In this notation, k is assumed to be a matrix. k_11 is the element in the first row and first column.
I used k to sound like count. The notation that you quote is R syntax. rowSums is a function that computes the row-wise sums of the argument k. H is a function defined elsewhere. On Sun, May 8, 2011 at 6:33 PM, Thomas Söhngen <[email protected]> wrote: > Thank you for the blog post and showing me the G-test formula. > > After going through your blog post, I still have some open questions: You > introduce k_11 to k_22, but I don't understand what "k" itself actually > stands for in your formular and how the sums are defined: LLR = 2 sum(k) > (H(k) - H(rowSums(k)) - H(colSums(k))) > > Am 09.05.2011 02:46, schrieb Ted Dunning: > > My guess is that the OP was asking about the generalized log-likelihood >> ratio test used in the Mahout recommendation framework. >> >> That is a bit different from what you describe in that it is the log of >> the >> ratio of two maximum likelihoods. >> >> See http://en.wikipedia.org/wiki/G-test for a definition of the test used >> in >> Mahout. >> >> On Sun, May 8, 2011 at 5:43 PM, Jeremy Lewi<[email protected]> wrote: >> >> Thomas, >>> >>> Are you asking a general question about log-likelihood or a specific >>> implementation usage in Mahout? >>> >>> In general the likelihood is just a number, between 0 and 1 which >>> measures the probability of observing some data under some distribution. >>> >>> >>>
