Re: [ROOT] TF1::Draw() with error bars

From: icpark@mail.cern.ch
Date: Wed Nov 14 2001 - 22:27:28 MET


Dear Rene,

Here is what I am doing:

1) create a 1D profile histgram (TProfile) to see the correlation between
variables x and y.

2) fill the profile with x and y of an event (inside event loop)

3) the result profile histogram is fitted with "pol1" (errors are set)

4) save "pol1" into a file (function is saved with error)

5) open the file and access the function by 

TF1 *pol1=(TF1*)file.Get("pol1")

6) draw by pol1->Draw("e") <-- I'm hoping it pass the option "e" to
TH1::Draw().

I found that there is no option "e" in TF1::Draw(). My guess is that it
create/fill a histogram, but not set the error. Am I right? 

Regards,
Inkyu

On Wed, 14 Nov 2001, Rene Brun wrote:

> Hi Inkyu,
> 
> What is your algorithm to compute the errors on the function ?
> 
> Rene Brun
> 
> On Wed, 14 Nov 2001 icpark@mail.cern.ch wrote:
> 
> > Dear Rooters,
> > 
> > Could somebody let me know how to draw a function (pol1 for example) with
> > error bar? 
> > 
> > Suppose we get a function "pol1" by fitting from a histogram. If I try
> > with TF1::Draw("e"), "e" is just my guess to plot error bars, it gives a
> > correct center line, but error bars are not the one from fit parameter.
> > 
> > Ciao,
> > Inkyu
> > 
> > 
> 
> 



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