Invalid minimum warning

Roofit and RooStats
1

Hi,
I am very new to MINUIT. I am using a chi-square function and MINUIT to minimize it with 4 free parameters. And, even though, my fit is very close to the expected, I am having messages that MINUIT did not converge and that FunctionMinimum is invalid. Does this mean that minimization is not successful and I am not having valid parameter values with these warnings? I’ve attached a log file with those warnings just in case.

Thanks in advance,

Mantis
Minimization results for Mosaic21.txt (14 KB)

2

HI,
Yes, the minimisation did not converge. If you compile Minuit2 with the option
-DWARNINGMSG
you might get more meaningful error messages

Best Regards

Lorenzo

3

Thank you, Lorenzo, I’ll try it.

BTW, I’ve noticed that while for most iterations of MINUIT F value atays at around 500, at some iterations it jumps up to 20 000. What could be the reason for this? I guess this has something to do with MINUIT warnings.