BCMTF.cxx

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/*
 * Copyright (C) 2008-2012, Daniel Kollar and Kevin Kroeninger.
 * All rights reserved.
 *
 * For the licensing terms see doc/COPYING.
 */

// ---------------------------------------------------------

#include <iostream>
#include <fstream>

#include <TCanvas.h>
#include <THStack.h>
#include <TH1D.h>
#include <TAxis.h>
#include <TF1.h>

#include "../../BAT/BCMath.h"
#include "../../BAT/BCLog.h"

#include "BCMTFChannel.h"
#include "BCMTFProcess.h"
#include "BCMTFTemplate.h"
#include "BCMTFSystematic.h"
#include "BCMTFSystematicVariation.h"

#include "BCMTF.h"

// ---------------------------------------------------------
BCMTF::BCMTF()
 : BCModel("Multi-template Fitter")
 , fNChannels(0)
 , fNProcesses(0)
 , fNSystematics(0)
 , fFlagEfficiencyConstraint(false)
{}

// ---------------------------------------------------------
BCMTF::BCMTF(const char * name)
 : BCModel(name)
 , fNChannels(0)
 , fNProcesses(0)
 , fNSystematics(0)
 , fFlagEfficiencyConstraint(false)
{}

// ---------------------------------------------------------
BCMTF::~BCMTF()
   // default destructor
{
   for (int i = 0; i < fNChannels; ++i)
      delete fChannelContainer.at(i);
}

// ---------------------------------------------------------
int BCMTF::GetChannelIndex(const char * name)
{
   // loop over all channels and compare names
   for (int i = 0; i < fNChannels; ++i) {
      // get channel
      BCMTFChannel * channel = GetChannel(i);

      // compare names
      if (!channel->GetName().compare(name))
         return i;
   }

   // if channel does not exist, return -1
   return -1;
}

// ---------------------------------------------------------
int BCMTF::GetProcessIndex(const char * name)
{
   // loop over all processs and compare names
   for (int i = 0; i < fNProcesses; ++i) {
      // get process
      BCMTFProcess * process = GetProcess(i);

      // compare names
      if (!process->GetName().compare(name))
         return i;
   }

   // if process does not exist, return -1
   return -1;
}

// ---------------------------------------------------------
int BCMTF::GetSystematicIndex(const char * name)
{
   // loop over all systematics and compare names
   for (int i = 0; i < fNSystematics; ++i) {
      // get systematic
      BCMTFSystematic * systematic = GetSystematic(i);

      // compare names
      if (!systematic->GetName().compare(name))
         return i;
   }

   // if process does not exist, return -1
   return -1;
}

// ---------------------------------------------------------
int BCMTF::SetTemplate(const char * channelname, const char * processname, TH1D hist, double efficiency)
{
   // get channel index
   int channelindex = GetChannelIndex(channelname);

   // check if channel exists
   if (channelindex < 0) {
      BCLog::OutWarning("BCMultitemplateFitter::SetTemplate() : Channel does not exist.");
         return -1;
   }

   // get process index
   int processindex = GetProcessIndex(processname);

   // check if process exists
   if (processindex < 0) {
      BCLog::OutWarning("BCMultitemplateFitter::SetTemplate() : Process does not exist.");
         return -1;
   }

   // get channel
   BCMTFChannel * channel = GetChannel(channelindex);

   // get template
   BCMTFTemplate * bctemplate = channel->GetTemplate(processindex);

   // normalize histogram
   if (hist.Integral())
      hist.Scale(1.0 / hist.Integral());

   // remove statistics box
   hist.SetStats(kFALSE);

   // set color and fill style
   hist.SetFillColor(2 + processindex);
   hist.SetFillStyle(1001);

   // create new histogram
   TH1D * temphist = new TH1D(hist);

   // set histogram
   bctemplate->SetHistogram(temphist);

   // set efficiency
   bctemplate->SetEfficiency(efficiency);

