Re: How to catch Fit results manually

Hi Arthur,

Thanks again for your reply.

I just knew {thanks to Darren} that it should be as easy as:

cout<<"Mean Value= "<<f1->GetParameter(1)<<"Error on Mean= "<<f1->GetParError(1)<<endl;

& it works fine.

Cheers, Asif

On Wed, Feb 29, 2012 at 6:32 PM, Arthur E. Snyder <snyder_at_slac.stanford.edu>wrote:

> Hi Asif,
>
> I believe error extraction is a function (a.k.a. method) of the TF1 rather
> than the TFormula it inherits from. A TFormula does not have errors, but
> only parameters, so errors are only available from something (a TF1) that
> can be fit.
>
> Ain't Object Oreintation grand? Anyway the header files should give you
> everything you need, even if you have to go climbing up and down the tree
> to find 'em.
>
> -Art
>
>
> A.E. Snyder, The Former Group C (TFC) \!c*p?/
> SLAC Mail Stop #95 ((. .))
> Box 4349 |
> Stanford, Ca, USA, 94309 '\|/`
> e-mail:snyder_at_slac.stanford.**edu <e-mail%3Asnyder_at_slac.stanford.edu>
> o
> phone:650-926-2701 _
> http://www.slac.stanford.edu/~**snyder<http://www.slac.stanford.edu/%7Esnyder> BaBar
> FAX:707-313-0250 Collaboration
> &
> Fermi/GLAST
>
>
>
> On Wed, 29 Feb 2012, Asif Saddique wrote:
>
> Thanks Arthur!
>> I got your point. So, parameter 1 is the Mean Value and parameter 2 is the
>> Sigma but still i don't understand how to get errors on these. Can you
>> please point out something about errors?
>>
>> Cheers, Asif
>>
>>
>>
>>
>> On Wed, Feb 29, 2012 at 5:24 PM, Arthur E. Snyder <
>> snyder_at_slac.stanford.edu>
>> wrote:
>> Assuming your fitting a TF1 to a histogram see
>>
>> http://root.cern.ch/root/html/**TF1.html<http://root.cern.ch/root/html/TF1.html>
>>
>> and (for inherited functions)
>>
>> http://root.cern.ch/root/html/**TFormula.html<http://root.cern.ch/root/html/TFormula.html>
>>
>> -Art S
>>
>> A.E. Snyder, The Former Group C (TFC) \!c*p?/
>> SLAC Mail Stop #95 ((. .))
>> Box 4349 |
>> Stanford, Ca, USA, 94309 '\|/`
>> e-mail:snyder_at_slac.stanford.**edu<e-mail%3Asnyder_at_slac.stanford.edu> o
>> phone:650-926-2701 _
>> http://www.slac.stanford.edu/~**snyder<http://www.slac.stanford.edu/%7Esnyder> BaBar
>> FAX:707-313-0250 Collaboration
>> &
>> Fermi/GLAST
>>
>>
>>
>>
>> On Wed, 29 Feb 2012, Asif Saddique wrote:
>>
>> Hi rooters,
>>
>> I am fitting a Gaussian on TH1D and I see following values
>> of Mean & Sigma
>> in my terminal:
>> ==============================**=============================
>> FCN=86.9094 FROM MIGRAD STATUS=CONVERGED 63
>> CALLS 64 TOTAL
>> EDM=2.49833e-09 STRATEGY= 1
>> ERROR MATRIX
>> ACCURATE
>> EXT PARAMETER **
>> STEP FIRST
>> NO. NAME VALUE ERROR
>> SIZE DERIVATIVE
>> 1 Constant 5.98744e+03 4.61314e+01
>> 1.65706e-01 -1.72560e-06
>> 2 Mean 9.20998e+01 1.10379e-01
>> 5.04750e-04 -4.60640e-05
>> 3 Sigma 1.82326e+01 8.71316e-02
>> 5.68693e-06 -5.16419e-02
>> ==============================**==============================
>>
>> I can see Mean & Sigma from here but how can get them
>> manually. Actually, i
>> want to print them in the title of my Histogram. I will
>> convert the value
>> into TString then i will put it in the title but how I can
>> get these values,
>> I mean
>>
>>
>> cout<<"Mean Value= "<<????<<<" with Error
>> ="<<????<<endl;
>> cout<<"Sigma Value= "<<????<<" with Error
>> ="<<????<<endl;
>>
>> should output following:
>>
>> Mean Value= 9.20998e+01 with Error =4.61314e+01
>> Sigma Value= 1.82326e+01 with Error =8.71316e-02
>>
>> But how ?
>>
>> Thanks for help.
>>
>> Cheers, Asif
>>
>>
>>
>>
>>
>>
>>
Received on Thu Mar 01 2012 - 03:10:52 CET