Allow specifying prior distribution in MMM models via config

[ferrine]

pymc-marketing/pymc_marketing/mmm/delayed_saturated_mmm.py

Lines 123 to 126 in d4feeea

	channel_prior = self._preprocess_channel_prior()
	beta_channel = self.model.register_rv(
	rv_var=channel_prior, name="beta_channel", dims="channel"
	)

Right now it is mixed logic of creating RV and registering it in the model. In principle that should be the only one method that returns already registered RV. That will allow a user to override prior specification

related to #267

[juanitorduz]

Thanks for the feedback! 👍 This was a change introduced in #286 as an attempt to make the API somehow easy for the user. We will probably change it in #295

[michaelraczycki]

The channel prior was completely removed in #295 , as model_config from model_builder allows for customisation of every parameter

[ricardoV94]

We are still hard-coding things like it must be a HalfNormal prior.

We should allow arbitrary distributions like in the CLV models like here:

pymc-marketing/pymc_marketing/clv/models/beta_geo.py

Line 136 in 0855e01

self.a_prior = self._create_distribution(self.model_config["a_prior"])

[MarkusSagen]

@ricardoV94 @twiecki Started working on this in PR #408

However, I encountered a minor issue and would like to get some help understanding how to solve it

[williambdean]

Closed with #397