Numerical pdf in RooFit

Roofit and RooStats
1

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.

2

Hi,

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

Wouter

3

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

4

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

5

I will try this. Thanks!