paul-buerkner/brms

Generalized Poisson distribution

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#739 opened on Aug 26, 2019

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Description

The generalized poisson distribution has some potential when it comes to the estimation of underdispersed count data and is much more efficient to evaluate the the conway-maxwell poisson distribution. It may have trouble due to its complex support and it remains to be evaluated whether this distribution is robust enough to be implemented as a native family in brms. More information about the generalized poisson distribution may for instance be found at https://rdrr.io/cran/VGAM/man/genpoisson.html.

Contributor guide

Research direction
Study the generalized Poisson distribution as described in the VGAM package and implement it as a new family in brms, paying special attention to handling its complex support and ensuring compatibility with Stan.
Tech stack
None
Domain
machine learningdata
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Needs investigation
Prerequisites
RStan
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20