LikelihoodIntervalPlot.cxx

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// @(#)root/roostats:$Id: LikelihoodIntervalPlot.cxx 34109 2010-06-24 15:00:16Z moneta $

/*************************************************************************
 * Project: RooStats                                                     *
 * Package: RooFit/RooStats                                              *
 * Authors:                                                              *
 *   Kyle Cranmer, Lorenzo Moneta, Gregory Schott, Wouter Verkerke       *
 *************************************************************************
 * Copyright (C) 1995-2008, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

//____________________________________________________________________
/*
LikelihoodIntervalPlot : 

This class provides simple and straightforward utilities to plot a LikelihoodInterval
object.
*/

#include "RooStats/LikelihoodIntervalPlot.h"

#include <algorithm>
#include <iostream>

#include "TROOT.h"
#include "TMath.h"
#include "TLine.h"
#include "TObjArray.h"
#include "TList.h"
#include "TGraph.h"
#include "TPad.h"


#include "RooRealVar.h"
#include "RooPlot.h"
//#include "RooProfileLL.h"
#include "TF1.h"

/// ClassImp for building the THtml documentation of the class 
ClassImp(RooStats::LikelihoodIntervalPlot);

using namespace RooStats;

//_______________________________________________________
LikelihoodIntervalPlot::LikelihoodIntervalPlot()
{
  // LikelihoodIntervalPlot default constructor
  // with default parameters
  fInterval = 0;
  fNdimPlot = 0;
  fParamsPlot = 0;
  fColor = 0;
  fFillStyle = 4050; // half transparent
  fLineColor = 0;
  fMaximum = 2.;
  fNPoints = 0;  // default depends if 1D or 2D 
  // default is variable range
  fXmin = 0;
  fXmax = -1;
  fYmin = 0;
  fYmax = -1;
  fPrecision = -1; // use default 
}

//_______________________________________________________
LikelihoodIntervalPlot::LikelihoodIntervalPlot(LikelihoodInterval* theInterval)
{
  // LikelihoodIntervalPlot copy constructor
  fInterval = theInterval;
  fParamsPlot = fInterval->GetParameters();
  fNdimPlot = fParamsPlot->getSize();
  fColor = kBlue;
  fLineColor = kGreen;
  fFillStyle = 4050; // half transparent
  fMaximum = 2.;
  fNPoints = 0;  // default depends if 1D or 2D 
  // default is variable range
  fXmin = 0;
  fXmax = -1;
  fYmin = 0;
  fYmax = -1;
  fPrecision = -1; // use default 
}

//_______________________________________________________
LikelihoodIntervalPlot::~LikelihoodIntervalPlot()
{
  // LikelihoodIntervalPlot destructor
}

//_____________________________________________________________________________
void LikelihoodIntervalPlot::SetLikelihoodInterval(LikelihoodInterval* theInterval)
{
  fInterval = theInterval;
  fParamsPlot = fInterval->GetParameters();
  fNdimPlot = fParamsPlot->getSize();

  return;
}

//_____________________________________________________________________________
void LikelihoodIntervalPlot::SetPlotParameters(const RooArgSet *params) 
{
  fNdimPlot = params->getSize();
  fParamsPlot = (RooArgSet*) params->clone((std::string(params->GetName())+"_clone").c_str());

  return;
}


//_____________________________________________________________________________
void LikelihoodIntervalPlot::Draw(const Option_t *options) 
{
   // draw the Likelihood interval or contour plot
   // For 1D problem draw the log profile likelihood function ratio and its interval 
   // The curve is draws in a RooPLot by default (i.e as a RooCurve) 
   // The plotting range (default is the full parameter range) and the precision of the RooCurve
   // can be specified by using SetRange(x1,x2) and SetPrecision(eps). 
   // SetNPoints(npoints) can also be used  (default is npoints=100) 
   // Optionally the function can be drawn as a TF1 (option="tf1") obtained by sampling the npoints
   // For 2D case, a contour is drawn. The number of contour points is controlled by 
   // SetNPoints(npoints) (default is npoints=40)
   // In case of problems finding the contour with Minuit, the option "nominuit" can be used. 
   // In this case the profile likelihood function is sampled in the npoints x npoints values and then 
   // an approximate contour is obtained. 

   if(fNdimPlot > 2){
      std::cout << "LikelihoodIntervalPlot::Draw(" << GetName() 
                << ") ERROR: contours for more than 2 dimensions not implemented!" << std::endl;
      return;
   }
   
   TIter it = fParamsPlot->createIterator();
   RooRealVar *myparam = (RooRealVar*)it.Next();
      
   RooAbsReal* newProfile = fInterval->GetLikelihoodRatio(); 

