Roofit PDF from a TF1 function

[dlin]

Dear experts,

I am using Roofit to do my data analysis, and I need a little complex function to describe part of the contribution, this function would be a piecewise function convoluted with a Gaussian (4 parameter in total). I have tried bindFunction from the TF1 function, and generate a RooRealSumPdf combining with three RooCBshape built-in functions in Roofit, but it seems there was a problem for the TF1 function’s normalization, and I didn’t get correct fit result. I am wondering if it’s possible to generate a RooAbsPdf by the bindPdf with the TF1 function, and then produced the fit PDF (i.e., RooRealSumPdf, or RooAddPdf), but it seems there is no way to pass the parameters to TF1 function in the bindPdf.

I had some searching, and found a friend had the very similar situation:

Bind TF1 into RooFit pdf using bindPdf()

Dear all, I have been trying to bind a python function to a TF1 and then bind this TF1 to a RooFit pdf using bindPdf(). Following the example I found online I managed to do this and I can plot said pdf without issues. My idea was then to use this pdf for fitting. That’s where the problems start as it seems there is no way to pass a RooArgList of floating parameters to bindPdf() (none of the overloaded fucntion seem to allow this at least). I see it is possible with bindFunction() though. I wo…

But I didn’t find a further update if he already solved his problem.
It would be really helpful, if any idea I can try. Thank you very much for the help!

Best,
dlin