User Guide to Common Analysis Format
Contents
1. If the CAFE CONFIG environment variable is defined the file it points to is used e If cafe config exists it is used If SRT PRIVATE CONTEXT cafe config exists it is used 5 2 Access from User Code BEGINNER Typically user algorithms also need configuration information that you don t want to hardcode in your source You can access the configuration file s via the Config class 5 Configuration Files 14 1 cafe Config config cafe std string input_spec config getString Input The code above will return the value of cafe input no matter if it was given in the configuration file or the command line You can also store your own information in this file You should prefix each entry with either your class or function name or the name of your processor instance i e the name you gave it in the run specification FilterMuonEvents NumMuons 2 for a class like this class FilterMuonEvents public FilterMuonEvents const char name cafe Config config name _numMuons config getInt NumMuons bool processEvent cafe Event amp event return event getMuons size gt _numMuons private int _numMuons 5 3 Specifying Groups ADVANCED There are several special Processor classes which provide more structure to the execution of the framework The most common one is called Group A Group object has a Run parameter just like the top level cafe entry W2. You can store any object or simple type in cafe Event provided that the object has a copy constructor and assignment defined Each object is stored together with a key consisting of a string Here is how you store a simple integer number event put myNumber 5 Any other Processor later in the chain can access this value like this int value if event get myNumber value 1 use value else err lt lt myNumber not found in Event lt lt std endl There is always a copy operation involved in both storing and retrieving the value so the operation is quite general but potentially expensive You might try to circumvent this problem by storing only a pointer in the event In this case the question of ownership arises The default behaviour for the cafe Event class is to take ownership of any pointer you pass it When all Processors have been called for the current event the Event clear method is called which deletes any user pointer stored in the event So the following is quite safe as far as memory leaks are concerned MyObject obj new MyObject event put myobject obj 4 6 Tagging Events BEGINNER A very common piece of information which is passed around between Processorss is a Tag This is just a string that marks a specific event There are default methods to tag an event and check for the existence of tags Here is how you tag an event event tag 2MU A tag is just a stri
3. title The name of the histogram is taken from the name of the Processor i e MuonHisto in this case Into which file and or directory will the histogram be written That depends on the current directory for the Processor The easiest way is to specify the output file in the top level configuration cafe Dutput myhistos root All histograms will go into this file However it is often useful to structure the output file itself Every Group can actually define a directory in the current file and each of its children will write its histogram into that directory cafe Run Group mygroup cafe Dutput myhists root mygroup Run HistiD test mygroup Directory MyDirectory test Draw In this case the test histogram will be stored in the MyDirectory folder inside the myhistos root file 7 2 Hist2D and Hist3D There are also 2 and 3 dimensional histograms available The Draw entry will use two or three specifications separated by a colon and the Bins entry takes 6 or 9 parameters 3 for each dimension number of bins minimum maximum cafe Run Hist2 test test Draw Muon Eta Muon Pt 7 3 Selecting Events BEGINNER cafe Run Select DimuonEvents DimuonEvents Select Muon 0 Pt gt 10 0 88 Muon 1 Pt gt 5 0 The expression in the DimuonEvents Select entry follows the syntax used by the TTree Draw command in ROOT If it evaluates to false the Processor rejects the event 7 Available Processors BEGIN
4. 9 3 The default RunController ADVANCED There is one special subclass of Controller named RunController It can be used to run over an arbitrary list of input files with a user specified list of Processors This is basically the main routine of the cafe program The additional method of interest to the user is RunController Run const std string amp input One can call it with a URL to specify a single file a list of files or a SAM definition E g int main RunController top main top add Muon_PT_Histo top Run listfile files txt However there is rarely need to do this yourself since this is exactly what the cafe executable is doing for you
