Hi, what is going here is a caching of phrase-internal n-gram model scores, so they do not have to be re-computed. Think about the output phrase "the very big and funny man" - if you use a trigram language model, then the computation of the language model scores for the words "big", "and", "funny", "man" are the same, no matter what the context. So, these are cached.
-phi > LanguageModel::CalcScore is adding ngram score to retFull score: > fullScore += ngramScore; > > But then in TranslationOption::CalcScore, this is subtracted back: > m_futureScore = retFullScore - ngramScore > + > m_scoreBreakdown.InnerProduct(StaticData::Instance().GetAllWeights()) - > phraseSize * StaticData::Instance().GetWeightWordPenalty(); > > > - Is the n-gram order (3) fixed for LM cost calculations > used in future cost? It does not look so. > > > It would be helpful if someone could clarify the > future cost calculation further. > > Thanks, > Ergun > > > Ergun Bicici > Koc University > > > On Wed, Sep 24, 2008 at 5:46 PM, Philipp Koehn <[email protected]> wrote: >> >> Hi, >> >> the future cost estimates includes an estimate of the phrase translation >> cost >> and language model cost, but not reordering costs. And yes, this is >> implemented >> as described in the Pharaoh manual. >> >> -phi >> >> On Wed, Sep 24, 2008 at 8:58 AM, Yee Seng Chan <[email protected]> >> wrote: >> > Hi list members, >> > >> > >> > >> > Inside TranslationOption.cpp::CalcScore(), m_futureScore is effectively: >> > retFullScore - (PhraseSize*WordPenalty) >> > >> > (Kindly correct me if I'm wrong). >> > >> > >> > >> > What's the reasoning for using the above as futureScore? I know >> > retFullScore >> > is n-gram score. Btw, does the approach here follows "Section 3.5 Future >> > Cost Estimation" in the Pharaoh manual? >> > >> > >> > >> > Best regards, >> > >> > Yee Seng Chan >> > >> > >> > >> > _______________________________________________ >> > 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 > > _______________________________________________ Moses-support mailing list [email protected] http://mailman.mit.edu/mailman/listinfo/moses-support
