APWeightHist Class Reference

Extended histogramming class. More...

#include <APWeightHist.h>

Inheritance diagram for APWeightHist:

Collaboration diagram for APWeightHist:

Public Member Functions
	APWeightHist (const char *name, const char *title, const int n_bins, const float x_min, const float x_max)
	Constructor which takes histo title, amount of bins and the range and optionally the preicision to use for the calculation of the uncertainty.
	APWeightHist ()
	Default constructor.
	~APWeightHist ()
	Default destructor.
int	Fill (const double value, APWeightEntry *weight)
	< Overloads TH1D's Fill method.
TGraphAsymmErrors *	GetGraphStatUncert (bool autocompute=true)
	Extracts the histogram with statistical uncertainties.
TGraphErrors *	GetGraphSystUncert (bool simple=true, bool autocompute=true)
	Extracts the histogram with systematic uncertainties.
void	ComputeGraph (const int prec=250)
	Computes the resulting graph from all added ntuples and calculates the uncertainties for all bins.
TH1D *	GetBinPDF (unsigned int bin, bool autocompute=true)
	ClassDef (APWeightHist, 1)
	ClassDef for ROOTCINT dictionary.

Private Attributes
double	m_computed_entries
	Flag to store information about the status of the computation.
std::vector< std::vector< APWeightEntry * > >	m_binned_weights
	Holds all filled weights weights as pointers.
std::vector< TH1D * >	m_bin_dists
	Holds the PDFs for the individual bins.
std::vector< double >	m_SumSys2
	Holds the variances of systematic uncertainties for the individual bins.
TGraphAsymmErrors *	m_graph_stat
	Holds the histogram with statistical uncertainties.
TGraphErrors *	m_graph_syst
	Holds the histogram with systematic uncertainties.

Detailed Description

Extended histogramming class.

Extended histogramming class (inheriting from TH1D) which allows propagation of uncertainties on the actual weights used for filling.

Author

fabia.nosp@m.n.Ko.nosp@m.hn@ce.nosp@m.rn.c.nosp@m.h

Definition at line 26 of file APWeightHist.h.

Constructor & Destructor Documentation

APWeightHist() [1/2]

APWeightHist::APWeightHist	(	const char *	name,
		const char *	title,
		const int	n_bins,
		const float	x_min,
		const float	x_max )

Constructor which takes histo title, amount of bins and the range and optionally the preicision to use for the calculation of the uncertainty.

Definition at line 18 of file APWeightHist.cxx.

  : TH1D(name, title, n_bins, x_min, x_max)
    //m_prec(0)
{
  m_graph_stat = new TGraphAsymmErrors();
  m_graph_stat->GetXaxis()->SetTitle(GetXaxis()->GetTitle());
  m_graph_stat->GetYaxis()->SetTitle(GetYaxis()->GetTitle());
  m_graph_syst = new TGraphErrors();
  m_graph_syst->GetXaxis()->SetTitle(GetXaxis()->GetTitle());
  m_graph_syst->GetYaxis()->SetTitle(GetYaxis()->GetTitle());
  m_binned_weights = vector< vector< APWeightEntry* > >(n_bins);
  Sumw2();
  m_SumSys2 = vector< double >(n_bins, 0.);
  m_computed_entries = 0.;
}

APWeightHist() [2/2]

APWeightHist::APWeightHist

(

)

Default constructor.

Definition at line 34 of file APWeightHist.cxx.

  : m_graph_stat(0),
    m_graph_syst(0)
    //m_prec(0)
{
  m_computed_entries = 0.;
}

~APWeightHist()

APWeightHist::~APWeightHist

(

)

Default destructor.

Definition at line 42 of file APWeightHist.cxx.

                            {
 
}

Member Function Documentation

ClassDef()

APWeightHist::ClassDef	(	APWeightHist	,
		1	)

ClassDef for ROOTCINT dictionary.

ComputeGraph()

void APWeightHist::ComputeGraph

(

const int

prec = 250

)

Computes the resulting graph from all added ntuples and calculates the uncertainties for all bins.

Definition at line 67 of file APWeightHist.cxx.