5. TMBMet getMet const const TMBGlobal getGlobal const 3 Using the CAF Environment Cafe 6 For a simple object that has its own branch like TMBGlobal we can just ask for a pointer to it For branches which consist of multiple objects e g all muons the class returns a Collection lt T gt object This is a lightweight wrapper around the internal TClonesArray implementation that makes it look like an STL container The usual methods like beginO end and size are available as well as the operator root 4 tree gt GetEntry 0 root 5 event getMuons size const unsigned int 5 root 6 cafe Collection lt TMBMuon gt muons event getMuons root 7 muons size const unsigned int 5 root 8 const TMBMuon amp muon muons 0 root 9 muon Pt 1 9234234 Don t be afraid to copy Collection objects around internally they are not more than a pointer and all the data actually remains in the original Event object If you have a function like include cafe Event hpp include lt iostream gt bool doSomething cafe Event amp event const TMBGlobal global event getGlobal std cout lt lt Event lt lt global evtno lt lt std endl return true you can call it now like this root L do_something C root for Int t i 0 i lt tree gt GetEntriesFast i tree gt LoadTree i do_something event event clear 3 3 cafe Event and User Def
6. can have multiple directories inside it If the Directory entry of a Group is defined a new subdirectory with the given name is created Again this directory is made the default directory for all children cafe Run Group One Group Two cafe Dutput histos root One Run One Directory HistosFromOne Two Run Two Directory HistosFromTwo If any of the Processors in One and Two produce histograms they will end up in the two different folders HistosFromOne and HistosFromTwo resp All of the histograms will be part of histos root While every Group can define its own output file it is usually most convenient to have just one file but multiple directories inside 5 3 3 Debug Output Each Processor has a method debug which returns the current debugging level a simple integer The higher the level the more detailed output should be produced The debug level can be set via the Debug entry of a Group for all its children MyGroup Debug 3 6 Extending the CAF Tree ADVANCED 16 and in your code if debugO gt 2 err lt lt Detailed info on what s going on lt lt endl 5 3 4 More Processor Methods To produce error or standard output call the err or out methods resp They will return a std ostream amp that you can use as any other 5 4 Including Configuration Files You can distribute the information in the configuration file over multiple physical files and include those Include files c
7. do some common tasks 8 1 Making a Selection by Triggers cafe Run Trigger MyTrigger Passed MyTrigger Triggers 2MU A L2MO 2MU_A_L2ETAPHI 8 2 Making a Selection by Physics Objects cafe Run Select MySelection Passed MySelection Select Muon isTight amp amp Muon nseg 9 Appendix 22 8 3 Creating a Histogram cafe Run Hist1D MyHisto cafe Dutput histos root MyHisto Draw Muon Pt MyHisto Bins 0 0 100 8 4 Writing Events cafe Run Select MySelection Write MyWrite MyWrite File MySkim root MySelection Select Muon isTight amp amp abs Muon nsegO 3 9 Appendix 9 1 Using the cafe Event with TSelector ADVANCED An alternative and more elaborated way is to define your own TSelector class and use it together with cafe Event include TSelector h include TFile h include TH1F h include cafe Event hpp include tmb tree TMBMuon hpp class MyAnalysis public TSelector public MyAnalysis O tree 0 output file 0 ptcent 0 void Init TTree new_tree tree new_tree event setBranchAddresses tree void Begin TTree tree 9 Appendix Init tree Create histograms output file new TFile plots root RECREATE ptcent new TH1F ptcent Central Muon pT 100 0 0 100 0 Bool_t ProcessCut Long64_t entry event clear tree 5GetEntry entry Maybe make a selection return kFALSE if event should not be pr
8. NER 20 7 4 Selecting Events by Trigger BEGINNER cafe Run Trigger DimuonEvents DimuonEvents Triggers 2MU_A_L2M0 2MU_A_L2ETAPHI Select events by trigger names While you can use the Select Processor as well this version is much easier to use and faster 7 5 Adding Friends BEGINNER cafe Run Friend MyFriend MyFriend File f myvars root MyFriend Tree MyTree Whenever a new input file is opened this package will try to open a corresponding file whose name is derived from the input file name the f plus the myvars root suffix It then adds the TTree as a friend to the standard tree so all branches are transparently available 7 6 Conditional Execution BEGINNER cafe Run If GoodEvent GoodEvent Select Muon 0 Pt gt 15 0 amp amp Muon 1 PtO gt 10 GoodEvent Then ProcessGood Passed GoodEvent Else ProcessBad Passed This controller will evaluate the GoodEvent Select expression and execute the Processors in the Then variable if it true Otherwise the Processors in the Else variable are executed 7 7 Permutations ADVANCED cafe Run BadRuns BadLBNs Permute AllPermuations AllPermutations Run Select pTCuts Select MetCut Select deltaPhiCut This controller will execute all permutations of its children It does this by creating a new Controller for every permutation Furthermore each controller will have a different default directory so histograms created in the children will end up in diffe
