We are using one function Z= (1/N!)*(nV- (nv0)N)^N * H (V - Nv0).
where this Z is calculated for charge multiplicity, N
whose root form is “[0] * TMath::Power(([1] - [2] * x), x) / TMath::Gamma(x + 1.0)”.
We want to apply Heaviside function, H( V- Nv0) with condition that V> Nv0. Condition should be in such a way that when above situation ( V > N*v0) is true then answer should be 1 otherwise 0.
P. S : One another constraint we need is both V and v0 should have positive value.
Full program for the above situation with data file are attached:
May be the solution of your problem is to use a function described by a piece of C++ code in which you will be able to apply the constraints you need. As illustrated here.