Fitting results are the same whatever the setting parameters change

ROOT
,
1

ROOT Version: 6.22/08
Platform: Ubuntu20.04

Dear experts,

I would like to fit a 3D histogram created by class “TH3F”; the fitting function is a standard plane equation, the detail is shown in the attachment.
The problem is the fitting plane is the same whatever I changed the initial parameters, I have no idea about this, could you please help me? Thanks very much.
rr.C (489 Bytes)

Best regards,
Jiechen

2

Hi,

Is your fit converging fine? E.g. is the output of the fit process indicating success w/o error?

Best,
D

3

Hi, Danilo,

Thank you for reply.
It’s converging, the value of “Edm” is 9.08704e-12. But the output fitting plane does not match the histogram well. I guess the conflict may be from different axis, but I am not sure.

Best regards,
Jiechen

4

Hi Jiechen,

The script you attached is not filling a histogram or fit a histogram.

Anyhow, from your title I understand that you are fitting a plane to the data.
That function will be linear in the fit parameters and therefore the final
fit result not dependent on the initial parameter values.

  • Eddy
5

Hi, Eddy,

Thank you for explanation.

Best regards,
Jiechen