source: trunk/c++_tools/classifier/FeatureSelectorRandom.cc @ 642

// $Id$

#include "FeatureSelectorRandom.h"
#include "MatrixLookup.h"
#include "MatrixLookupWeighted.h"
#include "Target.h"
#include "c++_tools/random/random.h"

#include <algorithm>

namespace theplu {
namespace classifier {


  FeatureSelectorRandom::FeatureSelectorRandom(size_t N)
    : FeatureSelector(N)
  {
  }



  void FeatureSelectorRandom::update(const MatrixLookup& data, 
                                     const Target& target)
  {
    assert(data.columns()==target.size());
    update(data.rows());
  }


  void FeatureSelectorRandom::update(const MatrixLookupWeighted& data, 
                                 const Target& target)
  {
    assert(data.columns()==target.size());
    update(data.rows());
  }


  void FeatureSelectorRandom::update(size_t total_N)
  {
    features_.resize(0);
    features_.reserve(total_N);
    for (size_t i=0; i<total_N; ++i)
      features_.push_back(i);
    random::DiscreteUniform rnd;
    // Peter should use random_sample here, but not included in std
    std::random_shuffle(features_.begin(), features_.end(), rnd);
    features_.resize(N_);
  }


} // end of namespace classifier
} // end of namespace theplu