WIP: Noise updates

[jeremy-baier]

Drafting a PR for 1) chromatic noise model functionality 2) discovery likelihood 3) enterprise extensions Gibbs sampler.
Also taps into la_forge functionality for post processing.

Chromatic noise models

• Adds dmgp, and chrom gp, and solar wind to the par files post noise.
• Enables user to run dmgp/chromgp in the model_noise function.

Discovery Likelihood

• adds functionality to interface with the discovery likelihood
• options 3 different types of noise samplers in numpyro (HMC, NUTS, HMC-GIBBS)

Gibbs Sampler

• Still a WIP, but using this PR in enterprise extensions.
• Modifies Nima Lal’s Gibbs sampler, based on van Haasteren & Vallisneri 2014, enabling DM and Chromatic models to be sampled using a free spec psd.
• future functionality will add Fourier coefficients into the timing model via the WaveX and DMWaveX and CMWaveX

Requirements

• La_forge for noise post-processing
• discovery need access
• numpyro: pip install numpyro[cuda] -f https://storage.googleapis.com/jax-releases/jax_cuda_releases.html (for GPU)
• jax: pip install -U "jax[cuda12]” (for GPU)
• enterprise_extensions gibbs sampler: PR here pip install git+https://github.com/jeremy-baier/enterprise_extensions@jgb-chromatic-gibbs

TO DO

Discovery
————

• solar wind !!!
• fix hmc-gibbs
• speed test everything
• figure out optimal sampler parameters for HMC, NUTs

Enterprise Extensions Gibbs
——————————————

• un-hard-code simultaneous use of dm, chrom, red noises in Gibbs
• put free specs into model as fourier coefficients via DMwaveX CMwaveX
• fix issues with CMWaveX ( i think this is just an import thing based off version of pint)
• add option to free up the chromatic index with a PTMCMC step

Misc
——

• interface with the auto-creation of diagnostic plots — add free spec and/or PL plots
• add empirical dists for WN + chrom idx
• test run PTMCMC vs e_e.gibbs_sampling vs discovery
• add Nitu+ solar wind
• test solar wind gp?

[jeremy-baier]

moving to-do list higher up