   // no error
   return 1;
}

// ---------------------------------------------------------
int BCMTF::SetTemplate(const char * channelname, const char * processname, std::vector<TF1 *> * funccont, int nbins, double efficiency)
{
   // get channel index
   int channelindex = GetChannelIndex(channelname);

   // check if channel exists
   if (channelindex < 0) {
      BCLog::OutWarning("BCMultitemplateFitter::SetTemplate() : Channel does not exist.");
         return -1;
   }

   // get process index
   int processindex = GetProcessIndex(processname);

   // check if process exists
   if (processindex < 0) {
      BCLog::OutWarning("BCMultitemplateFitter::SetTemplate() : Process does not exist.");
         return -1;
   }

   // get channel
   BCMTFChannel * channel = GetChannel(channelindex);

   // get template
   BCMTFTemplate * bctemplate = channel->GetTemplate(processindex);

   // set histogram
   bctemplate->SetFunctionContainer(funccont, nbins);

   // set efficiency
   bctemplate->SetEfficiency(efficiency);

   // no error
   return 1;
}

// ---------------------------------------------------------
int BCMTF::SetData(const char * channelname, TH1D hist)
{
   int channelindex = GetChannelIndex(channelname);

   // check if channel exists
   if (channelindex < 0) {
      BCLog::OutWarning("BCMultitemplateFitter::SetTemplate() : Channel does not exist.");
         return -1;
   }

   // get channel
   BCMTFChannel * channel = GetChannel(channelindex);

   // get template
   BCMTFTemplate * data = channel->GetData();

   // remove statistics box
   hist.SetStats(kFALSE);

   // set marker
   hist.SetMarkerStyle(20);
   hist.SetMarkerSize(1.1);

   // remove old data set if it exists
   if (data->GetHistogram()) {
      delete data->GetHistogram();
      data->SetHistogram(0);
   }

   // set histogram
   data->SetHistogram(new TH1D(hist));

   // no error
   return 1;
}

// ---------------------------------------------------------
int BCMTF::AddChannel(const char * name)
{
   // check if channel exists
   for (int i = 0; i < fNChannels; ++i) {
      // compare names
      if (GetChannelIndex(name) >= 0) {
      BCLog::OutWarning("BCMultitemplateFitter::AddChannel() : Channel with this name exists already.");
         return -1;
      }
   }

   // create new channel
   BCMTFChannel * channel = new BCMTFChannel(name);

   // create new data
   BCMTFTemplate * bctemplate = new BCMTFTemplate(channel->GetName().c_str(), "data");

   // add data
   channel->SetData(bctemplate);

   // add process templates
   for (int i = 0; i < fNProcesses; ++i) {
      // get process
      BCMTFProcess * process = GetProcess(i);

      // create new template
      BCMTFTemplate * bctemplate = new BCMTFTemplate(name, process->GetName().c_str());

      // add template
      channel->AddTemplate(bctemplate);
   }

   // loop over all systematics
   for (int i = 0; i < fNSystematics; ++i) {
      // get systematic
      BCMTFSystematic * systematic = GetSystematic(i);

      // create new systematic variation
      BCMTFSystematicVariation * variation = new BCMTFSystematicVariation(name, systematic->GetName().c_str(), fNProcesses);

      // add systematic variation
      channel->AddSystematicVariation(variation);
   }

   // add channel
   fChannelContainer.push_back(channel);

   // increase number of channels
   fNChannels++;

   // no error
   return 1;
}

// ---------------------------------------------------------
int BCMTF::AddProcess(const char * name, double nmin, double nmax)
{
   // check if process exists
   for (int i = 0; i < fNProcesses; ++i) {
      // compare names
      if (GetProcessIndex(name) >= 0) {
      BCLog::OutWarning("BCMultitemplateFitter::AddProcess() : Process with this name exists already.");
         return -1;
      }
   }