                                              {
  for (int i = 0, I = m_graph_stat->GetN(); i < I; ++i) m_graph_stat->RemovePoint(i);
  for (int i = 0, I = m_graph_syst->GetN(); i < I; ++i) m_graph_syst->RemovePoint(i);
  vector< TH1D* > original_dists = vector< TH1D* >(fXaxis.GetNbins());
  m_bin_dists = vector< TH1D* >(fXaxis.GetNbins());
  int point_count = 0;
  for (int j = 0; j < fXaxis.GetNbins(); ++j) {
    //Create Poisson distributions for original histogram.
    double unweighted_content = (double) (m_binned_weights[j]).size();
    double sig_low_o = (max((double) 0.0, (unweighted_content - 5 * sqrt(unweighted_content))));
    double sig_high_o = (unweighted_content + 5 * sqrt(unweighted_content));
    double step = (sig_high_o - sig_low_o) * 1e-3;
 
    original_dists[j] = new TH1D("", "", 1000, sig_low_o, sig_high_o);
 
    int bin_no = 1;
    double curr_fact = ln_factorialApp((m_binned_weights[j]).size());
    for (double lambda = sig_low_o; lambda < sig_high_o; lambda += step) {
      double value = exp(-lambda + unweighted_content * log(lambda) - curr_fact);
      if (value != value) value = 0.;
      (original_dists[j])->SetBinContent(bin_no, value);
      ++bin_no;
    }
    (original_dists[j])->Scale(1. / (original_dists[j])->GetSum());
    const double old_mode = (original_dists[j])->GetBinCenter((original_dists[j])->GetMaximumBin());
    const double inv_old_mode = 1. / old_mode;
 
    //Create different final sum of weights for this bin
    vector< double > bin_sumw(prec, 0.);
    double max_value = 1.e-100;
    double min_value = 1.e100;
 
    for (vector<double>::iterator it_hist = bin_sumw.begin(), it_histE = bin_sumw.end(); it_hist != it_histE; ++it_hist) {
      for (vector<APWeightEntry*>::iterator it_func = (m_binned_weights[j]).begin(), it_funcE = (m_binned_weights[j]).end(); it_func != it_funcE; ++it_func) {
        *it_hist += (*it_func)->GetRandom();
      }
      double cur_val = *it_hist;
      if (cur_val < min_value) {
        min_value = cur_val;
      } else if (cur_val > max_value) {
        max_value = cur_val;
      }
    }
 
    //Create final distribution for this bin
    TH1D* scaled_hist_l = (TH1D*) (original_dists[j])->Clone("");
    TH1D* scaled_hist_h = (TH1D*) (original_dists[j])->Clone("");
    double scale = min_value * inv_old_mode;
    scaled_hist_l->GetXaxis()->SetLimits(scale * sig_low_o, scale * sig_high_o);
    scale = max_value * inv_old_mode;
    scaled_hist_h->GetXaxis()->SetLimits(scale * sig_low_o, scale * sig_high_o);
 
    double quant[1];
    double prob[1] = {0.001};
 
    scaled_hist_l->GetQuantiles(1, quant, prob);
    double sig_low = quant[0];
    prob[0] = 0.999;
    scaled_hist_h->GetQuantiles(1, quant, prob);
    double sig_high = quant[0];
 
    m_bin_dists[j] = new TH1D("", "", 1000, sig_low, sig_high);
 
    //fill final distribution for this bin with scaled/weighted Poisson distributions
    if (unweighted_content > 0.) {
      for (int k = 0; k < prec; ++k) {
        double new_val = bin_sumw[k];
        TH1D* scaled_hist = (TH1D*) (original_dists[j])->Clone("");
        double temp_scale = new_val * inv_old_mode;
        scaled_hist->GetXaxis()->SetLimits(temp_scale * sig_low_o, temp_scale * sig_high_o);
        for (int l = 1; l < 1001; ++l) {
          (m_bin_dists[j])->AddBinContent(l, scaled_hist->GetBinContent(scaled_hist->FindBin((m_bin_dists[j])->GetBinCenter(l))));
        }
        delete scaled_hist;
      }
      double local_value = sig_low + (m_bin_dists[j])->GetMaximumBin() * ((sig_high - sig_low) * 1e-3);
      m_graph_stat->SetPoint(point_count, (GetXaxis()->GetXmin() + j * GetBinWidth(j + 1) + GetBinWidth(j + 1) / 2), local_value);
      m_graph_syst->SetPoint(point_count, (GetXaxis()->GetXmin() + j * GetBinWidth(j + 1) + GetBinWidth(j + 1) / 2), local_value);
      double quantile[ 2 ];
      double conf[ 2 ] = {0.1585, 0.8415};
      (m_bin_dists[j])->GetQuantiles(2, quantile, conf);
      m_graph_stat->SetPointError(point_count, GetBinWidth(j + 1) / 2, GetBinWidth(j + 1) / 2, local_value - quantile[0], quantile[1] - local_value);
      m_graph_syst->SetPointError(point_count, GetBinWidth(j + 1) / 2, local_value * (sqrt(m_SumSys2[j]) / GetBinContent(j + 1)));
      ++point_count;
    }
  }
  m_computed_entries = fEntries;
}

Fill()

int APWeightHist::Fill	(	const double	value,
		APWeightEntry *	weight )

< Overloads TH1D's Fill method.

