LIGGGHTS® - User Forum

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

Insert/stream error

Submitted by abdelmalek.bellal on Mon, 06/14/2021 - 05:37

I spent a lot of time on this error but I could not solve it:
ERROR: Fix insert/stream (id ins): unknown keyword or wrong keyword order (../fix_insert_stream.cpp:151)

This my code:

#region and insertion
group nve_group region reg
fix ins nve_group insert/stream seed 49979687 distributiontemplate pdd1 vol ${alphastart} 200 region inbox

I attached the script, I need also help in defining the possible errors in this code I want to create the model shown in the attached figure

ADFORCE

Submitted by Kashminder on Sat, 06/12/2021 - 00:06

I am trying to use a adforce command to apply a stoke's drag force on a single particle using the following syntax

atom_style granular
atom_modify map array
communicate single vel yes

boundary f f f
newton off
units si
#region reg sphere 0.1 0.1 0.1 0.4 side out
#region reg block -0.05 0.05 -0.05 0.05 0. 0.15 units box
#create_box 1 reg
region reg block -0.005 0.005 -0.005 0.005 0.000 0.002 units box

read_data velo

#processors 2 2 1

Compute used in variable between runs is not current

Submitted by Kashminder on Wed, 06/02/2021 - 19:56

I am using compute like this

compute kash all property/atom z

compute kashi all property/atom x

compute kish all property/atom y

variable b equal c_kash[1]

variable p equal c_kashi[1] #r

And I am getting an error "Compute used in variable between runs is not current. Use the update_on_run_end option for computes to avoid this". I want to Know how and where to use the update_on_run_end option. in Variable command or in compute command above variable.

Time dependent move rotate

Submitted by jagan1mohan on Wed, 06/02/2021 - 17:00

Hello All, I have a question on fix move rotate command in LIGGGHTS. Setup has a drum made up of particles, closely placed so that there is no gap.

I'm first using
fix wall particleWall freeze to freeze particles and then using
fix particleWallRotate particleWall move rotate 0.0 0.0 0.0 0.0 0.0 1.0 0.05 to rotate wall with a constant period of 0.05 sec.
This is working okay.

If command error

Submitted by Kashminder on Tue, 06/01/2021 - 14:50

I am using a If command (if "${b} <= ${bod1}" then "variable bod1 equal v_b") and getting an error (Compute used in variable between runs is not current. Use the update_on_run_end option for computes to avoid this.) I am trying to define update on run. when i try to do that they say illegal variable command. how and where to define update on run in variable defined in if command. I have defined variable like this (variable bod1 equal 1e-5) (variable b equal c_kash[1] ) (compute kash all property/atom z ). Can you please help me editing these commands to get rid of an error.

Periodic Boundary Condition for Cylindrical Geometries Possible?

Submitted by berlinphoenix on Mon, 05/17/2021 - 10:37

Hi all,

i have a cylindrical shear cell geometry. In order to lower the computational cost i want to use periodic boundaries. I know that i can not unfortunately use "pie slices" (sorry if thats not the correct term) only boxes. The geometry has the be able to rotate also to simulate shearing.
Is there a way to simulate half of the shear cell with a cartesic periodic boundary approach? How can set this up? Are there any other possibilities to reduce computational time i can think of?

Thanks a lot this forums helps tremendously.
Kind regards

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