   // create new process
   BCMTFProcess * process = new BCMTFProcess(name);

   // add process
   fProcessContainer.push_back(process);

   // add process templates
   for (int i = 0; i < fNChannels; ++i) {
      // get channel
      BCMTFChannel * channel = GetChannel(i);

      // create new template
      BCMTFTemplate * bctemplate = new BCMTFTemplate(channel->GetName().c_str(), name);

      // add template
      channel->AddTemplate(bctemplate);

      // loop over all systematic
      for (int j = 0; j < fNSystematics; ++j) {
         // get systematic variation
         BCMTFSystematicVariation * variation = channel->GetSystematicVariation(j);

         // add histogram
         variation->AddHistograms(0, 0);
      }
   }

   // increase number of processes
   fNProcesses++;

   // add parameter index to container
   fProcessParIndexContainer.push_back(GetNParameters());

   // add parameter
   AddParameter(name, nmin, nmax);

   // add a functional form for the expectation
   fExpectationFunctionContainer.push_back(0);

   // no error
   return 1;
}

// ---------------------------------------------------------
int BCMTF::AddSystematic(const char * name, double min, double max)
{
   // check if systematic exists
   for (int i = 0; i < fNSystematics; ++i) {
      // compare names
      if (GetSystematicIndex(name) >= 0) {
      BCLog::OutWarning("BCMultitemplateFitter::AddSystematic() : Systematic with this name exists already.");
         return -1;
      }
   }

   // create new systematic
   BCMTFSystematic * systematic = new BCMTFSystematic(name);

   // add systematic
   fSystematicContainer.push_back(systematic);

   // add systematic variations
   for (int i = 0; i < fNChannels; ++i) {
      // get channel
      BCMTFChannel * channel = GetChannel(i);

      // create new systematic variation
      BCMTFSystematicVariation * variation = new BCMTFSystematicVariation(channel->GetName().c_str(), name, fNProcesses);

      // add systematic variation
      channel->AddSystematicVariation(variation);
   }
   // ...

   // increase number of systematices
   fNSystematics++;

   // add parameter index to container
   fSystematicParIndexContainer.push_back(GetNParameters());

   // add parameter
   AddParameter(name, min, max);

   // add a functional form for the expectation
   fExpectationFunctionContainer.push_back(0);

   // no error
   return 1;
}

// ---------------------------------------------------------
int BCMTF::SetSystematicVariation(const char * channelname, const char * processname,  const char * systematicname, double variation_up, double variation_down)
{

   // get channel index
   int channelindex = GetChannelIndex(channelname);

   // check if channel exists
   if (channelindex < 0) {
      BCLog::OutWarning("BCMultitemplateFitter::SetTemplate() : Channel does not exist.");
         return -1;
   }

   // get process index
   int processindex = GetProcessIndex(processname);

   // check if process exists
   if (processindex < 0) {
      BCLog::OutWarning("BCMultitemplateFitter::SetTemplate() : Process does not exist.");
         return -1;
   }

   // get systematic index
   int systematicindex = GetSystematicIndex(systematicname);

   // check if systematic exists
   if (systematicindex < 0) {
      BCLog::OutWarning("BCMultitemplateFitter::SetTemplate() : Systematic does not exist.");
         return -1;
   }

   // get channel
   BCMTFChannel * channel = GetChannel(channelindex);

   BCMTFTemplate * bctemplate = channel->GetTemplate(processindex);

   TH1D * hist_template = bctemplate->GetHistogram();

   TH1D hist_up = TH1D(*hist_template);
   TH1D hist_down = TH1D(*hist_template);

   int nbins = hist_up.GetNbinsX();

   // loop over all bins
   for (int ibin = 1; ibin <= nbins; ++ibin) {
      hist_up.SetBinContent(ibin, variation_up);
      hist_down.SetBinContent(ibin, variation_down);
   }

