GROMACS 2018.5 release notes
----------------------------

This version was released on TODO, 2018. These release notes document
the changes that have taken place in GROMACS since version 2018.4, to fix known
issues. It also incorporates all fixes made in version TODO and
earlier, which you can find described in the :ref:`release-notes`.

Fixes where mdrun could behave incorrectly
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Fixed numerical derivative for normal-mode analysis with shell code
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

Due to higher precision needs when using polarizable shell particles
the normal mode code did not work reproducibly with shells. In order
to fix this the step-size used for numerically computing the Hessian
was reduced to near machine precision. The change does not affect
the results for non-polarizable systems, such as proteins or small
molecules.

Fixes for ``gmx`` tools
^^^^^^^^^^^^^^^^^^^^^^^

Fixes to improve portability
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Miscellaneous
^^^^^^^^^^^^^

Warn for problematic coupling times with Nose-Hoover and Parrinello-Rahman
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

When combining the Nose-Hoover and Parrinello-Rahman coupling algorithms,
resonances in the kinetic energy and pressure/volume can appear when
the two coupling times involved are similar. Now grompp warns when ``tau-p``
is less than two times ``tau-t``.

:issue: `2749`

Fixed efficiency issue with shell code minimization
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

Code cleanup touching unnecessarily complex code created an efficiency
issue.  Both the issue and some of the complexity are now fixed.

:issue: `2705`