Re: TGraph2DErrors

From: Margar Simonyan <Margar.Simonyan_at_cern.ch>
Date: Mon, 16 Mar 2009 15:41:49 +0100


Hi Bakur

yes, that is one solution. My understanding was that TGraph (2D) is a dynamic object and internally extends the arrays when needed. In my code at the time of creation of TGraph I don't know the number of points, of course the points can be filled into dynamic array and when the length is known one can create a TGraph with required number of points.

Thanks,

             Margar

PS. sorry for double posting, in the past it was impossible to send email to roottalk from gmail account

On Mon, Mar 16, 2009 at 3:25 PM, Bakur Parsamyan <bakur_at_cern.ch> wrote:
>
> Hi Margar,
>
> I guess you need to define number of points in your graph..
> Try to use g->Set(n);
> http://root.cern.ch/root/htmldoc/TGraph2DErrors.html#TGraph2DErrors:Set
>
> regards,
>
> Bakur.
>
>
>
> Margar Simonyan wrote:
>>
>> Hello ROOT team
>>
>> I don't understand why the following few lines result into ROOT crush
>>
>> root [0] TGraph2DErrors * g = new TGraph2DErrors()
>> root [1] g->SetNameTitle("a", "b")
>> root [2] g->SetPoint(0, 1.0, 1.0, 1.0)
>> root [3] g->SetPointError(0, 1.0, 1.0, 1.0)
>>
>> I have tested on ROOT version 5.16/00 (lxplus) and 5.20/00 (my
>> laptop). Any explanation ?
>>
>> Thanks,
>>            Margar
>>
>>
>> *** Break *** segmentation violation
>> (no debugging symbols found)
>> Using host libthread_db library "/lib64/tls/libthread_db.so.1".
>> Attaching to program: /proc/25479/exe, process 25479
>> (no debugging symbols found)...done.
>> [Thread debugging using libthread_db enabled]
>> [New Thread 182913018112 (LWP 25479)]
>>
>>
>> ------------------------------------------------------------------------------------------------------
>>  Margar Simonyan    ------     post-doctoral researcher, ATLAS
>>  LAPP, 9 Chemin de Bellevue, BP 110 F-74941, Annecy-le-Vieux
>>  Tel: +33450091785     +41227671123 (CERN)
>>
>> -----------------------------------------------------------------------------------------------------
>>
>>
>
>
Received on Mon Mar 16 2009 - 15:41:54 CET

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