This tutorial deals with DSTs produced using SL99d,SL99e versions of STAR offline software. The DSTs were produced using the macro bfc.C, located in $STAR/StRoot/macros.
Topics are:

1. Location of DSTs and Macros and info about them
2. How to run bfcread.C to look at DST
3. Example of adding another maker (i.e. St_QA_Maker) to bfcread

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Location of DSTs and Macros and info about them

==> Location of the DSTs:

• currently test DSTs are produced nightly for library validation purposes.
• location can be found by going to WWW page http://www.star.bnl.gov/STAR/comp/data/Test_files.html
• e.g. I see the directory listed and look for the file on disk:

      ls -al /disk00000/star/test/dev/tfs_Linux/Mon/year_2a/
     -rw-r--r--   1 didenko  rhstar   15181962 May 26 15:15 psc0208_01_40evts.dst.root
     -rw-r--r--   1 didenko  rhstar   13841827 May 26 15:15 psc0208_01_40evts.event.root
     -rw-r--r--   1 didenko  rhstar     32272 May 26 15:15 psc0208_01_40evts.hist.root
     -rw-r--r--   1 didenko  rhstar    875725 May 26 15:15 psc0208_01_40evts.log
     -rw-r--r--   1 didenko  rhstar   22990640 May 26 15:15 psc0208_01_40evts_dst.xdf
    

• The above .root files are different branches written out from bfc.C. The .dst.root file contains the same tables as *dst.xdf file -- but in root format instead of xdf format. The event.root file contains the persistent StEvent data. The .hist.root file contains all histograms created by all Makers. The log file is also available.
• by searching the log file for "Inp", I find the location of the input geant fz file:
  

     grep Inp /disk00000/star/test/dev/tfs_Linux/Mon/year_2a/*.log
     Input file name = /disk0/star/test/venus412/b0_3/year_2a/psc0208_01_40evts.fzd with No. of Events to process = 3
    

• Some of the DSTs have all branches of data written out to ROOT files (about 10 files). This will usually only be done in tests of "NEW" version of software.

==> QA of DSTs

• Some quality checks and studies of the DSTs have already been done. To find this, go to WWW pages: http://www.star.bnl.gov/STAR/comp/qa/
• For example, looking at www page qa_tfs_linux_2a_19may99.txt under above www page, one can see the method used to read the different branch files and information about contents of the different branches. Details of the dst branch are given:
  

  
                                                        Table Name    Table Type       Comments
       *** StTreeMaker::Make() == 0 ***
    0 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst    St_DataSet
    1 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst/event_header  dst_event_header  event_type messed up
    1 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst/event_summary dst_event_summary OK
    1 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst/globtrk       dst_track         OK
    1 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst/globtrk_aux   dst_track_aux     empty
    1 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst/vertex        dst_vertex        has z = NaN
    1 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst/globtrk2      dst_track         OK
    1 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst/primtrk       dst_track         OK
    1 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst/primtrk_aux   dst_track_aux     empty
    1 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst/dst_v0_vertex dst_v0_vertex     has dcav0 = NaN
    1 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst/dst_xi_vertex dst_xi_vertex     OK
    1 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst/dst_dedx      dst_dedx          OK
    1 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst/point         dst_point         OK
    1 - bfc/.make/treeRead/.data/bfcTree/dstBranch/dst/monitor_soft  dst_monitor_soft  OK
     

==> Location of ROOT macros

• macros used to run ROOT are kept in $STAR/StRoot/macros
• starting with version SL99e, a list of macros available, owner, if they've been tested and work in this version, and some comments, can be found on WWW page:
  http://www.star.bnl.gov/STAR/comp/root/RootMacrosAvail99e.html

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How to run bfcread.C to look at DST

Use bfcread.C to read in root file (any *.root file) produced when running bfc.C and look at the data.

==> set up your area
to run bfcread (from dev) and read

• We will set up to run bfcread.C (99e) to read in either 99d or 99e DSTs (postMDC2). Currently, this is what is working.
• Below is how I am doing my example:
    log onto sol.star.bnl.gov
    stardev (
    create working directory, e.g. /scr22/kathy/test26 and cd there

==> get bfcread macro and edit it

• cp $STAR/StRoot/macros/bfcread.C .
• edit bfcread.C and make changes if needed:

        The default reads in the "dst" branch of the root file 
           (i.e. the input file is .dst.root)
        If you want to read in a different branch, you must change:
         - the input file name, e.g. *.bname.root
         - treeMk->SetBranch("bnameBranch",0,"r");
         - chain->GetDataSet("bname")
       

