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Reference Guide
run_alice_esd.C File Reference

Detailed Description

Complex example showing ALICE ESD track visualization.

alice_esd.C - a simple event-display for ALICE ESD tracks and clusters

Only standard ROOT is used to process the ALICE ESD files.

No ALICE code is needed, only four simple coordinate-transformation functions declared in this macro.

A simple geometry of 10KB, extracted from the full TGeo-geometry, is used to outline the central detectors of ALICE.

All files are access from the web by using the "CACHEREAD" option.

Automatic building of ALICE ESD class declarations and dictionaries.

ALICE ESD is a TTree containing tracks and other event-related information with one entry per event. All these classes are part of the AliROOT offline framework and are not available to standard ROOT.

To be able to access the event data in a natural way, by using data-members of classes and object containers, the header files and class dictionaries are automatically generated from the TStreamerInfo classes stored in the ESD file by using the TFile::MakeProject() function. The header files and a shared library is created in the aliesd/ directory and can be loaded dynamically into the ROOT session.

See the run_alice_esd.C macro.

Creation of simple GUI for event navigation.

Most common use of the event-display is to browse through a collection of events. Thus a simple GUI allowing this is created in the function make_gui().

Eve uses the configurable ROOT-browser as its main window and so we create an extra tab in the left working area of the browser and provide backward/forward buttons.

Event-navigation functions.

As this is a simple macro, we store the information about the current event in the global variable 'Int_t esd_event_id'. The functions for event-navigation simply modify this variable and call the load_event() function which does the following:

  1. drop the old visualization objects;
  2. retrieve given event from the ESD tree;
  3. call alice_esd_read() function to create visualization objects for the new event.

Reading of ALICE data and creation of visualization objects.

This is performed in alice_esd_read() function, with the following steps:

