In this work Y is generated stochastically from a MC transport
routine and samples taken from an unknown parameter,
.
A stochastic method has advantages if little is known about
and
binning or other parameterisations are difficult. As Y is
distributed about
and
, their relationship is now
biased.
One solution is to gradually improve the quality of the new estimate Y by increasing the number of histories that contribute to it.
Hence a Monte Carlo method within Markov chain Monte Carlo (McMCMC)?
If the number of histories per iteration, h, is increased linearly then this method converges at a rate, O(1/n1/4), i.e. really slow!.