TauREx-Ultranest

version 0.5.0-alpha

A plugin for TauREx 3.1 that provides the Ultranest sampler by Johannes Buchner for the retireval

Installation

Installing is simply done by running

pip install taurex_ultranest

Installing from source

You can install from source by doing:

git clone https://github.com/ucl-exoplanets/taurex-ultranest.git
cd taurex_ultranest
pip install .

Running in TauREx

Once installed you can select the sampler through the optimize keyword under Optimizer.

[Optimizer]
optimizer = ultranest
num_live_points=500
dlogz=0.5
dkl=0.5

Input arguments:

The input arguments generally match the arguments from Ultranest.

Argument	Description	Type	Default	Required
num_live_points	minimum number of live points throughout the run	int	100
dlogz	Target evidence uncertainty.	float	0.5
dkl	Target posterior uncertainty.	float	0.5
frac_remain	Integrate until this fraction of the integral is left in the remainder.	float	0.01
cluster_num_live_points	require at least this many live points per detected cluster	Type	40
max_num_improvement_loops	limits the number of improvement loops.	int	Default
stepsampler	Choose which stepsampler to use. See StepSamplers	str	default
nsteps	number of accepted steps until the sample is considered independent.	int	10
step_scale	initial proposal size	float	1.0
adaptive_nsteps	Select a strategy to adapt the number of steps.	(False, 'proposal-distance', 'move-distance')	Default
region_filter	if True, use region to check if a proposed point can be inside before calling likelihood.	bool	False
resume	See docs	('resume', 'resume-similar', 'overwrite' or 'subfolder')	subfolder
log_dir	Directory to store sampling checkpoint files	str	.	Y

Step samplers

You can select a specific sampler by passing in the correct string to stepsampler. Documentation for each sampler is found here

Keyword	Sampler
cube-mh	CubeMHSampler
region-mh	RegionMHSampler
cube-slice	CubeSliceSampler
region-slice	RegionSliceSampler
region-sequentical-slice	RegionSequentialSliceSampler
ball-slice	BallSliceSampler
region-ball-slice	RegionBallSliceSampler