Table 1. Summary of pre-existing BEAST 2 operators.

Operator	Description	Parameters	Parameterisations
RandomWalk	Moves a single element by a tunable amount.	${\overrightarrow{\mathcal{R}}}^{},\sigma$	cat, real, quant
Scale	Applies RandomWalk on the log-transformation (suitable for parameters with positive domains).	${\overrightarrow{\mathcal{R}}}^{},\sigma$	cat, real, quant
Interval	Applies RandomWalk on the logit-transformation (suitable for parameters with upper and lower limits).	${\overrightarrow{\mathcal{R}}}^{}$	quant
Swap	Swaps two random elements within the vector [3].	${\overrightarrow{\mathcal{R}}}^{}$	cat, real, quant
Uniform	Resamples one element in the vector from a uniform distribution.	${\overrightarrow{\mathcal{R}}}^{}$	cat, quant
ConstantDistance	Adjusts an internal node height and recalculates all incident branch rates such that the genetic distances remain constant [33].	${\overrightarrow{\mathcal{R}}}^{},t$	real, quant
SimpleDistance	Applies ConstantDistance to the root node [33].	${\overrightarrow{\mathcal{R}}}^{},t$	real, quant
SmallPulley	Proposes new branch rates incident to the root such that their combined genetic distance is constant [33].	${\overrightarrow{\mathcal{R}}}^{}$	real, quant
CisScale	Applies Scale to σ. Then recomputes all rates such that their quantiles are constant (for real [33]) or recomputes all quantiles such that their rates are constant (quant).	${\overrightarrow{\mathcal{R}}}^{},\sigma$	real, quant

Summary of pre-existing BEAST 2 operators, which apply to either branch rates ${\overrightarrow{\mathcal{R}}}^{}$ or the clock standard deviation σ, and the substitution rate parameterisation they apply to. ConstantDistance and SimpleDistance also adjust node heights t.