Cannot adjust Range of Yaxis

ROOT
1

Hello,

I am plotting several histograms on the same canvas, with a logarithmic y-axis.

The lower limit of the histo with lowest stats is 10e-4 while the upper limit of the histo with highest stats is around 10.

By default, the histos are being drawn on the canvas with yrange from 10 to 10e-2.
I would like to make this from 10 to 10e-4.

I do something like:

TH1F *pt_g_ME_ = new TH1F(“pt_g_ME_”,"",100,0.,100.);
TH1F *pt_g_Isr_ = new TH1F(“pt_g_Isr_”,"",100,0.,100.);
TH1F *pt_g_MI_ = new TH1F(“pt_g_MI_”,"",100,0.,100.);

//
// Fill Histograms
//

pt_g_ME_->SetMinimum(10e-4);
pt_g_ME_->SetMaximum(10);
pt_g_Isr_->SetMinimum(10e-4);
pt_g_Isr_->SetMaximum(10);
pt_g_MI_->SetMinimum(10e-4);
pt_g_MI_->SetMaximum(10);

//
// Scale histograms
//

// Draw histos on canvas.

But I do not get the desired results :frowning:.

Could anyone point me out if this is the correct thing to do?

Best,

Devdatta.

2

Do you have empty bins in your histogram ?
If it is the case then the minimum on the Y scale is zero which is not valid in log scale. To bypass this problem do h->SetMinimum(0.00001); (h is the histogram)