Plotting Issue with ROOT (6.14) version

Dear Rooters,

I have a problem in the plotting of the results of a fit that to me seems a bug introduces in only when using the ROOT version 6.14.

We are fitting a 3D data histogram using a model constructed with the RooHistFactory package, and at the end of the fit we are plotting the results using the RooAbsPdf::plotOn() method. In order to get a histogram with all the fit components stacked one on top of each other, we are looping over a set of component names and using the command RooFit::Components() to draw only a subset of the components.

We do this recursevely to plot all of them. To be more clear, if we have three components we do

model->plotOn(frame, Components("first"), MoveToBack());
model->plotOn(frame, Components("first,second"), MoveToBack());
model->plotOn(frame, Components("first,second,third"), MoveToBack());

As long as we use ROOT v6.08, the plot looks fine and all the components are picked up correctly.
If we run the same code, though, with the ROOT 6.14, the code does not complain about components not found, but each component is drawn (both in normalization and shape) as the full model.

To reproduce the error, I have modified one of the histfactory tutorials in order to include most of the features we are including in our analysis (in case it can help to debug).

#include "TTree.h"
#include "TFile.h"
#include "TH1F.h"
#include "TF1.h"
#include "TCanvas.h"
#include "TLegend.h"
#include "RooPolynomial.h"
#include "RooCustomizer.h"
#include "RooChi2Var.h"
#include "RooAbsData.h"
#include "RooRealSumPdf.h"
#include "RooPoisson.h"
#include "RooGaussian.h"
#include "RooRealVar.h"
#include "RooMCStudy.h"
#include "RooMinuit.h"
#include "RooCategory.h"
#include "RooHistPdf.h"
#include "RooSimultaneous.h"
#include "RooExtendPdf.h"
#include "RooDataSet.h"
#include "RooDataHist.h"
#include "RooFitResult.h"
#include "RooMsgService.h"
#include "RooParamHistFunc.h"
#include "RooHist.h"
#include "RooRandom.h"
#include "RooPlot.h"
#include "RooCmdArg.h"
#include "TString.h"
#include "TH1D.h"
#include "RooStats/HistFactory/FlexibleInterpVar.h"
#include "RooStats/HistFactory/PiecewiseInterpolation.h"
#include "RooStats/HistFactory/HistFactorySimultaneous.h"
#include "RooStats/HistFactory/Channel.h"
#include "RooStats/HistFactory/MakeModelAndMeasurementsFast.h"
#include "RooStats/HistFactory/Measurement.h"
#include "RooStats/HistFactory/ParamHistFunc.h"
#include "RooStats/HistFactory/HistFactoryModelUtils.h"
#include "RooStats/HistFactory/RooBarlowBeestonLL.h"
#include "RooStats/ModelConfig.h"
#include "RooStats/ToyMCSampler.h"
#include "RooStats/MinNLLTestStat.h"
#include <boost/program_options/option.hpp>
#include <boost/program_options/parsers.hpp>
#include <boost/program_options/variables_map.hpp>
#include <fstream>
#include "RooTFnBinding.h" 
#include "RooUniform.h"
#include "TSystem.h"

using namespace RooStats;
using namespace HistFactory;


 A ROOT script demonstrating
 an example of writing a HistFactory
 model using c++ only.

 This example was written to match
 the example.xml analysis in

 Written by George Lewis, modified (Simone Meloni)


//void plotProjection(RooCategory* idx,RooAbsData* data,RooAbsPdf* model,RooRealVar* obs,TString folder, TString fitvar,RooStats::ModelConfig* mc,RooWorkspace* w, TString output_file_name, TFile* fin, const char* name_suffix)
void plotProjection(RooCategory* idx, RooAbsData* data, RooSimultaneous* model, RooRealVar* obs)
  RooPlot *frame = new RooPlot();
  frame = obs->frame("");
  RooPlot *pframe = new RooPlot();
  pframe = obs->frame(""); //frame used to plot the pulls

  //Define the colour of the component
  std::vector<int> colours;

  //Define the names of the components
  std::vector<const char*> component_names;  