  1. create the track container object - TEveTrackList;
  2. iterate over the ESD tracks, create TEveTrack objects and append them to the container;
  3. instruct the container to extrapolate the tracks and set their visual attributes.
#include "MultiView.C"
// Forward declarations.
#include "aliesd/AliESDEvent.h"
#include "aliesd/AliESDfriend.h"
#include "aliesd/AliESDtrack.h"
#include "aliesd/AliESDRun.h"
class AliExternalTrackParam;
void make_gui();
void load_event();
void alice_esd_read();
TEveTrack* esd_make_track(TEveTrackPropagator* trkProp, Int_t index,
AliESDtrack* at,
AliExternalTrackParam* tp=0);
Bool_t trackIsOn(AliESDtrack* t, Int_t mask);
void trackGetPos(AliExternalTrackParam* tp, Double_t r[3]);
void trackGetMomentum(AliExternalTrackParam* tp, Double_t p[3]);
Double_t trackGetP(AliExternalTrackParam* tp);
// Configuration and global variables.
const char* esd_file_name = "http://root.cern.ch/files/alice_ESDs.root";
// Temporarily disable reading of ESD friend.
// There seems to be no way to get it working without AliRoot.
// const char* esd_friends_file_name =
// "http://root.cern.ch/files/alice_ESDfriends.root";
const char* esd_friends_file_name = nullptr;
const char* esd_geom_file_name =
"http://root.cern.ch/files/alice_ESDgeometry.root";
// For testing
// const char* esd_file_name = "AliESDs.root";
// const char* esd_friends_file_name = "AliESDfriends.root";
TFile *esd_file = nullptr;
TFile *esd_friends_file = nullptr;
TTree *esd_tree = nullptr;
AliESDEvent *esd = nullptr;
TList *esd_objs = nullptr;
AliESDfriend *esd_friend = nullptr;
Int_t esd_event_id = 0; // Current event id.
TEveTrackList *gTrackList = nullptr;
TEveGeoShape *gGeomGentle = nullptr;
// Implemented in MultiView.C
MultiView *gMultiView = nullptr;
/******************************************************************************/
// Initialization and steering functions
/******************************************************************************/
//______________________________________________________________________________
void run_alice_esd()
{
// Main function, initializes the application.
//
// 1. Load the auto-generated library holding ESD classes and
// ESD dictionaries.
// 2. Open ESD data-files.
// 3. Load cartoon geometry.
// 4. Spawn simple GUI.
// 5. Load first event.
const TString weh("alice_esd()");
printf("*** Opening ESD ***\n");
esd_file = TFile::Open(esd_file_name, "CACHEREAD");
if (!esd_file)
return;
esd_tree = (TTree*) esd_file->Get("esdTree");
esd = (AliESDEvent*) esd_tree->GetUserInfo()->FindObject("AliESDEvent");
esd_objs = esd->fESDObjects;
if (esd_friends_file_name != 0)
{
printf("*** Opening ESD-friends ***\n");
esd_friends_file = TFile::Open(esd_friends_file_name, "CACHEREAD");
if (!esd_friends_file)
return;
esd_tree->SetBranchStatus ("ESDfriend*", 1);
}
// Set the branch addresses.
{
TIter next(esd_objs);
TObject *el;
while ((el = (TNamed*)next()))
{
TString bname(el->GetName());
if (bname == "AliESDfriend")
{
// AliESDfriend needs special treatment.
TBranch *br = esd_tree->GetBranch("ESDfriend.");
br->SetAddress(esd_objs->GetObjectRef(el));
}
else
{
TBranch *br = esd_tree->GetBranch(bname);
if (br)
{
br->SetAddress(esd_objs->GetObjectRef(el));
}
else
{
br = esd_tree->GetBranch(bname + ".");
if (br)
{
br->SetAddress(esd_objs->GetObjectRef(el));
}
else
{
Warning("AliESDEvent::ReadFromTree() "
"No Branch found with Name '%s' or '%s.'.",
bname.Data(),bname.Data());
}
}
}
}
}
{ // Simple geometry
TFile* geom = TFile::Open(esd_geom_file_name, "CACHEREAD");
if (!geom)
return;
TEveGeoShapeExtract* gse = (TEveGeoShapeExtract*) geom->Get("Gentle");
gGeomGentle = TEveGeoShape::ImportShapeExtract(gse, 0);
