mirror of
https://github.com/moses-smt/mosesdecoder.git
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71 lines
2.1 KiB
C++
71 lines
2.1 KiB
C++
/***********************************************************************
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Moses - statistical machine translation system
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Copyright (C) 2006-2012 University of Edinburgh
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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***********************************************************************/
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#include "tree_scorer.h"
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#include <cassert>
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namespace MosesTraining {
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namespace Syntax {
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namespace PCFG {
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TreeScorer::TreeScorer(const Pcfg &pcfg, const Vocabulary &non_term_vocab)
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: pcfg_(pcfg)
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, non_term_vocab_(non_term_vocab) {
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}
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bool TreeScorer::Score(PcfgTree &root) const {
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if (root.IsPreterminal() || root.IsLeaf()) {
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return true;
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}
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const std::vector<PcfgTree *> &children = root.children();
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double log_prob = 0.0;
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std::vector<std::size_t> key;
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key.reserve(children.size()+1);
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key.push_back(non_term_vocab_.Lookup(root.label()));
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for (std::vector<PcfgTree *>::const_iterator p(children.begin());
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p != children.end(); ++p) {
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PcfgTree *child = *p;
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assert(!child->IsLeaf());
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key.push_back(non_term_vocab_.Lookup(child->label()));
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if (!Score(*child)) {
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return false;
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}
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if (!child->IsPreterminal()) {
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log_prob += child->score();
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}
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}
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double rule_score;
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bool found = pcfg_.Lookup(key, rule_score);
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if (!found) {
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return false;
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}
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log_prob += rule_score;
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root.set_score(log_prob);
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return true;
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}
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} // namespace PCFG
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} // namespace Syntax
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} // namespace MosesTraining
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