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hsimple.C
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1/// \file
2/// \ingroup Tutorials
3/// \notebook
4/// This program creates :
5/// - a one dimensional histogram
6/// - a two dimensional histogram
7/// - a profile histogram
8/// - a memory-resident ntuple
9///
10/// These objects are filled with some random numbers and saved on a file.
11/// If get=1 the macro returns a pointer to the TFile of "hsimple.root"
12/// if this file exists, otherwise it is created.
13/// The file "hsimple.root" is created in $ROOTSYS/tutorials if the caller has
14/// write access to this directory, otherwise the file is created in $PWD
15///
16/// \macro_image
17/// \macro_output
18/// \macro_code
19///
20/// \author Rene Brun
21
22#include <TFile.h>
23#include <TNtuple.h>
24#include <TH2.h>
25#include <TProfile.h>
26#include <TCanvas.h>
27#include <TFrame.h>
28#include <TROOT.h>
29#include <TSystem.h>
30#include <TRandom3.h>
31#include <TBenchmark.h>
32#include <TInterpreter.h>
33
34TFile *hsimple(Int_t getFile=0)
35{
36 TString filename = "hsimple.root";
37 TString dir = gROOT->GetTutorialDir();
38 dir.ReplaceAll("/./","/");
39 TFile *hfile = 0;
40 if (getFile) {
41 // if the argument getFile =1 return the file "hsimple.root"
42 // if the file does not exist, it is created
43 TString fullPath = dir+"hsimple.root";
44 if (!gSystem->AccessPathName(fullPath,kFileExists)) {
45 hfile = TFile::Open(fullPath); //in $ROOTSYS/tutorials
46 if (hfile) return hfile;
47 }
48 //otherwise try $PWD/hsimple.root
49 if (!gSystem->AccessPathName("hsimple.root",kFileExists)) {
50 hfile = TFile::Open("hsimple.root"); //in current dir
51 if (hfile) return hfile;
52 }
53 }
54 //no hsimple.root file found. Must generate it !
55 //generate hsimple.root in current directory if we have write access
57 printf("you must run the script in a directory with write access\n");
58 return 0;
59 }
60 hfile = (TFile*)gROOT->FindObject(filename); if (hfile) hfile->Close();
61 hfile = new TFile(filename,"RECREATE","Demo ROOT file with histograms");
62
63 // Create some histograms, a profile histogram and an ntuple
64 TH1F *hpx = new TH1F("hpx","This is the px distribution",100,-4,4);
65 hpx->SetFillColor(48);
66 TH2F *hpxpy = new TH2F("hpxpy","py vs px",40,-4,4,40,-4,4);
67 TProfile *hprof = new TProfile("hprof","Profile of pz versus px",100,-4,4,0,20);
68 TNtuple *ntuple = new TNtuple("ntuple","Demo ntuple","px:py:pz:random:i");
69
70 gBenchmark->Start("hsimple");
71
72 // Create a new canvas.
73 TCanvas *c1 = new TCanvas("c1","Dynamic Filling Example",200,10,700,500);
74 c1->SetFillColor(42);
75 c1->GetFrame()->SetFillColor(21);
76 c1->GetFrame()->SetBorderSize(6);
77 c1->GetFrame()->SetBorderMode(-1);
78
79
80 // Fill histograms randomly
81 TRandom3 randomNum;
82 Float_t px, py, pz;
83 const Int_t kUPDATE = 1000;
84 for (Int_t i = 0; i < 25000; i++) {
85 randomNum.Rannor(px,py);
86 pz = px*px + py*py;
87 Float_t rnd = randomNum.Rndm();
88 hpx->Fill(px);
89 hpxpy->Fill(px,py);
90 hprof->Fill(px,pz);
91 ntuple->Fill(px,py,pz,rnd,i);
92 if (i && (i%kUPDATE) == 0) {
93 if (i == kUPDATE) hpx->Draw();
94 c1->Modified();
95 c1->Update();
97 break;
98 }
99 }
100 gBenchmark->Show("hsimple");
101
102 // Save all objects in this file
103 hpx->SetFillColor(0);
104 hfile->Write();
105 hpx->SetFillColor(48);
106 c1->Modified();
107 return hfile;
108
109 // Note that the file is automatically close when application terminates
110 // or when the file destructor is called.
111}
int Int_t
Definition: RtypesCore.h:45
float Float_t
Definition: RtypesCore.h:57
R__EXTERN TBenchmark * gBenchmark
Definition: TBenchmark.h:59
#define gROOT
Definition: TROOT.h:404
@ kFileExists
Definition: TSystem.h:44
@ kWritePermission
Definition: TSystem.h:46
R__EXTERN TSystem * gSystem
Definition: TSystem.h:559
virtual void SetFillColor(Color_t fcolor)
Set the fill area color.
Definition: TAttFill.h:37
virtual void Start(const char *name)
Starts Benchmark with the specified name.
Definition: TBenchmark.cxx:172
virtual void Show(const char *name)
Stops Benchmark name and Prints results.
Definition: TBenchmark.cxx:155
The Canvas class.
Definition: TCanvas.h:23
A ROOT file is a suite of consecutive data records (TKey instances) with a well defined format.
Definition: TFile.h:54
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:4011
Int_t Write(const char *name=nullptr, Int_t opt=0, Int_t bufsiz=0) override
Write memory objects to this file.
Definition: TFile.cxx:2362
void Close(Option_t *option="") override
Close a file.
Definition: TFile.cxx:889
1-D histogram with a float per channel (see TH1 documentation)}
Definition: TH1.h:575
virtual Int_t Fill(Double_t x)
Increment bin with abscissa X by 1.
Definition: TH1.cxx:3351
virtual void Draw(Option_t *option="")
Draw this histogram with options.
Definition: TH1.cxx:3074
2-D histogram with a float per channel (see TH1 documentation)}
Definition: TH2.h:251
Int_t Fill(Double_t)
Invalid Fill method.
Definition: TH2.cxx:358
A simple TTree restricted to a list of float variables only.
Definition: TNtuple.h:28
virtual Int_t Fill()
Fill a Ntuple with current values in fArgs.
Definition: TNtuple.cxx:169
Profile Histogram.
Definition: TProfile.h:32
Int_t Fill(const Double_t *v)
Definition: TProfile.h:55
Random number generator class based on M.
Definition: TRandom3.h:27
virtual Double_t Rndm()
Machine independent random number generator.
Definition: TRandom3.cxx:99
virtual void Rannor(Float_t &a, Float_t &b)
Return 2 numbers distributed following a gaussian with mean=0 and sigma=1.
Definition: TRandom.cxx:500
Basic string class.
Definition: TString.h:136
TString & ReplaceAll(const TString &s1, const TString &s2)
Definition: TString.h:692
virtual Bool_t AccessPathName(const char *path, EAccessMode mode=kFileExists)
Returns FALSE if one can access a file using the specified access mode.
Definition: TSystem.cxx:1296
virtual Bool_t ProcessEvents()
Process pending events (GUI, timers, sockets).
Definition: TSystem.cxx:419
return c1
Definition: legend1.C:41