Update formula when modifying workspace
If in workspace there is an object defined as RooFormulaVar::SigXsecOverSM_ggZHbb_kappa[ actualVars=(kappaL,kappa2V,kappat,den_mu) formula="(1.+(x[0]-1.0)*0.0)/x[3]" ] = 0.999862
(bbtautau kappa_lambda workspace for example), we are not able to simply rename variables used in these formula: if we rename 'kappaL' to 'klambda', the name of variables in formula won't change, so we will get error saying that
RooFormula 'SigXsecOverSM_ggZHbb_kappa' did not compile or is invalid.
Input:
(1.+(kappaL-1.0)*0.0)/kappat
Passed over to TFormula:
(1.+(kappaL-1.0)*0.0)/x[3]
This is something similar as mentioned here https://gitlab.cern.ch/atlas-physics/HDBS/DiHiggs/combination/hh_combination_fw/-/blob/master/deprecated/doc/troubleshooting.md?ref_type=heads#symptoms, however, since whether to specify the variables in RooFormulaVar or not is just a choice, I don't think the requirement on inputs make a lot of sense, instead, we should be able to update RooFormulaVar on the fly.