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

From: Tommaso Chiarusi <tommaso.chiarusi_at_bo.infn.it>
Date: Sat, 9 Oct 2010 13:19:49 +0200

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). Well, I share the same last consideration of Jean-Marc. I unfortunately failed when following such a suggestion...

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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

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Tommaso Chiarusi, Ph.D.
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INFN Sezione Bologna - Dip. Fisica Università di Bologna Viale Berti-Pichat 6/2
40127, Bologna
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Received on Sat Oct 09 2010 - 13:20:12 CEST