.. _physics-posteriorSampleStoppingCriterion:

Posterior Sampling Stopping Criteria
====================================

Class providing stopping criteria for Bayesian posterior sampling simulations---conditions that terminate the MCMC run before the convergence criterion is satisfied. Implementations might stop after a fixed number of steps, upon reaching a target log-likelihood, when an external signal is received, or when a user-defined condition on the simulation state is met. The ``stop`` method is queried at each sampling step and returns true when the stopping condition is triggered, allowing the sampler to exit cleanly.

**Default implementation:** ``posteriorSampleStoppingCriterionNever``

Methods
-------

``stop`` → ``logical``
   Returns true if the posterior sampling should terminate immediately given the current simulation state, allowing the sampler to exit cleanly before reaching the maximum step count.

   * ``class(posteriorSampleStateClass), intent(inout) :: simulationState``

.. _physics-posteriorSampleStoppingCriterionCorrelationLength:

``posteriorSampleStoppingCriterionCorrelationLength``
-----------------------------------------------------

This type will cause the simulation to stop when at least a number of correlation lengths (as specified in the ``[stopAfterCount]`` parameter) have accrued post-convergence.

**Parameters**

* ``[stopAfterCount]`` — The number of correlation lengths to continue after convergence before stopping.

.. _physics-posteriorSampleStoppingCriterionNever:

``posteriorSampleStoppingCriterionNever``
-----------------------------------------

A posterior sampling stopping criterion class that always returns false, allowing the sampler to run for the full maximum number of steps without terminating early based on any stopping condition.

**(Default implementation)**

.. _physics-posteriorSampleStoppingCriterionStepCount:

``posteriorSampleStoppingCriterionStepCount``
---------------------------------------------

This type will cause the simulation to stop when at least a number of steps (as specified by ``[stopAfterCount]``) have accrued post-convergence.

**Parameters**

* ``[countSteps]`` — The number of steps after which to declare the simulation as converged.
* ``[stopAfterCount]`` — The number of steps to continue after convergence before stopping.