9. User Guide to Common Analysis Format Reiner Hauser rhauser fnal gov v0 2 2 February 2005 This document describes how to use the DO Common Analysis Format CAF Contents 1 Introduction 2 Getting Started 2 1 Setting up the Release BEGINNER o o sosun 2 2 One time Preparations BEGINNER 0 0 0 0 0000000 4s 2 3 Simple Examples BEGINNER s 2 4 Explicit Loading of the CAF Classes ADVANCED o o 3 Using the CAF Environment Cafe 3 1 The cafe Event Class BEGINNER 0 2 0 0 0 000004 3 2 Using the cafe Event Class BEGINNER o o 3 3 cafe Event and User Defined Classes ADVANCED dl ple Objets 2i utor ee ox Po SUR SE GREY Ree bd eU d mud TClonsasArrays nf Objets o g se Xo RA a o X SACO oe Se RR ES 4 The CAF Environment Framework 4 1 Concepts BEGINNER orre dea ct ra moa 444000 kde oy eed 4 2 Writing your own Processors BEGINNER lee 12 1 Simple Funciona 225 2004 209 eR ERS a x9 eee e Re s 431 Jubel Gt Processor 21 XX RUE ORO Se NOR ERS 43 Input Specifications BEGINNER Re 44 Run Specifications BEGINNER en 45 Non Persistent Data in cafe Event BEGINNER 46 Tagging Events BEGINNER 222 22 880 0 ee ee RE 5 Configuration Files 51 Syntax BEGINNER 2 448055 484 hm SESS GS ER OE RUE S ee RORUR eS 5 2 Acce
10. an be nested arbitrarily deep When specifying the file names you can use environment variables which will be expanded automatically cafe Include otherFile cfg HOME myconfig Config cfg MYGROUP common cfg Every file is included only once even when it appears in more than one include directive Note the use of the plus sign to extend the definition of cafe Include This allows to have multiple such definitions in different files which will be all concatenated 6 Extending the CAF Tree ADVANCED Sometimes the information in the CAF tree is not enough for a given analysis or a group of people wants to share derived variables without recalculating them every time they need them In these cases the CAF tree should be extended Let s assume the following we want to produce some additional information for every event that we see in our Processor and write it to a new output file For this purpose we create a TTree and add a new branch to it include cafe Processor hpp include MyVariables hpp class MyProducer public Processor public void inputFileOpened TFile input file 1 std string input name input File GetName input name input name substr 0 input name rfind myvar root outfile new TFile input name c str RECREATE tree new TTree MyTree tree gt Branch MyAnalysis MyVariables amp myVariables 32000 99 6 Extending the CAF Tree ADVANCED 17 void inputFileClosing TFi
11. e above is to extend the existing tree with new branches and write the output all to one file This makes mostly sense if a selection is applied at the same time so the output tree is different from the input tree The only difference is that you would clone the input tree before adding your own branch void inputFileOpened TFile file TTree caf_tree TTree file Get TMBTree TTree mytree caf tree CloneTree 0 mytree gt Branch save_addressess true bool processEvent cafe Event amp event calculate variables mytree gt Fill write both event and myVariables 7 Available Processors BEGINNER This section describes various existing Processor classes that can be re used by an analyzer Often they do simple things but having them available and configurable saves a lot of trivial programming tasks 7 1 Creating Histograms BEGINNER We have shown an example of how to implement a simple Processor that creates a histogram and write it to a file This is such a common task that there is a standard Hist1D package available You configure it with the following parameters cafe Run HistiD MuonHisto 7 Available Processors BEGINNER 19 MuonHisto Draw Muon Pt MuonHisto Select Muon Pt gt 1 5 amp amp Muon Pt lt 100 0 amp amp Muon Eta lt 2 0 MuonHisto Title Muon pT MuonHisto Bins 100 O 100 Creates a new histogram with the given optional
