Let’s say I have a HistFactory-based signal model (let’s say the one produced via prepareHistFactory), and I’d like to edit the produced workspace to replace my signal histogram with an interpolation of N different histograms. This interpolation would depend on the parameter of interest (signal strength), i.e. from a parameter on which no constraints are applied.
Do you have any suggestions on how to do that?
Naively I would use
combined->factory("EDIT::simPdf(simPdf, signal_channel1_Hist_alphanominal=mynewclassinstance)"), where
mynewclassinstance would be an instance of a new class I have to write, inheriting from
RooHistFunc, which implements this interpolation/extrapolation. Is this a good idea? Or there are other elements which may be re-used for the purpose?
(I think they are not, as
PiecewiseInterpolation works with the assumption that the “pivots” of the interpolation consists of the up and down 1sigma histograms, and that the parameter is 0 when the histogram is identical to the nominal one.)