class AliHFPtSpectrum: public TNamed

 Default constructor

 Copy constructor

 Assignment operator

 Destructor

 Function to rebin the theoretical spectrum
  with respect to the real-data reconstructed spectrum binning

 Set the MonteCarlo or Theoretical spectra
  both for direct and feed-down contributions

 Set the MonteCarlo or Theoretical spectra
  for feed-down contribution

 Set the maximum and minimum MonteCarlo or Theoretical spectra
  both for direct and feed-down contributions
 used in case uncertainties are asymmetric and ca not be on the "basic histograms"

 Set the maximum and minimum MonteCarlo or Theoretical spectra
   for feed-down contributions
 used in case uncertainties are asymmetric and can not be on the "basic histogram"

 Set the Acceptance and Efficiency corrections
   for the direct contribution

 Set the Acceptance and Efficiency corrections
  both for direct and feed-down contributions

 Set the reconstructed spectrum

 Set the reconstructed spectrum (uncorrected yield) systematic uncertainties

 Main function to compute the corrected cross-section:
 variables : analysed delta_y, BR for the final correction,
             BR b --> D --> decay (relative to the input theoretical prediction)

   Sigma = ( 1. / (lumi * delta_y * BR_c * ParticleAntiPartFactor * eff_trig * eff_c ) ) * spectra (corrected for feed-down)

 Uncertainties: (stat) delta_sigma = sigma * sqrt ( (delta_spectra/spectra)^2 )
  (syst but feed-down) delta_sigma = sigma * sqrt ( (delta_spectra_syst/spectra)^2 + (delta_lumi/lumi)^2 + (delta_eff_trig/eff_trig)^2 + (delta_eff/eff)^2 )
      (feed-down syst) delta_sigma = sigma * sqrt ( (delta_spectra_fd/spectra_fd)^2 )

  In HIC the feed-down correction varies with an energy loss hypothesis:
      Raa(c-->D) / Raa(b-->D) for the "fc" method, Raa(b-->D) for the "Nb" method (see exact formulas in the functions)

 Function that computes the acceptance and efficiency correction
  based on the simulated and reconstructed spectra
  and using the reconstructed spectra bin width

  eff = reco/sim ; err_eff = sqrt( eff*(1-eff) )/ sqrt( sim )

 Function that computes the Direct  acceptance and efficiency correction
  based on the simulated and reconstructed spectra
  and using the reconstructed spectra bin width

  eff = reco/sim ; err_eff = sqrt( eff*(1-eff) )/ sqrt( sim )

 Function that computes the Feed-Down acceptance and efficiency correction
  based on the simulated and reconstructed spectra
  and using the reconstructed spectra bin width

  eff = reco/sim ; err_eff = sqrt( eff*(1-eff) )/ sqrt( sim )

 Initialization of the variables (histograms)

 Check the histograms consistency (bins, limits)

 Compute the corrected spectrum with no feed-down correction

 Compute fc factor and its uncertainties bin by bin
   fc = 1 / ( 1 + (eff_b/eff_c)*(N_b/N_c) )

 uncertainties: (conservative) combine the upper/lower N_b & N_c predictions together
                (extreme) combine the upper N_b predictions with the lower N_c predictions & viceversa
                systematic uncertainty on the acceptance x efficiency b/c ratio are included

  In addition, in HIC the feed-down correction varies with an energy loss hypothesis: Raa(c-->D) / Raa(b-->D) = Rcb
	       fc (Rcb) = ( 1. / ( 1 + (eff_b/eff_c)*(N_b/N_c)* (1/Rcb) ) );

 Compute the feed-down corrected spectrum if feed-down correction is done via fc factor (bin by bin)
    physics = reco * fc / bin-width

    uncertainty:             (stat) delta_physics = physics * sqrt ( (delta_reco/reco)^2 )
               (syst but feed-down) delta_physics = physics * sqrt ( (delta_reco_syst/reco)^2 )
                   (feed-down syst) delta_physics = physics * sqrt ( (delta_fc/fc)^2 )

    ( Calculation done bin by bin )

