TH1F "curve" draw option after Scale(...)

ROOT
1

Why is the curve option [TH1F::Draw(“c”)] ignored after TH1F::Scale(x) ?

from ROOT import TH1F, TCanvas, TRandom3

rand = TRandom3(0)

h1 = TH1F("h1","",10,0,100)
h2 = TH1F("h2","",10,0,100)

for i in range(0,10000) :
  h1.Fill( rand.Gaus(50,10) )
  h2.Fill( rand.Gaus(40,10) )

# Scale one of the histograms
h1.Scale( 2. )

c = TCanvas()
h1.Draw("c")
h2.Draw("csame")
c.Print("test.pdf")

test.pdf (14.4 KB)

ROOT Version: 6.08.06
Platform: x86_64-slc6
Compiler: gcc62-opt

2

it seems ok for me.

{
   TRandom3 *r3 = new TRandom3();
   auto h1 = new TH1F("h1","",10,0,100);
   auto h2 = new TH1F("h2","",10,0,100);
   h1->SetLineColor(kRed);

   for( int i=0; i<10000; i++) {
     h1->Fill( r3->Gaus(50,10) );
     h2->Fill( r3->Gaus(40,10) );
   }

   h1->Scale( 2. ); h1->SetMaximum(7500);

   h1->Draw("hist c");
   h2->Draw("c same hist");
}

12
Screenshot 2019-03-15 at 10.53.12.jpg1372×902 111 KB

3

Thank you! I can move forward, that’s great!

But, incidentally, your code is different - you changed “c” to “hist c”. Why is that necessary?

4

To avoid to see the errors bars.