CMS Software

1. CMS Software Physics Analysis in a Brave New Woorld Introduction for Summer Students, 13th July 2004 Vincenzo Innocente (original form Stephan Wynhoff)

2. FAMOS OVAL ORCA OSCAR SCRAM COBRA IGUANACMS IGNOMINY LCG/AA IGUANA Overview Not a talk to describe why things are the way they are • The main projectsand tools • The role of the central framework, the persistent store • A glance on how to use it

5. Challenges: Geographical Spread 1700 Physicists 150 Institutes 32 Countries (and growing!) CERN state 55 % NMS 45 % Major challenges associated with: Communication and collaboration at a distance Distributed computing resources Remote software development and physics analysis

6. Online System Experiment Tier 2 Tier2 Center Tier2 Center Tier2 Center Tier2 Center Tier2 Center CMS Computing Model ~Pbyte/sec ~100 MBytes/sec Offline Farm,CERN Computer Ctr > 20 TIPS Tier 0 +1 ~2.5 Gbits/sec Tier 1 IN2P3 Center INFN Center RAL Center FNAL Center ~2.5 Gbits/sec ~622 Mbits/sec Tier 3 Software to • keep the systems running • distribute data & jobs • simulation, reconstruction, analysis Institute ~0.25TIPS Institute Institute Institute 100 - 1000 Mbits/sec Physics data cache Tier 4 Workstations

7. (Some of the)Major Challenges for LHC SW • Events are big (raw event is 1MB, with Monte-Carlo 2MB) • Detector digitization has to take into account multiple crossings • Pileup: @1034 = 17 minimum bias events/crossing • Calorimetry needs -5 to +3 crossings • Muon DT ought to have +- 10 crossings • Tracker loopers can persist for many crossings • Typically need info from ~ 200 mb events per signal event • Study at different luminosities infers different pileup • include pileup in digitization (front end of reconstruction) • Track finding in very complex environment • High magnetic field and ~ 1 rad length of tracker material: • Lots of bremsstrahlung for the electrons, • TK-ECAL matching non-trivial

8. 1032 cm-2s-1 1033 cm-2s-1 1034 cm-2s-1 1035 cm-2s-1 HZZ ee event with MH= 300 GeV

9. Pileup • For 1 million Signal events need 200 million min bias events • Impossible with current CPU, storage etc • Solution is to sample a finite number pseudo-randomly • Problems can come when one single mb event by itself would trigger the detector • You would get this trigger many many times • Filter the minimum bias events, but remember to take into account the removed events • must sample from full range of mb events to ensure patterns do not repeat too often • 200mb events = 70MB • massive data movement problem • Pileup is CPU intensive

10. User Analysis User Analysis FAMOS ORCA CMSIM ZebraFZ CMSjet OODB OSCAR FAMOS CMSIM Ntuple Monte-Carlo generator Monte-Carlo generator Simulation, Reconstruction, Analysis

11. OODB SimHits HEPEVTNtuple MC generator RecReader SimReader OODBminbias OODB Digis OODBRecObs (DST) Histo OODBsignal The Analysis Chain OSCAR CMKIN Simulation Generation Production ORCA Reconstruction Digitization Analysis User Production

12. Mainly FORTRAN (some non-standard) use GEANT3, Zebra (almost) out of use Simulation CMSIM Tasks • Understand detector response • optimise geometry • set-up, test alignment • understand signal and background topologies • feasibility studies of analyses • optimise trigger • optimise physics selections OSCAR • OO design • use GEANT4 • integrated with CMS software (COBRA)

13. OSCAR in 2004 Official Simulation Production Program • Create and write to OO database and read with ORCA • User Interface (.orcarc) compatible with ORCA • Performance: • Cuts per volume with same values as in CMSIM • Magnetic field tracking tuned • Two times slower than CMSIM (133) Released version 3.3.0 Capabale of simulating several million events.