   // get systematic variation
   BCMTFSystematicVariation * variation = channel->GetSystematicVariation(systematicindex);

   // set histogram
   variation->SetHistograms(processindex, new TH1D(hist_up), new TH1D(hist_down));

   // no error
   return 1;
}

// ---------------------------------------------------------
int BCMTF::SetSystematicVariation(const char * channelname, const char * processname,  const char * systematicname, TH1D hist_up, TH1D hist_down)
{
   // get channel index
   int channelindex = GetChannelIndex(channelname);

   // check if channel exists
   if (channelindex < 0) {
      BCLog::OutWarning("BCMultitemplateFitter::SetTemplate() : Channel does not exist.");
         return -1;
   }

   // get process index
   int processindex = GetProcessIndex(processname);

   // check if process exists
   if (processindex < 0) {
      BCLog::OutWarning("BCMultitemplateFitter::SetTemplate() : Process does not exist.");
         return -1;
   }

   // get systematic index
   int systematicindex = GetSystematicIndex(systematicname);

   // check if systematic exists
   if (systematicindex < 0) {
      BCLog::OutWarning("BCMultitemplateFitter::SetTemplate() : Systematic does not exist.");
         return -1;
   }

   // get channel
   BCMTFChannel * channel = GetChannel(channelindex);

   // get systematic variation
   BCMTFSystematicVariation * variation = channel->GetSystematicVariation(systematicindex);

   // set histogram
   variation->SetHistograms(processindex, new TH1D(hist_up), new TH1D(hist_down));

   // no error
   return 1;
}

// ---------------------------------------------------------
int BCMTF::SetSystematicVariation(const char * channelname, const char * processname,  const char * systematicname, TH1D hist, TH1D hist_up, TH1D hist_down)
{
   // get number of bins
   int nbins = hist.GetNbinsX();

   TH1D * hist_up_rel = new TH1D(hist);
   TH1D * hist_down_rel = new TH1D(hist);

   // loop over all bins
   for (int ibin = 1; ibin <= nbins; ++ibin) {
      hist_up_rel->SetBinContent(ibin, (hist_up.GetBinContent(ibin) - hist.GetBinContent(ibin)) / hist.GetBinContent(ibin));
      hist_down_rel->SetBinContent(ibin, (hist.GetBinContent(ibin) - hist_down.GetBinContent(ibin)) / hist.GetBinContent(ibin));
   }

   // set the systematic variation
   return SetSystematicVariation(channelname, processname, systematicname, *hist_up_rel, *hist_down_rel);
}

// ---------------------------------------------------------
int BCMTF::PrintSummary(const char * filename)
{
   // open file
   std::ofstream ofi(filename);
   ofi.precision(3);

   // check if file is open
   if(!ofi.is_open()) {
      BCLog::OutWarning(Form("BCMultitemplateFitter::PrintSummary() : Could not open file %s", filename));
      return 0;
   }

   ofi
      << " Multi template fitter summary " << std::endl
      << " ----------------------------- " << std::endl
      << std::endl
      << " Number of channels      : " << fNChannels << std::endl
      << " Number of processes     : " << fNProcesses << std::endl
      << " Number of systematics   : " << fNSystematics << std::endl
      << std::endl;

   ofi
      << " Channels :" << std::endl;
      for (int i = 0; i < GetNChannels(); ++i) {
         ofi
            << " " << i
            << " : \"" << GetChannel(i)->GetName().c_str() << "\""
            << std::endl;
      }
      ofi
         << std::endl;

   ofi
      << " Processes :" << std::endl;
      for (int i = 0; i < GetNProcesses(); ++i) {
         ofi
            << " " << i
            << " : \"" << GetProcess(i)->GetName().c_str()  << "\""
            << " (par index " << GetParIndexProcess(i) << ")"
            << std::endl;
      }
      ofi
         << std::endl;

