LIGGGHTS® - User Forum

LIGGGHTS® related topics can be discussed here: discussion about models, installation, feature requests and general discussion

Segmentation Fault

Submitted by SHUBHAM AGARWAL on Sun, 01/24/2021 - 21:34

Hi
I have re-installed LIGGGHTS-flexible fibers version (https://github.com/schrummy14/LIGGGHTS_Flexible_Fibers.git) on my win10 pc using Ubuntu app. After compilation I am able to run the tutorial examples, however, when I try to run model for my problem, I get the following error.
Strange thing is that I was able to run the same code before. Also, my PC has 12 cores but I am not able to allocate more than 5 cores for the run. All the above problems were not there previously.

neighbor multi for granular systems

Submitted by June on Sun, 01/24/2021 - 06:11

Dear LIGGGHTS users,

In my granular systems, the largest particle diameter is 50 times the smallest particle diameter, and it is inefficient to use a single set of bins. For example, the simulation time of a mono disperse particle system is much shorter than that of binary particle system with the same particle number.

use the the variable command to flag specific atoms to exclude from a group

Submitted by zpy2021 on Tue, 01/19/2021 - 08:04

Dear LIGGGHTS users!
I want to use the variable command to include and exclude the specific particles from a group, and I used the similar commands like that in the Docs as following:

compute 1 all pe/atom
compute 2 all reduce sum c_1
thermo_style custom step temp pe c_2
run 0
variable eatom atom "c_1 > -3.0"
group hienergy variable eatom

errors with neighbor multi

Submitted by June on Mon, 01/18/2021 - 07:13

Dear LIGGGHTS users,

I am simulating packing systems with a very wide range of particle size, and use "neighbor 0.002 multi"+"communicate multi vel yes". However, the output kinetic energy and pressure are both zero. When using "neighbor 0.002 bin"+"communicate single vel yes", the output kinetic energy and pressure are not zero.

Could you please tell me the reason?
Any help will really be appreciated.

Best wishes
June

Stress/atom for superquadric particles

Submitted by RonMexico on Fri, 01/08/2021 - 18:04

I have been running simple shear stress simulations in LIGGGHTS using moving layers of particles along the top and bottom of the domain to mimic a Lees-Edwards boundary condition. I am able to get reasonable agreement with kinetic theory for normal and shear stresses for spherical particles using the compute stress/atom command. However, when I create spherical superquadric particles to run the same cases, I would expect very close to the same, exact result.

Energy minimization

Submitted by June on Fri, 01/08/2021 - 10:19

Dear LIGGGHTS users,

I want to relax the packing system statistically by minimizing the energy, and used the command "minimize 1.0e-4 1.0e-6 10000 100000".
The error message is "Minimization could not find thermo_pe compute". The manual explains this error as "This compute is created by the thermo command. It must have been explicitly deleted by a uncompute command". But I have not deleted this compute.

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