Alternative design packages

[jhelvy]

As of version 0.3.0, the Bayesian D-efficient designs are generated via the idefix package. However, as was raised in #10, idefix has some limitations. In particular, the idefix::Modfed() function is quite slow, and it is the only option available if using a restricted set of profiles.

So with that in mind, I'm posting this issue to discuss potential alternatives. I'm not necessarily looking to replace idefix, but perhaps supplement cbc_design() with even more options for generating D-efficient designs.

This summary of related packages was recently published. After a quick look, there appear to be quite a few possible alternatives that could be incorporated into `cbc_design():

• support.CEs: Looks pretty simple, but it doesn't look like it supports Bayesian designs with priors. The author has a book too with a lot of other examples.
• skpr: Looks promising but isn't clear if it's made for choice experiments.
• ExpertChoice: Clearly made for choice experiments, not clear if priors can be included.

[jhelvy]

v0.4.0 of the package now has a new method argument for supporting new design methods. It now supports full factorial, orthogonal, and Bayesian D-efficient designs.