Hi,
What you do seems to be OK, except your command [18]
where you use GetIntegral instead of Integral
Rene Brun
On Thu, 7 Aug 2003,
tcli wrote:
> Dear root users,
> From the manual, the commands to normalize a histogram (TH1 *h)
> is:
> Double_t scale = norm/h.Integral();
> h.Scale(scale);
>
> I tried to normalize a histogram to 1, but that doesn't work. The
> normalized histo isn't drawn. And root doesn't say it's an error.
> However, if I want to include the two lines mentioned above in a macro,
> an error "Error: / Illegal operator for pointer 3 .....
> Error: non class,struct,union object 1/pt used with . or ->..." appears.
>
> My commands when I do it on the command line, not in the macro:
> root [] TH1F *nj = new TH1F("nj","NJET",100,0,20)
> root [] t.Draw("NJET>>nj") //NJET is a leave name in a tree
> root [] nj.Draw() //an un-normalized histo drawn
> root [] Double_t scale = 1/nj.Integral()
> root [] nj.Scale(scale)
> root [] nj.Draw() //still, an un-normalized histo
>
>
> When I try to go further to normalize it per entry and per unit of X
> axis. An error appears.
>
> My command:
> root [18] Double_t scale = nj.GetXaxis().GetBinWidth(1)/nj.GetIntegral()
> Error: operator '/' divided by zero FILE:(tmpfile) LINE:1
> *** Interpreter error recovered ***
>
> Any suggestions?
>
> Thanks in advance!
>
> tcli
>
This archive was generated by hypermail 2b29 : Thu Jan 01 2004 - 17:50:14 MET