Re: GetUserInfo() for TChain

From: Hovhannes Khandanyan <khandan_at_cern.ch>
Date: Wed, 2 Mar 2011 15:15:15 +0100

Thanks much Rene, that worked.
~Hovhanes

On Mar 2, 2011, at 3:02 PM, Rene Brun wrote:

> You must have a Tree in teh chain. You can for example force the first Tree (entry=0) with
>    chain->LoadTree(0);
>   TH1F* h = (TH1F*)chain->GetTree()->GetUserInfo()->At(0);
> 
> Rene
> 
> 
> 
> On 02/03/2011 14:56, Hovhannes Khandanyan wrote:

>> Hello Rene,
>>

>>> TH1F* h = (TH1F*)chain->GetTree()->GetUserInfo()->At(0);

>> This approach did not work causing segmentation violation, and that's probably due to the fact that I use the chain only to;
>>
>> chain->Draw("Leaf>> Histo","","goff")
>>
>> dump a leaf into a histo. Since the content of UserInfo is exactly the same for all of the trees in chain, I could do smth like
>>

>>> TH1F* h = (TH1F*)chain->GetTree(0)->GetUserInfo()->At(0);

>> but GetTree() does not seem to take a tree index as an argument. What would be the best work around?
>>
>> Thanks,
>> Hovhannes
>>
>>
>>

>>> 
>>> Rene
>>> 
>>> 
>>> On 02/03/2011 13:08, Hovhannes Khandanyan wrote:
>>>> Dear ROOTers,
>>>> 
>>>> I have a TChain of TTrees each of which has UserInfo object with a TH1F in it. Things are OK when I operate with individual tree. Anyhow, as soon as I ask for :
>>>> 
>>>> TH1F* h = (TH1F*)chain->GetUserInfo()->At(0);
>>>> 
>>>> I get a NULL pointer. Please let me know what I am doing wrong.
>>>> 
>>>> Thanks,
>>>> Hovhannes
>>>> 
> 

Received on Wed Mar 02 2011 - 15:15:27 CET