Logo ROOT   6.12/07
Reference Guide
fillhistosauto2p.C File Reference

Detailed Description

Fill multiple histograms with different functions and automatic binning.

Illustrates merging with the power-of-two autobin algorithm

/// \date November 2017
#include "TF1.h"
#include "TH1D.h"
#include "TMath.h"
#include "TF1.h"
#include "TCanvas.h"
#include "TRandom3.h"
#include "TStatistic.h"
#include "TFile.h"
#include "TStyle.h"
TF1 *gam = new TF1("gam", "1/(1+0.1*x*0.1*x)", -100., 100.);
TF1 *gam1 = new TF1("gam", "1/(1+0.1*x*0.1*x)", -1., .25);
TF1 *iga = new TF1("inv gam", "1.-1/(1+0.1*x*0.1*x)", -100., 100.);
TF1 *iga1 = new TF1("inv gam", "1.-1/(1+0.1*x*0.1*x)", -.5, 1.);
void fillhistosauto2p(unsigned opt = 1, unsigned n = 1001)
{
UInt_t nh = 10;
UInt_t bsize = 1000;
TRandom3 rndm((Long64_t)time(0));
// Standard autobinning reference
auto href = new TH1D("myhref", "current", 50, 0., -1.);
href->SetBuffer(bsize);
// New autobinning 1-histo reference
auto href2 = new TH1D("myhref", "Auto P2, sequential", 50, 0., -1.);
href2->SetBit(TH1::kAutoBinPTwo);
href2->SetBuffer(bsize);
TList *hlist = new TList;
Int_t nbins = 50;
TStatistic x("min"), y("max"), d("dif"), a("mean"), r("rms");
for (UInt_t j = 0; j < nh; ++j) {
Double_t xmi = 1e15, xma = -1e15;
TStatistic xw("work");
TString hname = TString::Format("myh%d", j);
auto hw = new TH1D(hname.Data(), "Auto P2, merged", nbins, 0., -1.);
hw->SetBit(TH1::kAutoBinPTwo);
hw->SetBuffer(bsize);
Double_t xhma, xhmi, ovf, unf;
Bool_t emptied = kFALSE, tofill = kTRUE;
Bool_t buffering = kTRUE;
for (UInt_t i = 0; i < n; ++i) {
switch (opt) {
case 1: xx = rndm.Gaus(3, 1); break;
case 2: xx = rndm.Rndm() * 100. - 50.; break;
case 3: xx = gam->GetRandom(); break;
case 4: xx = gam1->GetRandom(); break;
case 5: xx = iga->GetRandom(); break;
case 6: xx = iga1->GetRandom(); break;
default: xx = rndm.Gaus(0, 1);
}
if (buffering) {
if (xx > xma)
xma = xx;
if (xx < xmi)
xmi = xx;
xw.Fill(xx);
}
hw->Fill(xx);
href->Fill(xx);
href2->Fill(xx);
if (!hw->GetBuffer()) {
// Not buffering anymore
buffering = kFALSE;
}
}
x.Fill(xmi);
y.Fill(xma);
d.Fill(xma - xmi);
a.Fill(xw.GetMean());
r.Fill(xw.GetRMS());
hlist->Add(hw);
}
x.Print();
y.Print();
d.Print();
a.Print();
r.Print();
TH1D *h0 = (TH1D *)hlist->First();
hlist->Remove(h0);
if (!h0->Merge(hlist))
return;
gStyle->SetOptStat(111110);
if (gROOT->GetListOfCanvases()->FindObject("c3"))
delete gROOT->GetListOfCanvases()->FindObject("c3");
TCanvas *c3 = new TCanvas("c3", "c3", 800, 800);
c3->Divide(1, 3);
c3->cd(1);
h0->DrawClone("HIST");
c3->cd(2);
href2->StatOverflows();
href2->DrawClone();
c3->cd(3);
href->StatOverflows();
href->DrawClone();
c3->Update();
std::cout << " ent: " << h0->GetEntries() << "\n";
h0->Print();
href->Print();
hlist->SetOwner(kTRUE);
delete hlist;
delete href;
delete href2;
delete h0;
}
Author
Gerardo Ganis

Definition in file fillhistosauto2p.C.