SVDMCFudgeFactorFunction.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/logging/Logger.h>
#include <TObject.h>
#include <TF1.h>
#include <TString.h>
#include <TROOT.h>
#include <TGraph.h>
 
#include <cmath>
#include <vector>
 
namespace Belle2 {
  class SVDMCFudgeFactorFunction : public TObject {
 
  public:
 
    typedef double (SVDMCFudgeFactorFunction::*fudgeFactorFunction)(double) const;
 
    double getFudgeFactor(double trkAngle) const
    {
      fudgeFactorFunction f = m_implementations[m_current];
      return (this->*f)(trkAngle) ;
    }
 
    SVDMCFudgeFactorFunction()
    {
      // The m_implementations vector is static.
      // We have to initialize it just once.
      if (m_implementations.size() == 0) {
        m_implementations.push_back(&SVDMCFudgeFactorFunction::cheby_v0);
        m_implementations.push_back(&SVDMCFudgeFactorFunction::tgraph_v0);
      }
 
      m_current = m_implementations.size() - 1;
 
    };
 
    void set_current(int current)
    {
      m_current = current;
    }
 
    //SETTERS FOR function ID = 0 (cheby_v0)
    void set_chebyCoeffs(std::vector<double> c)
    {
      m_chebyCoeffs = c;
    }
 
    //SETTERS FOR function ID = 1 (tgraph_v0)
    void set_graphPoints(std::vector<double> x, std::vector<double> y)
    {
      m_x = x;
      m_y = y;
    }
 
    SVDMCFudgeFactorFunction(const Belle2::SVDMCFudgeFactorFunction& a);
 
    SVDMCFudgeFactorFunction& operator=(const Belle2::SVDMCFudgeFactorFunction& a);
 
  private:
    std::vector<double> m_chebyCoeffs;
 
    double cheby_v0(double trkAngle) const
    {
      TF1* f = (TF1*) gROOT->GetFunction(TString::Format("chebyshev%lu", m_chebyCoeffs.size() - 1));
      f->SetParameters(&m_chebyCoeffs[0]);
 
      return f->Eval(trkAngle);
    };
 
    std::vector<double> m_x;
    std::vector<double> m_y;
 
    double tgraph_v0(double trkAngle) const
    {
      TGraph* g = new TGraph(m_x.size(), &m_x[0], &m_y[0]);
      double returnvalue = g->Eval(trkAngle);
      delete g;
 
      return returnvalue;
    };
 
    int m_current;
 
    static std::vector < fudgeFactorFunction > m_implementations; 
 
    ClassDef(SVDMCFudgeFactorFunction, 2);
  };
 
}