LIGGGHTS® - Developer Forum

Hi, liggghts users~~
I want to know what the specific forces included in the dump fx fy fz for per-atom? Because I calculate contact force and weight for per-atom. They cannot match the fx fy fz. Anybody knows?

Thanks!!
xiaobaishu

Hello,

Sorry for the offtopic, but you developers probably will know. The new Intel Xeon Phi coprocessors can be used for liggghts? I mean, each one of the 60 cores of one coproccesor is seen as one core by openMPI? can I use mpirun -np 60 liggghts < in.example?

Thanks in advance, and best regards.

Hey,

I've added a spring-dashpot boundary. Therefor I extended the fix move/mesh to constrain a mesh with a spring-dashpot. Now I need also to output the actual position of the mesh. The calculation of the position is already done inside the liggghts code, but how can I output it to use it in a input script of liggghts. First I thought to look for the servo walls of liggghts, but I would like to have the position directly in the fix move/mesh command and if possible not in the fix mesh/surface/stress. Does someone tried something like this maybe already?

A special question to the developer:
let's assume a single ball lies on a plane surface exactly at the corner of 6 triangles.
The expected force contribution for a single triangle would be 1/6*f_pw (m*g=sum(f_triangle)).
Now for comprehensible reasions Liggghts only handles the first contact and than checks for all other triangles if there was an allready handled contact with a coplanar neighbour-triangle. This leads to correct wall-ball behaviour and is OK.

Hi,

I have a question about the functions initial_integrate and final_integrate from fix_nve_sphere. Where is the difference in the functions? When are these function used?

Thanks
Joshua

Hey,

I'm trying to rotate and translate a mesh. But I want the mesh to move in z-direction in the rotated system and not in the inertia system. So I'm doing 3 rotations with

mesh_->rotate(totalPhix_,incrementalPhix,axisx_,reference_point);
vectorScalarMult3D(axisx_,omegax_,omegaVecx);
mesh_->rotate(totalPhiy_,incrementalPhiy,axisy_,reference_point);
vectorScalarMult3D(axisy_,omegay_,omegaVecy);
mesh_->rotate(totalPhiz_,incrementalPhiz,axisz_,reference_point);
vectorScalarMult3D(axisz_,omegaz_,omegaVecz);

hey,

in my script I needed the variable f_total_[0],f_total_[1], f_total_[2] which is protected: in fix_mesh_surface_stress.

My script is running fine as long as Im not trying to use this variable.
To get this variable I put in the header of fix_mesh_surface_stress
friend class myclass;

In the header of myclass I have
class FixMeshSurfaceStress *mymesh;

up to here no segmentation fault does occur, but if I want to get the variable now with

Dear all,
I saw in the file neigh_gran.cpp, in the ´void Neighbor::granular_bin_no_newton_ghost(NeighList *list)´ part, there is

Dear All,

in the public version liggghts, the overestimated mass doesn't discount for the fix rigid command. Has some one implement this?
If i want to adapt the codes, which source file should i look at?

Thank you very much.

Best regards,

Zyan

Hi,

I want to define a new atom property using "fix property/atom" and then access it in cpp files by "find_custom( char *name, int &flag)".
Is there any inconsistency between "fix property/atom" and "compute property/atom" in LIGGGHTS?
I want to use them together but I get an error. It works fine in LAMMPS.

In LIGGGHTS, I use:

fix 1 all property/atom d_watomc scalar yes no no 0.0
run 0
compute 1 all property/atom d_watomc

but I get : "ERROR: Compute property/atom integer vector does not exist"

In LAMMPS :