TTreeReader and TVector3

[nastein]

Hello, I cannot seem to get my TTreeReader to read TVector3s.

I’ve attached my code below.

I simply run:

 TChain* fChain = new TChain("T"); fChain->AddFile("anamuse.root");
 fChain->Process("MuseSelector.C")

And I get the error:

 Error in <TTreeReaderValueBase::GetBranchDataType()>: Unknown type and class combination: -1, TVector3
 Error in <TTreeReaderValueBase::CreateProxy()>: The branch recon_vertex contains data of type {UNDETERMINED TYPE}, which does not have a dictionary.

MuseSelector.C (2.2 KB)

[nastein]

I would really appreciate some help from fellow ROOTers

[Axel]

Hi Noah,

Sorry it took so long! I doubt that TTreeReader is able to convert a TVector3 to a TTreeReadArray<double>. Does it work if you declare it as TTreeReadValue<TVector3>?

Cheers, Axel.

[nastein]

I apologize, I uploaded the wrong piece of code, I have been declaring it as TTreeReaderArray and it still will not work. Thank you.

[Axel]

Sorry, my fingers didn’t do what my brain asked them to type. I meant to write TTreeReadValue<TVector3>. (I have edited my post.)

Does that help?

[nastein]

Neither
TTreeReaderValue<TVector3>
nor
TTreeReaderArray<TVector3>
work, they both return the same error as in my original post.

[Axel]

Hmm too bad, Noah, time for me to spin up gdb and debug what’s happening. I’ll be back…

[Axel]

Even worse - it works for me:

 root.exe -l -b vec3.root
root [0]
Attaching file vec3.root as _file0...
(TFile *) 0x7f8fb8671e20
root [1] TTreeReader r("t")
(TTreeReader &) Name: TTreeReader Title: A simple interface to read trees
root [2] TTreeReaderValue<TVector3> v(r, "v3")
(TTreeReaderValue<TVector3> &) @0x106cea110
root [3] r.Next()
(bool) true
root [4] v->X()
(double) 0.1
root [5] v->Z()
(double) 0.3
root [6] t->Print()
******************************************************************************
*Tree    :t         : vec3                                                   *
*Entries :        1 : Total =             984 bytes  File  Size =        492 *
*        :          : Tree compression factor =   1.04                       *
******************************************************************************
*Br    0 :v3        : TVector3                                               *
*Entries :        1 : Total  Size=        599 bytes  File Size  =        114 *
*Baskets :        1 : Basket Size=      32000 bytes  Compression=   1.04     *
*............................................................................*

Can you send tree->Print() for your tree?

Cheers, Axel.

[nastein]

Yep, I get the same sort of output as you. Except TTreeReaderValue doesn’t work for me.

[nastein]

What Version of ROOT are you using? I’m using v6-08-06

[Axel]

Ha! Indeed, I can reproduce this issue in 6.08/06.

It works not only in the master, but also with e.g. 6.10.08. Can you upgrade?