Пример #1
0
// Method to reduce, if possible the spans
void ReorderingStack::Reduce(Range current)
{
  bool cont_loop = true;

  while (cont_loop && m_stack.size() > 0) {

    Range previous = m_stack.back();

    if (current.GetStartPos() - previous.GetEndPos() == 1) { //mono&merge
      m_stack.pop_back();
      Range t(previous.GetStartPos(), current.GetEndPos());
      current = t;
    }
    else if (previous.GetStartPos() - current.GetEndPos() == 1) { //swap&merge
      m_stack.pop_back();
      Range t(current.GetStartPos(), previous.GetEndPos());
      current = t;
    }
    else { // discontinuous, no more merging
      cont_loop = false;
    }
  } // finished reducing, exit

  // add to stack
  m_stack.push_back(current);
}
Пример #2
0
// Method to push (shift element into the stack and reduce if reqd)
int ReorderingStack::ShiftReduce(Range input_span)
{
  int distance;  // value to return: the initial distance between this and previous span

  // stack is empty
  if(m_stack.empty()) {
    m_stack.push_back(input_span);
    return input_span.GetStartPos() + 1; // - (-1)
  }

  // stack is non-empty
  Range prev_span = m_stack.back(); //access last element added

  //calculate the distance we are returning
  if(input_span.GetStartPos() > prev_span.GetStartPos()) {
    distance = input_span.GetStartPos() - prev_span.GetEndPos();
  } else {
    distance = input_span.GetEndPos() - prev_span.GetStartPos();
  }

  if(distance == 1) { //monotone
    m_stack.pop_back();
    Range new_span(prev_span.GetStartPos(), input_span.GetEndPos());
    Reduce(new_span);
  } else if(distance == -1) { //swap
    m_stack.pop_back();
    Range new_span(input_span.GetStartPos(), prev_span.GetEndPos());
    Reduce(new_span);
  } else {      // discontinuous
    m_stack.push_back(input_span);
  }

  return distance;
}
Пример #3
0
void ChartParser::Create(const Range &range, ChartParserCallback &to)
{
  assert(m_decodeGraphList.size() == m_ruleLookupManagers.size());

  std::vector <DecodeGraph*>::const_iterator iterDecodeGraph;
  std::vector <ChartRuleLookupManager*>::const_iterator iterRuleLookupManagers = m_ruleLookupManagers.begin();
  for (iterDecodeGraph = m_decodeGraphList.begin(); iterDecodeGraph != m_decodeGraphList.end(); ++iterDecodeGraph, ++iterRuleLookupManagers) {
    const DecodeGraph &decodeGraph = **iterDecodeGraph;
    assert(decodeGraph.GetSize() == 1);
    ChartRuleLookupManager &ruleLookupManager = **iterRuleLookupManagers;
    size_t maxSpan = decodeGraph.GetMaxChartSpan();
    size_t last = m_source.GetSize()-1;
    if (maxSpan != 0) {
      last = min(last, range.GetStartPos()+maxSpan);
    }
    if (maxSpan == 0 || range.GetNumWordsCovered() <= maxSpan) {
      const InputPath &inputPath = GetInputPath(range);
      ruleLookupManager.GetChartRuleCollection(inputPath, last, to);
    }
  }

