Instances of Posterior are called by worker sampling processes for evaluation of a joint posterior distribution.

class xpsi.Posterior.Posterior(likelihood, prior, **kwargs)[source]

The (joint) posterior distribution.

A callable instance is required by emcee (but is not required for nested sampling).

  • likelihood – An instance of Likelihood.

  • prior – An instance of Prior.


Special method to make callable instances to feed to emcee.


The logarithm of the posterior density (up to a normalising constant), evaluated at p.

property likelihood

Get the likelihood object.

property prior

Get the prior object.

class xpsi.Posterior.PriorError[source]

Bases: ValueError

Raised if there is a problem with the value of the log-prior.