Use of upar.add

Hi guys,

I have a question on the usage of upar.add.
My problem is the following, I minimize using Minuit2 with about 150 parameters. All parameters are fine but one for which I know that its value should be different. The output value is too close to the guess, in other words Minuit2 does not explore all the space for this parameter. I use upar.add(“name”,value,0.1).

Is there a way to tell it to be able to have Minuit2 to find an optimal value in a range larger than what I am getting.

Thanking you in advance,


Hi @tappourc; I am inviting @moneta to this topic as the relevant expert.



You can try starting from a different initial value or maybe using a larger initial step size. However, if Minuit2 finds that value is because the function has a local minimum in that region


Thanks. How do we change the step size?


The step size is the parameter you pass after the value. You are using 0.1, try a larger value when calling:
upar.add("name", value, stepsize)

OK thanks. That will do !