Using Root based formulas

[alefisico]

Hi,

I have a ROOT-based formula from TFitResults, which I want to use correctionlib to evaluate. My function is like:

ROOT::Math::crystalball_cdf(x,[p5],[p4],[p1],[p0])*(0.5*(1+TMath::Erf((x-[p0])/[p6])))*([p3]-[p2])+[p2] 

Is it possible to use correctionlib for this?

[nsmith-]

Not without extending the parser grammar: we don't want to adopt a dependency on ROOT in this library and TFormula is not thread-safe. See #17 for some more motivation and history.
That said, there might be good motivation to extend the parser and/or merge efforts with formulate. See scikit-hep/formulate#55 for more details.