geom->Close();
delete geom;
gEve->AddGlobalElement(gGeomGentle);
}
// Standard multi-view
//=====================
gMultiView = new MultiView;
gMultiView->ImportGeomRPhi(gGeomGentle);
gMultiView->ImportGeomRhoZ(gGeomGentle);
// HTML summary view
//===================
fgHtmlSummary = new HtmlSummary("Alice Event Display Summary Table");
fgHtml = new TGHtml(0, 100, 100);
TEveWindowFrame *wf = slot->MakeFrame(fgHtml);
fgHtml->MapSubwindows();
wf->SetElementName("Summary");
// Final stuff
//=============
make_gui();
load_event();
gEve->Redraw3D(kTRUE); // Reset camera after the first event has been shown.
}
//______________________________________________________________________________
void load_event()
{
// Load event specified in global esd_event_id.
// The contents of previous event are removed.
printf("Loading event %d.\n", esd_event_id);
if (gTrackList)
gTrackList->DestroyElements();
esd_tree->GetEntry(esd_event_id);
// esd_tree->Show();
alice_esd_read();
gMultiView->DestroyEventRPhi();
gMultiView->ImportEventRPhi(top);
gMultiView->DestroyEventRhoZ();
gMultiView->ImportEventRhoZ(top);
update_html_summary();
}
/******************************************************************************/
// GUI
/******************************************************************************/
//______________________________________________________________________________
//
// EvNavHandler class is needed to connect GUI signals.
class EvNavHandler
{
public:
void Fwd()
{
if (esd_event_id < esd_tree->GetEntries() - 1) {
++esd_event_id;
load_event();
} else {
printf("Already at last event.\n");
}
}
void Bck()
{
if (esd_event_id > 0) {
--esd_event_id;
load_event();
} else {
printf("Already at first event.\n");
}
}
};
//______________________________________________________________________________
void make_gui()
{
// Create minimal GUI for event navigation.
TEveBrowser* browser = gEve->GetBrowser();
TGMainFrame* frmMain = new TGMainFrame(gClient->GetRoot(), 1000, 600);
frmMain->SetWindowName("XX GUI");
{
TString icondir( Form("%s/icons/", gSystem->Getenv("ROOTSYS")) );
EvNavHandler *fh = new EvNavHandler;
b = new TGPictureButton(hf, gClient->GetPicture(icondir+"GoBack.gif"));
hf->AddFrame(b);
b->Connect("Clicked()", "EvNavHandler", fh, "Bck()");
b = new TGPictureButton(hf, gClient->GetPicture(icondir+"GoForward.gif"));
hf->AddFrame(b);
b->Connect("Clicked()", "EvNavHandler", fh, "Fwd()");
}
frmMain->AddFrame(hf);
frmMain->MapSubwindows();
frmMain->Resize();
frmMain->MapWindow();
browser->StopEmbedding();
browser->SetTabTitle("Event Control", 0);
}
/******************************************************************************/
// Code for reading AliESD and creating visualization objects
/******************************************************************************/
enum ESDTrackFlags {
kITSin=0x0001,kITSout=0x0002,kITSrefit=0x0004,kITSpid=0x0008,
kTPCin=0x0010,kTPCout=0x0020,kTPCrefit=0x0040,kTPCpid=0x0080,
kTRDin=0x0100,kTRDout=0x0200,kTRDrefit=0x0400,kTRDpid=0x0800,
kTOFin=0x1000,kTOFout=0x2000,kTOFrefit=0x4000,kTOFpid=0x8000,
kHMPIDpid=0x20000,
kEMCALmatch=0x40000,
kTRDbackup=0x80000,
kTRDStop=0x20000000,
kESDpid=0x40000000,
kTIME=0x80000000
};
//______________________________________________________________________________
void alice_esd_read()
{
// Read tracks and associated clusters from current event.
AliESDRun *esdrun = (AliESDRun*) esd_objs->FindObject("AliESDRun");
TClonesArray *tracks = (TClonesArray*) esd_objs->FindObject("Tracks");
// This needs further investigation. Clusters not shown.
// esd_friend = (AliESDfriend*) esd_objs->FindObject("AliESDfriend");
// printf("Friend %p, n_tracks:%d\n",
