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[MCMC] Add diagnostics and a potential sequal

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
48/100
Issue type
Documentation
Clarity
Mostly clear
Activity status
Quiet
Tech stack
python
Domain
documentation

Research direction

Start by locating the existing MCMC lecture and its JAX sampler examples. Review how proposal scales and correlated posteriors are currently presented, then determine how the requested trace plots, autocorrelation plots, contours, and chain trajectories fit together. Done means the diagnostic material is added and the possible MALA, HMC/NUTS, and numpyro sequel is clearly scoped.

Written by the indexing model from the issue text.

Description

These are summerized from a discussion with @jstac:

Some minor suggestions that we could add to the lecture on how to diagnose MCMC and where the Metropolis–Hastings algorithm may not perform well:

  • Add trace plots for the JAX sampler under different proposal scales.
  • Add autocorrelation plots for the same chains.
  • Add a 2D correlated posterior example with contours and the chain trajectory overlaid.
  • Use the 2D example to illustrate where random-walk Metropolis struggles in finite samples.

In the sequel, we could:

  • Study how these issues motivate MALA and HMC/NUTS.
  • Connect these algorithms to what is used in numpyro.
Dominant language
TeX
Stars
37
Forks
26
Avg merge
2d 17h
Merged PRs (30d)
2

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