How to not store TEntryLists in UPDATE mode

ROOT
1

Hi rooters,

I am having some problem with TEntryList :

I have several artificial neural network outputs that I would like to add as a leaf on several files. At the same time, I want to use only a subset of the entries to fill histograms.

So I have

[code]TCut PreCut = “”; // This cut needs to change from run to run

TFile *input = new TFile(“myFile.root”);
TTree theTree = (TTree) input->Get(“tree”);

TEntryList *allentries, *entries;

gDirectory->cd(0);

theTree->Draw(">>myEListAll",PreCut,“entrylist”);
allentries = (TEntryList*) gDirectory->Get(“myEListAll”);

theTree->Draw(">>myEList",PreCut&&Tagged,“entrylist”);
entries = (TEntryList*) gDirectory->Get(“myEList”);
[/code]
Then I proceed with

[code]theTree->Branch(“branch_name”, &value, “branch_name/F”);

…

Int_t entry = allentries->GetEntry(0);

do{

if(entries->Contains(entry)) …

…

} while((entry = allentries->Next()) != -1);
[/code]
At the end:

input->ReOpen("UPDATE"); input->cd(); input->Write("branch_name",TObject::kOverwrite); input->Close();

My problem is the following:

When I rerun my script (to add a branch or update the one previously set) and want to create histograms based on another PreCut, I realise this is not possible: I keep processing the same entries as my initial run. Using TTree::Draw() in my macro with my new cut and plotting works well.

So I open myFile.root and notice that the entry lists have been saved in its root. Now I suspect that the entrylists I am fetching are the ones stored in the file, not those I just generated.

Now I have tried many things : either open the file immediately in UPDATE mode, pur input->cd(); or gDirectory->cd(0); at several positions but I cannot avoid the entry lists to be saved in the file.

Can someone help me with this ?

Thanks

Karolos

2

By default TEntryLists are added to the current dir (otherwise you have no way to retrieve them). You can exclude them from the cd before writing with the following changes

theTree->Draw(">>myEListAll",PreCut,"entrylist"); allentries = (TEntryList*) gDirectory->Get("myEListAll"); allentries->SetDirectory(0); //<========= theTree->Draw(">>myEList",PreCut&&Tagged,"entrylist"); entries = (TEntryList*) gDirectory->Get("myEList"); entries->SetDirectory(0); //<=========

Rene

3

Thanks Rene.