Error in <HandleInterpreterException>: Error evaluating expression

[avinay]

Hi experts
I have an output root file which I try to fill with two TTrees using the code attached below.

The code compiles and runs successfully and I can see the TTrees in the TBrowser window and also the Branches make complete sense. (Please see the screenshot). In addition to my TTrees, I see some additional histograms, which I never asked for.

Now when I try to print the contents of my root file, I get this:

root [4] .ls
TFile**		RecoEfficiency.root
 TFile*		RecoEfficiency.root
  KEY: TDirectoryFile	RecoEfficiency;1	RecoEfficiency (RecoEfficiency) folder
  KEY: TH1D	FRH;1	FRH
  KEY: TH1D	FRV;1	FRV
  KEY: TH1D	rICKR;1	rICKR
  KEY: TH1D	rICKI;1	rICKI
  KEY: TH1D	PreC;1	PreC
  KEY: TH1D	PostC;1	PostC
  KEY: TH1D	PostO;1	PostO
  KEY: TH1D	PreD;1	PreD
  KEY: TH1D	PostDO;1	PostDO
  KEY: TH1D	ER;1	ER

Basically I’m not able to see the TTrees which I see in the TBrowser window. If I try , I get this error:

-bash-4.1$ root -l RecoEfficiency.root
root [0]
Attaching file RecoEfficiency.root as _file0...
(TFile *) 0x31808c0
root [1] TCanvas c1;
root [2] Matchtree->Draw("MC_Track_StartX_det>>h0");
input_line_67:2:3: error: use of undeclared identifier 'Matchtree'
 (Matchtree->Draw("MC_Track_StartX_det>>h0"))
  ^
Error in <HandleInterpreterException>: Error evaluating expression (Matchtree->Draw("MC_Track_Length>>h0")).
Execution of your code was aborted.

I have no idea what’s going on.
When I use the TBrowser window and click on the TTree while I use the above command, only then will the TTree appear in the canvas. I’m just thinking why does it have to depend on the TBrowser to work at all?

_ROOT Version:6.12/06
_Platform:Linux
_Compiler:gcc 7.3.0

RecoEfficiency_module.cc (14.8 KB)

---

[pcanal]

This is not the expected behavior and there may be something unusual about the file. Can you share the ROOT file so we can look into this further?

[avinay]

Thanks for your reply @pcanal. The file is about 14 MB in size so I uploaded it to google drive:

https://drive.google.com/open?id=117ye3cc8BaKBwHAc7-rVZuqVf6r-tkKd

[pcanal]

The unusual feature is that the TTree is stored in a subdirectory, which (confusingly) has the same name as the file:

$ root.exe -b -l ~/Downloads/RecoEfficiency.root 
root [0] 
Attaching file /Users/pcanal/Downloads/RecoEfficiency.root as _file0...
(TFile *) 0x7fba7deb5d60
root [1] gFile->ls()
TFile**		/Users/pcanal/Downloads/RecoEfficiency.root	
 TFile*		/Users/pcanal/Downloads/RecoEfficiency.root	
  KEY: TDirectoryFile	RecoEfficiency;1	RecoEfficiency (RecoEfficiency) folder
  KEY: TH1D	FRH;1	FRH
  KEY: TH1D	FRV;1	FRV
  KEY: TH1D	rICKR;1	rICKR
  KEY: TH1D	rICKI;1	rICKI
  KEY: TH1D	PreC;1	PreC
  KEY: TH1D	PostC;1	PostC
  KEY: TH1D	PostO;1	PostO
  KEY: TH1D	PreD;1	PreD
  KEY: TH1D	PostDO;1	PostDO
  KEY: TH1D	ER;1	ER
root [2] gFile->cd("RecoEfficiency")
(bool) true
root [3] gDirectory->ls()
TDirectoryFile*		RecoEfficiency	RecoEfficiency (RecoEfficiency) folder
 KEY: TTree	Matchtree;1	Matchtree
 KEY: TTree	RecoTracktree;1	RecoTracktree
root [4] Matchtree->Print()
******************************************************************************
*Tree    :Matchtree : Matchtree                                              *
*Entries :    91395 : Total =        12846428 bytes  File  Size =    8255543 *
*        :          : Tree compression factor =   1.56                       *
******************************************************************************
*Br    0 :MC_Track_StartX_det : MC_Track_StartX_det/D                        *
*Entries :    91395 : Total  Size=     734082 bytes  File Size  =     663981 *
*Baskets :       23 : Basket Size=      32000 bytes  Compression=   1.10     *

Cheers,
Philippe.

[avinay]

That makes sense. Thank you very much and have a nice day @pcanal !