pub trait FitParametersInternalExternalTrait<const NPARAMS: usize>: FitParametersInternalDimlessTrait<f64, NPARAMS> + FitParametersOriginalDimLessTrait<NPARAMS> {
fn convert_to_internal(
norm_data: &NormalizedData<f64>,
orig: &[f64; NPARAMS]
) -> [f64; NPARAMS] { ... }
fn convert_to_external(
norm_data: &NormalizedData<f64>,
params: &[f64; NPARAMS]
) -> [f64; NPARAMS] { ... }
}