fractal dimensionality

[kmytsay]

Is there a way to set fdim as a constant in bg_homfractal model? Is it reasonable for getting conc = 0 as a result (the data is of low spin concentration)?

[luisfabib]

Yes, you can do that by using the freeze() method of the corresponding parameter.

For example, if you have constructed a dipolar model called Vmodel which contains the bg_homfractal as the background model you can fix the value as follows:

fdim_fixed = 2
Vmodel.fdim.freeze(fdim)

and then just run the fit as usual.

Due to the mathematical nature of the bg_homfractal model, it can be that the fractal concentration parameter adopts significantly low values. It might be getting rounded when printing the value. You can check whether the value stored in the fit results object is not exactly zero.

[kmytsay]

Awesome, thank you!