Reading data from sub-branch

[uzair90]

Hello,

I am having trouble reading a sub branch of a tree. I have seen other posts in on the root forum like:

https://root.cern.ch/root/html/tutorials/tree/tree4.C.html

Trying to read TTree subbranch

Hi all, I am trying to read a sub-branch from a TTree (called MGTree). When I do a print of the TTree, like so: MGTree->Print() I see the following: fWaveforms.fData : std::vector<double> fData[fWaveforms_] This seems to indicate to me that the sub-branch fData should be read into an array of vectors. Here are some of the things I have tried. I discovered on my own that the structure of the tree requires that I type MGTree->SetMakeClass(1) in order to read in any of the branches/sub-branche…

Reading sub-branches

Hi Coyote, thanks for the reply.Because, it is too big, I have attached a file(print.txt). print.txt (493 KB)

But I am still very confused and I was really hoping someone can help me out. The ROOT file I am looking at contains a tree called “dataTree” in which there is a branch called “summary” which contains all the variables I need to access.

When I do “dataTree->Print()” this is the output I get:

oot [1] dataTree->Print();

---

*Tree :dataTree : dataTree *
*Entries : 10 : Total = 354293 bytes File Size = 153961 *

•    :          : Tree compression factor =   2.16                       *
  

---

*Branch :summary *
*Entries : 10 : BranchElement (see below) *
…
*Br 0 :fUniqueID : UInt_t *
*Entries : 10 : Total Size= 625 bytes File Size = 101 *
*Baskets : 1 : Basket Size= 32000 bytes Compression= 1.19 *
…
*Br 1 :fBits : UInt_t *
*Entries : 10 : Total Size= 653 bytes File Size = 130 *
*Baskets : 1 : Basket Size= 32000 bytes Compression= 1.26 *
…
*Br 2 :weight : Double_t *
*Entries : 10 : Total Size= 650 bytes File Size = 101 *
*Baskets : 1 : Basket Size= 32000 bytes Compression= 1.55 *
…
*Br 3 :trueZen : Float_t *
*Entries : 10 : Total Size= 615 bytes File Size = 99 *
*Baskets : 1 : Basket Size= 32000 bytes Compression= 1.19 *
…
*Br 4 :trueAzi : Float_t *
*Entries : 10 : Total Size= 615 bytes File Size = 99 *
*Baskets : 1 : Basket Size= 32000 bytes Compression= 1.19 *
…
*Br 5 :recoZen : Float_t *
*Entries : 10 : Total Size= 615 bytes File Size = 116 *
*Baskets : 1 : Basket Size= 32000 bytes Compression= 1.02 *
…

Here I have shortened the output as there are over 50 variables in this file. Can someone please tell me explicitly how to do this.

I have tried to play around with:

Summary* summary=new Summary();
and
TBranch *summary=dataTree->GetBranch(“summary”);
and
dataTree->SetBranchAddress(“summary”,&summary);
and
dataTree->SetBranchAddress(“summary.trueZen”,&trueZen);

But I am not sure in what order to use (or not to use) them. I am really confused. I would really appreciate any help.

If open the ROOT browser I can plot the values of the “weights” on the Canvas and it shows to me the address on the axis as being “summary.weights”. How does ROOT access these data values if I cant seem to do it?

Thanks

---

_ROOT Version: 5.43
_Platform: Cent OS 7
_Compiler: GCC 4.8.5

---

[uzair90]

Never mind. I found the lib*.so files for the “summary” variable. After loading the required libraries it works.