Hi Damon,
a small macro drawing an histogram in BAR mode when the histogram has
errors.
Rene Brun
{
gROOT->Reset();
TH1F *h = new TH1F("h","demo with bars",20,-5,15);
h->Sumw2();
for (Int_t i=0;i<1000;i++) {
Float_t x = gRandom->Landau(0,1);
h->Fill(x);
}
TCanvas *c1 = new TCanvas("c1","demo",600,800);
c1->Divide(1,2);
c1->cd(1);
h->SetFillColor(kBlue);
h->SetMarkerStyle(21);
h->SetBarWidth(0.5);
h->SetBarOffset(0.25);
h->Draw("bhist");
c1->cd(2);
h->Draw("e1");
}
Damon Spayde wrote:
>
> I have written a script that reads in an ASCII file and generates three
> one-dimensional histograms of its contents. I would really like to look
> at these histograms in bar graph form; i.e. with a bar for each bin.
> However, when I specify the option "B" in TH1::Draw() the histogram gets
> drawn with little tiny points and error bars for each bin. Any help in
> understanding why this is happening would be greatly appreciated. My ROOT
> version is 2.21/08, run on a DEC Alpha with Digital Unix 4.0d. ROOT was
> compiled using gcc version 2.8.1. Below I have included a copy of the
> script.
>
> Thanks,
> Damon Spayde
>
> --------------------------------
> Damon Spayde
> Department of Physics
> University of Maryland
> PO Box 175
> College Park, MD 20742
> Phone: (301) 405-6113
> Fax: (301) 405-8558
> e-mail: dspayde@physics.umd.edu
> --------------------------------
>
> //////////////////////////////////////////////////////////////////
> // //
> // dotout_hist -- Create a histogram of a *.out file's contents //
> // //
> // Author: Damon Spayde //
> // //
> // Usage: //
> // //
> // Caveats: //
> // 1) Assumes that badruns file and ADC files are sorted. //
> // //
> //////////////////////////////////////////////////////////////////
>
> #include <fstream.h>
>
> struct Badrun
> {
> Int_t low;
> Int_t high;
> };
>
> struct Adc
> {
> Int_t runnumber;
> Int_t helicity;
> Int_t events;
> Double_t yield;
> Double_t yield_error;
> Double_t yield_width;
> Int_t pulsepairs;
> Double_t asym;
> Double_t asym_error;
> Double_t asym_width;
> };
>
>
> const Int_t IN = -1;
> const Int_t OUT = 1;
> const Double_t PPM = 1.0e6;
>
> Int_t dotout_hist(Char_t *adc_file,Int_t first_run,Int_t last_run, Char_t *badruns_file = "badruns.dat")
> {
>
> // Initialization
> Adc adc;
> Badrun badrun;
> ifstream BADRUNSfile(badruns_file); // Open badruns.dat for
> // reading
> if(BADRUNSfile.bad()) {
> cerr << "Error: Could not open badruns_file.\n";
> exit(7);
> }
>
> Char_t adc_filename[40];
> sprintf(adc_filename,"%s.out",adc_file);
> ifstream ADCfile(adc_filename); // Open appropriate .out file for
> // reading
> if(ADCfile.bad()) {
> cerr << "Error: Could not open adc_filename.\n";
> exit(8);
> }
>
> Char_t hname[20];
> Char_t htitle[80];
> sprintf(hname,"h_%s",adc_file);
> sprintf(htitle,"Weighted Asymmetry Histogram in %s over Runs
> %d to %d, Both Wave Plate States",adc_file,first_run,last_run);
> TH1F *adc_hist = new TH1F(hname,htitle,200,-100,100); //Create a new
> //histogram
>
> sprintf(hname,"h_in_%s",adc_file);