// esd_friend,
// esd_friend->fTracks.GetEntries());
if (gTrackList == 0)
{
gTrackList = new TEveTrackList("ESD Tracks");
gTrackList->SetMainColor(6);
gTrackList->SetMarkerColor(kYellow);
gTrackList->SetMarkerStyle(4);
gTrackList->SetMarkerSize(0.5);
gEve->AddElement(gTrackList);
}
TEveTrackPropagator* trkProp = gTrackList->GetPropagator();
trkProp->SetMagField( 0.1 * esdrun->fMagneticField ); // kGaus to Tesla
for (Int_t n=0; n<tracks->GetEntriesFast(); ++n)
{
AliESDtrack* at = (AliESDtrack*) tracks->At(n);
// If ITS refit failed, take track parameters at inner TPC radius.
AliExternalTrackParam* tp = at;
if (! trackIsOn(at, kITSrefit)) {
tp = at->fIp;
}
TEveTrack* track = esd_make_track(trkProp, n, at, tp);
track->SetAttLineAttMarker(gTrackList);
gTrackList->AddElement(track);
// This needs further investigation. Clusters not shown.
// if (frnd)
// {
// AliESDfriendTrack* ft = (AliESDfriendTrack*) frnd->fTracks->At(n);
// printf("%d friend = %p\n", ft);
// }
}
gTrackList->MakeTracks();
}
//______________________________________________________________________________
TEveTrack* esd_make_track(TEveTrackPropagator* trkProp,
Int_t index,
AliESDtrack* at,
AliExternalTrackParam* tp)
{
// Helper function creating TEveTrack from AliESDtrack.
//
// Optionally specific track-parameters (e.g. at TPC entry point)
// can be specified via the tp argument.
Double_t pbuf[3], vbuf[3];
if (tp == 0) tp = at;
rt.fLabel = at->fLabel;
rt.fIndex = index;
rt.fStatus = (Int_t) at->fFlags;
rt.fSign = (tp->fP[4] > 0) ? 1 : -1;
trackGetPos(tp, vbuf); rt.fV.Set(vbuf);
trackGetMomentum(tp, pbuf); rt.fP.Set(pbuf);
Double_t ep = trackGetP(at);
Double_t mc = 0.138; // at->GetMass(); - Complicated function, requiring PID.
rt.fBeta = ep/TMath::Sqrt(ep*ep + mc*mc);
TEveTrack* track = new TEveTrack(&rt, trkProp);
track->SetName(Form("TEveTrack %d", rt.fIndex));
track->SetStdTitle();
return track;
}
//______________________________________________________________________________
Bool_t trackIsOn(AliESDtrack* t, Int_t mask)
{
// Check is track-flag specified by mask are set.
return (t->fFlags & mask) > 0;
}
//______________________________________________________________________________
void trackGetPos(AliExternalTrackParam* tp, Double_t r[3])
{
// Get global position of starting point of tp.
r[0] = tp->fX; r[1] = tp->fP[0]; r[2] = tp->fP[1];
Double_t cs=TMath::Cos(tp->fAlpha), sn=TMath::Sin(tp->fAlpha), x=r[0];
r[0] = x*cs - r[1]*sn; r[1] = x*sn + r[1]*cs;
}
//______________________________________________________________________________
void trackGetMomentum(AliExternalTrackParam* tp, Double_t p[3])
{
// Return global momentum vector of starting point of tp.
p[0] = tp->fP[4]; p[1] = tp->fP[2]; p[2] = tp->fP[3];
Double_t cs=TMath::Cos(tp->fAlpha), sn=TMath::Sin(tp->fAlpha);
Double_t r=TMath::Sqrt(1 - p[1]*p[1]);
p[0]=pt*(r*cs - p[1]*sn); p[1]=pt*(p[1]*cs + r*sn); p[2]=pt*p[2];
}
//______________________________________________________________________________
Double_t trackGetP(AliExternalTrackParam* tp)
{
// Return magnitude of momentum of tp.
return TMath::Sqrt(1.+ tp->fP[3]*tp->fP[3])/TMath::Abs(tp->fP[4]);
}
Multi-view (3d, rphi, rhoz) service class using EVE Window Manager.
ROOT::R::TRInterface & r
Definition: Object.C:4
#define b(i)
Definition: RSha256.hxx:100
int Int_t
Definition: RtypesCore.h:45
const Bool_t kFALSE
Definition: RtypesCore.h:92
bool Bool_t
Definition: RtypesCore.h:63
double Double_t
Definition: RtypesCore.h:59
const Bool_t kTRUE
Definition: RtypesCore.h:91
@ kYellow
Definition: Rtypes.h:66
void Warning(const char *location, const char *msgfmt,...)
Use this function in warning situations.
Definition: TError.cxx:231