12. e work area 4 Enable shared libraries and binaries 5 Set the current working area 6 Add the shared binaries to your path 2 2 One time Preparations BEGINNER In your work area you should execute the following command once 4 autoroot py tmb tree cafe This will create a rootmap file in your current directory This is only needed when you run root interactively to make your life easier If root finds this file it will know which libraries to load for which classes and you won t get any funny warnings when you open a CAF file 2 Getting Started 4 2 3 Simple Examples BEGINNER Note that in the following we assume that you execute ROOT from this directory ROOT looks by default for certain configuration files in the current directory especially rootmap If you move to a different directory you have to either copy this file or move it to your home directory where ROOT will also look for it In the following we assume you have an root file in CAF format named input root available in your work directory Just replace the file name with whatever you are preferring 4 root This starts your root session If you have done all the steps before you should be able to access the CAF classes Iry it by typing root 0 TMBMuon m root 1 m Pt This will create and print an uninitialized TMBMuon object There is no need to load the shared libraries explicitly if you ve followed the previous recipe Now let s open t
13. ede eae ae Re EU eg 22 Ssa WHIMS vei ic a 9S ox eec RS le e YR e m PR CHR eec RED e a 22 9 Appendix 22 9 1 Using the cafe Event with TSelector ADVANCED 22 92 Controllers ADVANCED coo RR RR RR key e des 24 9 3 The default RunController ADVANCED o o 25 1 Introduction This document is a tutorial for the Common Analysis Format CAF This ROOT based format consists of several DO packages kinem_util met_util and tmb_tree reasons most classes live in the tmb_tree package and have a TMB prefix before the name e g For historical TMBJet 2 Getting Started 3 2 Getting Started In the following we assume that all examples are executed in a normal DO work environment However except for SAM related things everything should also work in a stand alone environment as long as a ROOT installation is available See the appendix for how to set up the software on a non DO system 2 1 Setting up the Release BEGINNER 4 setup DORunII t05 02 00 1 newrel t t05 02 00 work 2 cd work 3 setenv LINK SHARED yes 4 dOsetwa 5 set path pwd shbin SRT_SUBDIR path 6 or if you are using bash instead of tcsh 4 export LINK_SHARED yes 4 export PATH pwd shbin SRT_SUBDIR PATH 6 The steps should be familiar if you are used to the DO software environment 1 Set up the correct release version 2 Create a new work area 3 Enter th
14. fied on the command line 4 The CAF Environment Framework 10 The return value of the function is false if the framework should stop the processing of the event at this point true otherwise The funny arguments are explained later in the section about the configuration file syntax Basically the command line consists of a list of name value pairs The above says e Use input root as the input file e Run the PrintEventNo function on each event e Load the package my example before execution 4 2 2 Subclasses of Processor The method above is only good enough for very simple tasks Usually the user needs to have more information about the actual processing e g when new files are opened and closed etc In this case she can inherit directly from the cafe Processor base class and implement any of the virtual methods provided there One of them is the processEvent cafe Event amp event method which is called for every event There are however a few more available class Processor virtual void beginO virtual void finishO virtual void inputFileOpened TFile file virtual void inputFileClosing TFile file virtual bool processEvent cafe Event amp event int eventCount const The begin and finish methods are called at the beginning and end of the processing They can be used to create objects like histograms and save them at the end The inputFileOpened and inputFileClosed methods inform about the ope
15. hat it does is it executes all its children in sequence This may not seem much of a deal but it allows you to structure the execution of the code in such a way that multiple pieces can be easily added or removed The Processors that should run as part of a Group are specified int the corresponding Run parameter cafe Run Group Filter Group Process Group Output Filter Run FilterMuonEvents FilterGoodRuns Process Run Muon PT Histo Group PostProcess Output Run WriteMyVariables WriteStandardExtensions PostProcess Run ProduceMyVariables ProduceStandardExtensions 5 Configuration Files 15 Now if you don t want to run the Filter group just modify the first line instead of removing multiple entries Groups can be nested arbitrarily By default there is one top level Group called cafe In addition to the structuring the execution Groups also provide a few more configuration options 5 3 1 Output Files If a Group has an Output entry in the configuration file it will open a new root file with that name and make it the current directory Each Processor can ask what its current directory is with the getDirectory method All the output of a Processor should usually go into its current directory E g instead of just creating a histogrom it should do something like this getDirectory gt cd change to my directory hist new TH1F The default output directory is gROOT 5 3 2 Directories Each ROOT file