  //Try to see all the components (why shoudlnt you?)
  TString components = "";
  data->plotOn(frame,RooFit::MarkerSize(0.4), RooFit::DrawOption("ZP"), RooFit::DataError( RooAbsData::Poisson), RooFit::Cut(TString("channelCat==channelCat::")+TString(idx->getLabel())));
  int colour_count=0;
  for (int i = 0; i < component_names.size(); ++i)
    std::cout << component_names[i] << std::endl;
    if (components != "")
    std::cout << components << " " << colours[colour_count] << std::endl;
    model->plotOn(frame, RooFit::Slice(*idx), RooFit::ProjWData(*idx,*data), RooFit::DrawOption("F"),RooFit::LineColor(colours[colour_count]),RooFit::FillColor(colours[colour_count]),RooFit::Components(components),RooFit::MoveToBack(), RooFit::Name(component_names[i]));        
  //-----Construct the pulls plot
  model->plotOn(frame, RooFit::Slice(*idx), RooFit::ProjWData(*idx,*data),RooFit::DrawOption("L"),RooFit::LineColor(kBlue), RooFit::LineWidth(0.000001));
  RooHist *pulls = frame->pullHist();
  pframe->addPlotable(pulls, "B");
  //-----------Draw the fit result with the pulls plot below

  TCanvas *c1 = new TCanvas("c1", "c1");

  //----Dimensions of the single pads
  double xmin_1 = 0.005;
  double xmax_1 = 0.995;
  double ymin_1 = 0.35;
  double ymax_1 = 0.995;
  double xmin_2 = .005;
  double xmax_2 = .995;
  double ymin_2 = .05;  
  double ymax_2 = .35;

  c1->cd(1)->SetPad(xmin_1, ymin_1, xmax_1, ymax_1 );
  c1->cd(2)->SetPad(xmin_2, ymin_2, xmax_2, ymax_2 );

  //-draw the bottom pad 
  TPad *padbottom = new TPad("pullspad", "pullspad", 0., 0., 1., 0.3);


  pframe->GetYaxis()->SetTitleSize(0.060/(ymax_2-ymin_2));//rescale the title and the label sizes after dividing the pad


  Double_t xmin = pulls->GetMinimum();
  Double_t xmax = pulls->GetMaximum();
  TF1* upperLine_function = new TF1("upperLine", "3.", xmin, xmax);
  TF1* mediumLine_function= new TF1("mediumLine", "0.", xmin, xmax);
  TF1* lowerLine_function = new TF1("lowerLine", "-3.",xmin, xmax);
  RooAbsReal* upperLine_roofit = RooFit::bindFunction(upperLine_function, *obs);
  RooAbsReal* mediumLine_roofit= RooFit::bindFunction(mediumLine_function,*obs);
  RooAbsReal* lowerLine_roofit = RooFit::bindFunction(lowerLine_function, *obs);

  upperLine_roofit->plotOn(pframe, RooFit::LineStyle(3), RooFit::LineColor(12));
  mediumLine_roofit->plotOn(pframe, RooFit::LineStyle(3),RooFit::LineColor(12));
  lowerLine_roofit->plotOn(pframe, RooFit::LineStyle(3), RooFit::LineColor(12));


  //--draw the top pad 
  frame->GetYaxis()->SetTitleSize(0.060/(ymax_1-ymin_1)); //rescale the title and the label sizes after dividing the pad

int main() {

  //std::string InputFile = "./data/example.root";
  std::string InputFile = "./data/ShapeSys2D.root";
  // in case the file is not found
  bool bfile = gSystem->AccessPathName(InputFile.c_str());
  if (bfile) {
     std::cout << "Input file is not found - run prepareHistFactory script " << std::endl;
     gROOT->ProcessLine(".! prepareHistFactory .");
     bfile = gSystem->AccessPathName(InputFile.c_str());
     if (bfile) {
        std::cout << "Still no " << InputFile << ", giving up.\n";

  // Create the measurement
  Measurement meas("meas", "meas");

  meas.SetOutputFilePrefix( "./results/example_UsingC" );
  meas.SetPOI( "SigXsecOverSM" );

  meas.SetLumi( 1.0 );
  meas.SetLumiRelErr( 0.10 );
  meas.SetExportOnly( kTRUE );
  //meas.SetBinHigh( 2 );

