on a related note, you don't even have to use probabilities as features in the phrase-table.
for instance, using counts(e|f) and counts(f|e), instead of p(e|f) and p(f|e) gives ok translation. The features really are just scores. using probabilities: devtest2006: 27.55 BLEU-c ; 28.29 BLEU nc-dev2007: 22.26 BLEU-c ; 23.46 BLEU avg: 24.91 BLEU-c ; 25.88 BLEU using counts: devtest2006: 27.36 BLEU-c ; 28.11 BLEU nc-dev2007: 21.64 BLEU-c ; 22.90 BLEU avg: 24.50 BLEU-c ; 25.51 BLEU On 20/09/2011 22:14, Miles Osborne wrote: > exactly, the only correct way to get real probabilities out would be > to compute the normalising constant and renormalise the dot products > for each phrase pair. > > remember that this is best thought of as a set of scores, weighted > such that the relative proportions of each model are balanced > > Miles > > On 20 September 2011 16:07, Burger, John D.<j...@mitre.org> wrote: >> Taylor Rose wrote: >> >>> I am looking at pruning phrase tables for the experiment I'm working on. >>> I'm not sure if it would be a good idea to include the 'penalty' metric >>> when calculating probability. It is my understanding that multiplying 4 >>> or 5 of the metrics from the phrase table would result in a probability >>> of the phrase being correct. Is this a good understanding or am I >>> missing something? >> I don't think this is correct. At runtime all the features from the phrase >> table and a number of other features, some only available during decoding, >> are combined in an inner product with a weight vector to score partial >> translations. I believe it's fair to say that at no point is there an >> explicit modeling of "a probability of the phrase being correct", at least >> not in isolation from the partially translated sentence. This is not to say >> you couldn't model this yourself, of course. >> >> - John Burger >> MITRE >> _______________________________________________ >> Moses-support mailing list >> Moses-support@mit.edu >> http://mailman.mit.edu/mailman/listinfo/moses-support >> >> > > _______________________________________________ Moses-support mailing list Moses-support@mit.edu http://mailman.mit.edu/mailman/listinfo/moses-support
