[ROOT] How to extract some parameters from Minuit

From: Dmitri Litvintsev (litvinse@fnal.gov)
Date: Thu Jul 25 2002 - 22:45:25 MEST 

Hi ROOTers,

Suppose I fit the histogram with some function.
I get good old Minuit output:

 FCN=1219.15 FROM MINOS     STATUS=PROBLEMS     3921 CALLS        4334 TOTAL
                     EDM=1.67032e-07    STRATEGY= 1      ERROR MATRIX ACCURATE
  EXT PARAMETER                  PARABOLIC         MINOS ERRORS
  NO.   NAME      VALUE            ERROR      NEGATIVE      POSITIVE
   1  p0           1.85952e+02   1.41652e+01  -1.41428e+01   1.41874e+01
   2  p1           2.00000e-03     fixed
   3  p2           2.53562e-03   1.79748e-04  -1.79136e-04   1.81496e-04
   4  p3           1.25318e+02   1.12149e+01  -1.12132e+01   1.12165e+01
   5  p4           2.99889e-03   2.49013e-04  -2.42735e-04   2.57784e-04
   6  p5           1.42664e-08   2.16157e+00   at limit      2.13242e+00
                                 WARNING -   - ABOVE PARAMETER IS AT LIMIT.
   7  p6           3.94000e-02     fixed
   8  p7           1.37800e+00     fixed
   9  p8           1.28762e+00   2.78206e-04  -2.78443e-04   2.79953e-04
  10  p9           1.31982e+00   2.16318e-04  -2.18444e-04   2.15182e-04
  11  p10          2.05968e-05   4.27319e-05
  12  p11          1.56043e+06   3.22178e+06
  13  p12          0.00000e+00     fixed


Q1: How can I get to 'STATUS' of the fit (the one that is equal to
    PROBLEMS in the above output)?

I use TF1 interface to get to the fit parameters. I don't see
anything like status of the fit.

I gather that there is a TMinuit initialized by default and one
can get an access to its structure using global variable gMinuit.

But just after the fit I see that status is 0:

root [52] gMinuit->GetStatus()
(Int_t)0


It would be nice if the fit status was saved with the histogram's fit
function.

regards,

Dmitri Litvintsev

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