Hi,
Can anyone explain how the log likelihood value in EM learning is calculated in Genie? Suppose the underline inference algorithm is Junction Tree.
In my understanding the log P(x) is calculated by multiplying and dividing cliques, is that correct?
many thanks
How log likelihood value is calculated in EM?

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Re: How log likelihood value is calculated in EM?
The primary algorithm for calculating the probability of evidence is based on the junction tree cliques. If the junction tree cannot be created due to memory constraints, the algorithm switches to chain rule (slower, but potentially less memoryintensive).
Re: How log likelihood value is calculated in EM?
many thanks, so the log p(x)=log (product of cliques/product of sepsets)?
Could you please explain a bit more on chain rule calculation of the log p(x)?
best
Could you please explain a bit more on chain rule calculation of the log p(x)?
best

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 Posts: 1255
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Re: How log likelihood value is calculated in EM?
It's more complicated algorithm. We run relevance decomposition which may create a forest of junction trees (the same approach is used for the main exact inference algorithm).log p(x)=log (product of cliques/product of sepsets)?
See this post for the explanation of the chain rule algorithm and P(e)
viewtopic.php?f=3&t=4687&start=15#p10449
Re: How log likelihood value is calculated in EM?
I think I understand the chain rule algorithm.
But I can't understand the "Relevant decomposition of JT". Is there a link or more detailed explanation for that? appreciate a lot.
But I can't understand the "Relevant decomposition of JT". Is there a link or more detailed explanation for that? appreciate a lot.
Last edited by snowave on Tue Jul 28, 2020 9:43 am, edited 2 times in total.

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Re: How log likelihood value is calculated in EM?
Here is the article introducing the relevancebased decomposition algorithm:
http://www.pitt.edu/~druzdzel/psfiles/uai97.pdf
I hope this helps,
Marek
http://www.pitt.edu/~druzdzel/psfiles/uai97.pdf
I hope this helps,
Marek
Re: How log likelihood value is calculated in EM?
cool, very much appreciated.