How to Write and Read BtaAttributes using 12.3.0 or later

What are BtaAttributes?
How to write BtaAttributes in Kanga?
How to read BtaAttributes from Kanga files?

What are BtaAttributes?

When composite BtaCandidates are created in a module, Beta provides the possibility to add a list of these composites to the event in order to be able to use them in subsequent modules in the path. Additionally, information associated with these composites, e.g. a chi squared of a vertexing fit or the output of a tagging algorithm, can be passed to subsequent modules using BtaAttributes. This avoids carrying out the same time-consuming algorithms several times in different modules.

The BtaAttributes object contains the following pairs:
- a pointer to each BtaCandidate in the composite list
- an associated tag object in which the additional information mentioned above is stored in form of tag bits

The list of composites and their associated BtaAttributes can also be stored in Kanga files, additionally to the tag and micro branches, i.e the transient BtaAttributes introduced above can also be made persistent. The involved classes are shown in this UML diagram. When reading the events back from a Kanga file, this avoids carrying out the same time-consuming algorithms that have already been done in the previous Beta job (in which the Kanga file was written).

How to write BtaAttributes in Kanga?

The following applies to both data and MC running (setting BetaMCMicro to yes or no is enough, the rest happens automatically):

For reading MC:
 setenv BetaMCMicro yes
Otherwise, for reading data:
 setenv BetaMCMicro no

Then:
 setenv BetaMCAll no
 setenv BetaKanga yes

When reading kanga data:
 setenv BetaBdbMicro no
Otherwise, when reading Objy data:
 setenv BetaBdbMicro yes

Then:
 setenv BetaPhysMicro yes
 setenv BetaDisplayMicro no
 setenv ROPT -Shared-noOptimize-noDebug
 setenv ROOTSYS
 newrel -s ~/scratch -t 12.3.0 testRel_12.3.0
 cd testRel_12.3.0
 srtpath
 addpkg BetaUser
 addpkg workdir

You also have to check out the following tag of BtaDataR:
 addpkg BtaDataR tc020820

Somewhere in your path, the transient composite list and BtaAttributes need to be created:

 HepAList< BtaCandidate >* compList = new HepAList< BtaCandidate >
 IfdHepAListProxy< BtaCandidate > *proxy = new IfdHepAListProxy< BtaCandidate >(compList);
 if ( ! Ifd< HepAList< BtaCandidate > >::put( anEvent,proxy,"myCompListName" ) ) {
  ErrMsg(fatal) << "Cannot put list " << "myCompListName" << " in the event, aborting." << endmsg;
 }

-> Somewhere after that (could be in the same module or not), the BtaAttributes have to be added to the event:

  BtaAttributes* attrib = Ifd< BtaAttributes >::get( anEvent, "myBtaAttName" );
  if ( attrib == 0 ) {
   attrib = new BtaAttributes;
   if ( ! Ifd< BtaAttributes >::put( anEvent, attrib, "myBtaAttName" ) )
    ErrMsg( error ) << "Unable to add BtaAttributes object to event." << endmsg;
   else {
    if ( ErrLogging( trace ) )
   ErrMsg( trace ) << "Added BtaAttributes to event." << endmsg;
   }
  }

-> You probably want to fill the BtaAttributes at the same time as you apply e.g. vertex fits or tagging algorithms to the composite candidates:

  BtaCandidate* compCand;
  HepAListIterator< BtaCandidate > iterCompList(*compList);
  while ( 0 != ( compCand = iterMyComp()) )
  {
   ...
   //Determine e.g. chi squared of vertex fit
   float chiSquared = ...
   ...
   // Get a tag object
   AbsEventTag* tag = attrib->find(compCand);
   if (!tag) cout<< "No tag found"<< endl;
   else{
    tag->putFloat(chiSquared,"chi2");
   }
  }

The next step is writing the Kanga file including the BtaAttributes. If the previous module (that created the transient BtaAttributes) was e.g. in the MyAnalysis path, you probably want to edit your myAnalysis.tcl and add the following (maybe in a separate tcl file to be sourced by myAnalysis.tcl):

 sequence append MyAnalysis BtaTreeFlattener
 
 set RooOutputFile myExampleIncludeBtaAttributes-micro.root
 
 mod talk BtaTreeFlattener
   treeList set myCompListName
   flatList set myCompListNameFlat
   show
 exit

