Internal /External constraints in a fit

Hi,

I would like to know what is the difference between applying an internal constraint to a parameter of a fit with respect to applying an external constraint ? In which case should we use one or the other ?

Thanks a lot for helping,
Cheers,
Géraldine

Hi,

It’s up to you. It mostly matters when your p.d.f. is constructed and used in separate
pieces of code.

Internal constraints can be associated with a p.d.f. at the time when the
p.d.f. is constructed, which is sometimes convenient (usually when it is a 'standard’
constraint that you would often or always apply). External constraints need to
be constructed at the time you do the fit, which give you maximal flexibility.

Wouter