LIGGGHTS® - User Forum

Hi Christoph,

I was looking at the pour command and had two questions:

1) Is it possible to specify a rate of particle generation? i.e. say I want to create N particles/second. Other than trying to size my region where the particles are to be created to fit this rate, how could I go about this?

Dear all,

I wondered if anyone knows if it is possible to run LIGGHTS on Mac OS X 10.6 using the terminal (downloaded with the developer tools)? If so, could you please let us know step-by-step how you preformed the installation?

I seem to be having problems with the required packages, in particular I am unable to find a version of fftw3-devel which will install on a mac. I am told it is required for the fftw.h header file and I see the program fails after I type "make mac" with the message:

fft3d.h:164:18: error: error fftw.h no such file or directory
make[1]: *** [pppm.d] Error 1

Hi Everybody,

I'm running a larger big simulation (~150k particles) with granular interactions. Most other simulations wotk fine on my system, but this one simulations crash allways after exactly 320000 steps with this errors:

[prometheus:28676] *** Process received signal ***
[prometheus:28676] Signal: Bus error (10)
[prometheus:28676] Signal code: (2)
[prometheus:28676] Failing at address: 0xc
[prometheus:28674] [ 0] 2 libSystem.B.dylib 0x94fe42bb _sigtramp + 43
[prometheus:28674] [ 1] 3 ??? 0xffffffff 0x0 + 4294967295

Hi,
If I resize the mesh or change its position in simulation box then LIGGGHTS can not pour particles into box correctly or pour a little particles. Sometimes poured particles have "nan" energy and angular momentum due to resizing. However, I have kept a minimum distance between the wall and the insertion region that is equal to maximum particle radius + half the neighbor skin. What is meant by wall here? wall of mesh or wall of the simulation box?
Thanks...

Ram

Hello!
When I try to use the "fix viscous" command AND the "dump stl" command I get an ERROR: Dump stl can not process all fixes of type mesh/gran, boost nFixMeshGran in dump_stl.cpp and recompile

The same input file without "dump stl" OR without "fix viscous", respectively, works fine.

Christian

Hi Christoph!

Is there an estimation when the new features (e.g. non-spherical particles, ...) will be available for public?

Best regards,
Christian

Dear LIGGGHTS users!
When I run LIGGGHTS with more than one processor I get following errors, however, there is no errors but warnings when I use single processor....
1) errors for more than one processor: -

[ram@localhost stress]$ mpirun -np 4 lmp_l

Hello everybody,

I hope not to bother you too much with this, but i'm in some kind of dead end. I simply don't know whats going wrong. I'va made a little example to get used to the Liggghts features (see below). A 1*1*1 Box with particles falling in z direction and a pyramid structure at the bottom. The particles should fall against the sides of the pyramid and roll down. but instead they just ignore the pyramid and land on the lower wall of the box.

Would be great if you could point out my mistake (I am pretty shure there is one)

Regards,
Martin Koester

pyramid structure:

Hi!

Maybe this should go to the LAMMPS mailing list but I'm using LIGGGHTS ... :) Mainly for information:
Is it a bug or intended behavior that there can be a linear motion when using fix move/mesh/gran rotate?

#Example:
atom_style granular
dimension 3
boundary m m m
newton off
communicate single vel yes
units si
region R_gesamt block -0.05 0.05 -0.05 0.05 -0.15 0.15 units box
create_box 1 R_gesamt
# Material properties
fix m1 all property/global youngsModulus peratomtype 2.63e5
fix m2 all property/global poissonsRatio peratomtype 0.27

Hello everyone,

from my first attemts i think liggghts is a very nice simulation environment for high numbers of particles. However i have some questions.

1) What programs do you suggest for designing the complex walls ? (open source would be best)

2) Is there a way or is it planned to create a way to generate data about the stress/strain situation for each particle?

regards,
Martin Koester