Session 4

24 Nov 2008

Question 1: You are planning to start analysis, where would you go to look for information

• starts in http://cms.cern.ch/iCMS/
  • comments which sort an analysis (if already done, cms notes)
  • would think which group this fits and would go to wiki of the groups
  • looks at tabs goes to collabaration and then left bar, finds cms wiki
• goes to https://twiki.cern.ch/twiki/bin/view/CMS
  • looks for egamma POG
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/EgammaPOG
  • can see who he should contact
  • find subprojects but does not know where to go
  • states that looks for CMSSW
  • expects to find some go under the tasks e.g. HLT
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/EgammaHLTStudies
  • expect to find some code and how to use and access it here
  • finds links to instructions
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/SWGuideEgammaHLT
  • scrolls the table of contents
  • finds a piece of goes which helps implementing the HLT
  • comments that this is specific to trigger and if he would need to write code he would start to learn how to use CMSSW and where are the use routines which he can plug inside
  • expect to find a page for CMSSW
• goes back to wiki home page https://twiki.cern.ch/twiki/bin/view/CMS/WebHome
  • find computing
• goes to http://cms.cern.ch/iCMS/jsp/page.jsp?mode=cms&action=url&urlkey=CMS_COMPUTING
  • sees User Support and tutorials and states that he would probably go to tutorials to learn how to start an analysis
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/Tutorials
  • reads goals of the page and see the WorkBook which he thinks of bookmarking
• goes to WorkBook https://twiki.cern.ch/twiki/bin/view/CMS/WorkBook
  • scrolls the index
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/WorkBookSetComputerNode
  • reads the toc
  • scrolls down and says that he would start here and would writes Hello world program
• goes back to https://twiki.cern.ch/twiki/bin/view/CMS/WorkBook
  • states that The basics of CMS offline computing looks more like a general overview of the system and he would read later
  • sees "How to make an Analysis" and says that this sounds good
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/WorkBookMakeAnalysis
  • reads introduction
  • thinks this describes to format of making analysis
  • sees from the sample data file that this is an example that he could run
  • sees the config file which is ready
  • says he would start from here

Question 2: You have electrons in the analysis and you would need to know what the electron data contains. Find the information.

• starts from WorkBook https://twiki.cern.ch/twiki/bin/view/CMS/WorkBook * scrolls the analysis tools part * thinks that the information should be in chapter 4 * thinks that the 1st 3 link seem useful Intro, starter kit, pat tutorial
• goes to intro https://twiki.cern.ch/twiki/bin/view/CMS/WorkBookIntroAnalTools
• goes to starter kit https://twiki.cern.ch/twiki/bin/view/CMS/WorkBookAnalysisStarterKit
  • sees that this is a short-cut
  • seems a repetition of what he has already seen before, does not think this is not the place to look for elctron information
• goes back to https://twiki.cern.ch/twiki/bin/view/CMS/WorkBookIntroAnalTools
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/WorkBookParticleCandidates
  • thinks that this is something general
  • find code examples and instrcutions how to access the physics object in general, but not specific to electrons
  • sees candidates for high level physics objects (states that this is not trigger even if it seems)
  • tries to click on the electron in the figure
  • states that this just an explanation and icon are not links
  • reads that the references to the underlying component are stored in AOD (which thinks of meaning data format)
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/AOD
• comes back to https://twiki.cern.ch/twiki/bin/view/CMS/WorkBookParticleCandidates
  • reads further under RECO/AOD object adapter and says that to him it is not clear if he is in the right place
  • reads about candidate collection
  • states that have not read the intro to CMSSW and without this thinks that collections are collections vectors of objects
  • says that this page does not say how to include this collection in the code
  • says maybe not in the right place
  • reads under Particle candidate types
  • reads under what are particle candidates
  • is asked what type of keywords would be looking for - does not know - is adviced that the data is in AOD format
• goes https://twiki.cern.ch/twiki/bin/view/CMS/AOD
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/SWGuideDataFormatTable
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/SWGuideRecoDataTable
  • scrolls down and says having the names of the collections but is not telling how to use this i.e. how to insert this to the cose
  • is adviced to look in the beginning and find how to use the table https://twiki.cern.ch/twiki/bin/view/CMS/SWGuideRecoDataTable#How_to_use_the_table
  • says that needs an analyzer which he has learnt in the previous step and could cut and paste this in it
  • think this is an instruction how to loop over super cluster
  • guesses that he should replace the supercluster with the name of the electron collection
  • haves difficulties in finding the electron entry in this long page
  • sees the tracking tools
  • scrolls down and sees egamma electron collection
  • reads the description
• clicks on the data collection link to look what is in the electron http://cms-service-sdtweb.web.cern.ch/cms-service-sdtweb/doxygen/CMSSW_2_1_8/doc/html/d0/d6d/classreco_1_1GsfElectron.html
  • reads the page contents, sees the components, sees classification (thinks this is not very clear on the page) etc

Question 3: Find a useful example code, specific on how to access electron data collection

• says that he already has tools how to do this from the how to use the table
• asked if he would find a working example if he gets stuck with it
• is in http://cms.cern.ch/iCMS/jsp/page.jsp?mode=cms&action=url&urlkey=CMS_COMPUTING
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/Tutorials
  • reads through the tutorial list
  • clicks on ECAL CMSSW tutorial
• opens the pdf in http://indico.cern.ch/getFile.py/access?sessionId=8&resId=1&materialId=2&confId=1708
  • thinks this is promising
  • the date sounds bad (2006)
  • decides to find something more useful but scrolls through
• goes back to https://twiki.cern.ch/twiki/bin/view/CMS/Tutorials
  • thinks that these are in chrono order and looks for something more recent
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/September08PATTutorial
• goes back to https://twiki.cern.ch/twiki/bin/view/CMS/Tutorials
  • is advices to read the notion of updates tutorials in the workbook
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/WorkBook
  • reads the right bar about the CMS software documentation suite
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/SWGuide
  • reads the news for contributors and does not understand it
  • reads what is all about
  • finds the navigation bar
  • finds the "how to access" under ecal and decides to go under egamma
• goes to https://twiki.cern.ch/twiki/bin/view/CMS/WorkBookElectronAnalysis

-- KatiLassilaPerini - 02 Mar 2009