   ofi
      << " Systematics :" << std::endl;
      for (int i = 0; i < GetNSystematics(); ++i) {
         ofi
            << " " << i
            << " : \"" << GetSystematic(i)->GetName().c_str()  << "\""
            << " (par index " << GetParIndexSystematic(i) << ")"
            << std::endl;
      }
      ofi
         << std::endl;
      if (GetNSystematics() == 0)
         ofi
            << " - none - " << std::endl;

      ofi
         << " Goodness-of-fit: " << std::endl;
      for (int i = 0; i < GetNChannels(); ++i) {
         ofi
            << " i : \"" << GetChannel(i)->GetName().c_str() << "\" : chi2 = "
            << CalculateChi2( i, GetBestFitParameters() )
            << std::endl;
      }
      ofi
         << std::endl;


   // close file
   ofi.close();

   // no error
   return 1;
}

// ---------------------------------------------------------
double BCMTF::Expectation(int channelindex, int binindex, const std::vector<double> & parameters)
{
   double expectation = 0.;
    
   // loop over all processes
   for (int i = 0; i < fNProcesses; ++i) {
       // get efficiency
       double efficiency = Efficiency(channelindex, i, binindex, parameters);
       
       // get probability
       double probability = Probability(channelindex, i, binindex, parameters);
       
       // get parameter index
       int parindex = fProcessParIndexContainer[i];
       
       // add to expectation
       expectation += ExpectationFunction(parindex, channelindex, i, parameters)
          * efficiency
          * probability;
   }
    
   // check if expectation is positive
   if (expectation < 0)
      expectation = 0.;

   return expectation;
}

// ---------------------------------------------------------
double BCMTF::ExpectationFunction(int parindex, int channelindex, int processindex, const std::vector<double> & parameters)
{
  // get function container
  std::vector<TF1 *> * funccont = fChannelContainer[channelindex]->GetTemplate(processindex)->GetFunctionContainer();

  if (funccont->size()>0)
    return 1.;

  else if (!fExpectationFunctionContainer[parindex])
    return parameters[parindex];

  else {
    TF1 * func = fExpectationFunctionContainer[parindex];
    return func->Eval(parameters[parindex]);
  }
}

// ---------------------------------------------------------
double BCMTF::Efficiency(int channelindex, int processindex, int binindex, const std::vector<double> & parameters)
{
   // get channel
   BCMTFChannel * channel = fChannelContainer[channelindex];

   double efficiency = channel->GetTemplate(processindex)->GetEfficiency();

   double defficiency = 1.;

   // loop over all systematics
   for (int i = 0; i < fNSystematics; ++i) {
      if (!(fSystematicContainer[i]->GetFlagSystematicActive()))
         continue;

      // get parameter index
      int parindex = fSystematicParIndexContainer[i];

      // get histogram
      TH1D * hist = 0;

      if (parameters[parindex] > 0)
         hist = channel->GetSystematicVariation(i)->GetHistogramUp(processindex);
      else
         hist = channel->GetSystematicVariation(i)->GetHistogramDown(processindex);

      // check if histogram exists
      if (!hist)
         continue;

      // multiply efficiency
      defficiency += parameters[parindex] * hist->GetBinContent(binindex);
   }

   // calculate efficiency
   efficiency *= defficiency;

   // make sure efficiency is between 0 and 1
   if (fFlagEfficiencyConstraint) {
      if (efficiency < 0.)
         efficiency = 0.;
      if (efficiency > 1.)
         efficiency = 1.;
   }

   return efficiency;
}

// ---------------------------------------------------------
double BCMTF::Probability(int channelindex, int processindex, int binindex, const std::vector<double> & parameters)
{
   // get histogram
   TH1D * hist = fChannelContainer[channelindex]->GetTemplate(processindex)->GetHistogram();

   // get function container
   std::vector<TF1 *> * funccont = fChannelContainer[channelindex]->GetTemplate(processindex)->GetFunctionContainer();

