Abstract

We discuss a PSTuple package, which is intended for creation, accumulation and storage of histograms and tuples in psana PSHist - a histogramming package for PSANA project.

Objectives

In psana project PSANA framework we need in package which allows to accumulate data in form of histograms and tuples and save them in file for further analysis. Though it might be based on well-known underlying packages like ROOT, HBOOK, ROOT, or HippoTuple, we prefer to use an uniform interface with abstract base class, substituting the direct interaction with underlying methods. This intermediate abstract layer provides a flexibility in implementation of new things, for example multithreding in analysis, which algorithm is not yet defined.

Interface

An example of the program interface for this histogram-tuple-management package can be presented as follows. First, the underlying (derived) package needs to be choisen and instantiated. For example for ROOT

...

      hMan->write();
      delete hMan;

Structure and content of the package

Package PSTuple PSHist contains the base abstract class and methods, which have to be re-implemented in derived classes for HBOOK, ROOT, HippoTuple, etc., i.e. in packages HBookTuplelike HBookHist, RootTupleRootHist, HippoTuple, etc.

Histogramming in BABAR

HippoHist, etc.

QUESTIONS

• What kind of interface is preferable for tuple parameters: (1) name-based, (2) pointer-based, (3) index-based?

• Do we really have to care about different types of data for histograms and tuple parameters (int, float, double)?

• Arrays in tuples?

• What should be the right mapping between PSHist and Root classes?

  Code Block
  HManager <-> TFile H1 <-> TH1D Tuple <-> TTree or TBranch Parameter <-> TBranch or TBranch-item

APPENDIX

Histogramming in Root

// Base Class Headers --
#include "root/TROOT.h"
#include "root/TFile.h"
#include "root/TH1D.h"
#include "root/TTree.h"
#include "root/TBranch.h"
#include "root/TRandom.h"

Histograms

// Initialization
if(!TROOT::Initialized()) {static TROOT root( "RootManager", "RootManager ROOT God" );}

// Open output file
TFile* pfile = new TFile("file.root", "RECREATE", "Created for you by RootManager" );

// Create histograms
TH1D *pHis1 = new TH1D("pHis1","My comment to TH1D", 100, 0.5, 100+0.5);
TH2D *pHis2 = new TH2D("pHis2","My comment to TH1D", 100, 0.5, 100+0.5,
                                                     200, 0.5, 200+0.5);

// Fill histograms in each event
pHis1 -> Fill( value, [weight] );
pHis2 -> Fill( x, y, [weight] );

// Write histograms in file in the very end
pHis1 -> Write();
pHis2 -> Write();

//Close file
pfile -> Close();

NTuple

Assuming that file is already open,

// Define some structures for TTree
typedef struct {float x,y,z;} POINT;
static POINT point;
float new_v;

// Create TTree
TTree* ptree = new TTree("ptree", "My comment to TTree");

// Create branches
TBranch *pbranch = ptree->Branch("new_v", &new_v, "new_v/F");
                   ptree->Branch("point",&point,"x:y:z");

// Fill data structures for each event
      new_v   = gRandom->Gaus(0, 1);
      point.x = gRandom->Gaus(1, 1);
      point.y = gRandom->Gaus(2, 1);
      point.z = gRandom->Gaus(3, 1);

// Add an event record to the tree
      ptree->Fill();

// Write the tree to the file
ptree -> Write();

Histogramming in BABAR

All histograms in Workbook examples are based on plane Root...

Histograms

     HepHistogram myPlot("The Title",100,0.,1.);
     float x, weight;
       ...
     myPlot.accumulate( x, weight );

NTuple

#include "HepTuple/Histogram.h"
#include "HepTuple/TupleManager.h"

    HepTupleManager* manager = gblEnv->getGen()->ntupleManager();

    HepTuple *_ntuple = manager->ntuple("file-name.root");

   _ntuple->column("run",   eventID->run(), -99, "Event" );
   _ntuple->column("event", eventCounter,   -99, "Event" );

   _ntuple->dumpData(); // for each event

Histogramming in CLEO

Histograms

Declare Histogram in your .h file

...

module sel RootHistogramModule
root file root_suez_style_example_data31.root
root init

NTuple

Declare Ntuple in your Processor’s .h file

...