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Jean-Noël Grad edited this page Jan 2, 2024 · 5 revisions

These are the draft release notes for ESPResSo 4.2.2

ESPResSo 4.2.2

This release provides a number of corrections for the ESPResSo 4.2 line.

Added functionality

Changed requirements

Improved documentation

  • Installation instructions now mention the FFTW3 MPI dependency of long-range solvers and provide recommended version numbers for Jupyter Notebook dependencies (#4790).

Interface changes

Removed functionality

Improved testing

Bug fixes

  • Virtual sites no longer contribute to the kinetic energy of the system (#4839). The regression was introduced in April 2021 and affected the 4.2 branch of ESPResSo.

  • Inertialess tracers are now integrated along the z-axis (#4714). The regression was introduced in February 2022 and affected the 4.2 branch of ESPResSo.

  • Inertialess tracers now throw an exception when attempting to use LB GPU with 2 or more MPI ranks (#4714). Before, tracers on non-root MPI ranks would be silently ignored by the CUDA kernels, and would have a constant velocity, either 0 if the particle never visited the fluid domain on the root rank, or the last known velocity if the particle was once on the root rank. This bug affected all ESPResSo versions.

  • Particles close to the faces of the simulation box are now properly coupled to the LB fluid (#4827). Due to numerical instability, it was previously possible for particles to be outside the box simulation by a tiny amount and skip LB particle coupling. The probability of this bug occurring was low, but could be enhanced in simulations that purposefully placed particle near the faces of the simulation box: polymers sheared by Lees-Edwards boundary conditions, raspberry particles (colloids, bacteria, etc.) when crossing a periodic boundary, or cell membranes placed close to a periodic boundary.

  • Restrictions on the number of MPI ranks have been lifted from the checkpointing mechanism (#4724). It is now possible to use checkpointing again in MPI-parallel simulations when the system contains LB boundaries or Union shape-based constraints. These restrictions had been introduced in 4.2.0 for technical reasons that have since been resolved.

  • The per-type and per-mol_id contributions from system.analysis.energy(), system.analysis.pressure() and system.analysis.pressure_tensor() now return the correct values (#4788). Older version of ESPResSo were confusing the particle mol_id with the particle type. The total pressure was unreliable when mol_id properties were set to non-zero values.

  • The OpenGL visualizer now extracts the correct non-bonded potential parameter sigma when feature WCA is compiled in but LENNARD_JONES isn't (#4720). The regression was introduced in 4.2.1.

  • Resizing the box now throws a runtime error if there are constraints present (#4778), since constraint preconditions might no longer be fulfilled. For example, a wall constraint might end up outside the box boundaries when the box shrinks.

  • The velocity Verlet NpT propagator doesn't apply friction and noise on angular velocities. ESPResSo now throws an error when NpT encounters a rotating particle (#4843). This bug affected all ESPResSo versions.

  • The Brownian thermostat can no longer be configured with act_on_virtual=True due to an unresolved bug (#4295).

Under the hood changes

  • Several Clang 16 and GCC 13 compiler diagnostics have been addressed (#4715).

  • A non-critical GCC C++20 deprecation warning in Cython-generated code was disabled (#4725)

  • Several deprecation warnings emitted by CMake 3.27 have been silenced (#4792)

  • Add support for setuptools version 67.3.0 and above (#4709)

  • CI pipeline URLs have been fixed (#4736)

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