   // this needs to be fast
   if (!hist && !(funccont->size()>0))
      return 0.;

   if (hist)
     return hist->GetBinContent(binindex);
   else {
     int parindex = fProcessParIndexContainer[processindex];
     return funccont->at(binindex-1)->Eval(parameters[parindex]);
   }
}

// ---------------------------------------------------------
int BCMTF::PrintStack(const char * channelname, const std::vector<double> & parameters, const char * filename, const char * options)
{
   int index = GetChannelIndex(channelname);

   return PrintStack(index, parameters, filename, options);
}

// ---------------------------------------------------------
int BCMTF::PrintStack(int channelindex, const std::vector<double> & parameters, const char * filename, const char * options)
{
   // check if parameters are filled
   if (!parameters.size())
      return -1;

   // check options
   bool flag_logx   = false; // plot x-axis in log-scale
   bool flag_logy   = false; // plot y-axis in log-scale
   bool flag_bw     = false; // plot in black and white

   if (std::string(options).find("logx") < std::string(options).size())
      flag_logx = true;

   if (std::string(options).find("logy") < std::string(options).size())
      flag_logy = true;

   if (std::string(options).find("bw") < std::string(options).size())
      flag_bw = true;

   // get channel
   BCMTFChannel * channel = GetChannel(channelindex);

   // create canvas
   TCanvas * c1 = new TCanvas();
   c1->cd();

   // set log or linear scale
   if (flag_logx)
      c1->SetLogx();

   if (flag_logy)
      c1->SetLogy();

   // create stack
   THStack * stack = new THStack("", "");

   // create a container of temporary histograms
   std::vector<TH1D *> histcontainer;

   // get number of templates
   unsigned int ntemplates = GetNProcesses();

   // loop over all templates
   for (unsigned int i = 0; i < ntemplates; ++i) {

      // get histogram
      TH1D * temphist = channel->GetTemplate(i)->GetHistogram();

      // get function container
      std::vector<TF1 *> * funccont = channel->GetTemplate(i)->GetFunctionContainer();

      // create new histogram
      TH1D * hist(0);

      if (temphist)
         hist = new TH1D( *(temphist) );
      else if (funccont)
         hist = new TH1D( *(channel->GetData()->GetHistogram()));
      else
         continue;

      if (flag_bw) {
         hist->SetFillColor(0);
         hist->SetLineWidth(0);
         hist->SetLineStyle(int(1+i));
      }
      else {
         hist->SetFillColor(2 + i);
         hist->SetFillStyle(1001);
      }

      // get number of bins
      int nbins = hist->GetNbinsX();

      // scale histogram
      for (int ibin = 1; ibin <= nbins; ++ibin) {

         // get efficiency
         double efficiency = Efficiency(channelindex, i, ibin, parameters);

         // get probability
         double probability = Probability(channelindex, i, ibin, parameters);

         // get parameter index
         int parindex = GetParIndexProcess(i);

         // add to expectation
         double expectation = parameters[parindex] * efficiency * probability;

         // set bin content
         hist->SetBinContent(ibin, expectation);
      }

      // add histogram to container (for memory management)
      histcontainer.push_back(hist);

      // add histogram to stack
      stack->Add(hist);
   }

   //draw data
   channel->GetData()->GetHistogram()->Draw("PE");

   // set range user
   channel->GetData()->GetHistogram()->GetYaxis()->SetRangeUser(0., channel->GetData()->GetHistogram()->GetMaximum() + 2. * sqrt(channel->GetData()->GetHistogram()->GetMaximum()));

   // draw stack
   stack->Draw("SAMEHIST");

   //draw data again
   channel->GetData()->GetHistogram()->Draw("SAMEPE");

   // redraw the axes
   gPad->RedrawAxis();

   // print
   c1->Print(filename);

   // free memory
   for (unsigned int i = 0; i < histcontainer.size(); ++i) {
      TH1D * hist = histcontainer.at(i);
      delete hist;
   }
   delete stack;
   delete c1;

