Tf4, tf5?

Hello rooters,
I wonder if there is a possibility to define a function with 4 or even more arguments? In the reference I found TF1, TF2 and TF3. Now I wanted to add another variable…
Thanks for your help!
Cheers,
Michael

EDIT: Maybe I should mention, what I want to do: Minimizing a chi2 function from a fit: chi2 = sum((yi - f(xi,params))/deltayi)^2. The problem is that I know f(xi,params) only from Monte Carlo simulations and not analytically. #params = 4
Up to now, I used a TF3 and the function TF3::GetMinimumXYZ() which is quite handy…

We do not have a TF4, TF5. This could be implemented, the logic is already in the base class TFormula. However, in your request, it is not clear if you request a TF4 or a TF1,2,3 with 4 parameters. In the existing TF1,2,3 you may have as many parameters as you want.

Rene