yep, the source phrase is carried as part of the translation rule *only*
to calculate lexicalized reordering score.
If I can remember correctly, it's implemented slightly differently
depending on the whether the input is a sentence, confusion net or
lattice. It's optimised since you can easily get the source phrase from
a sentence but the source has to be calculated as you go along in the
other 2 types.
I would prefer it if the implementation was consistent, even at a cost
of slightly degraded speed.
I've added a regression test
phrase.lexicalized-reordering-bin
just in case you decide to play about with it
I don't see the bug, wadda you want me to fix?
On 15/10/2011 03:17, Kenneth Heafield wrote:
> Actually, the incorrect source phrase is used for more than logging. It
> makes it all the way to lexical reordering:
>
> const Phrase *sourcePhrase = transOpt.GetSourcePhrase();
> if (sourcePhrase) {
> Scores score = lexreordering.GetProb(*sourcePhrase,
> transOpt.GetTargetPhrase());
> if (!score.empty())
> transOpt.CacheScores(lexreordering, score);
>
> These are parts of Moses far afield. Hieu, the bug goes back to you in
> 1338. Want to fix it?
>
> On 10/14/11 20:48, Kenneth Heafield wrote:
>> Hi,
>>
>> Apparently target phrases keep track of their source phrases? This is
>> incorrect with e.g. PhraseTableMemory (this is the code from revision 4364):
>>
>> Phrase sourcePhrase(Input, 0);
>> sourcePhrase.CreateFromString( input, phraseVector);
>> //target
>> TargetPhrase targetPhrase(Output);
>> targetPhrase.SetSourcePhrase(&sourcePhrase);
>>
>> I'm currently refactoring it, but have provided the old version to make
>> it clear this isn't my fault.
>>
>> The last line stores a pointer to a stack allocated object in
>> targetPhrase. Furthermore, the sourcePhrase object does not even exist
>> in copy form, so there's nothing correct for it to point to.
>>
>> I tried to remove it, apparently it makes its way to TranslationOption
>> and Hypothesis, GetSourcePhraseStringRep in particular. That is called
>> only from Manager.cpp and used for logging purposes in e.g.:
>>
>> outputWordGraphStream<< "\tw="<< hypo->GetSourcePhraseStringRep()<<
>> "|"<< hypo->GetCurrTargetPhrase();
>>
>> On the basis that no logging is better than incorrect logging, I'm going
>> to stop tracking the source phrase in the target phrase.
>>
>> Kenneth
>> _______________________________________________
>> Moses-support mailing list
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>> http://mailman.mit.edu/mailman/listinfo/moses-support
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