  // Create a channel

  Channel chan( "channel1" );
  chan.SetData( "data", InputFile );
  chan.SetStatErrorConfig( 0.05, "Poisson" );

  // Now, create some samples

  // Create the signal sample
  Sample *signal = new Sample( "hNDpTauNu_sample", "signal", InputFile );
  signal->AddOverallSys( "syst1",  0.95, 1.05 );
  signal->AddNormFactor( "SigXsecOverSM", 1, 0, 3 );
  chan.AddSample( *signal );

  // Background 1
  Sample *background1 = new Sample( "hNDpMuNu_sample", "background1", InputFile );
  background1->AddOverallSys( "syst2", 0.95, 1.05  );
  chan.AddSample( *background1 );

  // Background 1
  Sample *background2 = new Sample( "hNDstTauNu_sample", "background2", InputFile );
  background2->AddOverallSys( "syst3", 0.95, 1.05  );
  chan.AddSample( *background2 );

  // Done with this channel
  // Add it to the measurement:
  meas.AddChannel( chan );

  Channel chan2 (chan);

  Channel chan3 (chan);

  Channel chan4 (chan);

  Channel chan5 (chan);

  // Collect the histograms from their files,
  // print some output,

  // One can print XML code to an
  // output directory:
  // meas.PrintXML( "xmlFromCCode", meas.GetOutputFilePrefix() );

  // Now, do the measurement

  RooWorkspace *w;
  w = MakeModelAndMeasurementFast( meas );

  RooStats::ModelConfig *mc = (RooStats::ModelConfig*) w->obj("ModelConfig");

  RooArgSet *obs   = (RooArgSet*) mc->GetObservables();
  RooCategory *idx = (RooCategory*) obs->find("channelCat");
  RooRealVar *x1    = (RooRealVar*) obs->find("obs_x_channel1");
  RooRealVar *x2    = (RooRealVar*) obs->find("obs_x_channel2");
  RooRealVar *x3    = (RooRealVar*) obs->find("obs_x_channel3");
  RooRealVar *x4    = (RooRealVar*) obs->find("obs_x_channel4");
  RooRealVar *x5    = (RooRealVar*) obs->find("obs_x_channel5");
  RooAbsData *data = (RooAbsData*) w->data("obsData");

  RooSimultaneous *model = (RooSimultaneous*)mc->GetPdf();
  RooSimultaneous *model_ = new RooSimultaneous("simPdf_modified","simPdf_modified", *idx);
  RooCustomizer* cust_;
  RooAbsPdf* pdf_;

  RooRealVar *syst2     = (RooRealVar*) mc->GetNuisanceParameters()->find("alpha_syst2");
  RooRealVar *newsyst2  = new RooRealVar("alpha_newsyst2", "alpha_newsyst2", 1., 0.80,1.20);
  for (unsigned int j = 0; j < 5; j++) {
    pdf_ = model->getPdf(idx->getLabel());
    cust_ = new RooCustomizer(*pdf_,"cust_");

  HistFactorySimultaneous* model_hf = new HistFactorySimultaneous(*model_);
  RooAbsReal* nll_hf = model_hf->createNLL(*data,RooFit::Offset(kTRUE));
  RooMinuit* minuit_hf = new RooMinuit(*nll_hf);


  for (unsigned int i = 0; i< 5; i++){
    if (i==0){
      plotProjection(idx, data, (RooSimultaneous*) model_, x1 );
    if (i==1){
      plotProjection(idx, data, (RooSimultaneous*) model_, x2 );
    if (i==2){
      plotProjection(idx, data, (RooSimultaneous*) model_, x3 );
    if (i==3){
      plotProjection(idx, data, (RooSimultaneous*) model_, x4 );
    if (i==4){
      plotProjection(idx, data, (RooSimultaneous*) model_, x5 );


  return 0;

which can be copied in the (I assumed under the name example.C) $ROOTSYS/tutorials/histfactory folder and compiled and run with the following python script.