> sprintf(htitle,"Weighted Asymmetry Histogram in %s over Runs %d to
> %d, Wave Plate In",adc_file,first_run,last_run);
> TH1F *adc_in_hist = new TH1F(hname,htitle,200,-100,100); //Create a new
> //histogram
>
> sprintf(hname,"h_out_%s",adc_file);
> sprintf(htitle,"Weighted Asymmetry Histogram in %s over Runs %d to
> %d, Wave Plate Out",adc_file,first_run,last_run);
> TH1F *adc_out_hist = new TH1F(hname,htitle,200,-100,100); //Create a new
> //histogram
>
> adc_hist->Sumw2(); // Record sum of weights for each bin of
> // histogram
> adc_in_hist->Sumw2(); // Record sum of weights for each bin of
> // histogram
> adc_out_hist->Sumw2(); // Record sum of weights for each bin of
> // histogram
>
> // Loop over the adc file until line corresponding to first run or
> // greater is loaded into the first struct
> do {
> ADCfile >> adc.runnumber >> adc.helicity;
> ADCfile >> adc.events >> adc.yield >> adc.yield_error;
> ADCfile >> adc.pulsepairs >> adc.asym >> adc.asym_error;
> // cout << adc.runnumber << ": " << adc.asym << "\n";
> } while (adc.runnumber < (first_run - 1));
>
> do {
> BADRUNSfile >> badrun.low >> badrun.high;
> } while (badrun.high < first_run);
>
> // Loop over all file lines
> Int_t i = ;
> Int_t j = ;
>
> while(adc.runnumber >= (first_run - 1) && adc.runnumber <= last_run) {
>
> ADCfile >> adc.runnumber >> adc.helicity;
> ADCfile >> adc.events >> adc.yield >> adc.yield_error;
> ADCfile >> adc.pulsepairs >> adc.asym >> adc.asym_error;
> adc.asym *= PPM;
> adc.asym_error *= PPM;
> adc.yield_width = adc.yield * sqrt(adc.events);
> adc.asym_width = adc.asym * sqrt(adc.pulsepairs);
>
> cout << adc.runnumber << ": " << adc.asym << "\n";
>
> do {
> if (badrun.high < adc.runnumber) { // Is it necessary to read
> // another line of
> // badruns.dat?
> BADRUNSfile >> badrun.low >> badrun.high;
> }
>
> if (adc.runnumber < badrun.low) {
> // Put hist fill here
> adc_hist->Fill((Axis_t) adc.helicity*adc.asym,(Stat_t)
> 1.0/(adc.asym_error * adc.asym_error));
> switch (adc.helicity) {
> case IN:
> adc_in_hist->Fill((Axis_t) adc.asym,(Stat_t) 1.0/(adc.asym_error * adc.asym_error));
> break;
> case OUT:
> adc_out_hist->Fill((Axis_t) adc.asym,(Stat_t) 1.0/(adc.asym_error * adc.asym_error));
> break;
> default:
> printf("Error: helicity not equal to +/-1 for run
> %d.\n",adc.runnumber);
> break;
> }
> }
>
> } while (badrun.high < adc.runnumber);
>
> }
>
> ADCfile.close();
> BADRUNSfile.close();
>
> Char_t ctitle[40];
> sprintf(ctitle,"%s Histograms",adc_file);
> TCanvas *c2 = new TCanvas("c2",ctitle,600,777);
> c2->SetBorderMode(0);
> c2->SetFillColor(0);
> gStyle->SetPadBorderMode(0);
> gStyle->SetFillColor(0);
> c2->Divide(1,3);
> c2->cd(1);
> adc_in_hist->Draw("B");
> adc_in_hist->Print();
> gPad->SetLogy(1);
> gPad->Modified();
> c2->cd(2);
> adc_out_hist->Draw("B");
> adc_out_hist->Print();
> gPad->SetLogy(1);
> gPad->Modified();
> c2->cd(3);
> adc_hist->Draw("B");
> adc_hist->Print();
> gPad->SetLogy(1);
> gPad->Modified();
> c2->Modified();
>
>
>
> }
>
>
>
>
>
>
>
>
>
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