What does mnexcm("SET ERR", ...) do for MINUIT exa


running MINUIT by hand I encountered a MNEXCM call that I do not understand (at least I do not find it in the fortran-MINUIT guide).

In example I found that before minimizers are called with MyMinuit->mnexcm("MIGRAD", arglist ,NoArgs,ierflg); a ‘SET ERR’ function is called also by mnexcm, i.e. MyMinuit->mnexcm("SET ERR", arglist ,NoArgs,ierflg);
Apparently, it uses one parameter, i.e. arglist[0]=1; NoArgs=1; but what does it do exactly?

Cheers & Thanks,

what you call NoArgs is the number of elements that you provide in the array arglist


Hi Rene,

sorry, my question was phrased a bit unlucky :wink:

I know that NoArgs is the number of arguments used from the arglist array
but I do not know what ‘SET ERR’ is. I thought that mnexcm calls only the minimizers but SET ERR seem to be no minimizer.

You can get an interactive help in Minuit, eg

root > gMinuit = new TMinuit root > gMinuit->Help() root > gMinuit->Help("SET ERR")

ROOT 5.26 and 5.24 TMinuit does not seem to have an interactive help

Nevertheless, I think I learned now that ‘SET ERR’ decides if you have a chi-squared (arglist[0]=1)or loglikelihood fit (arglist[0]=0.5) – if one does not consider the fcn return value explicitly.

Cheers & Thanks,