fn_process_labels.hpp

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// Copyright (C) 2011 the authors listed below
// http://ecocpak.sourceforge.net
// 
// Authors:
// - Dimitrios Bouzas (bouzas at ieee dot org)
// - Nikolaos Arvanitopoulos (niarvani at ieee dot org)
// - Anastasios Tefas (tefas at aiia dot csd dot auth dot gr)
// 
// This file is part of the ECOC PAK C++ library. It is 
// provided without any warranty of fitness for any purpose.
//
// You can redistribute this file and/or modify it under 
// the terms of the GNU Lesser General Public License (LGPL) 
// as published by the Free Software Foundation, either 
// version 3 of the License or (at your option) any later 
// version.
// (see http://www.opensource.org/licenses for more info)





template<typename eT1, typename eT2>
Col<u32>
process_labels
  (
  const Mat<eT1>& labels,
  Col<eT2>& n_samples_each_class,
  u32& n_classes
  )
  {
  arma_extra_debug_sigprint();
  
  // sort the labels in ascending order
  Mat<eT1> tmp = sort(labels);
  Mat<u32> tmp_pos = sort_index(labels);
  
  // number of element
  const u32 n_elem = labels.n_elem;
  
  // new vector of transformed labels
  Col<u32> labels_out(n_elem);
  
  // set size for n_samples_each_class  vector
  n_samples_each_class.set_size(n_elem);
  
  // initialize elements of n_samples_each_class to zero
  n_samples_each_class.zeros();
  
  // first step
  eT1 cur_value = tmp[0];
  n_classes++;
  u32 j = 0;
  n_samples_each_class[j]++;
  labels_out[tmp_pos[0]] = n_classes;
  
  // rest of steps
  for(u32 i = 1; i < n_elem; i++)
    {
    if(cur_value != tmp[i])
      {
      cur_value = tmp[i];
      n_classes++;
      j++;
      }

    n_samples_each_class[j]++;      
    labels_out[tmp_pos[i]] = n_classes;
    }
  
  // dump junk
  n_samples_each_class = n_samples_each_class.rows(0, n_classes - 1);
  
  return labels_out;
  }



template<typename eT1>
Col<u32>
process_labels
  (
  const Mat<eT1>& labels,
  u32& n_classes
  )
  {
  arma_extra_debug_sigprint();
  
  // sort the labels in ascending order
  Mat<eT1> tmp = sort(labels);
  Mat<u32> tmp_pos = sort_index(labels);
  
  // number of element
  const u32 n_elem = labels.n_elem;
  
  // new vector of transformed labels
  Col<u32> labels_out(n_elem);
  
  // first step
  eT1 cur_value = tmp[0];
  n_classes++;
  u32 j = 0;
  labels_out[tmp_pos[0]] = n_classes;
  
  // rest of steps
  for(u32 i = 1; i < n_elem; i++)
    {
    if(cur_value != tmp[i])
      {
      cur_value = tmp[i];
      n_classes++;
      j++;
      }
  
    labels_out[tmp_pos[i]] = n_classes;
    }
  
  return labels_out;
  }



template<typename eT1>
Col<u32>
process_labels
  (
  const Mat<eT1>& labels
  )
  {
  arma_extra_debug_sigprint();
  
  u32 n_classes = 0;
  
  // sort the labels in ascending order
  Mat<eT1> tmp = sort(labels);
  Mat<u32> tmp_pos = sort_index(labels);
  
  // number of element
  const u32 n_elem = labels.n_elem;
  
  // new vector of transformed labels
  Col<u32> labels_out(n_elem);
  
  // first step
  eT1 cur_value = tmp[0];
  n_classes++;
  u32 j = 0;
  labels_out[tmp_pos[0]] = n_classes;
  
  // for all the elements
  for(u32 i = 1; i < n_elem; i++)
    {
    // if current value is different than the i-th label
    if(cur_value != tmp[i])
      {
      cur_value = tmp[i];
      n_classes++; // increase number of classes
      j++;
      }

        // update the new labels vector
    labels_out[tmp_pos[i]] = n_classes;
    }
  
  return labels_out;
  }