TMinuit warning

ROOT
1

Hi all,
I fit an histogram with “pol1”. everything is fine, though I am receiving a warning (error?) message right at the first fit:

The relevant part of the code is this one:

  if ( fit ) {
    TF1 *f1 = new TF1("f1","pol1",0.,500.);
    gStyle->SetOptFit(111);
    aHisto->Fit("f1");
  }

Again: everything is perfect with the fit.
I googled a bit and had a look at TMinuit::Command, but I didn’t find any reasonable clue… Do you have one? :slight_smile:

Many thanks in advance,
Marco

2

Hi,
I cannot reproduce this message. Can you please send me the simples program reproducing this and tell me which ROOT version are you using,

Thank you

Lorenzo

3

Dear Lorenzo,
In attachment you can find a root file and the source of the program
This is the usage:

./FSSRDummy

ROOT version is 5.18.

I tried to reduce as much as I can the code, but this seems to be the minimum amount you have to put togheter to see the problem.

Many thanks in advance,
Marco
FSSRDummy.cpp (11.1 KB)
HistosFSSRCalib_0001556-ErfData.root (45 KB)

4

Hi,

there is a problem loading the TLinearFitter class via the plug-in manager.
If you don’t care about using the linear fitter you can use the option “F”,
force to use Minuit, and that should work,

aHisto->Fit("f1","F");

otherwise do before running the first fit you can do

gSystem->Load("libMinuit")

or add “-lMinuit” in the list of linking libraries of your application.

Thank you for reporting this. We will fix this problem in the next release
Best Regards
Lorenzo

5

Dear Lorenzo,
thanks for looking into this!

I went for ‘-lMinuit’ option.

Regards,
Marco