HistogramFitFCN Class Reference

#include <HistogramFitFCN.h>

List of all members.

Public Member Functions
	HistogramFitFCN (const TH1D *=NULL, const TH1D *=NULL)
	~HistogramFitFCN ()
void	SetTemplateHist (const TH1D *, double ped=-1)
void	SetPulseHist (const TH1D *)
void	SetRefineFactor (int refine_factor)
void	SetTimeOffset (double time_offset)
double	operator() (const std::vector< double > &par) const
	Used for calls with parameters The return value is the chi squared weighted by errors in fTemplateHist Parameters: 1. Pedestal 2. Amplitude 3. Timing.
double	Up () const
	Used for error... somehow?
int	GetNDoF ()
Private Attributes
int	fNDoF
double	fTimeOffset
	the time offset to use
double	fTemplatePedestal
int	fRefineFactor
const TH1D *	fTemplateHist
const TH1D *	fPulseHist

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Detailed Description

Definition at line 9 of file HistogramFitFCN.h.

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Constructor & Destructor Documentation

HistogramFitFCN::HistogramFitFCN	(	const TH1D *	hTemplate = NULL,
		const TH1D *	hPulse = NULL
	)

Definition at line 6 of file HistogramFitFCN.cpp.

                                                                         : fTemplateHist(hTemplate), fPulseHist(hPulse) {
}

HistogramFitFCN::~HistogramFitFCN

(

)

Definition at line 9 of file HistogramFitFCN.cpp.

                                  {
}

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Member Function Documentation

int HistogramFitFCN::GetNDoF

(

)

[inline]

Definition at line 34 of file HistogramFitFCN.h.

References fNDoF.

Referenced by TemplateFitter::FitPulseToTemplate().

{ return fNDoF; }

double HistogramFitFCN::operator()

(

const std::vector< double > &

par

)

const

Used for calls with parameters The return value is the chi squared weighted by errors in fTemplateHist Parameters: 1. Pedestal 2. Amplitude 3. Timing.

Definition at line 29 of file HistogramFitFCN.cpp.

References fNDoF, fPulseHist, fRefineFactor, fTemplateHist, and fTimeOffset.

                                                                      {
  // Chi2 fit with pedestal P, amplitude A, and timing T
  // Warning: The time is truncated to an int, so if there's
  // so if the step size in MINUIT is smalled than 1,
  // Any value of T will probably be seen as minimized, which it
  // almost certainly will not be.
  double chi2 = 0.;
  double P = par[0];
  double A = par[1];
  int T_int = (int)fTimeOffset;            // Integral part of time shift
  double T_flt = fTimeOffset - (double)T_int; // Floating point offset for linear interpolation

  bool print_dbg = false;
  if (strcmp(fTemplateHist->GetName(), "hTemplate_ScL") == 0) {
    print_dbg = false;
  }

  if (print_dbg) { 
    std::cout << "HistogramFitFCN::operator() (start):" << std::endl;
    std::cout << "\tpedestal = " << P 
              << ", amplitude = " << A 
              << ", time (integer part) = " << T_int 
              << " and time (float part) = " << T_flt << std::endl;
  }
 
  int half_range = 10*fRefineFactor; // remove a few bins from the fit
  int bounds[2];
  bounds[0] = half_range+1;//std::max(T_int - fTemplateHist->GetNbinsX() / 2, 1);
  bounds[1] = std::min(fTemplateHist->GetNbinsX(), fPulseHist->GetNbinsX()) - half_range-1; //std::min(T_int + fTemplateHist->GetNbinsX() / 2 - 1, fPulseHist->GetNbinsX());

  fNDoF = ((bounds[1] - bounds[0] + 1)/fRefineFactor) - par.size(); // +1 because we include both ends of the bounds when we loop through

  if (print_dbg) {
    std::cout << "NBinsX: hTemplate = " << fTemplateHist->GetNbinsX() << ", hPulse = " << fPulseHist->GetNbinsX() << std::endl;
    std::cout << "Bound Defns: " << std::endl;
    std::cout << "\tbounds[0] = " << bounds[0] << std::endl;
    std::cout << "\tbounds[1] = " << bounds[1] << std::endl;
  }

