mosesdecoder/phrase-extract/pcfg-extract/rule_collection.cc
2015-06-04 14:36:39 +01:00

66 lines
2.1 KiB
C++

/***********************************************************************
Moses - statistical machine translation system
Copyright (C) 2006-2012 University of Edinburgh
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
***********************************************************************/
#include "rule_collection.h"
#include "syntax-common/pcfg.h"
#include <cmath>
namespace MosesTraining
{
namespace Syntax
{
namespace PCFG
{
void RuleCollection::Add(std::size_t lhs, const std::vector<std::size_t> &rhs)
{
++collection_[lhs][rhs];
}
void RuleCollection::CreatePcfg(Pcfg &pcfg)
{
std::vector<std::size_t> key;
for (const_iterator p = begin(); p != end(); ++p) {
std::size_t lhs = p->first;
const RhsCountMap &rhs_counts = p->second;
std::size_t total = 0;
for (RhsCountMap::const_iterator q = rhs_counts.begin();
q != rhs_counts.end(); ++q) {
total += q->second;
}
for (RhsCountMap::const_iterator q = rhs_counts.begin();
q != rhs_counts.end(); ++q) {
const std::vector<std::size_t> &rhs = q->first;
std::size_t count = q->second;
double score = std::log(static_cast<double>(count) /
static_cast<double>(total));
key.clear();
key.push_back(lhs);
key.insert(key.end(), rhs.begin(), rhs.end());
pcfg.Add(key, score);
}
}
}
} // namespace PCFG
} // namespace Syntax
} // namespace MosesTraining