- Online Documents
- Some root basics
- ? - help
- .q, .qqq - to exit
- .! - shell commands
- h2root - converts from hst4 to root format
- .rootrc - order of evaluation
$ROOTSYS/.rootrc, then $HOME/.rootrc, then ./.rootrc
- Files ant their ntuples and histograms
- Open a file:
TFile* f = new TFile("http://...file.root");
- Access to a histogram or an ntuple under a subdirectory in file f:
TTree* t = f.Get("/TOPPLOT/h21");
- Draw an ntuple variable
t->Draw("Met");
- Use of cuts
t->Draw("Met","(Met<50)&&(abs(Pz)<40)");
- Scatter plots
t->Draw("tcpu:nhit","nhit<2000.","BOX");
- Macros
- PAW's uwfunc counterpart in root
t->Makecode("uw1.C");
- To execute a macro
.x uw1.C
- To book a histogram from a macro
TH1F* h_met = new TH1F("met","missing Et",...);
- To set histogram attributes
h_met->SetFillColor(color);
h_met->SetFillStyle(style); (style = 3000..3025)
- To fill histogram from a macro
h_met->Fill(Met);
- To define a class based on an ntuple
t->MakeClass("Name");
- To load it and use it
.L Name.C
Name x;
x.Loop();
- Functions
- User defined function:
TFormula* form = new TFormula("form","[0]*sin([1]*x)*exp(-[2]*x)");
- To plot a function:
TF1* fun = new TF1("fun","form",0,25);
- PAW translations
- get/content 10 x
Float_t* arr = h1->GetArray();
- sigma xx=vecsum(x); v/pri xx
h1->GetSum();
- h/fit 10 g
h1->Fit("gaus");
- opt fit
gStyle->SetOptFit();
- opt grid
c1->SetGrid();
c1->SetGridx(); c1->SetGridy();
- To get a pointer to a histogram in memory
TH1F *h1 = (TH1F*)gROOT->Get("hname");
- To fit over a subrange
TF1 *g1 = new TF1("g1","gaus",-1,1);
h1->Fit("g1","R");
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