  // Chi2 will be zero if shift is too high
  if (print_dbg) {
    if (bounds[1] <= bounds[0])
      std::cout << "ERROR: Fit of two histograms involves shifting one out-of-bounds (no overlap)!" << std::endl;
  }

  double f;
  double temp_ped=fTemplateHist->GetBinContent(1);
  for (int i = bounds[0]+(fRefineFactor/2.0); i <= bounds[1]-(fRefineFactor/2.0); i += fRefineFactor) { 
    // calculate the chi^2 based on the centre of the 5 bins to avoid getting
    // abonus from mathcing all 5.  We shift and scale the template so that it
    // matches the pulse.  This is because, when we have a normalised template,
    // we will get the actual amplitude, pedestal and time from the fit and not
    // just offsets
    f = fTemplateHist->GetBinContent(i - T_int) ;
    f += T_flt*(fTemplateHist->GetBinContent(i - T_int + 1) - f); // linear interpolation between the i'th and the (i+1)'th bin
    if (print_dbg) {
      std::cout << "i = " << i << ", i - T_int = " << i-T_int << std::endl;
      std::cout << "f (before) = " << f << std::endl;
    }
    f = A * (f - temp_ped) + P; // apply the transformation to this bin
    if (print_dbg) {
      std::cout << "f (after) = " << f << std::endl;
    }


    double delta = fPulseHist->GetBinContent(i) - f;
    if (print_dbg) {
      std::cout << "Pulse Value = " << fPulseHist->GetBinContent(i) << ", delta = " << delta << std::endl;
    }
    double hTemplate_bin_error = fTemplateHist->GetBinError(i - T_int);
    //double hPulse_bin_error = fPulseHist->GetBinError(i);
    chi2 += delta*delta / (A*hTemplate_bin_error*hTemplate_bin_error);
    if (print_dbg) {
      std::cout << "Template Error = " << hTemplate_bin_error << ", chi2 (added) = " << delta*delta/(hTemplate_bin_error*hTemplate_bin_error) << ", chi2 (total) = " << chi2 << std::endl;
    }
  }

  if (print_dbg) {
    std::cout << "HistogramFitFCN::operator() (end): " << std::endl;
    std::cout << "\tFit:\tChi2 " << chi2 << "\tP "
              << P << "(" << par[0] << ")\tA " << A << "(" << par[1] << ")\tT " << T_int
              << std::endl << std::endl;
  }
  return chi2;
}

void HistogramFitFCN::SetPulseHist

(

const TH1D *

hPulse

)

Definition at line 21 of file HistogramFitFCN.cpp.

References fPulseHist.

Referenced by TemplateFitter::FitPulseToTemplate().

                                                     {
  fPulseHist = hPulse;
}

void HistogramFitFCN::SetRefineFactor

(

int

refine_factor

)

[inline]

Definition at line 18 of file HistogramFitFCN.h.

References fRefineFactor.

Referenced by TemplateFitter::TemplateFitter().

{fRefineFactor = refine_factor;}

void HistogramFitFCN::SetTemplateHist	(	const TH1D *	hTemplate,
		double	ped = -1
	)

Definition at line 12 of file HistogramFitFCN.cpp.

References fTemplateHist, and fTemplatePedestal.

Referenced by TemplateFitter::FitPulseToTemplate().

                                                                            {
  fTemplateHist = hTemplate;
  if(pedestal>0){
    fTemplatePedestal = pedestal;
  } else {
    fTemplatePedestal = fTemplateHist->GetBinContent(1);
  }
}

void HistogramFitFCN::SetTimeOffset

(

double

time_offset

)

Definition at line 25 of file HistogramFitFCN.cpp.

References fTimeOffset.

Referenced by TemplateFitter::FitPulseToTemplate().

                                                      {
  fTimeOffset = time_offset;
}

double HistogramFitFCN::Up

(

)

const

Used for error... somehow?

Definition at line 115 of file HistogramFitFCN.cpp.

                                 {
  return 1.;
}

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Member Data Documentation

int HistogramFitFCN::fNDoF [mutable, private]

record this for TemplateFitter to retrieve later (NB mutable so that it can be set in operator(), which is const)

Definition at line 39 of file HistogramFitFCN.h.

Referenced by GetNDoF(), and operator()().

const TH1D* HistogramFitFCN::fPulseHist [private]

Definition at line 48 of file HistogramFitFCN.h.

Referenced by operator()(), and SetPulseHist().

int HistogramFitFCN::fRefineFactor [private]

Definition at line 45 of file HistogramFitFCN.h.

Referenced by operator()(), and SetRefineFactor().

const TH1D* HistogramFitFCN::fTemplateHist [private]

Definition at line 47 of file HistogramFitFCN.h.

Referenced by operator()(), and SetTemplateHist().

double HistogramFitFCN::fTemplatePedestal [private]

Definition at line 43 of file HistogramFitFCN.h.

Referenced by SetTemplateHist().

double HistogramFitFCN::fTimeOffset [private]

the time offset to use

Definition at line 42 of file HistogramFitFCN.h.

Referenced by operator()(), and SetTimeOffset().

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The documentation for this class was generated from the following files:

• rootana/src/TAP_generators/utils/HistogramFitFCN.h
• rootana/src/TAP_generators/utils/HistogramFitFCN.cpp