LIGGGHTS® - User Forum

Hi everyone,

I am a new user to liggghts and applying the packing problem in the examples to practise. In a case, I want to know the equivalent, or saying apparent, pressure of the packing system in x, y, z direction. I find that in the thermo_style command the pij may give the quantity. however, in the source code, it doesn't have those option actually, resulting in a error when I add them as the keyword.

Can anyone suggest me how to get the equivalent pressure or force for a packing in xyz directions.

Thanks
Weijing

Hi there, I've been experiencing a little bit with LIGGGHTS for the last weeks. I could get the software installed and running. The tutorial and the test cases available were of great help.

Right now my "problem" is how to run a simulation parallelly. I'm aware of the "processors" command and made this change to one of the input files I'm handling:

processors 2 2 2

Besides that, to launch LIGGGHTS I issue this command:

$ mpirun -np 8 /lmp_fedora -in input_file

So, is it enough to get the simulation running parallelly?

I've been looking for some documentation on the "characteristic" velocity used in the Hooke contact model. I have a simulation that is essentially a hopper filling/draining problem, but I also have the particles fall on and impact different surfaces once they leave the hopper. Thus, I have 2 different characteristic velocities in my simulation:

1. The very low velocities present in the hopper
2. The relatively higher velocities the particles have when they strike the surfaces outside the hopper.

Hi All,

I am doing some hopper flow discharge simulation of granular material. The hopper is fitted with a "stopper" at the discharging outlet. I want to periodically open the stopper (translation motion) from closed position to fully open within say 10 seconds of simulation time.

Which command do I use to allow the "stopper" fix to open periodically.

I look forward to your help.

Regards,

Theo_Score

Hallo,

in order to use the fix bond/create and fix bond/break command for my bond model i need the MC package, which is not available in LIGGGHTS-PUBLIC version 3.5 . Therefore, i have copied the MC file from LAMMPS (17 Nov 2015) stable version in my LIGGGHTS-PUBLIC src directory and tried to compile it using the command make g++. When i tried to compile it it gave the following error:

Hello,

I have coded an algorithm to generate multi-spheres to describe the shapes I need.

The problem I have now is that, since the spheres generating the multi-spheres are in the order of microns (10-60 microns) and use units SI, when I try to run the LIGGGHTS script I get the following error:

ERROR: Fix particletemplate/multisphere (id pts1): Volume expectancy too small. Change 'volume_limit' if you are sure you know what you're doing (../fix_template_sphere.cpp:447)

Hi,

Why Fix wall/gran and pair/gran allow only one compute of type wall/gran/local and pair/gran/local ???
I want to have normal contact force, tangential velocity and contact length (history) of a contact, simultaneously.

Hossein

Hallo LIGGGHTS expert,

i am using LIGGGHTS-PUBLIC version 3.5. I was wondering if i can install any packages which provides the tool to use the atom_style bond/gran style. If yes then can anyone tell me the procedure for that.

This will be great help for me.

Thanking You
Braj

Hi, I am installimg the public software for the first time in my computer and at first un error with mpi appeared but I was able to solve to then face an error with something about VTK, or so I think. the error message is the following:

I am having trouble extracting data using "compute multisphere". I added the line "compute multi all multisphere property xcm" to the in.multisphere example file just below the already-existing compute command. I then run in.multisphere through the python interface by typing:

from lammps import lammps
lmp=lammps()
lmp.file('in.multisphere')

The file ran fine on 1 processor and all output seemed normal. Then I attempted to extract the value from the compute by typing: xcm = lmp.extract_compute('multi',1,0).