LIGGGHTS 2.2 released

ckloss's picture
Submitted by ckloss on Mon, 10/08/2012 - 16:00

LIGGGHTS 2.2: (released 8 October 2012)

A couple of updates and improvements for surface mesh import and handling:
+ LIGGGHTS is now more stringent in how STL meshes are checked upon loading by fix mesh/surface. More quality checks and according error/warning messages were added to check for corrupt/numerically bad meshes upon import into LIGGGHTS. Criteria that are now checked for are duplicate elements, coplanar overlapping elements, element aspect ratio, number of neighbors per element, mesh elements leaving the domain and a curvature sanity check. For all these changes, see doc for fix mesh/surface for further details.
+ Also, for each issue, LIGGGHTS now indicates the exact line number in the STL file where the problem happens (LIGGGHTS 1.5 did give approximate locations in the file).
+ Added a 'heal auto_remove_duplicates' function to fix mesh/surface that tries to repair a geometry that suffers from duplicate elements.
+ Keyword 'accuracy' for fix mesh/surface was renamed to 'precision'.
+ A new keyword 'verbose' for fix mesh/surface to control the verbosity of warnings and outputs.
+ Added a new fix mesh/surface/planar with additional functionality for planar meshes.
+ Added a "region" keyword to dump mesh/stl that allows the user to dump just these mesh element where the element center is in the specified region.
+ Niels Dallinger (Chemnitz UT) contributed "viblin" and "vibrot" styles for fix move/mesh. These mimic mesh movements which are are typically used e.g. for vibratory conveyors. Thanks for this contribution!
+ Fixed an inconsistency in the doc for fix move/mesh/rotate/variable. Keyword 'period' is renamed to keyword 'omega' as the number specified after this keyword is actually an angular velocity (as was stated correctly in the doc). Thanks to Stefan Amberger (JKU) for the note.
+ Fixed a bug in the fix neighlist/mesh routines that could - under rare circumstances - result in LIGGGHTS to hang. Thanks to M. Sandlin (Georgia Tech) for posting an example that showed this problem.

New features and improvements for particle insertion:
+ Added the missing 'all_in yes' functionality for fix insert/stream, which uses the aforementioned fix mesh/surface/planar. The new functionality should perform much better for large insertion meshes than the old method in LIGGGHTS 1.5.
+ Based on a contribution of Stefan Radl (Graz UT, thanks!), "vel uniform" and "vel gaussian" velocity options were added for the fix insert/pack, fix insert/stream and fix insert/rate/region commands.
+ Made random seeds for particle insertion processor-dependant so particle size distributions are covered more accurately for large # of processors for species that contain just few particles. Thanks to David Heine (Corning Inc) for the suggestion.

However, there are some restrictions in 2.2 (see below) which will be relaxed over time:
+ region tetmesh is not yet available
+ fix breakparticle/force is not yet available