RooWorkspace import not working with PyROOT 6

Roofit and RooStats
1

Dear all,

I am having some trouble importing objects into RooWorkspace using PyROOT that came with ROOT 6.02.05. The variable x is imported as a “generic object” with no name. Everything work with ROOT 5.34.25.

Both ROOT versions are the ones from ATLAS’s ALRB.

Any idea what could be wrong?

The code is as follows:

#!/usr/bin/env python

from ROOT import *

w=RooWorkspace('w','workspace')

x=RooRealVar("x","x",0,100)

getattr(w,'import')(x)
w.Print()

The ROOT 6 output is:

RooFit v3.60 -- Developed by Wouter Verkerke and David Kirkby 
                Copyright (C) 2000-2013 NIKHEF, University of California & Stanford University
                All rights reserved, please read http://roofit.sourceforge.net/license.txt


RooWorkspace(w) workspace contents

generic objects
---------------
RooRealVar::

The ROOT 5 output is:

RooFit v3.60 -- Developed by Wouter Verkerke and David Kirkby 
                Copyright (C) 2000-2013 NIKHEF, University of California & Stanford University
                All rights reserved, please read http://roofit.sourceforge.net/license.txt

[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::x

RooWorkspace(w) workspace contents

variables
---------
(x)
2

Hi Karol,

that should not happen.
Is this maybe an issue of PyROOT? In other words, does this work in C++?

Cheers,
Danilo

3

Dear Danilo,

Yes, it does seem to be a PyROOT issue. The following is the output of the C++ version of the code.

void test()
{
  RooWorkspace w("w","workspace");

  RooRealVar x("x","x",0,100);

  w.import(x);
  w.Print();
}
Processing test.C...                                                                                                                                                                                                                         
                                                                                                                                                                                                                                             
RooFit v3.60 -- Developed by Wouter Verkerke and David Kirkby                                                                                                                                                                                
                Copyright (C) 2000-2013 NIKHEF, University of California & Stanford University                                                                                                                                               
                All rights reserved, please read http://roofit.sourceforge.net/license.txt                                                                                                                                                   
                                                                                                                                                                                                                                             
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::x

RooWorkspace(w) workspace contents

variables
---------
(x)

Also I did a quick check with a version of ROOT 6 that I compiled locally. I noticed that the PyROOT version calls the following import:

Bool_t RooWorkspace::import(TObject& object, Bool_t replaceExisting)

The C++ version calls the following import:

Bool_t RooWorkspace::import(const RooAbsArg& inArg,
			    const RooCmdArg& arg1, const RooCmdArg& arg2, const RooCmdArg& arg3, 
			    const RooCmdArg& arg4, const RooCmdArg& arg5, const RooCmdArg& arg6, 
			    const RooCmdArg& arg7, const RooCmdArg& arg8, const RooCmdArg& arg9)

Could PyROOT be getting confused with overloading and inherited classes?

4

Hello Karol,

thanks a lot for your report: this looks like some kind of method resolution issue.
Could you attach the rootfile and script so that I can open a ticket for our pyroot expert?

Cheers,
Danilo

5

Dear Danilo,

I’ve attached the Python and C++ versions of the script.

There is no ROOT file. I create a RooRealVar x and RooWorkspace in the code, import the x variable into the workspace and print the contents of the workspace.
test.py (138 Bytes)
test.C (113 Bytes)

6

Hello Karol,

this has been filed: sft.its.cern.ch/jira/browse/ROOT-7166
It will be fixed soon.
Meanwhile, I tested the script also on the master branch of ROOT and that one is not affected by the issue.

Cheers and thanks,
Danilo

7

Dear Danilo,

Thank you for opening the ticket!

I tried master and it works for me too.

8

sft.its.cern.ch/jira/browse/ROOT-6785