Dear Attila, you are right that the algorithm described into the Moses website differs from what is implemented in symal.
But in the moses website (http://www.statmt.org/moses/?n=Moses.Background) there is also this description "Our heuristic proceeds as follows: We start with intersection of the two word alignments. We only add new alignment points that exist in the union of two word alignments. We also always require that a new alignment point connects at least one previously unaligned word." which does match the symal implementation. As both procedures are heuristic, both are good in principle. Nevertheless I personally prefer symal one, because it adds points earlier which will be added later in the final step. Philip (and other developers), what do you think of? Which is the most reliable heuristic procedure? best regards, Nicola On 5/12/09 12:16 PM, "Attila Zséder" <zse...@gmail.com> wrote: Hello, I wanted to understand grow-diag() algorithm described here: http://www.statmt.org/moses/?n=FactoredTraining.AlignWords , in order to check where the script generates non-distinct alignment pairs ( I mean: 1-2 1-3 2-3 is non-distinct; 1-2 2-2 1-3 2-3 ( and no more with these words) is a distinct pairing) in this description there is a line: if ( e-new not aligned and f-new not aligned ) It would mean that we can add new aligns only if both of new words weren't covered before by the alignment (and so, only distinct pairs would have been generated). But in the source code (symal.cpp) these are the corresponding lines: //check if it connects at least one uncovered word if (!(ea[point.first] && fa[point.second])) So i think the description of this algorithm is not fully proper. I'm not absolutely sure, but its worth a review. Btw, any comments to my original intentions regarding to distinct pairing are appreciated. Thank you! Br, Attila _______________________________________________ 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