   // analyze options 
   TString opt = options; 
   opt.ToLower(); 
   // use RooPLot for drawing the 1D PL
   // if option is TF1 use TF1 for drawing
   bool useRooPlot = opt.Contains("rooplot") ||  ! (opt.Contains("tf1"));
   opt.ReplaceAll("rooplot","");
   opt.ReplaceAll("tf1","");
   // use Minuit for drawing the contours of the PL 
   bool useMinuit = !opt.Contains("nominuit");
   opt.ReplaceAll("nominuit","");

   RooPlot * frame = 0; 

   TString title = GetTitle(); 
   int nPoints = fNPoints; 
   
   if(fNdimPlot == 1){

     //      if (title.Length() == 0) 
     //         title = "- log profile likelihood ratio";

      if (nPoints <=0) nPoints = 100; // default in 1D

      const Double_t xcont_min = fInterval->LowerLimit(*myparam);
      const Double_t xcont_max = fInterval->UpperLimit(*myparam);

      RooRealVar* myarg = (RooRealVar *) newProfile->getVariables()->find(myparam->GetName());
      double x1 = myarg->getMin(); 
      double x2 = myarg->getMax();


      // use TF1 for drawing the function
      if (!useRooPlot) { 

         // set a first estimate of range including 2 times upper and lower limit
         double xmin = std::max( x1, 2*xcont_min - xcont_max); 
         double xmax = std::min( x2, 2*xcont_max - xcont_min); 
         if (fXmin < fXmax) { xmin = fXmin; xmax = fXmax; }
         
         TF1 * tmp = newProfile->asTF(*myarg); 
         tmp->SetRange(xmin, xmax);      
         tmp->SetNpx(nPoints);

         // clone the function to avoid later to sample it
         TF1 * f1 = (TF1*) tmp->Clone(); 
         delete tmp;
         
         f1->SetTitle(title);
         TString name = TString(GetName()) + TString("_PLL_") + TString(myarg->GetName());
         f1->SetName(name);
         
         // set range for displaying x values where function <=  fMaximum
         // if no range is set amd 
         // if no reasanable value found mantain first estimate
         x1 = xmin; x2 = xmax;  
         if (fMaximum > 0 && fXmin >= fXmax ) { 
            double x0 = f1->GetX(0, xmin, xmax);
            // check that minimum is between xmin and xmax
            if ( x0 > x1 && x0 < x2) { 
               x1 = f1->GetX(fMaximum, xmin, x0); 
               x2 = f1->GetX(fMaximum, x0, xmax); 
               f1->SetMaximum(fMaximum);
            //std::cout << "setting range to " << x1 << " , " << x2 << " x0 = " << x0 << std::endl;
            }
         }
         
         f1->SetRange(x1,x2);
         
         
         f1->SetLineColor(kBlue);
         f1->GetXaxis()->SetTitle(myarg->GetName());
         f1->GetYaxis()->SetTitle(Form("- log #lambda(%s)",myparam->GetName()));
         f1->Draw(opt);

      } 
      else { 
         // use a RooPlot for drawing the PL function        
         double xmin = myparam->getMin(); double xmax =  myparam->getMax();
         if (fXmin < fXmax) { xmin = fXmin; xmax = fXmax; }  

         // set nbins (must be used in combination with precision )
         // the curve will evaluate 2 * nbins if preciaon is > 1
         int prevBins = myarg->getBins();
         myarg->setBins(fNPoints);

         // want to set range on frame not function
         frame = myarg->frame(xmin,xmax,nPoints);
         // for ycutoff line
         x1= xmin;
         x2=xmax;
         frame->SetTitle(title);
         frame->GetYaxis()->SetTitle(Form("- log #lambda(%s)",myparam->GetName()));
         //    frame->GetYaxis()->SetTitle("- log profile likelihood ratio");
         

         // plot 
         RooCmdArg cmd; 
         if (fPrecision > 0) cmd = RooFit::Precision(fPrecision); 
         newProfile->plotOn(frame,cmd); 
         
         frame->SetMaximum(fMaximum);
         frame->SetMinimum(0.);

         myarg->setBins(prevBins);

      }

      
      //myarg->setVal(xcont_max);
      //const Double_t Yat_Xmax = newProfile->getVal();
      Double_t Yat_Xmax = 0.5*TMath::ChisquareQuantile(fInterval->ConfidenceLevel(),1);
      
      TLine *Yline_cutoff = new TLine(x1,Yat_Xmax,x2,Yat_Xmax);
      TLine *Yline_min = new TLine(xcont_min,0.,xcont_min,Yat_Xmax);
      TLine *Yline_max = new TLine(xcont_max,0.,xcont_max,Yat_Xmax);
      
      Yline_cutoff->SetLineColor(fLineColor);
      Yline_min->SetLineColor(fLineColor);
      Yline_max->SetLineColor(fLineColor);
      
      if (!useRooPlot) { 
         // need to draw the line 
         Yline_cutoff->Draw();
         Yline_min->Draw();
         Yline_max->Draw();
      } 
      else { 
         // add line in the RooPlot
         frame->addObject(Yline_min);
         frame->addObject(Yline_max);
         frame->addObject(Yline_cutoff);
         frame->Draw(opt);
      }
      

      return;
   }
   else if(fNdimPlot == 2){

      RooRealVar *myparamY = (RooRealVar*)it.Next();

