LIGGGHTS 3.0.0-beta preamble: (released 03 December 2013)
Dear LIGGGHTS user community,
as you might know, LIGGGHTS has not been designed from scratch, but rather grew organically, with inputs from fields as diverse as molecular modelling, fluid mechanics, chemical engineering, mechanical enigineering, bulk solids handling, high performance computing and some more. We have seen applications across a multitude of disciplines of science and engineering, and we're very happy about that.
As LIGGGHTS grew organically, there is continuous need for adaptions as the code and its applications grow and diversify. Things that were excellent a couple years ago are not necessarily good in a couple years from now. We need to be ready to tackle issues like maintainability and be able to react on paradigm shifts in hardware architecture
We have been working pretty hard in the last couple months to bring LIGGGHTS one step further. The major LIGGGHTS 3 update consists of the following "puzzle pieces":
1) A re-write of the way granular interaction forces has been implemented
A new template-based mechanism was introduced, and particle-particle and particle-wall implementations are now unified. LIGGGHTS grew considerably over the last couple years, and anticipating further development, the old way of doing things would not have been sustainable, not even for the next year or 2.
2) Merge with the latest version of LAMMPS
Bridging communities, making latest development in the LAMMPS molecular modelling community available also for LIGGGHTS users.
3) Testing and bug-fixing
There is now a much more profound regression test running behind the scenes, so LIGGGHTS 3 is more rigorously tested better than all the versions before. Daniel Queteschiner (JKU) was working full-time for almost two months preparing a set of regression tests. Thanks for this!
Just to give you an impresison of the sheer numbers:
+ the git diff patch (just for the C++ source code) is roughly 415,000 lines
+ developing the new granular interaction force framework, merging, testing and bug-fixing took roughly one man-year
+ during the tests, 5 bugs in the LAMMPS codebase were detected and fixed (thanks to Steve Plimpton/Sandia and Axel Kohlmeyer/ICTP for the great collaboration!)
All this was accomplished and is now provided to the community without any direct funding for this! LIGGGHTS 3.0 beta is not perfect yet. So we need your help to double-check, test, and improve it. The discussion boards now have a new forum container dedicated to feedback about LIGGGHTS 3. We're looking forward to your feed-back and suggestions!
Christoph Kloss
Managing partner
DCS Computing GmbH
Senior scientist,
JKU Linz Department of Particulate Flow Modelling
Richard Berger
Senior developer,
JKU Linz Department of Particulate Flow Modelling
Preliminary LIGGGHTS 3.0.0-beta release notes: (released 03 December 2013)
IMPORTANT NOTE: the 3.0.0-beta release is in a separate repository,
which can be reached at https://github.com/CFDEMproject/LIGGGHTS-3-beta-PUBLIC
+ All-new modular granular pair styles and wall implementation
+ Implementations for granular pair and wall are no longer duplicate/redundant
+ Included all LAMMPS updates till 23 Nov 2013
+ Contact history has now a much more efficient storage for polydisperse systems
+ Fixed various minor memleaks and fixed a number of LAMMPS bugs
+ Added a clear error message when mesh was unfixed while dump mesh/stl was active
+ Fixed some bugs in fix massflow/mesh
+ Fixed an issue where the sjkr2 cohesion mode was not applicable to granular walls.
Known issues:
+ Restart functionality is still showing some issues
Backward comaptibility:
No restart backward compatibility to LIGGGHTS 2.X
Input script syntax was changed. Details to be found in doc/liggghts_3.X_tutorial.html