==> run bfcread

• rootPstar (use rootPstar on sol for now)
• .x bfcread.C
• You will read in 1 event (default but you can change this), list the contents of the directory (dst in this case) and then pop a TBrowser so you can look at the data.
• Use the path printed to the root screen when it lists the contents of the directory to know how to find the data in the browser. e.g. to find the dst tables in the browser, click on:
  bfc/.make/treeRead/.data/bfcTree/dstBranch/dst and then you will see the tables.
• hold the mouse over a data icon and click on 3rd button, and you will get a list of methods you can use for this object

==> look at results
In Browser:

• Use the path printed to the root screen when it lists the contents of the directory to know how to find the data in the browser. e.g. to find the dst tables in the browser, click on:
  bfc/.make/treeRead/.data/bfcTree/dstBranch/dst and then you will see the tables.
• hold the mouse over a data icon and click on 3rd button, and you will get a list of methods you can use for this object

In Root window:

• Soon there will be $STAR/StRoot/macros/Example*.C macros available to show you how to look at the data, plot a histogram, fill an ntuple etc. from the command line (these weren't working on 5/26/99 for some reason)
• One of these is $STAR/StRoot/macros/Example_root_look_at_tables_after_bfcread.C
• For now, I can just type commands in by hand to look at the table:
  

    //  get dataset for globtrk
    St_DataSet *ds=chain->GetDataSet("dst/globtrk");
  
    // create iterator for the dataset
    St_DataSetIter globtrkiter(ds);
    globtrkiter.Du();
    globtrkiter.Pwd();
  
    // find the table
    St_dst_track *glob = (St_dst_track *) globtrkiter.Find("globtrk");
  
    // print out info about it
    glob.ls();
    glob->Print(9,1);
    glob->Print(8,1);
    glob->Print(8,2);
    glob->Print(1,1);
    glob->Print(0,5);
  
    // get the table header data
    table_head_st *tdt_h = glob->GetHeader();
    tdt_h->name
    tdt_h->type
    tdt_h->maxlen
    tdt_h->nok
  
    // get the table and print out info about it (it's printing row 0)
    dst_track_st *sth = glob->GetTable();
    sth->ndegf
    sth->x0
    sth->impact
    sth->invpt
    sth->y0
  
   

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Example of adding another maker (i.e. St_QA_Maker) to bfcread

==> what we want to do
We will add to bfcread.C macro so that it reads in the dst produced from bfc.C and now executes code from another Maker. Eventually this will probably be implemented in bfc.C, but for now ones adds this functionality in bfcread.C

==> cp bfcread.C to a new macro DrawDstHistNew.C

• still in /scr22/kathy/test26
• cp bfcread.C DrawDstHistNew.C
  (or you could just pick it out of $STAR/StRoot/macros )
• make sure it's setup to read a postMDC2 (99d,99e) *.dst.root file

==> edit DrawDstHistNew.C

• Edit and make following changes to run St_QA_Maker

        Add to macro input list
           const Char_t *psFile="QA_hist.ps")  --- output ps file name
        Add at beg.
           gSystem->Load("St_QA_Maker");    --- load St_QA_Maker library
        Add after setting up chain      
           //  add other makers to chain:
                 St_QA_Maker  *QA  = new St_QA_Maker;
        Add after chain->Init 
           // method to print out list of histograms (this is just for QA Maker) 
             Int_t NoHist=0;
             NoHist = QA->ListHists();
             cout << " DrawDstHistNew.C, No. of Hist we have == " << NoHist << endl;
        Remove code that lists contents of directory and pops Browser which was after event loop
        Add after event loop (this is just stuff for setting up QA Maker to write out file with hist)
          // the following methods are already set to default values in St_QA_Maker::Init - now write over them
            QA->SetDraw(kTRUE);
            QA->SetPostScriptFile(psFile);
            QA->SetZones();
            QA->SetPaperSize()
  
            Int_t numLog = 0;
            numLog = QA->ExamineLogYList();
            cout <<" DrawDstHistNew.C, Number hist to plot with log scale = " << numLog << endl;
        Add at end 
          // Finish method in St_QA_Maker is where the actual DrawHist is done
             chain->Finish();
             cout <<  "DrawDstHistNew.C, passed chain->Finish" << endl ; 
        

==> run DrawDstHistNew.C

• rootPstar
• .x DrawDstHistNew.C
• will read .dst.root file, process 1 event (or more if you changed it), book and fill QA histograms, then at end (from Finish) it will draw the histograms to a canvas and then send them to an output ps file.
• If you actually read to here, I give you a gold star (hey, I just got that!!)

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