std::complex<T>* const X, const uword n_elem)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   uword index   = 0;
Chris@49:   T     min_val = priv::most_pos<T>();
Chris@49:   
Chris@49:   for(uword i=0; i<n_elem; ++i)
Chris@49:     {
Chris@49:     const T tmp_val = std::abs(X[i]);
Chris@49:     
Chris@49:     if(tmp_val < min_val)
Chris@49:       {
Chris@49:       min_val = tmp_val;
Chris@49:       index   = i;
Chris@49:       }
Chris@49:     }
Chris@49:   
Chris@49:   return X[index];
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T>
Chris@49: inline 
Chris@49: std::complex<T>
Chris@49: op_min::direct_min(const std::complex<T>* const X, const uword n_elem, uword& index_of_min_val)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   uword index   = 0;
Chris@49:   T     min_val = priv::most_pos<T>();
Chris@49:   
Chris@49:   for(uword i=0; i<n_elem; ++i)
Chris@49:     {
Chris@49:     const T tmp_val = std::abs(X[i]);
Chris@49:     
Chris@49:     if(tmp_val < min_val)
Chris@49:       {
Chris@49:       min_val = tmp_val;
Chris@49:       index   = i;
Chris@49:       }
Chris@49:     }
Chris@49:   
Chris@49:   index_of_min_val = index;
Chris@49:   
Chris@49:   return X[index];
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T>
Chris@49: inline 
Chris@49: std::complex<T>
Chris@49: op_min::direct_min(const Mat< std::complex<T> >& X, const uword row)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   const uword X_n_cols = X.n_cols;
Chris@49:   
Chris@49:   uword index   = 0;
Chris@49:   T   min_val = priv::most_pos<T>();
Chris@49:   
Chris@49:   for(uword col=0; col<X_n_cols; ++col)
Chris@49:     {
Chris@49:     const T tmp_val = std::abs(X.at(row,col));
Chris@49:     
Chris@49:     if(tmp_val < min_val)
Chris@49:       {
Chris@49:       min_val = tmp_val;
Chris@49:       index   = col;
Chris@49:       }
Chris@49:     }
Chris@49:   
Chris@49:   return X.at(row,index);
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T>
Chris@49: inline
Chris@49: std::complex<T>
Chris@49: op_min::min(const subview< std::complex<T> >& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   arma_debug_check( (X.n_elem == 0), "min(): given object has no elements" );
Chris@49:   
Chris@49:   const Mat< std::complex<T> >& A = X.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:   const uword start_row = X.aux_row1;
Chris@49:   const uword start_col = X.aux_col1;
Chris@49:   
Chris@49:   const uword end_row_p1 = start_row + X_n_rows;
Chris@49:   const uword end_col_p1 = start_col + X_n_cols;
Chris@49:   
Chris@49:   T min_val = priv::most_pos<T>();
Chris@49:   
Chris@49:   uword best_row = 0;
Chris@49:   uword best_col = 0;
Chris@49:     
Chris@49:   if(X_n_rows == 1)
Chris@49:     {
Chris@49:     best_col = 0;
Chris@49:     
Chris@49:     for(uword col=start_col; col < end_col_p1; ++col)
Chris@49:       {
Chris@49:       const T tmp_val = std::abs( A.at(start_row, col) );
Chris@49:       
Chris@49:       if(tmp_val < min_val)
Chris@49:         {
Chris@49:         min_val  = tmp_val;
Chris@49:         best_col = col;
Chris@49:         }
Chris@49:       }
Chris@49:     
Chris@49:     best_row = start_row;
Chris@49:     }
Chris@49:   else
Chris@49:     {
Chris@49:     for(uword col=start_col; col < end_col_p1; ++col)
Chris@49:     for(uword row=start_row; row < end_row_p1; ++row)
Chris@49:       {
Chris@49:       const T tmp_val = std::abs( A.at(row, col) );
Chris@49:       
Chris@49:       if(tmp_val < min_val)
Chris@49:         {
Chris@49:         min_val  = tmp_val;
Chris@49:         best_row = row;
Chris@49:         best_col = col;
Chris@49:         }
Chris@49:       }
Chris@49:     }
Chris@49:   
Chris@49:   return A.at(best_row, best_col);
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: typename arma_cx_only<typename T1::elem_type>::result
Chris@49: op_min::min(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:   typedef typename get_pod_type<eT>::result T;
Chris@49:   
Chris@49:   const Proxy<T1> P(X.get_ref());
Chris@49:   
Chris@49:   const uword n_elem = P.get_n_elem();
Chris@49:   
Chris@49:   arma_debug_check( (n_elem == 0), "min(): given object has no elements" );
Chris@49:   
Chris@49:   T min_val = priv::most_pos<T>();
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:     ea_type A = P.get_ea();
Chris@49:     
Chris@49:     uword index = 0;
Chris@49:     
Chris@49:     for(uword i=0; i<n_elem; ++i)
Chris@49:       {
Chris@49:       const T tmp = std::abs(A[i]);
Chris@49:       
Chris@49:       if(tmp < min_val)
Chris@49:         {
Chris@49:         min_val = tmp;
Chris@49:         index   = i;
Chris@49:         }
Chris@49:       }
Chris@49:     
Chris@49:     return( A[index] );
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:     uword best_row = 0;
Chris@49:     uword best_col = 0;
Chris@49:     
Chris@49:     if(n_rows == 1)
Chris@49:       {
Chris@49:       for(uword col=0; col < n_cols; ++col)
Chris@49:         {
Chris@49:         const T tmp = std::abs(P.at(0,col));
Chris@49:         
Chris@49:         if(tmp < min_val)
Chris@49:           {
Chris@49:           min_val  = tmp;
Chris@49:           best_col = col;
Chris@49:           }
Chris@49:         }
Chris@49:       }
Chris@49:     else
Chris@49:       {
Chris@49:       for(uword col=0; col < n_cols; ++col)
Chris@49:       for(uword row=0; row < n_rows; ++row)
Chris@49:         {
Chris@49:         const T tmp = std::abs(P.at(row,col));
Chris@49:         
Chris@49:         if(tmp < min_val)
Chris@49:           {
Chris@49:           min_val = tmp;
Chris@49:           
Chris@49:           best_row = row;
Chris@49:           best_col = col;
Chris@49:           }
Chris@49:         }
Chris@49:       }
Chris@49:     
Chris@49:     return P.at(best_row, best_col);
Chris@49:     }
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! @}