16. he file root 2 TFile file input root root 3 TTree tree TTree file Get TMBTree You can now e g draw the variables in the CAF tree or use the TBrowser to view them root 4 tree gt Draw Muon Pt Muon Pt lt 40 0 root 5 tree gt Draw Muon Pt Muon Eta Muon Pt lt 40 0 root 6 new TBrowser 2 4 Explicit Loading of the CAF Classes ADVANCED If you want to compile code on the fly with ROOT s ACIiC system you need to load the necessary libraries explicitly in addition to setting the include paths root 0 gSystem gt Load libPhysics so root 1 gSystem gt Load libmet_util so root 2 gSystem gt Load libtmb_tree so root 3 gSystem gt Load libcafe so root 4 include SRT_PRIVATE_CONTEXT include root 4 include SRT_PUBLIC_CONTEXT include Afterwards all CAF classes should be available in the interactive session If you have used the autoroot py script you can also trigger the loading of all necessary libraries by a statement like root 0 TMBMuon m 3 Using the CAF Environment Cafe 5 3 Using the CAF Environment Cafe The CAF environment is a set of classes which make it easier to work with the objects in the common analysis format More specifically it includes an Event class that integrates all the various branches and provides type safe access to all the physics objects In addition it has framework classes which make it easy to break your analysis
17. her people s code and modify it to make it work in your environment The CAF Environment framework provides the common functionality needed to implement most of the above things in a consistent way By following a few simple rules you can extend the framework in a well defined way and mix and match your code with code that other people have written The framework also provides services for configuration and transparent access to files via SAM 4 1 Concepts BEGINNER The basic unit in the framework is a so called Processor In its most simple form it has a method that takes a cafe Event object and returns a bool The user can specify a series of Processors that will be executed for each event If any of them returns false the processing of the event stops at this point The Processor objects are orchestrated by another entity called a Controller Controllers are themselves a Processor and they can be nested i e a Controller can contain other Controllers The most common Controller is the Group All it does is execute its children in order 4 The CAF Environment Framework 9 4 2 Writing your own Processors BEGINNER Most of these concepts will become clearer in the following examples From now on we assume that you are working in a compiled environment rather than the root interpreter You should start by creating a new package for these exercises cd work ctnewpkg 1 my examples cd include ln s my example
18. ined Classes ADVANCED By default the Event class knows only about the objects and branches which are part of the CAF classes In fact Event is only a convenience class for the user Actually its base class EventBase doesn t know anything about the CAF classes at all However it has methods to access arbitrary branches e g for non standard objects that are not part of the default CAF format 3 Using the CAF Environment Cafe 7 3 3 1 Simple Objects Let s assume that you ve added a new branch to your root file which contains variables very specific to your analysis These definitions will never go into the tree use for central production We first consider the simply case where all these variables are in one object class MyVariables public TObject public MyVariables int myVariableA float myVariableB private variables int _A float _B public ClassDef MyVariables 1 h The name of branch you ve chosen to save it in is MyAnalysis We explain later how to add a branch to a CAF file for now we assume your input file already contains these data You can access it after you filled the event like this tree gt LoadTree 0 const MyVariables var event get lt MyVariables gt MyAnalysis The result will be a NULL pointer if the branch does not exist If you don t like the use of templated member functions and specifying the branch name every time you should probably wri
