Re: [ROOT] box option small log scale

From: Rene Brun (Rene.Brun@cern.ch)
Date: Sat Jun 15 2002 - 11:39:58 MEST


Hi Ben,

Thanks for reporting this problem with log scales and the "box" option.
Now fixed in the CVS version.

Rene Brun

On Fri, 14 Jun 2002, Ben Kilminster wrote:

> Hi,
> 
> I find that the box option fails for 2-D histograms plotted on a log scale
> for tiny values (some limit in precision for calculating box size ?).
> 
> Here is a variation of the log-scale-tutorial showing in canvas 2 that no
> entries are plotted with the box option.
> 
> The problem occurs with cint and with aclic, and happens at least as
> recently as root v3_03_05c
> 
> Cheers,
> Ben
> 
> 
> #include "TCanvas.h"
> #include "TH2.h"
> #include "TRandom.h"
> #include "TStyle.h"
> 
> void loglog()
> {
> 
> TCanvas *c1 = new TCanvas("c1");
> TCanvas *c2 = new TCanvas("c2");
> TCanvas *c3 = new TCanvas("c3");
> gStyle->SetOptStat(1111111);
> c1->SetLogx();
> c1->SetLogy();
> c2->SetLogx();
> c2->SetLogy();
> c3->SetLogx();
> c3->SetLogy();
> 
> // box option works
> Axis_t low = 1E-2;
> Axis_t hi = 1E0;
> TH2F *h1 = new TH2F("h1","h1 range 1",40,low,hi,40,low,hi);
> 
> // box option fails  
> low = 1E-22;
> hi = 1E-19;
> TH2F *h2 = new TH2F("h2","h2 range 2",40,low,hi,40,low,hi);
>   
> for (Int_t i=0;i<1000;i++) {
> 
> h1->Fill(fabs(1E-2*gRandom->Landau(5,2)),(fabs(1E-2*gRandom->Landau(5,10))));
> 
> h2->Fill(fabs(1E-22*gRandom->Landau(5,10)),(fabs(1E-22*gRandom->Landau(5,10))));
>  }
> c1->cd();	
> h1->Draw("box");
> c2->cd();	
> // fails
> h2->Draw("box");
> c3->cd();	
> // without box option, it works
> h2->Draw();
> }
> 
> 
> 



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