14. OSCAR Information • Albert De Roeck et al. • http://cmsdoc.cern.ch/oscar • cms-oscar-developers@cern.ch, cms-oscar-support@cern.ch • Meetings: SPROM = Simulation PROject Managementevery 2 weeks Monday 16:30h in 40-2A-01

15. Detector Description DataBase

16. DDD Information • Michael Case • http://cmsdoc.cern.ch/cms/software/ddd/www/index.html • cms-ddd-forum@cern.ch

17. Geometry • Collects XML description of the CMS detector • Materials • Positions • (cuts for OSCAR) • Contact: Pedro Arce • http://cmsdoc.cern.ch/cms/software/geometry/index.html CMSIM 133 Geometry 182

18. Reconstruction • Combination of Signal & Pile-up events • Detector digitisation • (this is the stuff that comes out of the detector) • Reconstruction of detector and simple objects • Tracks, Clusters, Vertices • Reconstruction of physics objects • Jets, Electrons, Photons, Muons • Simulation of L1 Trigger decisions • The Higher Level Trigger algorithms

19. Digitisation and Pileup • High luminosity -> 17 minimumbias events in one bunch crossing • Overlay crossings -5 to +3 • 200 min.bias for 1 signal event • "recycle" min.bias events

20. 4vectors SimHits Digis RecHits RecObj Stages of Reconstruction Produced by MC stored in Ntuple Produced by Geant, stored in DB Include Pileup, some stored in DB (Tk) Pre-processed digits, some stored in DB (Calo) Tracks,Clusters etc, some stored in DB

21. ORCA • the flagship OO software project • started in Sept. 1998 • currently in eighth major release (8.2.0) • widely used by physicists • HLT studies • DAQ TDR • Physics TDR • DC04 • not everything can be stored in the database • Storing with POOL root-streaming • a prototype is not a final product

22. ORCA Applications Fully embedded in COBRA framework, currently: • G3Reader (Also called ooHits) • Read cmsim fz files • Write cmsim hits to Db • SimReader (also called ooDigi) • Pileup arbitrary numbers of crossings pseudo-randomly • Full digitization • persistent storage of results • RecReader _ Read and write Digis and RecObj (DST) • Calorimetric clustering • Jet finding (with any types of objects) • Muon Segment and track finding • Track finding • Primary vertices

23. ORCA Project Structure

24. ORCA Information • Stephan Wynhoff et al. • http://cmsdoc.cern.ch/orca • cms-orca-developers@cern.ch, cms-orca-users@cern.ch, cms-orca-feedback@cern.ch • Meetings: RPROM = Reconstruction PROject Managementevery 2 weeks Monday 16:30h in 40-2A-01

25. COBRA CMS Analysis and Reconstruction Framework • Glue it all together • Insulate user code from services • Manage persistent data transparently • user code does not see any ROOT/IO related code • Manage Collections, Runs etc • Manage the order of reconstruction • Ensure a uniform interface to all CMS code

26. Architecture Overview Data Browser Generic analysis Tools GRID Distributed Data Store & Computing Infrastructure Analysis job wizards LCGtools ORCA COBRA OSCAR FAMOS Detector/Event Display CMS tools Federation wizards Software development and installation Coherent set of basic tools and mechanisms Consistent User Interface

27. Specific Framework Data Monitoring Physics Analysis Event Filter Reconstruction Algorithms ConfigurationObjects Calibration Objects GeometryObjects Event Objects ODBMS (POOL) C++ standard library Extension toolkit SEAL CLHEP ROOT Geant3/4 GRID tools COBRA Components Physics modules Generic Application Framework CMS adapters and extensions Utility Toolkit

28. COBRA Information • Vincenzo Innocente et al. • http://cern.ch/cobra • cms-support-cobra@cern.ch

29. IGUANA • browse federations • display stored histograms • event display

30. OSCAR Visualization • Interactive Geant4 3D CMS detector geometry: physical volume tree; • Interactive overlap detection: find overlaps and show result details in list.

