LIGGGHTS® - User Forum

Hello,

My objective was to calculate coordination number for each atom in a system having two atom types. I wanted to calculate the coordination number for same type atom contacts for both groups and different type atom contacts also.

I have used the following compute:

compute 1 all coord/atom along with the "mix - yes or no" option to get selective outputs for coordination number by contacts between atoms of different types.

All,

When I am trying to compile LIGGGHTS with Makefile.g++VTK (as attached) then I am getting following error:
Please note it compiles finely without -DLAMMPS_VTK switch.

make[1]: Entering directory `/lustre/scratch/rsoni/LIGGGHTS/LIGGGHTS-PUBLIC-350-VTK/src/Obj_g++VTK'
g++ -g -O -DMPI_NO_CPPBIND -DLAMMPS_GZIP -DLAMMPS_JPEG -DLAMMPS_PNG -DLAMMPS_VTK -DMPICH_SKIP_MPICXX -DFFT_SCSL -l/usr/include/ -c ../dump_atom_vtk.cpp
../dump_atom_vtk.cpp:47:24: fatal error: vtkVersion.h: No such file or directory
#include


Hello,

I've built LIGGGHTS with the sphere package but have problem defining the pair_style between them. I checked the online documentation that the hertz contact requires torque and angular velocity given by atom_style and also per-atom radius, which I have no idea how to define for ellipsoid. I have not tried the hooke one yet but from the documentation I think it also only works for spherical particles. Any suggestion is greatly appreciated!

Thanks,
Liuchi

There should be three vtk files when I open paraview, but after trying to install CFDEM, only one exists now. When I run the test-case, I can't see particles now.

Hi

I'm new using LIGGGHTS.
I'd like to simulate a sand glass with LIGGGHTS. It works quite good for now, but i need a usable value for my sand's friction.

fix m4 all property/global coefficientFriction peratomtypepair 1 ??

If i had a Ra value, would it be possible to assess or even to compute the friction of my sand? (see the SEM picture)
Or has someone experience in simulating sand and knows a usable value?

something else:

Hello,

I am a user of LIGGGHTS and I am applying a high pressure (10% of the Young's modulus) through a servo wall.
After some time I have the loss of particles (from 10 to 100 out of 12000), but the simulation runs well for more than half its duration.
Why there is this problem? Is it solely due to the choice of the timestep?

I am choosing a timestep suitable for my properties, indeed I am doing a check and it is always positive and the simulation runs without problem at the beginning.

Thank you and have a nice day,
rob1

Hello LIGGGHTS users,

I'm trying to set up a heat source which changes with time. The documentation suggests that it should be possible to set up a time and/or space-dependent heat source by using the set command and using an atom-style variable. Space dependence works for me, but time does not. Below is a simple example of how I specify a time-dependent heat source:

variable H atom step
set atom * property/atom heatSource v_H

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?