Re: [ROOT] Determine Number of Events from Fit

From: Rene Brun (Rene.Brun@cern.ch)
Date: Fri Oct 18 2002 - 09:17:40 MEST


Hi Gail,

What do you mean by "determine the number of events"?
Do you mean the integral of the fit function in some range?
If this is the case, see an example at
$ROOTSYS/tutorials/myfit.C

Look at the call to TF1::Integral

Rene Brun

On Tue, 15 Oct 2002, Gail Ruby wrote:

> Dear ROOT,
> 
> I have fit a user defined function to my histogram
> and want to determine the number of events.
> 
> This is an example of the statistics provided
> by ROOT:
> 
> FCN=123.037 FROM MIGRAD    STATUS=CONVERGED     248 CALLS         249
> TOTAL
>                      EDM=4.00443e-07    STRATEGY= 1  ERROR MATRIX
> UNCERTAINTY   2.3 per cent
>   EXT PARAMETER                                   STEP         FIRST   
>   NO.   NAME      VALUE            ERROR          SIZE      DERIVATIVE 
>    1  p0           2.45000e+03   3.35254e+01  -8.16812e-02   2.34887e-06
>    2  p1           1.86271e+00   9.63489e-05   6.31083e-07  -7.22575e+00
>    3  p2           6.97904e-03   1.01692e-04   5.32488e-08  -8.57834e-01
>    4  p3           4.26596e+03   6.04316e+01   2.02481e-01   1.19979e-04
>    5  p4           9.53409e+02   1.09962e+01   3.78864e-02  -1.15613e-04
>    6  p5          -1.93792e+02   5.89416e+00  -1.78104e-02  -2.04623e-04
>    7  p6          -4.73612e+02   9.12748e+00  -2.99322e-02   7.74198e-04
> 
> Thank-you
> Gail Ruby
> 
> 
> 



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