Hi All,
I have been using minuit to fit multiple Gaussians. My code is
becoming more elegant now and I don't want to keep using global
variables so I dug in TMinuit.cxx and found this at the beggining:
//*-* - The functions SetObjFit(TObject *obj) and GetObjFit() can be *
//*-* used inside the FCN function to set/get a referenced object *
//*-* instead of using global variables. *
I have no clue as what to do to actually make use of this. I found
the definition (?) of this function in G__Minuit.cxx but that only
made me more confuse. I guess first of all the my object containing
the data to be fit needs to be transformed to a TObject and then I can
use SetObjectFit (note there is no SetObjFit - I am saying this not to
be picky just to point out a little inconsistency between the comment
and the code) within FCN to have access to my object. However, how do
I get this object inside FCN? I must confess there is a couple
arguments in the FCN function whose meaning I never quite understood:
void fcn(Int_t &npar, Double_t *gin, Double_t &f, Double_t *par, Int_t iflag)
{
// computes Chi^2
// &npar = number os parameters
// *gin = ???????? , not used here
// &f = returns the chisq^2 value in this variable
// *par = the array of parameters
// iflag = ???????? , not used here
so far I have survived without messing with them... But neither one
is of type TObject, therefore I gather they are not what I am after.
If anyone has some example code showing the use of SetObjectFit
(hopefully showing the creation of the TObject as well) I would
appreciate it.
thanks, have you all a nice day,
Antonio
Antônio Kanaan
Departamento de Física - Universidade Federal de Santa Catarina
CP 476 -- CEP 88040-900 -- Florianópolis -- SC -- Brasil
http://www.astro.ufsc.br/~kanaan e-mail: kanaan@astro.ufsc.br
Phone: 55,48,3319069 FAX : 55,48,3319946
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