unit tests for /soft pair styles

[abhiShandy]

Summary

• coul/cut/soft: needed hybrid/overlay
• coul/long/soft: needed hybrid/overlay
• tip4p/long/soft: needed hybrid/overlay
• lj/charmm/coul/long/soft: had RESPA bug
• lj/cut/coul/long/soft: had RESPA bug
• lj/cut/soft: had RESPA bug
• lj/class2/coul/cut/soft
• lj/class2/coul/long/soft
• lj/class2/soft
• lj/cut/coul/cut/soft
• lj/cut/tip4p/long/soft
• morse/soft: had restart settings bug

Bugs fixed

• missing restart_settings in morse/soft
• respa neighbor lists

Related Issues

#2099

Author(s)

Abhishek Shandilya, RPI

Licensing

By submitting this pull request, I agree, that my contribution will be included in LAMMPS and redistributed under either the GNU General Public License version 2 (GPL v2) or the GNU Lesser General Public License version 2.1 (LGPL v2.1).

Backward Compatibility

Implementation Notes

Post Submission Checklist

• The feature or features in this pull request is complete
• Licensing information is complete
• Corresponding author information is complete
• The source code follows the LAMMPS formatting guidelines
• Suitable new documentation files and/or updates to the existing docs are included
• The added/updated documentation is integrated and tested with the documentation build system
• The feature has been verified to work with the conventional build system
• The feature has been verified to work with the CMake based build system
• Suitable tests have been added to the unittest tree.
• A package specific README file has been included or updated
• One or more example input decks are included

Further Information, Files, and Links

[abhiShandy]

@akohlmey I need your help in identifying the RESPA-related bug in these three pair-styles:

• lj/charmm/coul/long/soft: RESPA bug
• lj/cut/coul/long/soft: RESPA bug
• lj/cut/soft: RESPA bug

It's not the initialization of cut_respa which is causing segmentation fault, it's something else.

[abhiShandy]

Found the bug in neighbor list

[sjplimp]

@abhiShandy @akohlmey Can you clarify what the rRESPA bug was in the 3 pair styles, you also mentioned a neighbor list bug (maybe the same thing). For lj/cut/soft it looks like you removed a bunch of rRESPA logic that presumably was copied from lj/cut? Are you saying that logic was incorrect, or is now outdated?

[akohlmey]

@abhiShandy @akohlmey Can you clarify what the rRESPA bug was in the 3 pair styles, you also mentioned a neighbor list bug (maybe the same thing). For lj/cut/soft it looks like you removed a bunch of rRESPA logic that presumably was copied from lj/cut? Are you saying that logic was incorrect, or is now outdated?

Looking at the git history shows that he respa neighborlist request logic in lj/cut was updated in 2017 in commit 0966e14, while the corresponding section in lj/cut/soft was unchanged since its addition in 2015. I suppose you forgot to update it, when you updated other pair styles.

[abhiShandy]

The stack-trace in failing tests hinted towards bug in neighbor list. So, I copied the neighbor logic from lj/cut to lj/cut/soft (and similarly for other 2) and it fixed the bug.