Re: [ROOT] GetUserInfo() for an array of Float_t

From: Rene Brun (brun@pcbrun.cern.ch)
Date: Thu Sep 16 2004 - 23:06:41 MEST


Hi Jonathan,

The idea of storing things that are constants in treename->GetUserInfo()
is good. However, you can only add objects deriving from TObject in this
list. To store your array (or multiple arrays), you can use objects
like TVectorF or TH1F. Adding it as a TH1F (or TGraph) has the advantage
that you can still visualize quickly the contents of the array.

For roottalk readers, note that I introduced this facility in version
4.00/08.

Rene Brun

On 
Thu, 16 Sep 2004, Jonathan Eisch wrote:

> Hi,
> 
> I'm rather new to ROOT, so please bear with me.
> 
> I'm using ROOT 4.00/08 and I'm trying to build a tree with waveforms.  
> I have one branch that is an array of type Float_t for the time and 
> another for the voltage.  The time array is constant for each branch, 
> so I'd like to be able to be able to tell root that it's always 
> constant and to only store it once (it takes up much more space than 
> the mostly zero filled voltage array.  I've tried:
> 
> Float_t time[10000]; // holds the point times
> treename->GetUserInfo()->Add(time);
> waves1.Branch("chx_time",&time,"chx_time[numpoints]/F");
> 
> but I know that my use of GetUserInfo() is incorrect, and I can't find 
> much for documentation/examples of it's use.
> 
> -Jonathan
> 



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