> Incidentally, it looks like Moses lets you do alignment purely with Model 1, > by setting "-final-alignment-model 1", although like hmm, it's hard-coded to > pick up the 5th iteration.
Ah, my apologies. I think this is new since the last time I looked at this (4-5 years ago). I do remember going through some minor contortions to get Giza to dump (and Moses to use) a non-standard alignment file. - JB On Mar 6, 2014, at 19:38 , Momo Jeng <[email protected]> wrote: > Marcin, John, > > Thanks! This works for me with the --hmm-align option. > > One note: it only works if the number of hmm iterations is set >= 5. Looking > at the train-model.perl script, it has: > > $___GIZA_EXTENSION = 'Ahmm.5' if $___FINAL_ALIGNMENT_MODEL eq 'hmm'; > > This seems to mean that it's specifically looking for the output of the 5th > hmm iteration. If I set the number of hmm iterations to 4, Moses fails, > saying it can't find an alignment file. If I set the number of hmm iterations > to 10, GIZA does 10 iterations, but then picks the 5th hmm iteration (hmm > dump frequency being set to 5 by default). Not a problem for me, since I can > always manually change the extension in the perl script if I want to pick up > a different iteration, but this seems like a bug. > > Incidentally, it looks like Moses lets you do alignment purely with Model 1, > by setting "-final-alignment-model 1", although like hmm, it's hard-coded to > pick up the 5th iteration. > > Cheers, > > Momo > > > Date: Thu, 6 Mar 2014 21:46:05 +0000 > > From: [email protected] > > To: [email protected] > > Subject: Re: [Moses-support] No Moses translation without model >=3 > > > > You can use the HMM model with the --hmm-align option for > > train-model.perl. The training scripts fails because you only changed > > the options of Giza without informing the script that it should not > > expect any *.A3 files. The --hmm-align option does this for you. > > > > Also there is no reason why you could not produce alignment files using > > only model 1, you would just need to adjust the training script > > accordingly. The uniform distribution is assumed for the first initial > > step, parameters change to something more meaningful after several > > iterations of the EM algorithm. However, most probably pure Model 1 > > alignment won't be very good, as it incorporates no > > word-position-related information, the HMM model is much better usually. > > Some people claim, that you can abandon Model 3 and 4 altogether and > > stop after the HMM model. > > Best, > > Marcin > > > > W dniu 06.03.2014 21:29, John D. Burger pisze: > > > On Mar 6, 2014, at 16:00 , Momo Jeng <[email protected]> wrote: > > > > > >> I'm having a problem getting results from Moses, although I think it's > > >> really a problem with GIZA++; please let me know if there's a better > > >> place for GIZA questions. > > >> > > >> When I run Moses instructing GIZA++ to only do model1 and hmm iterations > > >> ( "--giza-option > > >> model1iterations=3,hmmiterations=3,model3iterations=0,model4iterations=0" > > >> ), Moses fails, because GIZA++ doesn't produce an alignment file (the > > >> .A3.final file). > > >> > > >> Based on a quick look at the GIZA++ code, this failure is explicit in > > >> the code. In main.cpp, m3.viterbi(...) is only called at line 652 if at > > >> least one iteration is set for model 3, 4, 5, or 6, and m3.viterbi(...) > > >> is where the code for writing the alignment file is called. So I'm > > >> wondering if this a bug, or by design. Is there some reason that I > > >> shouldn't create alignments without using model 3 or higher? > > > You can't produce actual alignments with Model 1 - it assumes a uniform > > > distribution from each word over all the words in the other half of the > > > sentence pair. It's really only useful for initializing the word > > > translation probabilities for one of the more sophisticated models. > > > > > > - JB > > > _______________________________________________ > > > Moses-support mailing list > > > [email protected] > > > http://mailman.mit.edu/mailman/listinfo/moses-support > > > > _______________________________________________ > > Moses-support mailing list > > [email protected] > > http://mailman.mit.edu/mailman/listinfo/moses-support > _______________________________________________ > Moses-support mailing list > [email protected] > http://mailman.mit.edu/mailman/listinfo/moses-support
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