19. into little packages and run them in any given order share code with others etc You can use many of the CAFE classes in an interactive session as well which is the way we introduce most of them here 3 1 The cafe Event Class BEGINNER The cafe Event class provides easy access to all common physics objects used in an analysis Here is one way to use it root 0 cafe Event event root 1 TFile file input root root 2 TTree tree TTree file Get TMBTree root 3 event setBranchAddresses tree Now every call to tree gt GetEntry i will fill the event object In practice you only have to call tree gt LoadTree i This avoids that the full event is read at once Instead the Event class will read the data as you ask for it which can speed up processing tremendously 3 2 Using the cafe Event Class BEGINNER The interface of this class provides methods to access all common physics objects Here is how the interface looks like class Event public EventBase public Event Collection lt TMBMuon gt getMuons const Collection lt TMBEMCluster gt getEMcellNN const Collection lt TMBEMCluster gt getEMscone const Collection lt TMBJet gt getJCCA const Collection lt TMBJet gt get JCCB const Collection lt TMBJet gt getJets const std string amp name const Collection lt TMBTrack gt getTracks const Collection lt TMBVertex gt getPrimaryVertices const many more const
20. le input_file outfile gt Write outfile gt Close delete outfile bool processEvent cafe Event amp event calculate myVariables tree gt Fill public TFile outfile TTree tree MyVariables myVariables F In this example we create for every input file a new file called after the original name and myvar root appended In a later run we want to use the information we created together with the original file The typical way to do this is to add the tree in the new file as a friend and then use the methods described in 3 3 Extending cafe Event An example is here class AddMyVariables public Processor public void begin cafe Event amp event 1 event addBranch lt MyVariables gt MyAnalysis VE oa void inputFileOpened TFile file std string input name input_File gt GetName input_name input_name substr 0 input_name rfind myvar root myfile TFile Open input name c str READ if myfile IsOpen if TTree mytree TTree myfile Get MyTree TTree caf_tree TTree file gt Get TMBTree caf tree AddFriend mytree 7 Available Processors BEGINNER 18 void inputFileClosing TFile file myfile gt Close delete myfile private TFile myfile However you should try to re use some of the existing utilities described in the next section instead of writing this code yourself An alternative to th
21. ng which you can attach to an event You can tag an event with as many tags as you like Here is how you check for the existences of a tag if event hasTag 2MU Y do something with event 5 Configuration Files 13 You can also check for the existence of any of a list of tags std list lt std string gt tags fill tags if event hasTag tags do something with event The latter method works with any STL container Le you can store the tag list in a list a vector ora deque the implementation doesn t care 5 Configuration Files 5 1 Syntax BEGINNER While specifying arguments on the command line is convenient for developement it can soon become cum bersome if there are more than a few processors All the command line arguments can be specified in a configuration file which follows the TEnv syntax also used in the rootrc files Here is an example of such a file cafe Input file input root cafe Run PrintEventNo Group test cafe Events 0 test Run MyFilter PrintEventNo The relation to the command line arguments should be straightforward Any entry without a prefix on the command line is interpreted as if it had the cafe prefix in the configuration file Furthermore any other entry in the configuration file can be overwritten explicitly on the command line with its full name The configuration file is searched for in the following places If the first command line argument is a file name it is used
22. ning and closing of input files Finally the eventCount method returns the number of events that this object has processed This is such a common task that the framework keeps track of it and uses it at the end to print out the event counts of the various steps If a Processor implements a filter with an analysis cut this is a quick way to look at the result 4 3 Input Specifications BEGINNER The Input argument to cafe can be any of the following a single filename optionally prefixed with file example file data root or just data root a file with a list of filenames example listfile mydata lst e a SAM dataset definition example sam My2MUSkim any other prefix known to ROOT e g http rootk etc 4 The CAF Environment Framework 11 Note the files in a file list can in turn have any known ROOT file prefix but not another file list or a SAM definition Some examples cafe Input file test root cafe Input sam MyDataSet cafe Input listfile myfiles lst cafe Input rootk wensley clued0 fnal gov work wensley clued0 data root 4 4 Run Specifications BEGINNER The Run argument takes a list of Processors like this cafe Input data root Run PrintEventNo MyFilter Muon PT Histo In the simplest case the names you specify on the command line are just the names of the functions and classes you wrote for your analysis In this case it is also the value of the string parameter given to your class in the co
