labelAndSortF4Matrix()

void NCF4::labelAndSortF4Matrix ( )

private

Definition at line 837 of file NCF4.cpp.

{
  size_t sz = mColumnMonomials.size();
  std::vector<int> columnIndices;
  std::vector<Word> tempWords;
  
  tempWords.reserve(sz);
  columnIndices.resize(sz);
  std::iota(columnIndices.begin(), columnIndices.end(), 0);
  
  // store all the column monomials in a temporary to sort them
  // and also set the reducer column for them on the same pass
  for (auto& i : mColumnMonomials)
    tempWords.emplace_back(i.first);
 
  // create the monomial sorter object
  MonomSort<std::vector<Word>> monomialSorter(&freeAlgebra().monoid(),&tempWords);
  // stable sort was here before, but this sort is based on a total ordering
  // with no ties so we can use an unstable (and hence parallel!) sort.
  if (mIsParallel)
    mtbb::parallel_sort(columnIndices.begin(),columnIndices.end(),monomialSorter);
  else
    std::stable_sort(columnIndices.begin(),columnIndices.end(),monomialSorter);
 
  auto applyLabelingColumns = [&](const mtbb::blocked_range<int>& r) {
    for (auto count = r.begin(); count != r.end(); ++count)
      {
        auto& val = mColumnMonomials[tempWords[columnIndices[count]]];
        val.first = count;
        mColumns[count].word = tempWords[columnIndices[count]];
        mColumns[count].pivotRow = -1;
      }
    };
 
  // apply the sorted labeling to the columns
  mColumns.resize(sz);
  if (mIsParallel)
    mtbb::parallel_for(mtbb::blocked_range<int>{0,(int)sz}, applyLabelingColumns);
  else
    applyLabelingColumns(mtbb::blocked_range<int>{0,(int)sz});
 
  auto applyLabelingRows = [&](const mtbb::blocked_range<int>& r) {
    for (auto i = r.begin(); i != r.end(); ++i)
      {
        auto& comps = mRows[i].columnIndices;
        auto& words = mRows[i].columnWords;
        // sets the pivot row in the column if this is a reducer row
        if (i < mFirstOverlap)
          {
            mColumns[mColumnMonomials[words[0]].first].pivotRow = i;
            mColumnMonomials[words[0]].second = i;
          }
        for (int j = 0; j < words.size(); ++j)
          comps[j] = mColumnMonomials[words[j]].first;
      }
    };
 
  // now fix the column labels in the rows and set pivot rows in columns
  if (mIsParallel)
    mtbb::parallel_for(mtbb::blocked_range<int>{0,(int)mRows.size()},applyLabelingRows);
  else
    applyLabelingRows(mtbb::blocked_range<int>{0,(int)mRows.size()});
}

References freeAlgebra(), mColumnMonomials, mColumns, mFirstOverlap, mIsParallel, and mRows.

Referenced by process().