R__EXTERN TEveManager * gEve
Definition: TEveManager.h:243
#define gClient
Definition: TGClient.h:166
@ kDeepCleanup
Definition: TGFrame.h:50
char * Form(const char *fmt,...)
R__EXTERN TSystem * gSystem
Definition: TSystem.h:559
Html table and event summary for alice_esd.C.
A TTree is a list of TBranches.
Definition: TBranch.h:89
virtual void SetAddress(void *add)
Set address of this branch.
Definition: TBranch.cxx:2620
An array of clone (identical) objects.
Definition: TClonesArray.h:29
TObject * Get(const char *namecycle) override
Return pointer to object identified by namecycle.
Specialization of TRootBrowser for Eve.
Definition: TEveBrowser.h:130
virtual void SetElementName(const char *name)
Virtual function for setting of name of an element.
Definition: TEveElement.h:455
Base class for TEveUtil visualization elements, providing hierarchy management, rendering control and...
Definition: TEveElement.h:36
virtual void AddElement(TEveElement *el)
Add el to the list of children.
virtual void DestroyElements()
Destroy all children of this element.
Globally positioned TGeoShape with rendering attributes and an optional list of daughter shape-extrac...
Wrapper for TGeoShape with absolute positioning and color attributes allowing display of extracted TG...
Definition: TEveGeoShape.h:24
static TEveGeoShape * ImportShapeExtract(TEveGeoShapeExtract *gse, TEveElement *parent=0)
Import a shape extract 'gse' under element 'parent'.
TEveViewerList * GetViewers() const
Definition: TEveManager.h:145
void AddElement(TEveElement *element, TEveElement *parent=0)
Add an element.
void AddGlobalElement(TEveElement *element, TEveElement *parent=0)
Add a global element, i.e.
TEveBrowser * GetBrowser() const
Definition: TEveManager.h:137
static TEveManager * Create(Bool_t map_window=kTRUE, Option_t *opt="FIV")
If global TEveManager* gEve is not set initialize it.
void Redraw3D(Bool_t resetCameras=kFALSE, Bool_t dropLogicals=kFALSE)
Definition: TEveManager.h:168
TEveEventManager * GetCurrentEvent() const
Definition: TEveManager.h:149
TEveVectorT< TT > fP
TEveVectorT< TT > fV
A list of tracks supporting change of common attributes and selection based on track parameters.
Definition: TEveTrack.h:140
virtual void SetMarkerStyle(Style_t s)
Set marker style for the list and the elements.
Definition: TEveTrack.cxx:897
virtual void SetMarkerColor(Color_t c)
Set marker color for the list and the elements.
Definition: TEveTrack.cxx:929
void MakeTracks(Bool_t recurse=kTRUE)
Regenerate the visual representations of tracks.
Definition: TEveTrack.cxx:635
virtual void SetMainColor(Color_t c)
Set main (line) color for the list and the elements.
Definition: TEveTrack.cxx:801
TEveTrackPropagator * GetPropagator()
Definition: TEveTrack.h:175
virtual void SetMarkerSize(Size_t s)
Set marker size for the list and the elements.
Definition: TEveTrack.cxx:961
Holding structure for a number of track rendering parameters.
void SetMagField(Double_t bX, Double_t bY, Double_t bZ)
Set constant magnetic field and rebuild tracks.
Visual representation of a track.
Definition: TEveTrack.h:33
void SetAttLineAttMarker(TEveTrackList *tl)
Set line and marker attributes from TEveTrackList.
Definition: TEveTrack.cxx:318
virtual void SetStdTitle()
Set standard track title based on most data-member values.
Definition: TEveTrack.cxx:264
void Set(const Float_t *v)
Definition: TEveVector.h:82
void DeleteAnnotations()
Delete annotations from all viewers.
Definition: TEveViewer.cxx:475
Encapsulates TGFrame into an eve-window.
Definition: TEveWindow.h:336
static TEveWindowSlot * CreateWindowInTab(TGTab *tab, TEveWindow *eve_parent=0)
