Re: [ROOT] TProfile empty bins not empty

From: K.-Michael Aye (klaus-michael.aye@dur.ac.uk)
Date: Wed Oct 01 2003 - 14:43:44 MEST


Hi Rene,

If one looks at this oversimplified situation created by this little script

{
    TProfile prof("prof","",10,0,10,"i");
    prof.Fill(1,1);
    prof.Fill(2,2);
    prof.Fill(3,0);
    prof.Fill(7,1);
    prof.Fill(8,0);
    prof.Fill(9,1);
    prof.Fill(10,1);

    prof.Draw();
}

one can see, that the only means for deciding if there are empty bins by 
look at the plot is to see if there are errors drawn. In this case it is 
possible, but when one has more data, the errors can be small.

To illustrate I attach a Canvas created by my program.
The lower histogram is a TProfile, the upper a TH2D scatter plot, 
plotted over a month's time filled by the same set of data, with bin 
width of one hour and data filled approx every 15 seconds.
The upper plot shows easily by the lack of drawing where no data has 
been filled, while the lower plot gives me certainly more information 
otherwise. :-)
So I would like to get rid of that line at zero in the TProfile, because 
in quiet times (weather-wise), all values may be around zero and then it 
might
be confusing to have that line at bins which have not been filled.

Michael

PS.: root 3.03/09, gcc 3.2 on Linux Mandrake 9.1

Rene Brun wrote:
> Hi Michael,
> 
> In a TProfile, empty bins are not drawn.
> Could you send me an example (script, file.root,??) showing this problem?
> Note that there is always a problem with bins having one entry only
> or bins having always the same value. See discussion in class TProfile
> 
>   http://root.cern.ch/root/htmldoc/TProfile.html#TProfile:BuildOptions
>   http://root.cern.ch/root/htmldoc/src/TProfile.cxx.html#TProfile:GetBinError
>   http://root.cern.ch/root/htmldoc/TProfile.html#TProfile:Approximate
> 
> Rene Brun
> 
> 
> "K.-Michael Aye" wrote:
> 
>>Hi!
>>
>>I plot data over a longer period of time with TProfile, but sometimes
>>there is no data, so these bins are not filled.
>>Empty Bins are Draw()n with a zero in it, but sometimes the measured
>>value is also zero, which makes it impossible to distuingish between
>>times when there is no data and times when a zero has been measured.
>>
>>Is there a way to leave empty bins really empty in the plot with TProfile?
>>
>>Thanks,
>>Michael
>>--
>>K.-Michael Aye, University of Durham, Dept. of Physics
>>Phone@Work: +44-191-334-3665, Fax@Work: +44-191-334-3521
>>"Because the exploration of space knows no national boundaries,
>>the loss of the Columbia is a loss to all humankind!"(Kofi Annan)


-- 
K.-Michael Aye, University of Durham, Dept. of Physics
Phone@Work: +44-191-334-3665, Fax@Work: +44-191-334-3521
"Because the exploration of space knows no national boundaries,
the loss of the Columbia is a loss to all humankind!"(Kofi Annan)





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