Method removeRow

highs/mip/HighsDynamicRowMatrix.cpp:147–199

removes the row with the given index from the matrix, afterwards the index can be reused for new rows

/// removes the row with the given index from the matrix, afterwards the index
/// can be reused for new rows
void HighsDynamicRowMatrix::removeRow(HighsInt rowindex) {
  HighsInt start = ARrange_[rowindex].first;
  HighsInt end = ARrange_[rowindex].second;

  if (colsLinked[rowindex]) {
    for (HighsInt i = start; i != end; ++i) {
      HighsInt col = ARindex_[i];

      if (ARvalue_[i] > 0) {
        HighsInt prev = AprevPos_[i];
        HighsInt next = AnextPos_[i];

        if (next != -1) {
          assert(AprevPos_[next] == i);
          AprevPos_[next] = prev;
        }

        if (prev != -1) {
          assert(AnextPos_[prev] == i);
          AnextPos_[prev] = next;
        } else {
          assert(AheadPos_[col] == i);
          AheadPos_[col] = next;
        }
      } else {
        HighsInt prev = AprevNeg_[i];
        HighsInt next = AnextNeg_[i];

        if (next != -1) {
          assert(AprevNeg_[next] == i);
          AprevNeg_[next] = prev;
        }

        if (prev != -1) {
          assert(AnextNeg_[prev] == i);
          AnextNeg_[prev] = next;
        } else {
          assert(AheadNeg_[col] == i);
          AheadNeg_[col] = next;
        }
      }
    }
  }

  // register the space of the deleted row and the index so that it can be
  // reused
  deletedrows_.push_back(rowindex);
  freespaces_.emplace(end - start, start);

  // set the range to -1,-1 to indicate a deleted row
  ARrange_[rowindex].first = -1;
  ARrange_[rowindex].second = -1;
}