31. Zoom and search; • Context help; • Viewpoints. • Multiple (cloned) views; • Slices and cuts; • Printout for selected object; • Interactive 3D CMS detector geometry (Geant3) for sensitive volumes with levels of details; • Interactive 3D reps of reconstructed and simulated events including visualisation of physics quantities such as tangent of a simhit; • Access event by event or automatically fetching events (no batch mode); • Event and run number displayed. ORCA Visualization • Interactive 3D CMS detector geometry (Geant3) for sensitive volumes with levels of details; • Interactive 3D reps of reconstructed and simulated events including visualisation of physics quantities such as tangent of a simhit; • Access event by event or automatically fetching events (no batch mode); • Event and run number displayed.

32. IGUANA Information • Lucas Taylor, Ianna Osborne, Lassi Tuura • http://cern.ch/iguana • iguana-developers@cern.ch

33. MC 4-vector SimHit RecHit / Digi Analysis obj Fast MonteCarlo Simulation • FAMOS for OSCAR • less geometry volumes • less detailed GEANT4 options • FAMOS for ORCA • faster algorithms • FAMOS for ORCA • simple parametrisation of resolutions & efficiencies • tuned to full simulation/reconstruction 100-200 sec 1-10 sec 10-100 sec Working for all sub-detectors, soon also for HTL

34. FAMOS Information • Patrick Janot • http://cmsdoc.cern.ch/famos • cms-famos-developers@cern.ch

35. FAMOS 0.9.0 ORCA 8.2.0 OSCAR 3.3.0 COBRA 7.8.5 IGUANACMS 1.9.0 IGNOMINY 1.9.0 IGUANA 5.0.1 LCG/AA Project Relations • All Projects listed onhttp://cmsdoc.cern.ch/cmsoo/cmsoo.html

36. External Projects

37. SCRAM • manage our code building and configuration(more reproducable than make and autoconf) • typical commands are • scram listThis gets the list of all the current code releases known to scram • scram project ORCA ORCA_8_2_0This gets scram to create a local area for you that contains all the directories and configuration files you will need in order to work with this release of ORCA • eval `scram runtime -csh`set required environment variables • scram bThis gets scram to compile and/or link the code • Information • Shaun Ashby • http://cmsdoc.cern.ch/Releases/SCRAM/current/cgi/scrampage.cgi • scram-developers@cern.ch

38. Varia • CVS • that is where the code is stored • maintains many versions of one file • full history, parallel development • OVAL • tool to automatize validation • Ecole Polytechnique • http://polywww.in2p3.fr/cms/software/oval/ • Savannah • Feature (bug) reporting system • http://savannah.cern.ch

39. Pure C++ • We work entirely in C++ • You can use any standard tools of C++ • COBRA pins DB objects in memory for duration of event • You access C++ objects • The fact that they may have be transient or in the DB is invisible to you • This is true for most “developer” code and all “user” code • Direct ROOT usage only for very private code • Avoid it if you think your code will ever become official • You can change local copies of the data, but you can’t unconsciously change persistent data even as viewed by another module in this reconstruction job.

40. Generic WWW • Main CMS page http://cmsdoc.cern.ch/cms.html • Public relations http://cmsdoc.cern.ch • OO softwarehttp://cmsdoc.cern.ch/cmsoo/cmsoo.html • Finding MC events (very little for ORCA-7)http://cmsdoc.cern.ch/cms/production/www/html/general/index.html • PRS groupshttp://cmsdoc.cern.ch/cms/PRS/www/prs.php • meetings every 2nd Tuesday/Wednesday

41. CMS Software • There is much that will be very new • But you should be able to quickly do the things you were used to do • And the future possibilities are exciting and can offer you and CMS a significant advantage to get at the Physics first. • C++/OO code can be hard to understand • Everyone has a steep learning curve to follow • Use the documentation tools • Ask people, they want to help • Not everything works as intended! • Be a little patient also, sometimes the thing that seems to you the highest requirement may have not yet reached the top of the stack. • All meetings RPROM, SPROM, PRS are open to all and video-conferenced at times that, while not always convenient, are not impossible for most time-zones

42. New Woorld for the BraveBrave New Woorld Summary • LHC is extremly demanding on software • Object Oriented techniques will help in answering that challenge • CMS is well advanced deploying Tools for Simulation, Reconstruction and Analysis • Physicists can work successfully with the Software • Summer Students can contribute!