This tool applies Voronoi weights to clusters. It makes a shallow copy container of the clusters with the pT of the clusters modified appropriately.

This package makes use of UChicago's xAODAnaHelpers package and Giordon Stark's xAODJetReclustering package.

To install,

mkdir myRootCore && cd $_
rcSetup Base,2.3.41
git clone https://github.com/kratsg/xAODJetReclustering
git clone https://github.com/UCATLAS/xAODAnaHelpers
git clone https://github.com/AvivCukierman/VoronoiWeightTool
rc checkout_pkg atlasoff/AsgExternal/Asg_FastJet/tags
rc checkout_pkg atlasoff/AsgExternal/Asg_FastJetContrib/tags
rc find_packages
rc compile

(You might have to do a rcSetup -u && rcSetup before the final rc compile just because.)

Add this package as a dependency in cmt/Makefile.RootCore.

Add a header

#include <VoronoiWeightTool/VoronoiWeightTool.h>

Set up the tool in the initialize() portion of your algorithm as a pointer

  m_VoronoiTool = new VoronoiWeightTool(m_name);
  m_VoronoiTool->setProperty("InputContainer", m_InputContainer);
  m_VoronoiTool->setProperty("OutputContainer", m_OutputContainer);
  m_VoronoiTool->setProperty("doSpread", m_doSpread);
  m_VoronoiTool->setProperty("doLCWeights", m_doLCWeights);
  m_VoronoiTool->setProperty("nSigma", m_nSigma);
  m_VoronoiTool->initialize();

And then simply call m_VoronoiTool->execute() in the execute() portion of your algorithm to fill the TStore with the appropriate container(s). Don't forget to delete the pointer when you're done.

if(m_VoronoiTool) delete m_VoronoiTool;

You can then do jet clustering as normal on the output cluster container.

N.B. The doLCWeights option indicates whether to apply LC weights (if true) or EM weights (if false) to clusters. The output clusters have their pTs modified in the given state. I.e. with doLCWeights set to true, only the LC pT of the new cluster collection is modified, and with doLCWeights set to false, only the EM pT of the new cluster collection is modified. In order to set the state of the output (or any) cluster collection, the CaloClusterChangeSignalStateList tool should be used in your algorithm, as follows:

#include "xAODCaloEvent/CaloClusterChangeSignalState.h"

 const xAOD::CaloClusterContainer*             new_clusters   (nullptr);
 if(evtStore()->retrieve(new_clusters,m_OutputContainer).isFailure()) Error(APP_NAME,"Could not retrieve the Voronoi cluster container");

 CaloClusterChangeSignalStateList stateHelperList;
 for(auto clust: *new_clusters){
   if(m_doLCWeights) stateHelperList.add(clust,xAOD::CaloCluster::State(1)); //default is calibrated but we can make it explicit anyway
   else stateHelperList.add(clust,xAOD::CaloCluster::State(0));
   //now clust->pt() will give Voronoi modified pT, and jet reconstruction will use Voronoi modified pT
 }

Note that as it behaves like an AsgTool, the functions setProperty() and initialize() have a return type StatusCode.

• Aviv Cukierman

Giordon Stark, from whom I plagiarized this readme and also whose code I used for inspiration.