LIGGGHTS® - User Forum

Hi!

I am using the compute pair/gran/local for working out the magnitude of the crossed interactions. However, I'm not able to put my output file, apart from the particles ID, the radius and velocities of each particle.

I can extract these values dumping with the "custom" style, but not extracting with a c_ID using the dump "local" style.

Thanks!

Hi All,

I want to print the diameter of a single atom. I am running into some trouble. Here is my logic:

#find the atom I want to measure
group one_atom id 3
#compute the diameter
compute diam one_atom property/atom diameter
#run the model for zero timesteps (or 1 ts, it doesn't make a difference)
run 0
#store the diameter
variable diameter equal c_diam[1]
print "diameter ${diameter}"

I get an error that says:
ERROR: Compute used in variable between runs is not current (variable.cpp:858)

Hi,

to differ moving particles from fixed, I am using fix store/state to store a displace/atom compute as per atom vector on different time steps. So I can make a dump after the last run with all displacements over several time steps and calculate the magnitude of all displacements.

...
compute disp all displace/atom
...
run...
...
fix disp1 all store/state 0 c_disp[1] c_disp[2] c_disp[3] c_disp[4]
...
run...
...
fix disp2 all store/state 0 c_disp[1] c_disp[2] c_disp[3] c_disp[4]
...


Dear all,
i'm trying to use the fix massflow/mesh with liggghts version 2.3.6 and get a segmentation fault after some timesteps. My setup to test and reproduce the message is a simple cube without a bottom or lid. Some atoms will be placed inside, fall down and leave the box throuth the bottom and re-enter the box from above (since there is a periodic boundry in z-axis).

I attached the testcase with my liggghts script, the logfile and two mesh files. Please remove the ".txt" extension before using it.

Many thanks in advance!

Cheers,
Daniel

Hi all,

When I perform a hybrid simulation (granular-peridynamics), I observe in the pair_gran_h*.cpp that the mass of the particle (rmass) is equal to the density.

If I try to fix the problem from the file loaded by the command read_data, it's worse !!!

So, if I compute the mass of the particle into the file pair_gran_h*.cpp, Do I have to take care to affect the good value of the mass in an other file ?

Or Have you a simple way to fix this problem ?

Thanks in advance for your request

Regards
JF

Hi!

I want to use some of the output variables of LIGGGHTS, such as fx or x, for a range of particle. I want to make some calculations in the input file for, finally, export them at the dump file.

However, I don't know how to call and store them in an array.

Thank you for your help!

Ramon

I tried to make one of my mesh accelerating with time, so after digging in documentation I found this fix move/mesh linear/variable, however whatever variable I tried to put I constantly had an error:

"Variable name 1 for fix move/mesh linear/variable does not exist"

an error comes from the file "mesh_mover.cpp" line 112 and it is natural consequence if something goes wrong in lines above.

Correct me if I am wrong but lines 97 to 110 in this file are not quite correct and as it is so, there always something is going wrong.

I have a question about pair_style. I'd like to simulate solid materials such as shale, clay, sand, and like this. I need to know what the appropriate pair_style for doing that is?

Another question is about integration. In my project I have to decrease temperature from X1 to X2. How can I do that?
And using "fix integer nvt/sphere temp X1 X2 DX" is true or not?

Thanks a lot for the response in advance.

For doing a project I face some unknowns.

The one is that I want to simulate crack propagation in shale (a type of
sand) and investigate crack pattern in shale if I decrease the temperature by LIGGGHTS. I need to know how I can decrease it (temperature of the simulation box)?

Second is that do you know the material properties of shale?

The easiest way is to fix the temperature of some particles, I need to know how I can set it to a certain temperature every few time-steps?

Thanks a lot for your attention in advance.

Sincerely,
Rasoul

Hello everybody!

I was running my first simulation in LIGGGHTS and it appears one error message when it is reading the mesh archive of the bottom of my geometry. The content is: