MINOS: increase verbosity?

[siragoni]

ROOT Version: 6.30

Hi everyone,
I am performing fits to invariant mass distributions, and the fit is executed via TF1::Fit() with options LREM to have access to MINOS uncertainties (E). Unfortunately the terminal prints out just a single column of the uncertainties, while I am expecting two columns to reflect the asymmetric uncertainties. Is this an issue with verbosity?

Thanks,
Simone

[Danilo]

Hello Simone,

Thanks for the question. I add @moneta in the loop, who might have a solution.

Best,
Danilo

[siragoni]

Thank you! An example of what I meant:

 FCN=43.1541 FROM MINOS     STATUS=SUCCESSFUL    365 CALLS        1923 TOTAL
                     EDM=3.93021e-08    STRATEGY= 1      ERROR MATRIX ACCURATE
  EXT PARAMETER                                   STEP         FIRST
  NO.   NAME      VALUE            ERROR          SIZE      DERIVATIVE
   1  p0           5.07261e-02     fixed
   2  p1           3.09931e+00   6.63774e-03  -7.42221e-06  -2.37970e-03

[moneta]

Hello,
You can use the option “V” in TH1::Fit to increase the verbosity, but it will print a lot of information. Otherwise, you can print the FitResult objec, which contains information about Minos, by doing

auto result = hist->Fit(function,"S");
result->Print();

Or use as minimiser Minuit2, which is now the default in ROOT 6.30

Best regards

Lorenzo

[siragoni]

Thanks a lot, it was very helpful!