FBDTClassifier.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
 
#pragma once
 
#include <framework/datastore/RelationsObject.h>
#include <FastBDT.h>
 
#include <tracking/trackFindingVXD/filterTools/FBDTClassifierHelper.h>
#include <tracking/trackFindingVXD/filterTools/DecorrelationMatrix.h>
#include <array>
#include <vector>
#include <iostream>
 
typedef FastBDT::Forest<unsigned int> FBDTForest;
 
namespace Belle2 {

  template<size_t Ndims = 9>
  class FBDTClassifier : public RelationsObject {
 
  public:
 
    FBDTClassifier() { ; }// = default; /**< default constructor */

    FBDTClassifier(const FBDTForest& forest, const std::vector<FastBDT::FeatureBinning<double> >& fB,
                   const Belle2::DecorrelationMatrix<9>& dM) : m_forest(forest), m_featBins(fB), m_decorrMat(dM) { ; }
 
    ~FBDTClassifier() { ; } 

    double analyze(const std::array<double, Ndims>& hits) const;

    void train(const std::vector<Belle2::FBDTTrainSample<Ndims> >& samples,
               int nTree, int depth, double shrinkage = 0.15, double ratio = 0.5);

    void readFromStream(std::istream& is);

    void writeToStream(std::ostream& os) const;

    FBDTForest getForest() const { return m_forest; }

    std::vector<FastBDT::FeatureBinning<double> > getFeatureBinnings()  const { return m_featBins; }

    Belle2::DecorrelationMatrix<9> getDecorrelationMatrix() const { return m_decorrMat; }
 
  private:
 
    FBDTForest m_forest{}; 
 
    std::vector<FastBDT::FeatureBinning<double> > m_featBins{}; 
 
    Belle2::DecorrelationMatrix<Ndims> m_decorrMat{}; 
 
    // TODO: make this work with the externals -> tell Thomas Keck what is needed for this stuff to work in the externals
    ClassDef(FBDTClassifier, 2); // first version: only Forest and FeatureBinnings present
  };
 
 
 
  // =================================== IMPLEMENTATION ==============================
 
  template<size_t Ndims>
  double FBDTClassifier<Ndims>::analyze(const std::array<double, Ndims>& hits) const
  {
    std::vector<double> positions = m_decorrMat.decorrelate(hits);
 
    std::vector<unsigned> bins(Ndims);
    for (size_t i = 0; i < Ndims; ++i) {
      bins[i] = m_featBins[i].ValueToBin(positions[i]);
    }
 
    return m_forest.Analyse(bins);
  }

} // end namespace Belle2