Proof entrylist generator

ROOT
1

Hello !

I was wondering if there was a way to generate a TEntryList from a proof execution ?
I usually declare a TChain with 300 files and then I would like to generate 300 entrylist files with respect of the TChain.

I get the tree using the Init() method.
So as far I understood it is a shrinked TChain and the trees are send package by package, is it correct ?
From here how should I get back the offset for a same filename ?

  • tree #1 contains file1.root file2.root
  • tree #2 contains file2.root file3.root

Is tree#1 and tree#2 taking into account the offset of the entry, I don’t think so…
My plan would be to then generate by myself the entrylists… using TEntryList::Enter()

If someone has an idea that would be wonderful ! Thank you

2

Dear meyerma,

You can fill the entry list objects in each worker, add it to the output list and they will get merged in one TTEntryList object automatically, representing all the dataset or TChain.
See tutorials/tree/h1analysis.C and follow the logical flow with ‘filllist’ TRUE .

G Ganis

3

Hi Ganis,

Thank you for your help again !

An idea how to introduce the ChainOffset ?
I would split the elist into one for each file in my chain

On the other hand, I noticed this, displaying the entry number in the Process() function :

129823 129824 129825 129826 15:28:54 32332 Wrk-0.6 | Info in <TEventIterTree::GetTrees>: the tree cache is in learning phase -- Init 0 1 2 3 4

It looks like the entry number is reset after sometime. Do you know how it is handled on one worker ?

4

Ok I found my answer looking deeper into the code :