Disable PME tuning with the group scheme
PME tuning with the group cut-off scheme does not work, as it did not
set fr->bTwinRange. Thus interactions between charge-group pairs at
distances between rlist and rcoulomb are missing. The search cost
does go up, so the PME tuning does not produce very large cut-off's
and grid spacings. This limits the error, but also the chance of
detection.
The fr->bTwinrange bug is easily fixed, but also the cut-off for
the domain decomposition communication is set incorrectly.
Since the code paths of the deprecated group scheme are too much
effort to fix, we simply disable PME tuning with the group scheme.
PME tuning is now completely disabled with the group scheme, and
documented.
Fixes #2200.
Change-Id: I6d8ceeecf54f392e1e8d22a57bfc8646c9b7e722