import sys
import os
import ROOT
from ROOT import *

os.system("g++ -o example example.C `root-config --cflags --libs` -lstdc++ -lMinuit -lFoam -lRooFit -lRooFitCore -lRooStats -lHistFactory -lMathMore")


The code outputs the following figure when run with ROOT 6.08 (which displays the three fit components correctly)

fit_result_channel1.pdf (14.2 KB)

When run with ROOT 6.14 instead it outputs the following one, in which only the full model with the color assigned to the last component is drawn

fit_result_channel1_6_14.pdf (14.1 KB)

One bit of evidence for a potential bug is that this only happens when working with 2D/3D models in Roofit, the plot looks fine when using a 1D model.

Lastly the code gives a very bad error on exit that starts with
*** glibc detected *** ./example: double free or corruption (out): 0x0000000003b7a760 ***
and ends with a very long backtrace.

Can I ask for any help?

Thanks in advance,

It seems to be a roofit issue. may be @moneta can help.

Hi Simone,

some quick feedback:

  1. My compiler warns that you are setting RooFit::LineWidth to zero (which is true) because you convert from a double (0.00…1) to a short. That shouldn’t lead to a crash, but it could interfere with the plotting.
  2. I have fixed double frees when exiting RooFit in root 6.14/08 and 6.16/00 (not yet out). I cannot say if this the problem you see, but that could at least be tested by using one of the releases from
  3. With root master, I see a different problem when compiling your example.
#9  0x00007ffff15a6d90 in RooStats::HistFactory::RooBarlowBeestonLL::initializeBarlowCache (this=0x2f41c50)
    at /home/shageboe/root-src/roofit/histfactory/src/RooBarlowBeestonLL.cxx:308
#10 0x00007ffff1553629 in RooStats::HistFactory::HistFactorySimultaneous::createNLL (this=0x3052f30, data=..., cmdList=...)
    at /home/shageboe/root-src/roofit/histfactory/src/HistFactorySimultaneous.cxx:130
#11 0x00007ffff155352c in RooStats::HistFactory::HistFactorySimultaneous::createNLL (this=0x3052f30, data=..., arg1=..., arg2=..., arg3=..., arg4=..., arg5=..., 
    arg6=..., arg7=..., arg8=...) at /home/shageboe/root-src/roofit/histfactory/src/HistFactorySimultaneous.cxx:100
#12 0x00000000004101f2 in main () at testMacros/simeloni.C:320

The BarlowBeestonLL seems to try to read 4 bins, but the cache only contains 2. Can you make sense of these numbers? Does it sound like any histogram you supplied?
(I am asking this because if none of your histograms have these numbers of bins, it could be a simple memory corruption leading to bogus numbers, and that would have to be searched for in a different place.)

Hi @StephanH,

For the first question, yes I am aware I am setting the line to have zero width. I am doing this because I wanted to draw the pulls and therefore I needed the last object drawn after the data to be the full model, but to not show up in the plot. Maybe there is a better way I do not know, but this should not produce the problem in the plots I have attached, since it did not in ROOT 6.08.

For what concerns the 4->2 bins problem, I should have supplied it with only 2D histograms, containing 4 bins (except underflow and overflow). If you have run the script yourself, the data and histograms provided are anyway recreated by the script in the $ROOTSYS/tutorial/histfactory/data folder and are saved in the file ShapeSys2D.root, which only contains 2D histograms, if you need to check yourself.

Otherwise, if you did not run the code, they are created using the command
preparehistfactory .

In any case, the problem memory corruption problem is common to both ROOT versions, whereas the plot problem arises only in ROOT 6.14.


As a follow up on this I have run the same code sourcing a ROOT version (6.14.08) on lxplus from the following path:

source /cvmfs/

As @StephanH said, the double free corruption is solved, thanks a lot for this.

The plotting issue still remains: I am having the same plotting issues as reported in the first message even using this version of ROOT. In order to run the code, though I have to comment all the ActivateStatError() calls.