   // no error
   return 1;
}

// ---------------------------------------------------------
double BCMTF::CalculateChi2(int channelindex, const std::vector<double> & parameters)
{
   if (parameters.size() == 0)
      return -1;

   double chi2 = 0;

   // get channel
   BCMTFChannel * channel = GetChannel(channelindex);

   // get data
   BCMTFTemplate * data = channel->GetData();

   // get histogram
   TH1D * hist = data->GetHistogram();

   // check if histogram exists
   if (hist) {
      // get number of bins in data
      int nbins = hist->GetNbinsX();

      // loop over all bins
      for (int ibin = 1; ibin <= nbins; ++ibin) {
         // get expectation value
         double expectation = Expectation(channelindex, ibin, parameters);

         // get observation
         double observation = hist->GetBinContent(ibin);

         // add Poisson term
         chi2 += (expectation - observation) * (expectation - observation) / expectation;
      }
   }

   // return chi2;
   return chi2;
}

// ---------------------------------------------------------
double BCMTF::CalculateChi2(const std::vector<double> & parameters)
{
   if (parameters.size() == 0)
      return -1;

   double chi2 = 0;

   // get number of channels
   int nchannels = GetNChannels();

   // loop over all channels
   for (int i = 0; i < nchannels; ++i) {
      chi2 += CalculateChi2(i, parameters);
   }

   // return chi2
   return chi2;
}

// ---------------------------------------------------------
double BCMTF::CalculateCash(int channelindex, const std::vector<double> & parameters)
{
   if (parameters.size() == 0)
      return -1;

   double cash = 0;

   // get channel
   BCMTFChannel * channel = GetChannel(channelindex);

   // get data
   BCMTFTemplate * data = channel->GetData();

   // get histogram
   TH1D * hist = data->GetHistogram();

   // check if histogram exists
   if (hist) {
      // get number of bins in data
      int nbins = hist->GetNbinsX();

      // loop over all bins
      for (int ibin = 1; ibin <= nbins; ++ibin) {
         // get expectation value
         double expectation = Expectation(channelindex, ibin, parameters);

         // get observation
         double observation = hist->GetBinContent(ibin);

         // calculate Cash statistic
         cash += 2. * (expectation - observation);

         // check negative log
         if (observation > 0)
            cash += 2. * observation * log (observation/expectation);
      }
   }

   // return cash;
   return cash;

}

// ---------------------------------------------------------
double BCMTF::CalculateCash(const std::vector<double> & parameters)
{
   if (parameters.size() == 0)
      return -1;

   double cash = 0;

   // get number of channels
   int nchannels = GetNChannels();

   // loop over all channels
   for (int i = 0; i < nchannels; ++i) {
      cash += CalculateCash(i, parameters);
   }

   // return cash
   return cash;
}

// ---------------------------------------------------------
double BCMTF::LogLikelihood(const std::vector<double> & parameters)
{
   double logprob = 0.;

   // loop over all channels
   for (int ichannel = 0; ichannel < fNChannels; ++ichannel) {

      // get channel
      BCMTFChannel * channel = fChannelContainer[ichannel];

      // check if channel is active
      if (!(channel->GetFlagChannelActive()))
         continue;

     // get data
      BCMTFTemplate * data = channel->GetData();

      // get histogram
      TH1D * hist = data->GetHistogram();

      // check if histogram exists
      if (!hist)
         continue;

      // get number of bins in data
      int nbins = data->GetNBins();

      // loop over all bins
      for (int ibin = 1; ibin <= nbins; ++ibin) {

         // get expectation value
         double expectation = Expectation(ichannel, ibin, parameters);

         // get observation
         double observation = hist->GetBinContent(ibin);

         // add Poisson term
         logprob += BCMath::LogPoisson(observation, expectation);
      }
   }

   return logprob;
}

// ---------------------------------------------------------