/cvmfs/atlas.cern.ch/repo/sw/ASG/AnalysisBase/2.4.31/MVAUtils/MVAUtils/BDT.h

// dear emacs, this is really -*- C++ -*-
#ifndef MVAUtils_BDT_H
#define MVAUtils_BDT_H

#include<vector>
#include "TString.h"

#include "MVAUtils/Node.h"

namespace TMVA { 
  class DecisionTreeNode; 
  class MethodBDT; 
}
class TTree;

namespace MVAUtils 
{
  class BDT
  {
  public:
    BDT(TTree *tree);
    BDT(TMVA::MethodBDT *bdt);

    // create new tree from root file
    void newTree(const std::vector<int>& vars, const std::vector<float>& values);
    
    // create new tree from decision tree
    void newTree(const TMVA::DecisionTreeNode *node); 

    unsigned int GetNTrees() const { return m_forest.size(); }

    float GetOffset() const { return m_offset; }

    // these return offset + sum
    float GetResponse(const std::vector<float>& values) const;
    float GetResponse(const std::vector<float*>& pointers) const;

    float GetResponse() const { 
      return (m_pointers.size() ? GetResponse(m_pointers) : -9999.); 
    }

    // these return 2.0/(1.0+exp(-2.0*sum))-1, with no offset.
    float GetGradBoostMVA(const std::vector<float>& values) const;
    float GetGradBoostMVA(const std::vector<float*>& pointers) const;

    // special function when there are mutliple classes (for b-tagging)
    std::vector<float> GetMultiResponse(const std::vector<float>& values, unsigned int numClasses) const;
    std::vector<float> GetMultiResponse(const std::vector<float*>& pointers, unsigned int numClasses) const;
    
    std::vector<float> GetValues() const;
    
    std::vector<float*> GetPointers() const { return m_pointers; }

    void SetPointers(std::vector<float*>& pointers) { m_pointers = pointers; }
    
    //dump out a TTree
    TTree* WriteTree(TString name = "BDT");
    
    //for debugging, print out tree or forest to stdout
    void PrintForest() const;
    void PrintTree(Node::index_t index) const;

  private:

    float GetTreeResponse(const std::vector<float>& values, Node::index_t index) const;
    float GetTreeResponse(const std::vector<float*>& pointers, Node::index_t index) const;

    float m_offset; 
    std::vector<Node::index_t> m_forest; 
    std::vector<float*> m_pointers; 
    std::vector<Node> m_nodes; 
    
  };
}

#endif

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