#include "T49DedxFunction.h"

T49DedxFunction


class description - source file - inheritance tree (.pdf)

class T49DedxFunction : public TF1

Inheritance Chart:
TObject
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TNamed
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TFormula
TAttLine
TAttFill
TAttMarker
<-
TF1
<-
T49DedxFunction
    private:
T49DedxFunction() Int_t Binom(Int_t n, Int_t k) void PolyFit(const Int_t NPoints, Float_t* x, Float_t* y, Float_t* err, Int_t Order, Float_t* Result) public:
T49DedxFunction(Char_t* name) ~T49DedxFunction() static TClass* Class() Float_t GetAmplitude(Int_t i) void GetBBPars(Float_t& c, Float_t& d, Float_t& e, Float_t& f) Float_t GetPosition(Int_t i) Float_t GetPtot() void GetRatio(Int_t part, Float_t& val, Float_t& err) void GetRatio2(Int_t part, Float_t& val, Float_t& err) Float_t GetRelPosition(Int_t i) Float_t GetRelRise(Int_t part) Float_t GetResolution() void Init(TH1F* Hist, Char_t* Opt = "") void InitPositions(Float_t pipos) virtual TClass* IsA() const Bool_t IsAmplitudeFixed(Int_t i) Float_t RelRise(Float_t Ptot, Int_t Part) void ResetFreePosition(Int_t i) void RestoreParameters() void SetAmplitude(Int_t i, Float_t x, Float_t lowlim, Float_t uplim) void SetAmplitude(Int_t i, Float_t x) void SetBBPars(Float_t c, Float_t d, Float_t e, Float_t f) void SetFixedAmplitude(Int_t i, Float_t x) void SetFixedAmplitude(Int_t i) void SetFixedPosition(Int_t i, Float_t x) void SetFixedPosition(Int_t i) void SetFree() void SetFreePosition(Int_t i, Float_t x) void SetFreePosition(Int_t i) void SetPosition(Int_t i, Float_t x, Float_t lowlim = 0, Float_t uplim = 0) void SetPtot(Float_t p) void SetResolution(Float_t x) virtual void ShowMembers(TMemberInspector& insp, char* parent) void StoreCovMat() void StoreParameters() virtual void Streamer(TBuffer& b) void StreamerNVirtual(TBuffer& b)

Data Members


    protected:
Float_t fParaC Constants for rel rise parametrisation Float_t fParaD Float_t fParaE Float_t fParaF Float_t fPtot Bool_t fAmpFix[4] Double_t fStoredPars[9] Double_t fStoredLowLim[9] Double_t fStoredUpLim[9] Bool_t fStored public:
Double_t fCovMatMinuit[9][9] Float_t fCovMat[9][9]

Class Description

  dE/dx fit function class

  This is an interface to a TF1, used to fit a dE/dx spectra.
  The function consists of four gaussians, with identical relative
  widths. Different methods are provide to fix or release the
  positions of the different peaks. Internally, the pion peak position
  is absolute, whereas the other peak positions are relative
  to it.

T49DedxFunction(Char_t* name): TF1(name, "[6]*exp(-0.5*(x-[2])*(x-[2])/([2]*[2]*[0]))+[5]*exp(-0.5*(x-[1]*[2])*(x-[1]*[2])/([1]*[2]*[1]*[2]*[0]))+[7]*exp(-0.5*(x-[3]*[2])*(x-[3]*[2])/([3]*[2]*[3]*[2]*[0]))+[8]*exp(-0.5*(x-[4]*[2])*(x-[4]*[2])/([4]*[2]*[4]*[2]*[0]))")

void SetFree()
  Release bounds on relative positions (N.B. the pion position
  is not affected)

void SetFreePosition(Int_t i,Float_t x)
  Release bound on peak position i, and set position to x.

void SetFixedPosition(Int_t i,Float_t x)
  Set fixed value for peak position i

void SetFreePosition(Int_t i)
  Release bounds on position of peak i

void SetFixedPosition(Int_t i)
  Fix position of peak i

void ResetFreePosition(Int_t i)
  Set position to Bethe Bloch value, and

void SetPosition(Int_t i, Float_t x, Float_t lowlim, Float_t uplim)
  Set position and bounds. (N.B.: the bounds of non-pion peaks
  change with the pion peak position, since they are relative positions)

void InitPositions(Float_t pipos)
  Sets pion position to pipos, and relative positions of other peaks
  acoording to Bethe-Bloch parametrization

void SetAmplitude(Int_t i, Float_t x,Float_t lowlim, Float_t uplim)

void SetAmplitude(Int_t i, Float_t x)

void SetFixedAmplitude(Int_t i, Float_t x)
  Facility to fix the amplitude. Mainly used to fix amplitudes at zero.

void SetFixedAmplitude(Int_t i)

void SetResolution(Float_t x)

Float_t GetPosition(Int_t i)

Float_t GetRelPosition(Int_t i)

Float_t GetAmplitude(Int_t i)

Float_t GetResolution()

void GetRatio(Int_t part, Float_t &val, Float_t &err)

void GetRatio2(Int_t part, Float_t &val, Float_t &err)

void StoreCovMat()

void StoreParameters()
  The class may hold one alternative set of parameters. This method
  stores the parameters internally.

void RestoreParameters()
  Sets the parameters to the values stored using StoreParameters().

Float_t GetRelRise(Int_t part)
  Returns the value of dE/dx from the Bethe-Bloch-parametrization. First
  call SetPtot()

void Init(TH1F* Hist,Char_t* Opt)
  This method uses the histogram to provide an estimate for the peak
  positions, amplitudes and widths. Relies heavily on the Bethe-Bloch
  parametrization, so first call SetPtot(). Option "V" triggers
  verbose behaviour.

Float_t RelRise(Float_t Ptot, Int_t Part)
  Returns expected dE/dx values, according to Bethe-Bloch parametrization
  (Called by GetRelRise())
  ** Code provided by Christof Roland **

void PolyFit(const Int_t NPoints, Float_t* x, Float_t* y, Float_t* err, Int_t Order, Float_t* Result)
  Fits polynomial of form par[0] + par[1]*x +par[2]*x^2, etc
  Uses the provided errors as weights.
  (Called internally by Init())

Int_t Binom(Int_t n,Int_t k)
  Calculates binomial coefficient n over k.
  Called by PolyFit()



Inline Functions


                   void ~T49DedxFunction()
                TClass* Class()
                TClass* IsA() const
                   void ShowMembers(TMemberInspector& insp, char* parent)
                   void Streamer(TBuffer& b)
                   void StreamerNVirtual(TBuffer& b)
                   void SetBBPars(Float_t c, Float_t d, Float_t e, Float_t f)
                   void GetBBPars(Float_t& c, Float_t& d, Float_t& e, Float_t& f)
                   void SetPtot(Float_t p)
                 Bool_t IsAmplitudeFixed(Int_t i)
                Float_t GetPtot()
        T49DedxFunction T49DedxFunction()


Last update: Thu Aug 17 15:30:52 2006


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