LIGGGHTS® - User Forum

I've had some questions about applying coarse-grain models in LIGGGHTS public version. I would like to put a self-defined coarse grain ratio into the formula in the code. When I checked the normal contact and force model in the code, I happened to notice that there are serval keywords related to the coarse-grained model, such as:
class Force : protected Pointers {
friend class Coarsegraining;

I'm trying to install LIGGGHTS using intel compilers. I get an error that a simple MPI program cannot be compiled while using $make auto. After manually entering the include and lib paths in Makefile.user, I still get the same error. I tried compiling with $make mpi and just replacing mpic++ with mpiicpc in Makefile.mpi, which worked. While this workaround works, it would be nice to figure out what's going on with make auto. Does anybody have any ideas as to what's going on?

Hey everyone,

I'm using DEM for the first time and I have some troubles using the lpp/pizza postprocessing package.

when I'm running the lpp.py script in my post directory where the dumo files are located I get following error:

"python lpp.py
File "lpp.py", line 45
raise ValueError "Invalid or no argument given for chunksize"
^
SyntaxError: invalid syntax"

Is it a problem becaus of python2 and 3? Or what is the main issue I'm facing here?

Hi all,

Is it possible to drop a CAD file under the action of gravity? For example, I would like to drop a sphere CAD file into a bed of particles. I would like to see the depth at which the sphere stops moving.

I looked at the "movecad" command, but it seems like it is actively driving the CAD file with set kinematic parameters. But I want my CAD to start from rest, fall into bed of particles, and stop naturally by the action of the particles resisting. Is this possible?

Best,
Brian

We seem to have developed a segmentation fault on our CENTOS 8 system. Everything was working fine, then all of a sudden we started getting seg faults on our scripts. I've tried downloading a fresh copy of LIGGGHTS and recompiling with $make auto, and I've reinstalled openmpi and openmpi-devel, but we're still getting the same faults. I'm unable to even run the examples. Has anyone had a similar problem?

output from running cohesion :

Hi
I am doing triaxial test simulation. I want to use radius expansion method to prepare initial configuration of particle. Is there any such command in LIGGGHTS.
I am using LIGGGHTS 3.7.0 version

Hi Everyone,

Is there anyway to get ONLY the pair contact stresses without considering the kinetic energy contribution and others ?

I have used the compute stress/atom , but this includes the other contribution of stresses as well as mentioned in the doc.

Thanks

Khan

Hello,

I am trying to read a dump file to start a new simulation using the atom locations and velocities from a previous simulation.

I am using the compute cluster/atom with a distance of 10 times the radius of my atoms. However, I am getting an error because my cluster/atom cutoff is longer than my pairwise cutoff distance.

I have two questions:
1) How do I increase the pairwise cutoff distance?

2) Will I run into potential errors by increasing the pairwise cutoff distance to a much larger value?

Dear all
I am using the following command to dump the particle information. I am interested total force acting on the particle including weight of particle and all interaction forces. For this I am using the following command.

------------------
dump dmp all custom/vtk ${nstep} post/two_wall/particle_*.vtk id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius
----------------

The above command dumps the value of forces as zero for most of the time. I am NOT sure about what LIGGGHTS is dumping as fx fy fz