Atlas ACAT2000 Batavia, IL, USA 16-20 October 2000 More Performance and Implementation of an Object Oriented Track Reconstruction Model in Different OO

ACAT2000 Batavia, IL, USA 16-20 October 2000

Atlas

More Performance and Implementation of an Object Oriented

Track Reconstruction Modelin Different OO Environments

OO Tracker Model Implementation S. Qian 2


CMS & Atlas

Atlas Outline• Overview of LHC, CMS and Atlas• Review of the OO track reconstruction model• Previous Implementation of the OO model into

CMS ORCA and two Atlas LVL-2 trigger SW environments

• New performance result• Implementation of the OO model into the new

Atlas OO offline framework Athena• Summary and prospects



CMS & Atlas

Atlas L H C



CMS & Atlas

Atlas CMS and ATLASCMS



CMS & Atlas

Atlas Trackers of CMS and Atlas

CMS

ATLAS



CMS & Atlas

Atlas OO Tracker Model (I)• Brief history -- Was originally designed by Irwin GAINES and Sijin QIAN for CMS offline software (3/1995)

-- Preliminarily integrated into ORCA (8-9/1999)

-- 1998~1999, was implemented into Atlas LVL-2 triggerOO reference software framework

-- 8~11/1999, was implemented into LVL-2 Ctrig framework, which produces ntuples for trigger performance study

===> Atlas Trig/DAQ Technical Proposal (4/2000)

-- 27/8/2000, was preliminarily implemented in Athena

-- was reported at CHEP’97, ‘98, ‘2000 and AINHEP’99, ...



CMS & Atlas

Atlas OO Tracker Model (II)• Main ingredients of the OO model:

– Problem statement ==> class diagram– Function statement ==> object diagrams and message trace

diagrams

• Main features of the model:– Use well known HEP concepts for classes– Extensive use of Standard Template Library (STL), in both model

design and C++ coding– Initially successful re-use of FORTRAN legacy code (for Kalman

filtering method) in the member functions of various classes; later converted them to C++ in a straightforward manner; now pure C++

– Flexible enough to be re-used in multiple HEP experiments (only implementation of layer class is different)



CMS & Atlas

Atlas

The latest version of class diagram



CMS & Atlas

Atlas Object DiagramsFirst scenario Second scenario



CMS & Atlas

Atlas CMS Implementation• Uses first scenario (internal hit triplets

as seeds)• Conceptual structure of “mytest.cpp” in

the ORCA example directory– RecHit objects (in ORCA) are converted to “hit” object of the

OO model.– Layer objects of OO model are instantiated with hard-wired

code at this stage, can be done from ORCA tracker geometry in future.

– All classes in the OO KF tracking model are brought in straightforwardly without any major change.



CMS & Atlas

Atlas

Conceptual structure of “mytest.cxx” in ORCA example directory



CMS & Atlas

Atlas Previous Atlas Implementation• LVL-2 trigger requirement (O(10ms) time slot)

==> execution time is a factor of concern.– use 2nd scenario (outside seeds)– work in Region of Interest (RoI) instead of in full - range

• Frameworks– LVL-2 Reference Software System (OO designed, input ASCII data)– Ctrig (input from ASCII files, produce ntuples, etc.)

• Seed modes: (1) TRT guided (inward pattern recognition) (2) pixel guided (outward pattern recognition)

• Tracking corrections: (1) Multiple scattering (yes); (2) Energy loss (yes for electrons); (3) Non-uniform B field (in near future).



CMS & Atlas

Atlas Energy Loss Correction (1/Pt) distribution (1/GeV) 1 GeV 5 GeV 20 GeVelectrons electrons electrons



CMS & Atlas

Atlas Performance– Execution speed (on 600 MHz AMD Athlon, under Linux)

B-physics (at low lumi.) TRT seeded Pixel seeded PT min (GeV/c) No. of seed Time(ms) No. of seed Time(ms)0.5 <114> <112>/event <36> <19>/event1.0 <55> <54>/event <16> <9>/event

– Memory usage is in O(10 MB), depends on data volume– Efficiencies (single track events, B-physics events), Resolutions (momentum, impact parameter, etc.) – B-physics study in the channel B --> – Many more latest results are at(1) "Atlas Trig/DAQ Technical Proposal" (CERN/LHCC/2000-17) http://atlasinfo.cern.ch/Atlas/GROUPS/DAQTRIG/SG/TP/draft_tp.html

(2) ATL-DAQ-2000-031 (6/2000) http://documents.cern.ch/cgi-bin/setlink?base=atlnot&categ=Note&id=daq-2000-031

(3) http://www.usatlas.bnl.gov/~sijin/oo.html



CMS & Atlas

Atlas B-physics mass reconstruction

Reconstruction of B --> mass hypothesis in ATLAS Level-2 trigger using theKalman filtering method



