LIGGGHTS 2.3: (released 26 February 2013)
+ Added a new fix mesh/gran/surface/stress/servo to represent force-controlled boundaries with a PID controller. Thanks to Andreas Aigner (JKU) for implementing and testing the PID controller.
+ Added new fix property/atom/tracer and fix property/atom/tracer/stream commands along with a new compute nparticles/tracer/region command for the calculation of residence time distributions. Thanks to Rouven Weiler (BASF) for the suggestion as well as helpful discussions and providing test cases.
+ Added a new fix massflow/mesh command that counts #particles and mass penetrating thru an STL surface mesh. Thanks to Rouven Weiler and Moritz Höfert (BASF) for the suggestion as well as helpful discussions and providing test cases.
+ Added sanity checks for the values of Young's modulus, Poisson's ratio and coefficient of restitution as required by pair/gran/hooke, pair/gran/hooke/history and pair/gran/hertz/history.
+ Added output possibility for # of inserted particles and inserted mass to the fix insert/* commands.
+ Added an 'nparticles INF' option to fix insert/stream and fix insert/rate/region to be able to pour an infinite stream of particles.
+ Added a new keyword 'mix' to compute coord/atom to quantifiy species mixing. Thanks to Moritz Höfert (BASF) for contributing a code snippet for this.
+ Added an error check to fix mesh/surface/* to check for illegal args, such as a zero-rotation axis.
+ Fixed a typo bug in the SPH spiky2D kernel. Thanks to Markus Schörgenhumer and Andreas Aigner (both JKU) for tracing this back and providing a fix.
+ Fixed a typo in the doc of compute pair/gran/local. The "torque" output is the torque divided by the particle radius, not diameter. Thanks to user mojgan for bringing this up.
+ Added files for fix wall/gran/hooke/simple that were unintentionally left out in the last releases.
+ Fixed a small issue with fix adapt that could have led to a crash when unfixed before the end of the simulation.
+ Fixed a problem that could lead to a crash upon simulation restart in some cases when simulations using pair hybrid/overlay with gran/* was used . Thanks to Evan Smuts (U Cape Town) for sending a test case.
+ Fixed some broken macros in the source code. Thanks to Richard Berger (JKU) for patching this.
+ Added a patch by Richard Berger (JKU) that is necessary to compile the latest version of LIGGGHTS with cygwin gcc.
+ Fixed a problem with the cross-plaform Cmake makefile contribution by Anton Gladky (TU Freiberg). Thanks to Anton and Richard Berger (JKU) for the note that this was broken.
+ Fixed a small memory issue for a (rarely used) functionality of fix property/global.
However, there are some restrictions in 2.3 (see below) which will be relaxed over time:
+ fix breakparticle/force is not yet available