Waring using IntegralError

Dear Experts,

I am fitting the Z invariant mass distribution with DoubleSidedCB function.
I want to get the Z signal events (in mean+/- 4Sigma) range. I am using Integral and IntegralError to get the Z signal and corresponding uncertainty.

Getting this warning:
''Warning in TF1Helper::IntegralError: numerical error from integration is too large ‘’

Have attached the macro. Many thanks double_SCB.C (1.9 KB)

Hi @ktariq; I am sure @moneta can help you with this issue.


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Can you please attach also the input data file with the histogram so I can reproduce this issue ?
In general, I would recommend to use the TF1NormSum class to get the corrected fitted Z signal events instead of IntegralError.
See the tutorial ROOT: tutorials/fit/fitNormSum.C File Reference


invar_mass_SS_data_v34.root (3.9 KB)
Hi @moneta ,
Here I have attached the input root file. Thanks

Thank you for uploading the files. The warning seems to not be relevant (I would need to fix this).
To avoid it, you can just run with a different eps when calling TF1::IntegralError (e.g. 1.E-6)
Change line 63 of your code to be:

double Z_sig_err =  dcb->IntegralError(z_sig_min,z_sig_max,nullptr, nullptr, 1.E-6);


thanks you so much.

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