  In addition, in HIC the feed-down correction varies with an energy loss hypothesis: Raa(c-->D) / Raa(b-->D) = Rcb

 Compute the feed-down corrected spectrum if feed-down correction is done via Nb (bin by bin)
    physics =  [ reco  - (lumi * delta_y * BR_b * eff_trig * eff_b * Nb_th) ] / bin-width

    uncertainty:   (stat)  delta_physics = sqrt ( (delta_reco)^2 )  / bin-width
     (syst but feed-down)  delta_physics = sqrt ( (delta_reco_syst)^2 )  / bin-width
         (feed-down syst)  delta_physics = sqrt ( (k*delta_lumi/lumi)^2 + (k*delta_eff_trig/eff_trig)^2
                                                   + (k*delta_Nb/Nb)^2 + (k*delta_eff/eff)^2  + (k*global_eff_ratio)^2 ) / bin-width
                    where k = lumi * delta_y * BR_b * eff_trig * eff_b * Nb_th

  In addition, in HIC the feed-down correction varies with an energy loss hypothesis: Raa(b-->D) = Rb
    physics =  [ reco  - ( Tab * Nevt * delta_y * BR_b * eff_trig * eff_b * Nb_th * Rb ) ] / bin-width

 Function that re-calculates the global systematic uncertainties
   by calling the class AliHFSystErr and combining those
   (in quadrature) with the feed-down subtraction uncertainties

 Example method to draw the corrected spectrum & the theoretical prediction

 Function to  reweight histograms for testing purposes:
 This function takes the histo hToReweight and reweights
  it (its pt shape) with respect to hReference

 Function to  reweight histograms for testing purposes:
 This function takes the histo hToReweight and reweights
  it (its pt shape) with respect to hReference /hMCToReweight

 Function to find the y-axis bin of a TH2 for a given y-value

 Set the calculation option flag for feed-down correction: 0=none, 1=fc , 2=Nb

 Set if the calculation has to consider asymmetric uncertaInt_ties or not

 Set if the yield is for particle plus anti-particle or not

 Set if the calculation has to consider Ratio(c/b eloss) hypothesis

 Set the luminosity and its uncertainty

 Set the trigger efficiency and its uncertainty

 Set global acceptance x efficiency correction uncertainty (in percentages)

 Set the normalization factors

 Set the Tab parameter and its uncertainty

 Getters

 Return the theoretical predictions used for the calculation (rebinned if needed)

 Return the acceptance and efficiency corrections (rebinned if needed)

 Return whether the Ratio(c/b eloss) hypothesis has been considered

 Return the TGraphAsymmErrors of the feed-down correction (extreme systematics)

 Return the TGraphAsymmErrors of the feed-down correction (conservative systematics)

 Return the histogram of the feed-down correction

 Return the histograms of the feed-down correction bounds

 Return the histogram of the feed-down correction times the Ratio(c/b eloss)

 Return the TGraphAsymmErrors of the yield after feed-down correction (systematics but feed-down)

 Return the TGraphAsymmErrors of the yield after feed-down correction (feed-down extreme systematics)

 Return the TGraphAsymmErrors of the yield after feed-down correction (feed-down conservative systematics)

 Return the histogram of the yield after feed-down correction

 Return the histogram of the yield after feed-down correction bounds

 Return the histogram of the yield after feed-down correction vs the Ratio(c/b eloss)

 Return the equivalent invariant cross-section TGraphAsymmErrors (systematics but feed-down)

 Return the equivalent invariant cross-section TGraphAsymmErrors (feed-down extreme systematics)

 Return the equivalent invariant cross-section TGraphAsymmErrors (feed-down conservative systematics)

 Return the equivalent invariant cross-section histogram

 Return the equivalent invariant cross-section histogram bounds

 Return the cross section systematics from data systematics

 PbPb special calculations
 Return the equivalent invariant cross-section histogram vs the Ratio(c/b eloss)

 Return the ntuple of the calculation vs the Ratio(c/b eloss)

 Histograms to keep track of the influence of the efficiencies statistical uncertainty on the cross-section

 Histograms to keep track of the influence of the efficiencies statistical uncertainty on the feed-down correction factor