Removed mdrun features

Removed SD2 integrator

This integrator has known problems, and is in all ways inferior to sd. It has no tests, and was deprecated in GROMACS 5.0. There are no plans to replace it.

Issue 1137

Removed the twin-range scheme

Only the (deprecated) group scheme supports this, and the Verlet scheme will not support it in the foreseeable future. There is now the explicit requirement that rlist >= max(rcoulomb,rvdw).

Removed support for twin-range with VV integrators

Group-scheme twin-ranged non-bonded interactions never worked with velocity-Verlet integrators and constraints. There are no plans to make that combination work.

Issue 1137, Issue 1793

Removed Reaction-Field-nec

The reaction-field no-exclusion correction option was only introduced for backward compatibility and a performance advantage for systems with only rigid molecules (e.g. water). For all other systems the forces are incorrect. The Verlet scheme does not support this option and even if it would, it wouldn’t even improve performance.

Removed AdResS module

This feature requires the (deprecated) group scheme, and there are no plans to port it to the Verlet scheme.

Issue 1852

Removed mdrun -compact

It is too complicated to support multiple ways of analysing per-step data.

Removed lambda printing from mdrun log file

Issue 1773

Removed GMX_NOCHARGEGROUPS

This undocumented feature was only useful with the (deprecated) group scheme.