findPreviousReducerSuffix()

std::pair< bool, int > NCF4::findPreviousReducerSuffix ( const Word & w )

private

Definition at line 808 of file NCF4.cpp.

{
  // basically the same as above, except with suffixes
 
  // get suffix of m
  // search for suffix in mPreviousColumnMonomials
  // if it.second.second != -1, then return (true,it.second.first)
  // else return (false, -1)
  if (w.size() == 0) return std::make_pair(false,-1);
  
  std::pair<bool,int> retval;
  
  Word suffix(w.begin()+1,w.end());
  const auto it = mPreviousColumnMonomials.find(suffix);
  if (it == mPreviousColumnMonomials.end()) //not in table
    retval = std::make_pair(false,-1);
  else
  {
    int colNum = (*it).second.first;
    if (mPreviousColumns[colNum].pivotRow == -1)  // in column table and not a reducer monomial
      retval = std::make_pair(false,-1);
    else  // in table and a reducer monomial
      retval = std::make_pair(true,mPreviousColumns[colNum].pivotRow);
  }
  return retval;
}

References Word::begin(), Word::end(), mPreviousColumnMonomials, mPreviousColumns, Word::size(), and suffix().

Referenced by findDivisor().