23. nstructor Sometimes however it is useful to have more than one instance of the same class run As long as the classes don t need to be distinguished e g for the names of the histograms they write out you don t care Otherwise you need a way to give each a unique name You do this with the following syntax cafe Input data root Run Muon PT Histo first Muon PT Histo second This syntax is supposed to mimic calling the constructor of Muon PT Hist with the string first as name In a C program you would say something like Processor p new Muon PT Histo first If the Muon PT Hist class uses the string passed to its constructor in naming the histograms you can distinguish their output one of them using first as prefix the other second Muon PT Hist Muon PT Hist const char name string histoName string name _muon_pt hist new TH1F histName c_str Muon pT 0 0 100 0 100 Lilies Note that you have to enclose the argument in quotes This is because the has a special meaning for the shell If you quote the parameter you can use either space or comma to separate the Processors 4 The CAF Environment Framework 12 4 5 Non Persistent Data in cafe Event BEGINNER A quite common need is the ability to share information between different Processors Instead of using global variables the cafe Event class provides a light weight way of passing information from one step to another
24. ocessed return kTRUE void ProcessFill Long64_t entry using namespace cafe Fill histograms Collection lt TMBMuon gt muons event getMuons for Collection lt TMBMuon gt iterator it muons begin it muons end it ptcent Fill it Central PtO ptcent gt Fi11 it Pt0 void Terminate Write histograms output_file gt Write output_file gt Close delete output_file private TTree tree cafe Event event TFile output file THIF ptcent You can either compile these classes e g with 9 Appendix 24 root 0 include SRT PRIVATE CONTEXT include root 1 include SRT PUBLIC CONTEXT include root 2 TMBMuon m root 3 L MyAnalysis C Step 2 is to trigger the loading of all necessary libraries before you compile the code Alternatively you can load the required libraries explicitly root 2 gSystem gt Load libPhysics so root 3 gSystem gt Load libmet_util so root 4 gSystem gt Load libtmb_tree so Then pass a pointer to the object to the TTree Process method root 0 MyAnalysis analyse new MyAnalysis root 1 tree gt Process analyse or you can pass the file name directly to the method root 0 include SRT_PRIVATE_CONTEXT include root 1 include SRT_PUBLIC_CONTEXT include root 2 tree gt Process MyAnalysis C 9 2 Controllers ADVANCED There is a special type of Processor called a Controller What i
25. rent places 7 8 Creating Subsets of Particles ADVANCED cafe Run SelectObjects GoodJets GoodJets Select Jets Pt gt 10 0 amp amp Jets emfrac lt 0 15 GoodJets ToBranch GoodJets GoodJets FromBranch Jets 8 A Quick Tour through Typical Use Cases 21 7 9 Writing out Events BEGINNER cafe Run Select GoodEvents Write MyFile GoodEvents Select Muon nseg MyFile File MySkim root Write out events into the specified file Note that this is different from the cafe Qutput file which is used to store histograms The Write object will store the events themselves 7 10 Controller Group ADVANCED Apart from executing the methods of its children a Controller provides a number of additional features The only required configuration option is Run all the others are optional cafe Run Group test test Run Proci Proc2 Proc3 test utput results root test Directory Results test Debug 2 The Output parameter allows you to create a new ROOT file Typically this is only done on the top level The Directory parameter allows to create a new directory in the current file This can be used in interme diate Controllers to differentiate between different execution paths The Debug parameter sets the debug level for all its children This level can be checked inside a Processor via the debugO method 8 A Quick Tour through Typical Use Cases The following we give small but complete configuration files to
