mixed solvents are only support with Gromacs 2018 and higher versions

[VOD555]

Based on the tests on our local workstation, Gromacs with version 2018.6 or higher support mixed molecule solvent. And the solvation process in MDPOW which modifies the topology file would make the top file mismatch the gro file generated after solvation.

Maybe we can use Gromacs preprocessor directives in the file and define a variable MDPOWPREGMX2019 (As discussed in PR #103 )

DRUG               1
#ifdef MDPOWPREGMX2019
OcOH               1
#endif

And then add to to the MDP file:

define  = -DMDPOWPREGMX2019

[VOD555]

Current version supports GROMACS with version >2018, but doesn't support lower versions.

[orbeckst]

that's ok, we just have to document it and fail when we detect unsupported gmx

[orbeckst]

Is this why our Gromacs 4.6.5 tests fail?

[orbeckst]

yes

[orbeckst]

WIll mark the failing mixed solvent tests with XFAIL for 4.6.5

[orbeckst]

2018 also works, as see in the tests for #159

[orbeckst]

It's not worth our time to make this work for 4.6.5 (and 5?) — I am closing with a won't fix. The XFAIL test references this issue.