LIGGGHTS® - Developer Forum

Hi everybody,

I'm wondering why rmass is not changing while I let my radii of the particles grow?
A logical reason might be, that rmass is calculated (by the formula 4/3*PI*radius^3) just once - at the beginning of the simulation.
Is that right?
Where can I find it in the code?

By the way:
What does the "r" mean in "rmass"? :)

kind regards,
Sebastian

Hi everybody,

I'd like to allocate memory in a fix for an array to store certain particle properties.

I thought I define the array within the headerfile with following line:

double *particle_prop_;

Then I wanted to allocate memory in the constructor of the fix, like:

int nlocal = atom->nlocal;
particle_prop_ = (double*)memory->create_1d_double_array(nlocal, 0,"particle_prop_");

and later I wanted to use the array in a method for some calculations.

Dear LIGGGHTS-Developers,

"insert/stream" is a command that can be used for granular simulation (example insert_stream). I would like to set up a similar simulation like the example "insert_stream" but for sph. The aim of this is to simulate a water jet that impacts on a wall.

For this reason it is necessary to modify the "particleToInsert.ccp/h" and some other files. I think the first things which have to be modified are the insertion properties in the "particleToInsert.h" file.

Is anybody familiar with an adjustment like that?

Hi,

I would like to make new two dimensional array for calculation of maximum contact area between particle and wall in each contact detection. I intend to modify form "contact_area" to "contact_area[i][npartners[i]-1] in "fix_wall_gran.cpp". How can I set two dimensional array?

Thanks,

Masa

I'm not quite familiar with physics and architecture of LIGGGHTS. Please, could you give me some basic reading about where should I put the code?

Hi

I would like to include a new material property (in this case "yield stress") into the Hertz-History model. Could you tell me which of the headers/cpp files I need to modify.

Thank you

Hi,

I want to introduce new parameter to the LIGGGHTS code. I have tried to define the parameter but I couldn't that. So, first, I should understand, for example, how Young's modulus is got from LIGGGHTS code such as "in.cohesion" to inside of the LIGGGTHS code such as "pair_gran_hooke_history.cpp". Please tell me how to get parameters from LIGGGHTS code to inside or please tell me the flow of the variable from "in.cohesion" to "pair_gran_hooke_history".

Regards,

Masa

valgrind is a very useful memory debugger which can be used to find segfaults and other memory errors.
you can run it on ubuntu by

valgrind liggghts < in.script &> LOG

this will print debugging information into the LOG file. if you compile LIGGGHTS with the '-d' flag, it will also show you the code line which causes the trouble. if running in parallel, you should use

mpirun -np X valgrind liggghts < in.script &> LOG

Christoph

I have put together a sort-of-working sintering pair interaction, and now I would like to make a wall/gran/sinter fix to contain and compact my sintering particles. My pair/gran/sinter pair style is based on pair/gran/hooke/history/stiffness and so I have tried to simply re-create/re-name the wall/gran/hooke/history/stiffness to be compatible with my particles (since wall and particle interaction must be the same).

Hi Christoph!
Thanks for the new release! I noticed something in fix breakparticle/force-code, which is buzzing me. In the fix_breakparticle_force.cpp:362 v_ins is defined, but it is never used (?). Instead v_insert is used in set_x_v_omega(...) (fix_breakparticle_force.cpp:371), which is (0,0,0), if it is not given in start-up script. Correct me if I'm wrong, but shouldn't the created particles have a momentum conserved velocity, instead of zero velocity what they now have?

Thanks,
Timo