grompp warns about md + FEP even for fully coupled states - Redmine #2767

gmx grompp with FEP .mdp inputs and non-SD integrators issues

WARNING 1 [file grompmdp, line 62]:
  For proper sampling of the (nearly) decoupled state, stochastic dynamics
  should be used

It does so even for a fully coupled state. We should not be issuing warnings when there’s no data to support that, because that will train users to use -maxwarn.

We should check if this warning is still appropriate

  • at least check the git history for which Redmine added it - is full VDW but no charge OK?
  • is the warning based on ancient implementations and needs updating?

If we keep it, it should be sensitive to the calculation being done. For example, even slow growth (TI) starting from a not-nearly decoupled state should not issue it. FEP should only issue it for suitable values of lambda (if any).

(from redmine: issue id 2767, created on 2018-11-19 by mark.j.abraham, closed on 2019-12-20)

  • Changesets:
    • Revision 253b576b by Berk Hess on 2019-12-18T10:34:07Z:
Change grompp decoupling SD warning to note

The warning that grompp issues when decoupling a molecule
without the use of the SD integrator has been changed to a note,
since there are valid use cases for using normal MD when not
running in the completely decoupled state.

Note that checking for actual decoupled VdW states requires a lot of
code and would still not be 100% correct.

Fixes #2767

Change-Id: I55c84afcbcb7b19bdb8a7a8bc586a65c50f8d0c1