LIGGGHTS® - User Forum

Hi,
I'm trying LIGGGHTS in parallel. For example:
mpirun -np 8 lmp_openmpi < in.case
When it starts it prints:
1 by 1 by 8 processor grid
The problems is that sometime it works well, sometime it crashes with this error:
ERROR on proc 0: Failed to allocate -1738615408 bytes for array neigh:binhead

For example it works well with:
communicate multi vel yes
units si
neighbor 0.001 bin
neigh_modify delay 0
variable radius1 equal 0.005 # m

It doesn't work with:
communicate multi vel yes

Hi,
I get error when I run simulation from restart file, the error message is :

......
ERROR: Could not locate a fix/property storing value(s) for coefficientRollingFriction

However, when I run simulation without MPI then it works fine (with restart).

Thanks,
Ram

Hello.
How to calculate the pressure and shear stress on a triangles of the mesh?
Is it the integral of the contact forces averaged by triangle's area?
Thanks.

Hi,
Is there a way to find total volume occupied by particles in simulation region during the run?
Thanks in advance,
Ram

Hi,

I'm doing some work relevant to the cohesion force. I'm confused with the cohesion model in LIGGGHTS. Could someone tell me what model and equations are used in the cohesion force in LIGGGHTS and what source files are implementing this model?

Thanks!

Jerry

Hello

I am having a problem installing LIGGGHTS... a very strange error...

I have used git to pull LIGGGHTS, but when compiling I get a whole list of errors going...
[root@Jay src]# make fedora
grep: cfd_regionmodel_*.h: No such file or directory
make[1]: Entering directory `/home/Jay/LIGGGHTS/myliggghts/src/Obj_fedora'
Makefile:93: region_cone.d: No such file or directory
Makefile:93: improper.d: No such file or directory
Makefile:93: ewald.d: No such file or directory
Makefile:93: fix_wall_gran_hooke.d: No such file or dir....
etc etc....

Hi
I have tried to run Chute_wear example but because of another problem (syntax error) I could not use the normal 3 line commands to change dump file to VTKs.so I did some changes inside the input file to outputs directly vtk files (instead of dump file) . after visualization with Paraview I see a Chute which in animation some moving triangles appear on the surface .so I doubt if it is the real simulation or I am missing something like some particles which I see just affect of them on the surface (without seeing themselves).

Hello,

I'm new in LIGGGHTS and would like to have a look at the input skript of "Particle segregation in a slot geometry".
Where can I obtain it, because I think it doesn't exist in the normal examples-folder, does it?

Cheers

I've done a simulation with three thousand granular particles in a container with a blade stirring them around. See video on the URL below:
https://docs.google.com/leaf?id=0B2EIcnb16wvuZWRmZWRiYTktMGQ4OS00OWMzLTk...

If you look closely, you see that some of the particle's got a "popping" behaviour, it's like small explosions shooting away some of the particles. What am I doing wrong?

Dear Liggghts users,

I have difficulties in defining an additional force due to a couette flow. Therefor I want to add a force depending on the atom position. I define a per atom variable "b" and I want to refer to it as "v_b" in the fix addforce.

I guess I didn't got the idea how to use per atom variables within fixes like addforce.
I attached a simple input file in which I summarized, what I have already tried.

Maybe someone can show me a working example of an addforce/setforce fix with per atom force values.

With kind regards,
Thomas Wagner.