Adds a weighted value to the calculation.

Definition at line 46 of file APWeightHist.cxx.

                                                                {
  //   if (fBuffer) return BufferFill(value,w);
  double w = weight->GetExpectancy();
  int bin = fXaxis.FindBin(value);
  fEntries++;
  AddBinContent(bin, w);
  if (fSumw2.fN) fSumw2.fArray[bin] += w * w;
  if (bin == 0 || bin > fXaxis.GetNbins()) {
    if (!GetStatOverflowsBehaviour()) return -1;
  }
  Double_t z = (w > 0 ? w : -w);
  fTsumw += z;
  fTsumw2 += z*z;
  fTsumwx += z*value;
  fTsumwx2 += z * value*value;
  (m_binned_weights[bin - 1]).push_back(weight);
  fSumw2.fArray[bin] += weight->GetVariance() + z*z;
  m_SumSys2[bin - 1] += weight->GetSysUncert2();
  return bin;
}

GetBinPDF()

TH1D * APWeightHist::GetBinPDF	(	unsigned int	bin,
		bool	autocompute = true )

Definition at line 178 of file APWeightHist.cxx.

                                                                {
  if (autocompute && fEntries > m_computed_entries) ComputeGraph();
  return m_bin_dists[bin - 1];
}

GetGraphStatUncert()

TGraphAsymmErrors * APWeightHist::GetGraphStatUncert

(

bool

autocompute = true

)

Extracts the histogram with statistical uncertainties.

Definition at line 156 of file APWeightHist.cxx.

                                                                    {
  if (autocompute && fEntries > m_computed_entries) ComputeGraph();
  return m_graph_stat;
}

GetGraphSystUncert()

TGraphErrors * APWeightHist::GetGraphSystUncert	(	bool	simple = true,
		bool	autocompute = true )

Extracts the histogram with systematic uncertainties.

Definition at line 161 of file APWeightHist.cxx.

                                                                            {
  if (simple) {
    for (int i = 0, I = m_graph_syst->GetN(); i < I; ++i) m_graph_syst->RemovePoint(i);
    int point_count = 0;
    for (int j = 0; j < fXaxis.GetNbins(); ++j) {
      if ((m_binned_weights[j]).size() > 0) {
        m_graph_syst->SetPoint(point_count, (GetXaxis()->GetXmin() + j * GetBinWidth(j + 1) + GetBinWidth(j + 1) / 2), GetBinContent(j + 1));
        m_graph_syst->SetPointError(point_count, GetBinWidth(j + 1) / 2, sqrt(m_SumSys2[j]));
        ++point_count;
      }
    }
    return m_graph_syst;
  }
  if (autocompute && fEntries > m_computed_entries) ComputeGraph();
  return m_graph_syst;
}

Member Data Documentation

m_bin_dists

std::vector< TH1D* > APWeightHist::m_bin_dists

private

Holds the PDFs for the individual bins.

Definition at line 44 of file APWeightHist.h.

m_binned_weights

std::vector< std::vector< APWeightEntry* > > APWeightHist::m_binned_weights

private

Holds all filled weights weights as pointers.

Definition at line 43 of file APWeightHist.h.

m_computed_entries

double APWeightHist::m_computed_entries

private

Flag to store information about the status of the computation.

Definition at line 42 of file APWeightHist.h.

m_graph_stat

TGraphAsymmErrors* APWeightHist::m_graph_stat

private

Holds the histogram with statistical uncertainties.

Definition at line 46 of file APWeightHist.h.

m_graph_syst

TGraphErrors* APWeightHist::m_graph_syst

private

Holds the histogram with systematic uncertainties.

Definition at line 47 of file APWeightHist.h.

m_SumSys2

std::vector< double > APWeightHist::m_SumSys2

private

Holds the variances of systematic uncertainties for the individual bins.

Definition at line 45 of file APWeightHist.h.

---

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

• APWeightHist.h
• APWeightHist.cxx