Problem with passing color to histograms

[maliev]

Dear root experts,

I have a problem, which I’ve posted here, Problem with passing color to histograms but a proof expert thinks this is more a rooty problem.
Can you please help to resolve it?

Many thanks in advance.
Malik

[couet]

When you draw an histogram which contains errors bars in its data structure and you want to see it as a bar chart you need to draw it with option HIST

h->Draw(“HIST”)

[maliev]

Thanks for the reply, though I had already made this “great” discovery myself. Now I wonder what made to change the default behavior of root. Earlier I was plotting without using the “HIST” option in Draw() method and everything was fine.

[couet]

The plotting behaviour has not changed: Histogram containing errors are drawn by default with error bars and to plot them as bar chart you need the option option HIST.

What changed is that some histograms which did not have errors data structure now do have some…

[couet]

May be try :

h->Sumw2(0)

also see:

Statistical errors not propagated correctly

Hi, I don’t think is a bug. As written in the documentation of the static function TH1::SetDefaultSumw2(), root.cern.ch/doc/master/classTH … ed2ac153c2 [quote]all new histograms will automatically activate the storage of the sum of squares of errors [/quote] So this refers only for the new ones. You need to do : TH1::SetDefaultSumw2(1); TH1D *h=new TH1D("h","",10,0,10); or using the non-static member function Sumw() TH1D *h=new TH1D("h","",10,0,10); h->Sumw2(); Then you will get the corre…