26. s my examples Then as usual put your header files into the my examples my examples subdirectory and the source files into my examples src All your source files should be named in the COMPONENTS file In addition you should add root to the LIBDEPS file Note that we don t have any bin directory As you will see we won t need it 4 2 1 Simple Functions Let s start with a very simple example we want to print out the event number for each event in a file This should not be a big programming task Write a file src PrintEventNo cpp like this include lt iostream gt include cafe Event hpp include cafe Function hpp bool PrintEventNo cafe Event amp event const TMBGlobal global event getGlobal std cout lt lt Event no lt lt global gt evtno lt lt std endl return true CAFE_FUNCTION PrintEventNo That s it Notice the CAFE_FUNCTION macro at the end You ll need this to register your function with the cafe environment Now type make and check that the build system created the shlib SRT_SUBDIR libmy_example so library You can now execute this function in the framework by running the following command cafe Input input root Run PrintEventNo Packages my_example Note that there is no need for linking In fact we are going to use the same executable cafe for all our programs from now on It will load our newly compiled shared library at run time and execute the function we have speci
27. ss from User Code BEGINNER 0000000000048 5 8 Specifying Groups ADVANCED o e XA 1 cO Ct Cc Q o o Q0 1 Introduction 2 BRI Ciiput Piles ooo casa xoxo ko o9 eee ees qo ua 15 Deka doo Lo ee BE DEE ORR OS pc a a 4 X S 3 4 9 ox S 15 Dana Debug WOME cs s xoxo 4 9 9 4 B be oe OR Oe Oa Se Ron dd n 15 bot Wore Processor Methods lt c sssaaa peard aard iha poe y OR RICE RUNE do 16 5 4 Including Configuration Files ocre ee SRK See ES a aa a ee Wow ox 16 6 Extending the CAF Tree ADVANCED 16 7 Available Processors BEGINNER 18 7 1 Creating Histograms BEGINNER e 0000000000008 18 T Ete sud HORE 2 2o x gcn om Oe ERE RO OMe SS qe EUROS AL K 19 7 3 Selecting Events BEGINNER ee es 19 7 4 Selecting Events by Trigger BEGINNER cen 20 7 5 Adding Friends BEGINNER rs 20 7 6 Conditional Execution BEGINNER 00000000004 20 LI Permutations ADVANCED ocer c cadia aada yoke Ra 20 7 8 Creating Subsets of Particles ADVANCED o 20 7 9 Writing out Events BEGINNER s 21 710 Controller Grp AD VANCED oec u cua set ha Feux e rome xS oS 21 8 A Quick Tour through Typical Use Cases 21 amp l Making a Selection by Triggers oc lt u coss cos rh hoy ee n RR 21 82 Making a Selection by Physics Objects 2222s dg eee eee bebe dee ees 21 Bp Oresdns a BUBUHETAAE lt p o ke da en SRE Rea Ea
28. t does is it creates a new processing chain below itself and calls each of its children in turn when any of its methods are called Processors can be added to a Controller in a variety of ways E g you can add a function or object directory to it if you have access to them cafe Controller contr top contr add PrintEventNo contr add new MyProcessor proc Alternatively you an add a Processor by name This assumes that the original function or class is known to ROOT contr add PrintEventNo contr add Muon_PT_Histos contr add MyProcessor Now calling contr processEvent event will call the corresponding method on all the registered objects in the order they were added In practice you don t need to know any of this since the framework will use the configuration file to create the proper sequence of Processors for you Controllers can be nested arbitrarily deep When you specify a Controller on the command line you should give it a name You can then tell it which Processors to run by specifying another Run parameter 9 Appendix 25 Instead of spelling out the whole class name you can also use the short alias Group or simply nothing before the C cafe Run Group test test Run PrintEventNo Muon PT Histos MyProcessor cafe Run test test Run PrintEventNo Muon PT Histos MyProcessor Theses short cuts exist because Controllers are very common to structure the execution of the analysis
29. te a little helper function const MyVariables getMyVariables const cafe Event amp event x event get lt MyVariables gt MyAnalysis and use that in your code 3 3 2 TClonesArrays of Objects If you want to store a branch with more than one object you should preferably put it into a TClonesArray The recipe is very similar to the one above except that now you call getCollection and the return type is a Collection lt T gt where T is your type Assuming you have this definition class MyParticle public TPhysObject 4 The CAF Environment Framework 8 public MyParticle float Pt const private float _pt public ClassDef MyParticle 1 you would access it like this Collection lt MyParticle gt my_particles event getCollection lt MyParticle gt MyAnalysisParticles for Collection lt MyParticle gt iterator it my_particles begin it my particles end it 1 float pt it PtO Finally if you prefer to use the TClonesArray directly you can do this as well const TClonesArray tca event getClonesArray MyAnalysisParticles 4 The CAF Environment Framework Putting all your analysis code into a single function or even a TSelector method is not very scalable Usually you have lots of tasks which you want to run either separately or together maybe even in a different order Sharing and reusing code is very difficult in this way since all you can do is copy and paste ot
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