Create a new tab in a given tab-widget and populate it with a default window-slot.
A ROOT file is a suite of consecutive data records (TKey instances) with a well defined format.
Definition: TFile.h:54
static Bool_t SetCacheFileDir(ROOT::Internal::TStringView cacheDir, Bool_t operateDisconnected=kTRUE, Bool_t forceCacheread=kFALSE)
Definition: TFile.h:324
static TFile * Open(const char *name, Option_t *option="", const char *ftitle="", Int_t compress=ROOT::RCompressionSetting::EDefaults::kUseCompiledDefault, Int_t netopt=0)
Create / open a file.
Definition: TFile.cxx:3997
void Close(Option_t *option="") override
Close a file.
Definition: TFile.cxx:879
virtual void AddFrame(TGFrame *f, TGLayoutHints *l=0)
Add frame to the composite frame using the specified layout hints.
Definition: TGFrame.cxx:1102
virtual void SetCleanup(Int_t mode=kLocalCleanup)
Turn on automatic cleanup of child frames in dtor.
Definition: TGFrame.cxx:1057
virtual void MapSubwindows()
Map all sub windows that are part of the composite frame.
Definition: TGFrame.cxx:1149
virtual void Resize(UInt_t w=0, UInt_t h=0)
Resize the frame.
Definition: TGFrame.cxx:590
virtual void MapWindow()
map window
Definition: TGFrame.h:228
Definition: TGHtml.h:872
void SetWindowName(const char *name=0)
Set window name. This is typically done via the window manager.
Definition: TGFrame.cxx:1749
virtual Bool_t SetTab(Int_t tabIndex, Bool_t emit=kTRUE)
Brings the composite frame with the index tabIndex to the front and generate the following event if t...
Definition: TGTab.cxx:509
A doubly linked list.
Definition: TList.h:44
virtual TObject ** GetObjectRef(const TObject *obj) const
Return address of pointer to obj.
Definition: TList.cxx:671
virtual TObject * FindObject(const char *name) const
Find an object in this list using its name.
Definition: TList.cxx:578
The TNamed class is the base class for all named ROOT classes.
Definition: TNamed.h:29
Mother of all ROOT objects.
Definition: TObject.h:37
virtual const char * GetName() const
Returns name of object.
Definition: TObject.cxx:359
virtual void SetName(const char *name)
Change (i.e.
void StartEmbedding(Int_t pos=kRight, Int_t subpos=-1) override
Start embedding external frame in the tab "pos" and tab element "subpos".
void SetTabTitle(const char *title, Int_t pos=kRight, Int_t subpos=-1)
Set text "title" of Tab "subpos" in TGTab "pos".
void StopEmbedding(const char *name=nullptr) override
Definition: TRootBrowser.h:151
TGTab * GetTabRight() const
Definition: TRootBrowser.h:140
Basic string class.
Definition: TString.h:136
virtual const char * Getenv(const char *env)
Get environment variable.
Definition: TSystem.cxx:1661
A TTree represents a columnar dataset.
Definition: TTree.h:79
virtual TBranch * GetBranch(const char *name)
Return pointer to the branch with the given name in this tree or its friends.
Definition: TTree.cxx:5252
virtual Int_t GetEntry(Long64_t entry=0, Int_t getall=0)
Read all branches of entry and return total number of bytes read.
Definition: TTree.cxx:5601
virtual TList * GetUserInfo()
Return a pointer to the list containing user objects associated to this tree.
Definition: TTree.cxx:6320
virtual void SetBranchStatus(const char *bname, Bool_t status=1, UInt_t *found=0)
Set branch status to Process or DoNotProcess.
Definition: TTree.cxx:8481
TPaveText * pt
Double_t x[n]
Definition: legend1.C:17
const Int_t n
Definition: legend1.C:16
Double_t Sqrt(Double_t x)
Definition: TMath.h:691
Double_t Cos(Double_t)
Definition: TMath.h:643
Double_t Sin(Double_t)
Definition: TMath.h:639
Short_t Abs(Short_t d)
Definition: TMathBase.h:120
void tracks()
Definition: tracks.C:49
Author
Matevz Tadel

Definition in file run_alice_esd.C.