Hi Rene,
Yesterday, I wrote my own fitter that has something very similar to what
you added, but with one more method:
virtual Double_t Get1Parameter(Int_t ipar);
virtual Double_t Get1Error(Int_t ipar);
virtual void GetEMat(Double_t *emat, Int_t ndim);
I was just writing to you to tell you about it. Anyway, a method to get
a single error might be nice also.
Thanks very much for updating the classes! I'm continually impressed
with the responsiveness of all the ROOT authors/developers.
- John
Rene Brun wrote:
> Hi John,
>
> I agree with your comments.
> I have extended TVirtualFitter (now in CVS), adding two new functions
> Double_t* GetCovarianceMatrix
> Double_t GetParameter(int ipar)
>
> Rene Brun
>
> On Wed, 6 Aug
> 2003, Dr. John Krane wrote:
>
>
>>Hi,
>>
>>I'm trying to get the final fit parameter values and the covariance
>>matrix out of TVirtualFitter or TFitter. Is there no way to do this?
>>
>>I see
>>
>>Int_t GetParameter(Int_t ipar,char *parname,Double_t &value,Double_t
>>&verr,Double_t &vlow, Double_t &vhigh)
>>
>>...but this looks like a cut'n'paste of SetParameter. Why would I have
>>to provide the initial values just to get the current one?! Should this
>>not be
>>
>>Double_t GetParameter(Int_t ipar)
>>
>>...with a simple inline implementation? There also appears to be *no
>>way* to get the covariance matrix. Perhaps I should have bypassed
>>TVirtualFitter entirely and just used TMinuit directly. This course
>>seemed unwise to me at first, or at least non-aesthetic, but
>>TVirtualFitter seems to lack even the basic functionality I need.
>>
>>If I am wrong, could somebody please tell me how to (for instance)
>>modify the code of
>>
>>http://root.cern.ch/cgi-bin/print_hit_bold.pl/root/html/examples/minexam.cxx.html
>>
>>to get the parameters and covariance matrix with high-precision? I am
>>looking for something similar to mnemat for the latter.
>>
>> - John
>>
>
>
>
>
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