Re: again accessing gMinuit when using TVirtualFitter in a Stand-Alone program

From: Rene Brun <Rene.Brun_at_cern.ch>
Date: Sat, 9 Oct 2010 17:36:59 +0200


  Are you linking your application with -lMinuit ?

Rene Brun

On 09/10/2010 13:19, Tommaso Chiarusi wrote:
> Dear Rooters,
>
> I'd like to retrieve the estimators Contour Plot after a minimization
> via TVirtualFitter.
> i.e.: I'd like getting the TGraph as I'd used he gMinuit->Contour(...).
>
> Note: I*'m in a stand-alone programming, out of CINT*.
>
> In the Rootalk archive I've found an old suggestion (2004) by Rene,
> addressing to the use of the gMinuit pointer, after including the
> TMinuit.h file
> (http://root.cern.ch/phpBB3//viewtopic.php?p=5002&sid=ac2d285d56096d4442414cd2d171b0c2
> <http://root.cern.ch/phpBB3//viewtopic.php?p=5002&sid=ac2d285d56096d4442414cd2d171b0c2>).
>
> Well, I share the same last consideration of Jean-Marc.
> I unfortunately failed when following such a suggestion...
>
> ----
> The main reason for that is my ignorance about gMinuit pointer:
> As far as I could retrieve, gMinuit should be a global pointer,
> introduced by TMinuit.h as R__EXTERN TMinuit *gMinuit;
>
> if correctly interpret Rene's words (and I'm not sure of that!),
> by including the TMinuit.h header file, gMinuit should be
> consequently addressed to point the right item by the used TVirtualFitter.
> At least after that the TVirtualFitter itself is initiated
>
> ( i.e. after
>
> TVirtualFitter* fitter_ = TVirtualFitter::Fitter(0,parno_);
>
> )
>
> Assuming that I'm right, so far, after the minimization I should be
> able to access the methods of the object pointed by gMinuit...
> Unfortunately, when compiling my codes, the linking phase fails and
> I get the following errors:
>
> Undefined symbols:
> "_gMinuit", referenced from:
> _gMinuit$non_lazy_ptr in ccvoAYzr.o
> (maybe you meant: _gMinuit$non_lazy_ptr)
> ld: symbol(s) not found
> collect2: ld returned 1 exit status
> Exit 1
>
> Where is my bug?
> Thanks,
> Tommaso
>
> *Used platform: MacBook Pro with SnowLeopard
> ROOT: ROOT 5.26 precompiled*
>
>
>
> ----
> Tommaso Chiarusi, Ph.D.
> -
> INFN Sezione Bologna - Dip. Fisica Università di Bologna
> Viale Berti-Pichat 6/2
> 40127, Bologna
> -
> tel : +39.051.209.52.34
> fax : +39.051.209.52.69
>
>
>
Received on Sat Oct 09 2010 - 17:37:09 CEST

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