Fit with an user defined function

Roofit and RooStats
1

Hi,
I want to make a fit using a Fermi-Dirac-like function, depending on 3 parameters.
While running, the program gives this warning

FUNCTION VALUE DOES NOT SEEM TO DEPEND ON ANY OF THE 3 VARIABLE PARAMETERS.
VERIFY THAT STEP SIZES ARE BIG ENOUGH AND CHECK FCN LOGIC.

too many times.

I don’t understand what goes wrong in my fit
exer578.C (4.73 KB)
exer578.h (4.91 KB)

2

Hi,
Can you please attach also the ROOT file, otherwise we cannot run your fit

Lorenzo