If you are reading Objy data, you have to add the following two lines:
 sourceFoundFile RooSequences/RooSequence.tcl
 path append Everything RooSequence

Then:
 sourceFoundFile RooSequences/RooOutputSequence.tcl
 sourceFoundFile RooSequences/RooWriteMicro.tcl

If you are reading Objy data, you have to add the following four lines:
 module disable BdbEventOutput
 module disable FileOutput
 module disable RooEventUpdate
 module disable RooBuildEnv

Then:
 mod talk BtaRooLoad
   writeAttributes set myBtaAttName
   writeCmpList set myCompListNameFlat
   show
 exit
 
 mod enable RooEventOutput
 mod output RooEventOutput
 mod talk RooEventOutput
   output reset
   output create microDST myExampleIncludeBtaAttributes-micro.root
   output path microDST Everything
   output enable microDST
   useInPath set t
 exit

Make sure that the arguments for the composite list and BtaAttributes coincide with the names used for the creation of the transient objects in the precedent modules!

Then you build:
 gmake workdir.setup
 gmake installdirs
 gmake lib
 setboot
 gmake BetaUser.bin
 cd workdir

When reading kanga data, you do:
 BetaApp kanga.tcl
Otherwise, when reading Objy data, you do:
 BetaApp bdbMicro.tcl

You can browse the produced kanga-file myExampleIncludeBtaAttributes-micro.root. You should now find two additional branches for the BtaAttributes and the composite list (besides the tag and BtaAod branches, and the BtaStdHep and MicroTruMap branch in the case of MC).

How to read BtaAttributes from Kanga files?

The following applies to both data and MC running (setting BetaMCMicro to yes or no is enough, the rest happens automatically):

For reading MC:
 setenv BetaMCMicro yes
For reading data:
 setenv BetaMCMicro no

Then:
 setenv BetaMCAll no
 setenv BetaKanga yes
 setenv BetaBdbMicro no
 setenv BetaPhysMicro yes
 setenv BetaDisplayMicro no
 setenv ROPT -Shared-noOptimize-noDebug
 setenv ROOTSYS
 newrel -s ~/scratch -t 12.3.0 testRel_12.3.0
 cd testRel_12.3.0
 srtpath
 addpkg BetaUser
 addpkg workdir
 addpkg BtaDataR tc020820

The Kanga file containing the BtaAttributes is read in as usual, but in some tcl file (maybe in myAnalysis.tcl or a separate tcl file to be sourced), the following needs to be added:

 mod talk BtaRooLoad
   readAttributes set myBtaAttName
   readCmpList set myCompListNameFlat
   show
 exit
 
 sequence append MyAnalysis BtaTreeUnFlattener
 
 mod talk BtaTreeUnFlattener
   treeList set myCompListName
   flatList set myCompListNameFlat
   show
 exit

Make sure that the arguments for the composite list and BtaAttributes coincide with the names used when writing the Kanga files!

You can now access the composite list and BtaAttributes in your Beta job by doing the following:

 HepAList< BtaCandidate >* compList = Ifd< HepAList< BtaCandidate > >::get(anEvent, "myCompListName");
  BtaAttributes* attributes = Ifd< BtaAttributes >::get(anEvent, "myBtaAttName");
  if(!attributes) cout << "No attributes found" << endl;
  else{
   BtaCandidate* compCand;
   HepAListIterator<BtaCandidate> iterMyComp(*compList);
   while ( 0 != ( compCand = iterMyComp()) )
   {
    const AbsEventTag *theTag = attributes->find( compCand );
    float chiSqu(-999);
    bool foundChi2 = theTag->getFloat(chiSqu,"chi2");
   }
  }

Then you build:
 gmake workdir.setup
 gmake installdirs
 gmake lib
 setboot
 gmake BetaUser.bin
 cd workdir

And you run
BetaApp kanga.tcl