Filling TTree in object loop with RDataFrame?

[jieun_choi]

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ROOT Version: 6.18
Platform: lxplus
Compiler: Not Provided

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Hi,

I am wondering if there is a way to fill the tree object by object instead of event by event in RDataFrame.

For example, in “normal” ROOT, we used to fill in object loop before as follows:

for(int i = 0 ; i < jets.size(); i++){
…
tree.fill();
}

I am making a combination with RDataFrame.

Thank you very much for any help.

Regards,
Jieun

[eguiraud]

Hi,
please check this post about posting code.

You can Define, event by event, a column that is a vector of objects. Would that work?

Cheers,
Enrico

[jieun_choi]

I mean, I already got the objects as a vector with Define and filled the tree using Snapshot event by event as a vector of objects.

If I print out the tree with Snaphot, I got this:

root [2] tree->Scan()
***********************************************
*    Row   * Instance *    signal *       mbb *
***********************************************
*        0 *        0 *         0 * 283.59848 * 
*        0 *        1 *         1 * 184.48533 * 
*        0 *        2 *         0 * 181.59184 * 
*        1 *        0 *         0 * 421.54138 * 
*        1 *        1 *         0 * 469.25665 * 
*        1 *        2 *         0 * 91.167800 * 
*        2 *        0 *         0 * 83.889991 * 

In this case, Row is the event.
But I would like to fill the tree object by object like this:

root [2] tree->Scan()
************************************************
*    Row   *    signal *     event *    nbjets *
************************************************
*        0 *         0 *       409 *         4 * 
*        1 *         0 *       409 *         4 *         
*        2 *         1 *       409 *         4 *        
*        3 *         0 *       409 *         4 *     
*        4 *         0 *       409 *         4 *         
*        5 *         0 *       409 *         4 *        
*        6 *         0 *       564 *         3 *     
*        7 *         0 *       564 *         3 * 
*        8 *         1 *       564 *         3 *      
*        9 *         0 *       646 *         3 *     
*       10 *         0 *       646 *         3 *      
*       11 *         0 *       646 *         3 *       
*       12 *         0 *       890 *         3 *        

Here, Row is the combination.

Do you have any good ideas?

Thank you very much,

Regards,
Jieun

[eguiraud]

Ah I see, that would require this feature, that has been proposed a few times and allows processing vector elements one after another disregarding event boundaries.

In the meantime, I think something like that is better done with the classic TTree interfaces.

Cheers,
Enrico