Burnin

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Burnin (or Burn-in or Burning-in).

  • Typically the chain will take some time before trees are sampled according to their probability
  • Initially probability of trees increases with time
  • Programmes need to be allowed to run until the probabilities are fluctuating randomly about a constant mean
  • Data generated before the chain reaches a steadystate are discarded
  • There are some disadvantages of picking trees near our current tree
  • Our very first tree might not have a good P(D|T), and the first part of the chain might be in a valley. This will distort the calculation of posterior probabilities
  • In practice: "burning-in" of the chain: start somewhere random, but run the process for a while, and discard the first part of the chain as atypical.

This article is curently a "stub". This means it is an incomplete article needing further elaboration.

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Topics in phylogenetics
Relevant fields: phylogenetics | computational phylogenetics | molecular phylogeny | cladistics
Basic concepts: synapomorphy | phylogenetic tree | phylogenetic network | long branch attraction
Phylogeny inference methods: maximum parsimony | maximum likelihood | neighbour joining | UPGMA