## Typo in Bayesian Core

**F**rancisco García from Santiago, Chile, sent me the following email about * Bayesian Core*:

I’m trying to implement algorithm 6.5 “Simulated Tempering by Pumping” from your book

.Bayesian Corex(t)1 is generated in line 1 from MCMC(x(t),1), x(t)2 is generated in line 2 from MCMC(x(t),2), and so on. There is a correspondence between the line number and the order of the generated value x(t)i.

But in the line 2p-1 it says “generate x(t)2p from MCMC(x(t)2p1,1)”. It seems it should say “generate x(t)2p-1 from MCMC(x(t)2p2,1)”

Am I right? If so, Is line 2p: “generate x(t)2p from MCMC(x(t)2p1, )”?

Indeed, this is a typo, the last item of the algorithm should be *2p* not *2p-1*. In addition, the last ratio in the acceptance probability should be

the power used on page 169 being a special case of indexing in the tempering sequence. We surely should not have made the mistake pointed out by Francisco as tempering requires an *even* number of steps to cancel the normalising constants of the tempered targets.

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