CMS & Atlas

Atlas Implementation in AthenaOnce per run Once per event Loop over seeds

Transient

Data

Store

Geome-tricaldata

SCT-Kalman

Layers Digi SeedsSeed

sourceSpaceponits

Recon- structed

tracks

Space point

builder

Seedbuilder

Layerbuilder



CMS & Atlas

Atlas Athena Run Log File (1)ApplicationMgr DEBUG Creating Top Algorithm RunKFApplicationMgr INFO Application Manager Configured successfullyChronoStatSvc INFO Service initialized successfullyEventDataSvc INFO Service initialized successfullyEventPersistenc... INFO Service initialized successfullyEventPersistenc... INFO Added successfully Conversion service:ZebraTDRCnvSvc...ParticlePropert... DEBUG StdHepID Map size =201ZebraTDRCnvSvc INFO Service initialized successfullyApplicationMgr INFO Detector description not requested to be loadedEventSelector INFO Service initialized successfully

RunKF INFO initialize() in RunKFApplicationMgr INFO Application Manager Initialized successfully

RunKF INFO execute() in RunKFRunKF INFO Got event.

execute in KFEventLoader

Space points inputted==================

total # of hits: 11 rfz (0): 51.57, error: 10.00 rfz (1): 0.37, error: 2.00

rfz (2): 82.62, error: 0.00 section: 7 hit-id: 1200010



CMS & Atlas

Atlas Athena Run Log File (2)------------------------------------------ rfz (0): 50.40, error: 10.00 rfz (1): 0.37, error: 2.00

rfz (2): 82.62, error: 0.00 section: 7 hit-id: 1200020------------------------------------------ rfz (0): 52.79, error: 10.00

rfz (1): 0.37, error: 2.00 rfz (2): 82.62, error: 0.00

section: 7 hit-id: 1200030-------------------------------------------

rfz (0): 51.57, error: 10.00 rfz (1): 0.37, error: 2.00 rfz (2): 82.62, error: 0.00 section: 7 hit-id: 1200040

---------------------------------------------...

Seed created============nhseed: 3 parameter(0-4): 29.74 0.37 45.08 0.53 -0.01 1/pt = -0.04



CMS & Atlas

Atlas Athena Run Log File (3)Recontructed trackes (1)====================Track parameters: 92.500, 53.290, 20.698, 0.524, 0.363, -0.000, 1

Weight matrix: 37198.793 -96615.164, 251010.844 -380.575, -147.010, 20536.547 1997824.125, -5181015.000, 52.231, 120808296.000 -21384064.000, 55373708.000, -613.444, -1414695040.000, 17693335552.000

Hit list on the track: track::show : 1200040 51.57 0.37 82.62 0.00 track::show : 1300010 53.84 0.43 91.62 0.00 track::show : hit id:1200040 1300010

Seed ID = 1Chi2 = 3.1Missing points = 0Hit Chi2 contribution: hit dchi2 (1): 0.00 hit dchi2 (2): 2.95

Recontructed trackes (2)==================== …..

•



CMS & Atlas

Atlas Lessons Learned• C++’s new features (for previous Fortran

programmers) now can be handled by some powerful debugging tools, e.g.

– “INSURE++” to detect the memory leaks– “DDD” graphic debugger to detect the pointer bugs

• Integration of an OO model into a general OO environment of whole experiment needs a stable framework with a stable interface. As soon as all functionality of I/O objects needed by the model are available, the integration is straightforward.



CMS & Atlas

Atlas Conclusions

• OO makes it easier to do cooperative development among widely separated collaborators (promotes truly modular designs)

• OO makes re-use easier: the implementation of this OO model into several frameworks of two LHC experiments demonstrates

-- the implementation structure is very similar for different experiments-- the experience in code development can be shared among different experiments immediately



CMS & Atlas

Atlas Summary and Prospects

• We are moving towards a realistic OO track reconstruction model for HEP experiments– the memory usage of this OO model is moderate– the track finding efficiency is satisfactory– the execution speed is approaching the LVL-2 trigger

requirement

• It can be used in different experiments and frameworks with only minor modifications



CMS & Atlas

Atlas Ongoing Works for Athena• Space points input (add correct errors)• Complete the package decomposition• Set more properties in various modules to

replace the hardwired things• Aim for the near future: to re-produce the Atlas

Trig/DAQ TP result and beyond• To test more modes for Space-points-builder

and Seed-builder• To implement the non-uniform B-field

correction



CMS & Atlas

Atlas Efficiencies for and e muons electrons



CMS & Atlas

Atlas Efficiencies for B-physics (1) vs. Pt for e from B0 --> J/ vs.



CMS & Atlas

Atlas Efficiencies for B-physics (2) vs. Pt for e from B0 --> vs.



CMS & Atlas

Atlas Resolutions Pt 20 GeV (tops: barrel; bottoms: endcap) D0

Documents

Atlas ACAT2000 Batavia, IL, USA 16-20 October 2000 More Performance and Implementation of an Object Oriented Track Reconstruction Model in Different OO