Log scale does not work

Newbie
1

ROOT Version: 6.26/02
Platform: Windows
Compiler: MSVC 19.31.31104.0

Hi,

I can’t get it done to plot an axis logarithmically. The code is:

	Double_t partEdep;	
	tree = myFile->Get<TTree>("depE_sum");
	tree->SetBranchAddress("fdepEnergy_sum", &partEdep);
	auto HdepEnergy = new TH1F("HdepEnergy", "Histo_depE", 10000, 0.0001, 1.);  
	for (int iEntry = 0; iEntry < tree->GetEntriesFast(); ++iEntry)
	{
		tree->GetEntry(iEntry);
		HdepEnergy->Fill(partEdep);
	}

	TCanvas* c2 = new TCanvas("c2", "", 20, 20, 1000, 500);
	c2->Divide(1,4);

	c2->cd(1);
	c2->SetLogx();
	HdepEnergy->Draw("EHIST");
	HdepEnergy->SetFillColor(kCyan-2);
	HdepEnergy->SetLineColor(kOrange-3);
	HdepEnergy->GetXaxis()->SetTitle("[keV]");
	c2->SetLogx();

It’ll always plot regularly. Could you please tell me what I am doing wrongly?
Thanks in advance!

2

gPad->SetLogx();

1 Like
3

You can also change:

c2->cd(1);
c2->SetLogx();

to:

c2->cd(1)->SetLogx();

and remove c2->SetLogx();

1 Like
4

Thank you, this worked! But why? Respectively why does this work and not the other way around?

5

You have several pads. You need to set the log scale on the right pad. It was not the case in your initial code.

1 Like