      Double_t cont_level = TMath::ChisquareQuantile(fInterval->ConfidenceLevel(),fNdimPlot); // level for -2log LR
      cont_level = cont_level/2; // since we are plotting -log LR

      RooArgList params(*newProfile->getVariables());
      // set values and error for the POI to the best fit values 
      for (int i = 0; i < params.getSize(); ++i) { 
         RooRealVar & par =  (RooRealVar &) params[i];
         RooRealVar * fitPar =  (RooRealVar *) (fInterval->GetBestFitParameters()->find(par.GetName() ) );
         if (fitPar) {
            par.setVal( fitPar->getVal() );
         }
      }
      // do a profile evaluation to start from the best fit values of parameters 
      newProfile->getVal(); 

      if (title.Length() == 0)
         title = TString("Contour of ") + TString(myparamY->GetName() ) + TString(" vs ") + TString(myparam->GetName() ); 

      if (nPoints <=0) nPoints = 40; // default in 2D

      if (!useMinuit) { 
      
         // draw directly the TH2 from the profile LL
         TH2F* hist2D = (TH2F*)newProfile->createHistogram("_hist2D",*myparam,RooFit::YVar(*myparamY),RooFit::Binning(nPoints),RooFit::Scaling(kFALSE));


         hist2D->SetTitle(title);
         hist2D->SetStats(kFALSE);

         hist2D->SetContour(1,&cont_level);

         hist2D->SetFillColor(fColor); 
         hist2D->SetFillStyle(fFillStyle); 
         hist2D->SetLineColor(fLineColor);

         TString tmpOpt(options);

         if(!tmpOpt.Contains("CONT")) tmpOpt.Append("CONT");
         if(!tmpOpt.Contains("LIST")) tmpOpt.Append("LIST"); // if you want the contour TGraphs

         hist2D->Draw(tmpOpt.Data());
         //    hist2D->Draw("cont2,list,same");

         gPad->Update();  // needed for get list of specials 

         // get TGraphs and add them
         //    gROOT->GetListOfSpecials()->Print();
         TObjArray *contours = (TObjArray*) gROOT->GetListOfSpecials()->FindObject("contours"); 
         if(contours){
            TList *list = (TList*)contours->At(0); 
            TGraph *gr1 = (TGraph*)list->First();
            gr1->SetLineColor(kBlack);
            gr1->SetLineStyle(kDashed);
            gr1->Draw("same");
         } else{
            std::cout << "no countours found in ListOfSpecials" << std::endl;
         }
      }
      else { 

         // find contours  using Minuit       
         TGraph * gr = new TGraph(nPoints+1); 
         
         int ncp = fInterval->GetContourPoints(*myparam, *myparamY, gr->GetX(), gr->GetY(),nPoints); 

         if (int(ncp) < nPoints) {
            std::cout << "Warning - Less points calculated in contours np = " << ncp << " / " << nPoints << std::endl;
            for (int i = ncp; i < nPoints; ++i) gr->RemovePoint(i);
         }
         // add last point to same as first one to close the contour
         gr->SetPoint(ncp, gr->GetX()[0], gr->GetY()[0] );
         opt.Append("LF");
         // draw first a dummy 2d histogram gfor the axis 
         if (!opt.Contains("same")) { 

            double xmin = myparam->getMin(); double xmax =  myparam->getMax();
            double ymin = myparamY->getMin(); double ymax =  myparamY->getMax();
            if (fXmin < fXmax) { xmin = fXmin; xmax = fXmax; }  
            if (fYmin < fYmax) { ymin = fYmin; ymax = fYmax; }  

            TH2F* hist2D = new TH2F("_hist2D",title, nPoints, xmin, xmax, nPoints, ymin, ymax );
            hist2D->GetXaxis()->SetTitle(myparam->GetName());
            hist2D->GetYaxis()->SetTitle(myparamY->GetName());
            hist2D->SetBit(TH1::kNoStats); // do not draw statistics
            hist2D->SetFillStyle(fFillStyle); 
            hist2D->SetMaximum(1);  // to avoid problem with subsequents draws
            hist2D->Draw("AXIS");
         }
         gr->SetFillColor(fColor); 
         //gr->SetFillStyle(fFillStyle); 
         gr->SetLineColor(kBlack); 
         if (opt.Contains("same"))  gr->SetFillStyle(fFillStyle); // put transparent
         gr->Draw(opt);
         TString name = TString("Graph_of_") + TString(fInterval->GetName());
         gr->SetName(name);
         
      }

   }

   return;
}

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