Hello all,

I would like to perform a fit, where the value of one of the fit parameters depends on the value of another fit parameter. For example, lets say I have a functions that has two parameters, then what I would like to do is the following:

```
Int_t fixedValue = 2;
fitFunction->SetParameter(0, 1.);
fitFunction->FixParameter(1, fitFunction->GetParamter(0) + fixedValue);
```

Basically, if I know the value of `par[0]`

, then `par[1] = par[0] + fixedValue`

. However, this is a much more simplified version of my actual situation, so I do not want to define `par[1] = par[0] + fixedValue`

in my user defined function, and I was wondering if I could obtain the same results by using the above block of code? Or, is there a better method to achieve what I want?

Thank you very much and any help is appreciated!