If I instead compile it and run it with the ActivateStatError() calls, the code compiles but it stops while running with the following error:

[#1] INFO:Minization -- p.d.f. provides expected number of events, including extended term in likelihood.
[#1] INFO:Minization --  Including the following contraint terms in minimization: (lumiConstraint,alpha_syst1Constraint,alpha_syst2Constraint,alpha_syst3Constraint,gamma_stat_channel1_bin_0_0_constraint,gamma_stat_channel1_bin_1_0_constraint,gamma_stat_channel1_bin_0_1_constraint,gamma_stat_channel1_bin_1_1_constraint,gamma_stat_channel2_bin_0_0_constraint,gamma_stat_channel2_bin_1_0_constraint,gamma_stat_channel2_bin_0_1_constraint,gamma_stat_channel2_bin_1_1_constraint,gamma_stat_channel3_bin_0_0_constraint,gamma_stat_channel3_bin_1_0_constraint,gamma_stat_channel3_bin_0_1_constraint,gamma_stat_channel3_bin_1_1_constraint,gamma_stat_channel4_bin_0_0_constraint,gamma_stat_channel4_bin_1_0_constraint,gamma_stat_channel4_bin_0_1_constraint,gamma_stat_channel4_bin_1_1_constraint,gamma_stat_channel5_bin_0_0_constraint,gamma_stat_channel5_bin_1_0_constraint,gamma_stat_channel5_bin_0_1_constraint,gamma_stat_channel5_bin_1_1_constraint)
RooAbsTestStatistic::initSimMode: creating slave calculator #0 for state channel1 (4 dataset entries)
RooAbsTestStatistic::initSimMode: creating slave calculator #1 for state channel2 (4 dataset entries)
RooAbsTestStatistic::initSimMode: creating slave calculator #2 for state channel3 (4 dataset entries)
RooAbsTestStatistic::initSimMode: creating slave calculator #3 for state channel4 (4 dataset entries)
RooAbsTestStatistic::initSimMode: creating slave calculator #4 for state channel5 (4 dataset entries)
[#1] INFO:Fitting -- RooAbsTestStatistic::initSimMode: created 5 slave calculators.
terminate called after throwing an instance of 'std::out_of_range'
  what():  vector::_M_range_check: __n (which is 2) >= this->size() (which is 2)

Can anyone reproduce this plotting issue I am having?


That’s precisely the issue I got. That’s why I was asking for the 2 bin --> 4 bin difference. I don’t have an idea, yet, what’s causing this.

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.

Hi Simone,

I’m working on a different problem, but the following came up:


is a problem sometimes, because the (temporary) RooArgSet is not handled correctly by RooFit. In case you are using something like this, could you try not making it a temporary:

RooArgSet xset(x);
functionCall(...., RooFit::Components(xset), ...);

Hi @Stephan,

Thanks again for getting back to this and reopening the topic.

As you can see from the code we are using the ‘RooFit::Components(const char*)’ implementation of the RooFit option, so there is no explicit RooArgset defined for it.

Are we also affected by the problem of the wrong handling of a implicitely defined RooArgSet? If so, why only in ROOT 6.14 and not 6.08? And how can we solve it?


Hi Simone,

everyone is affected, but in C++ it usually works. From Python, you get in trouble, because Python manages the lifetime of the RooArgSets a bit differently. The problem only occurs when the ArgSet is deleted before the function executes. The workaround is easy: just give all RooArgSets a name.

Sorry I think there is some misunderstanding here.

I am using C++. And I am not defining any RooArgSet.
The python piece of code is only calling the executable, which is compiled from C++ code.

I am calling the plotOn function recursevely using the option :

RooFit::Component(TString("component name with regexp")) 

The problem is that the (C++) piece of code that I have pointed out draws each component when compiled with ROOT 6.08, but does not when compiled using ROOT 6.14.

There is neither python or RooArgSet involved here.

I am sorry if I am missing something :slight_smile:

Hi Simone,

It’s not a misunderstanding, just a lack of time on my side. Since I have to work on other things until April, I can only mention stuff that might be remotely related to the problem you are seeing, like the temporaries in Python.

One thing you could try is to run RooFit in super verbose mode, and we compare the outputs. That could speed up finding the problem with the 2 vs 4 bins. Have a look at
for directions on how to do this.