| 1 | Note on the implementation of the CMS Iterative Plugin
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| 2 |
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| 3 | The code is initially the CMSSW implementation in
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| 4 | CMSIterativeConeAlgorithm.cc in /CMSSW/RecoJets/JetAlgorithms
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| 5 | (more precisely, Revision 14 of the cc file)
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| 6 |
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| 7 | To avoid importing too many files from CMSSW, we did a couple of
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| 8 | modifications starting from the CMSIterativeConeAlgorithm file:
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| 9 |
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| 10 | - directly used the FastJet PseudoJet instead of the InputItem
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| 11 | present initially. Note that access to the info then has to be done
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| 12 | using . instead of -> which implies a few small modifications here
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| 13 | and there.
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| 14 |
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| 15 | - added a small piece of code to compute Et. That peice of code is
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| 16 | the same as tracked down in the CMS code. It comes from the Root
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| 17 | Lorentzvector, more precisely, the PxPyPzE4D implementation.
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| 18 |
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| 19 | - The ordering in Et, NumericSafeGreaterByEt, is imported from
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| 20 | EtComparator.h in PhysicsTools/Utilities/
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| 21 |
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| 22 | - The DeltaR2 computation is imported from DeltaR.cc and DeltaPhi.cc
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| 23 | in CMSSW/DataFormats/Math
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| 24 |
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| 25 | - finally, instead of the ProtoJet construction, we use the
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| 26 | ClusterSequence-compatible clustering. That one follows the line of
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| 27 | what is done in the SISCone plugin. Note that ve've checked in the
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| 28 | CMSSZ code that the protojet is indeed reconstructed using E-scheme
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| 29 | recombination (while the stability test is done using Et-scheme)
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| 30 |
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| 31 | Finally, we want to thank Andreas Oehler for pointing us to the CMS
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| 32 | code.
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