We have some acceleration schemes that are no quasi-Newton schemes. However, they still write the QN-related columns QNColumns, DeletedQNColumns, and DroppedQNColumns in *-iterations.log. It would be better to drop these columns. However, this would be a breaking change.

ToDo

If we decide to introduce this change, we could already create the corresponding PR now, since it should be quite simple:

• Update BaseCouplingScheme::initializeTXTWriters(): Only addData("QNColumns") for QN-related columns if qnAcceleration && not doesFirstStep()
• Update BaseCouplingScheme::advanceTXTWriters(): Only writeData for QN-related columns if qnAcceleration && not doesFirstStep()

Compare to 92ae987

Context

In #2107 I already proposed this change, but we decided to move the breaking changes into an issue since this would break post-processing scripts if they depend on the order of the columns. In #2107 I introduced some changes that simplify the Acceleration class hierarchy without user-observable changes.