LIGGGHTS® - Developer Forum

Hello friends, I created an array in hooke model to dump vdw force components. The values are accumulating over time. Let us say, I have two particles that are coming closer, colliding, and moving away in 10 steps. Here are a few details.

step fvdw fc
1 0 0
2 0 0
3 non-zero 0
4 non-zero non-zero // Collision
5 non-zero non-zero // Collision
6 non-zero non-zero // Collision
7 non-zero 0
8 non-zero 0
9 non-zero 0
10 0 0

Hi,
I am working with liggghts to simulate the motion of a number of particles in a defined block. I have obtained some results for that, but I wanna see the initial condition effect on my result. To this end, I have changed the seed number in my insertion command

fix ins all insert/pack seed 32452843 distributiontemplate pdd1 vel constant 0. 0. 0. insert_every once overlapcheck yes all_in yes particles_in_region 417 region reg

Hi

I have a doubt in implementation of Hertz model in LIGGGHTS. The following code is implemented in LIGGGHTS to calculate Normal hertz stiffness.
---------------------------------------------------------------------
double kn=4./3.*Yeff[itype][jtype]*sqrtval;
---------------------------------------------------------------------

Hello team, greetings. I have added the van der Waals forces on the top of normal_model_hooke. I switch this force contribution via a flag "vdw on" in the input script in the pair style. Everything is working fine and I could match results from an article. In the dump, when we use fx fy fz, the output is the sum total of all the forces acting on each of the particles. How can we create a new set of variables say vdwx vdwy vdwz which has only vdw contribution for post-processing? Thank you, Jagan Mohan.

Is there any method to clear the RAM during the execution of LIGGGHTS program?
Currently, I am using an octa-core CPU with 8GB of RAM and it has been exhausted in the middle of the program.

Hello Team, greetings. I'm trying to account for the van der waals forces in my simulation. In order to that

1. I first started with copy-pasting and editing the existing cohesion model and very soon found that ".is_wall" in surfacesClose( ) is always false. That means, it does not detect the presence of walls. There is also a post on this and its implementation is in progress.

Hey all,
I just wanted to know that whether LIGGGHTS-Public is compatible with GPU or not? Is there any process to install LIGGGHTS using GPU? Does the premium version support GPU? Any information will be too useful for me.
Thanks in advance.

Best regards,
Tarun
Research Scholar
IIT KGP, India

Dear Forum,

Looking at the architectural similarity of both LAMMPS and LIGGGTHS codes, I was wondering at their compatibility when it comes to modifying or extending one software with already existing code of the other software. In particular, I am interested in taking a particular case for the superquadric particles (ellipsoids). which are already implemented in LAMMPS, and using the LIGGGTHS modules for contact detection to implement a hooke or GH pair potential in LAMMPS. That way it would be possible to perform CGMD calculations by using an hybrid pair gayrberne/hertz.

Hello,
I am adding code to the insert function of the particleToInsert class.
It is working for sparse insertions but hits a segmentation fault error once it starts to get dense.

I have started to block in segments of code and have narrowed down where it breaks. The issue is that it breaks between two fprintf statements...

I have a few questions that will hopefully narrow down where the issue is.
As spheres are added, via the create_atoms function, do all arrays also grow?
During particle insertion, do other function run as a different thread?

Hello every one...
i used Hertz contact model in my simulations in following form:
F=(Kn δn- γn Vn ) + (Kt δt- γt Vt )
The first term represents the normal force between two particles while the second term represents the tangential force. Here Vn and Vt are normal and tangential components of the relative velocity. The coefficients K_n, K_t, γ_n, and γ_t are calculated from the material properties.