Espresso 4.1.2 released

[Jean-Noël Grad]

Dear Espresso users,

The Espresso team is pleased to announce the release of Espresso 4.1.2. 
The source can be downloaded at 
https://github.com/espressomd/espresso/releases/download/4.1.2/espresso-4.1.2.tar.gz
Please see the release notes below.


Many thanks to all contributors!
Regards,
Jean-Noël Grad

============

This release provides a number of corrections for the ESPResSo 4.1 line.
We recommend that this release be used for all production simulations.
The interface has not been changed between ESPResSo 4.1.1 and 4.1.2.
However, some bugs were discovered which can affect simulation results.
Below, please find the list of changes. The numbers in brackets refer to
ticket numbers on https://github.com/espressomd/espresso

General corrections and improvements:

* Remove correlation between the rotational noise and translational
  noise in the Langevin thermostat (#3355)

* Fix a bug that may cause the wrong temperature to be set by the
  Langevin and DPD thermostats in the first time step after the system
  was altered from the Python level, e.g., by changing particles or
  interactions (#3341)

* Fix a bug that caused the DPD thermostat to generate an incorrect
  velocity distribution when used together with the Langevin thermostat
  (#3352)

* Fix a bug in MMM2D and ELC with potential boundary conditions, where
  one of the correction factors was over-counted resulting in wrong
  energies (#3310)

* Fix a bug that caused the wrong bonds to be deleted when removing
  particles from the system (#3356)

* Fix an ambiguity in `ParticleSlice`: the values in the square brackets
  refer to particle ids, not array indices (#3367). This means the
  ill-defined syntax `system.part[0:-1]` is no longer valid. See the
  User Guide section on Setting up particles for more information.

* Remove the mass prefactor in the `ComForce` observable and use
  the correct Particle ids in the `ParticleAngularVelocities`
  and `ParticleBodyVelocities` observables (#3380)

* Fix a rounding error that caused debug builds of ESPResSo running with
  multiple MPI threads to crash when a particle was placed exactly on
  the boundary between two cells (#3377)

* Fix `espressomd.has_features()` for the corner case where the list of
  all compiled-in features is passed as argument, returning ``False``
  instead of ``True`` (#3318)

* Refactor the random number generator code (#3349)

* Minor fixes (#3351, #3336)

Documentation and tutorials corrections and improvements:

* Improve documentation of Monte Carlo methods (#3254, #3330)

* Minor fixes (#3342, #3334)

Build system and platform-related corrections and improvements:

* List all Python dependencies in `requirements.txt` with the supported
  version numbers (#3300). Please note that most of them are optional.

* Add `MPIEXEC_PREFLAGS` and `MPIEXEC_POSTFLAGS` to the command lines of
  parallel tests (#3221)

* Add the `-oversubscribe` flag to the command lines of parallel tests
  running with OpenMPI v2.X to avoid exiting early from a Python test
  configured without `MAX_NUM_PROC` on a machine with a hyperthreaded
  CPU where OpenMPI is configured such that the number of threads cannot
  exceed the number of cores (#3335)

* Refactor the CI, maintainer, Doxygen and pypresso shell scripts to
  make them more portable and support filepaths containing whitespaces
  (#3326, #3373)

* Fix a nvcc compiler warning on the empty config (#3329)

Improved testing:

* Add a test for ELC and MMM2D using analytic expressions of the force
  and energy (#3331)

* Sped-up seven Python tests (#3319)

* Fix a test that broke on s390x architectures with Fedora 31 (#3312)

* Fix tests that broke on i586 architectures with OpenSUSE Tumbleweed
  (#3327, #3358)