  if (range.GetNumWordsCovered() == 1 && range.GetStartPos() != 0 && range.GetStartPos() != m_source.GetSize()-1) {
    bool alwaysCreateDirectTranslationOption = StaticData::Instance().IsAlwaysCreateDirectTranslationOption();
    if (to.Empty() || alwaysCreateDirectTranslationOption) {
      // create unknown words for 1 word coverage where we don't have any trans options
      const Word &sourceWord = m_source.GetWord(range.GetStartPos());
      m_unknown.Process(sourceWord, range, to);
    }
  }
}
LRModel::ReorderingType
LRModel::
GetOrientation(Range const& prev, Range const& cur) const
{
  UTIL_THROW_IF2(m_modelType == None, "No reordering model type specified");
  return ((m_modelType == LeftRight)
          ? prev.GetEndPos() <= cur.GetStartPos() ? R : L
        : (cur.GetStartPos() == prev.GetEndPos() + 1) ? M
          : (m_modelType == Monotonic) ? NM
          : (prev.GetStartPos() ==  cur.GetEndPos() + 1) ? S
          : (m_modelType == MSD) ? D
          : (cur.GetStartPos() > prev.GetEndPos()) ? DR : DL);
}
LRModel::ReorderingType
LRModel::
GetOrientation(Range const& prev, Range const& cur,
               Bitmap const& cov) const
{
  return ((m_modelType == LeftRight)
          ? cur.GetStartPos() > prev.GetEndPos() ? R : L
        : IsMonotonicStep(prev,cur,cov) ? M
          : (m_modelType == Monotonic) ? NM
          : IsSwap(prev,cur,cov) ? S
          : (m_modelType == MSD) ? D
          : cur.GetStartPos() > prev.GetEndPos() ? DR : DL);
}
bool
IsSwap(Range const& prev, Range const& cur, Bitmap const& cov)
{
  size_t s = prev.GetStartPos();
  size_t e = cur.GetEndPos();
  return (e+1 == s || (e < s && !cov.GetValue(s-1)));
}
float
DistortionScoreProducer::
CalculateDistortionScore(const Hypothesis& hypo,
                         const Range &prev, const Range &curr, const int FirstGap)
{
  // if(!StaticData::Instance().UseEarlyDistortionCost()) {
  if(!hypo.GetManager().options()->reordering.use_early_distortion_cost) {
    return - (float) hypo.GetInput().ComputeDistortionDistance(prev, curr);
  } // else {

  /* Pay distortion score as soon as possible, from Moore and Quirk MT Summit 2007
     Definitions:
     S   : current source range
     S'  : last translated source phrase range
     S'' : longest fully-translated initial segment
  */

  int prefixEndPos = (int)FirstGap-1;
  if((int)FirstGap==-1)
    prefixEndPos = -1;

  // case1: S is adjacent to S'' => return 0
  if ((int) curr.GetStartPos() == prefixEndPos+1) {
    IFVERBOSE(4) std::cerr<< "MQ07disto:case1" << std::endl;
    return 0;
  }

  // case2: S is to the left of S' => return 2(length(S))
  if ((int) curr.GetEndPos() < (int) prev.GetEndPos()) {
    IFVERBOSE(4) std::cerr<< "MQ07disto:case2" << std::endl;
    return (float) -2*(int)curr.GetNumWordsCovered();
  }

  // case3: S' is a subsequence of S'' => return 2(nbWordBetween(S,S'')+length(S))
  if ((int) prev.GetEndPos() <= prefixEndPos) {
    IFVERBOSE(4) std::cerr<< "MQ07disto:case3" << std::endl;
    int z = (int)curr.GetStartPos()-prefixEndPos - 1;
    return (float) -2*(z + (int)curr.GetNumWordsCovered());
  }

  // case4: otherwise => return 2(nbWordBetween(S,S')+length(S))
  IFVERBOSE(4) std::cerr<< "MQ07disto:case4" << std::endl;
  return (float) -2*((int)curr.GetNumWordsBetween(prev) + (int)curr.GetNumWordsCovered());

}
bool
IsMonotonicStep(Range  const& prev, // words range of last source phrase
                Range  const& cur,  // words range of current source phrase
                Bitmap const& cov)  // coverage bitmap
{
  size_t e = prev.GetEndPos() + 1;
  size_t s = cur.GetStartPos();
  return (s == e || (s >= e && !cov.GetValue(e)));
}
/// return orientation for the first phrase
LRModel::ReorderingType
LRModel::
GetOrientation(Range const& cur) const
{
  UTIL_THROW_IF2(m_modelType == None, "Reordering Model Type is None");
  return ((m_modelType == LeftRight) ? R :
          (cur.GetStartPos() == 0) ? M  :
          (m_modelType == MSD)     ? D  :
          (m_modelType == MSLR)    ? DR : NM);
}
Пример #10
0
Phrase Phrase::GetSubString(const Range &range) const
{
  Phrase retPhrase(range.GetNumWordsCovered());

  for (size_t currPos = range.GetStartPos() ; currPos <= range.GetEndPos() ; currPos++) {
    Word &word = retPhrase.AddWord();
    word = GetWord(currPos);
  }

  return retPhrase;
}
Пример #11
0
Phrase Phrase::GetSubString(const Range &range, FactorType factorType) const
{
  Phrase retPhrase(range.GetNumWordsCovered());

  for (size_t currPos = range.GetStartPos() ; currPos <= range.GetEndPos() ; currPos++) {
    const Factor* f = GetFactor(currPos, factorType);
    Word &word = retPhrase.AddWord();
    word.SetFactor(factorType, f);
  }

  return retPhrase;
}