Hello,

I would like to use a numerical function instead of an analytic function for a PDF in RooFit. Is there a RooFit class for this?

Thanks.

Hello,

I would like to use a numerical function instead of an analytic function for a PDF in RooFit. Is there a RooFit class for this?

Thanks.

Hi,

Can you be more precise what you mean with a ‘numerical function’?

Wouter

Hello,

Instead of a pdf of the form f(x) = exp(x^2), I would like to give two arrays, x and y, to describe the function for the pdf. The pdf I want to use does not have an analytic form so I’d like to make the pdf using two arrays of numbers.

Thanks,

Yvonne

Hi Yvonne,

There are several options.

These simplest one is RooHistPdf, which takes a RooDataHist histogram as input (essentially your x and y values example).

Another option, if the source data is an unbinned dataset, is to use RooKeysPdf, which

constructs a smooth distribution from a given set of points.

Wouter

I will try this. Thanks!