Hi,

I am trying to run a LAMMPS job for SiC. I studied the same script with 3 different boundary condition.

- boundary p p p
- boundary s s s
- boundary p p s

The part of the input script is as follows:

Hi,

I am trying to run a LAMMPS job for SiC. I studied the same script with 3 different boundary condition.

- boundary p p p
- boundary s s s
- boundary p p s

The part of the input script is as follows:

Hi,

I am trying to run a LAMMPS job for SiC. I studied the same script with 3

different boundary condition.

1. boundary p p p

2. boundary s s s

3. boundary p p sThe part of the input script is as follows:

------------------------------------------------------------------------

# SiC run

dimension 3

boundary p p p # ( s s s -OR- p p s)

units metalatom_style atomic

neigh_modify delay 5# create geometry

lattice custom 4.28 a1 1.0 0.0 0.0 a2 0.0 1.0 0.0 a3 0.0 0.0 1.0 &

basis 0.0 0.0 0.0 basis 0.5 0.0 0.5 basis 0.5 0.5 0.0 basis 0.0 0.5 0.5 &

basis 0.25 0.25 0.25 basis 0.75 0.25 0.75 basis 0.75 0.75 0.25 basis 0.25

0.75 0.75# define simulation domain

region domain block 0.0 40.0 0.0 40.0 0.0 40.0 units lattice# set simulation domain

create_box 2 domain# create atoms in domain region

create_atoms 2 region domain basis 1 1 basis 2 1 basis 3 1 basis 4 1

basis 5 2 basis 6 2 basis 7 2 basis 8 2#MASS

mass 1 28.0855

mass 2 12.0107# TERSOFF-ZBL potentials

pair_style tersoff/zbl

pair_coeff * * SiC.tersoff.zbl Si C# MINIMIZE

minimize 2.3e-16 1.0e-5 20000 20000dump 1 all custom 1 dump.SiC id type x y z

----------------------------------------------------------------------------------I noticed that for,

****************************

Case 1: boundary p p p

OUTPUT:

****************************

LAMMPS (6 Feb 2012)

Lattice spacing in x,y,z = 4.28 4.28 4.28

Created orthogonal box = (0 0 0) to (171.2 171.2 171.2)

2 by 3 by 4 MPI processor grid

Created 512000 atoms

WARNING: Resetting reneighboring criteria during minimization (min.cpp:167)

Setting up minimization ...

Memory usage per processor = 13.6247 Mbytes

Step Temp E_pair E_mol TotEng Press

0 0 -3294138.7 0 -3294138.7 -672.14628

1 0 -3294138.7 0 -3294138.7 -672.14628

Loop time of 1.50818 on 24 procs for 1 steps with 512000 atomsTHIS IS EXPECTED

****************************

Case 2: boundary s s s

OUTPUT:

****************************

LAMMPS (6 Feb 2012)

Lattice spacing in x,y,z = 4.28 4.28 4.28

Created orthogonal box = (0 0 0) to (171.2 171.2 171.2)

2 by 3 by 4 MPI processor grid

Created 521721 atoms

WARNING: Resetting reneighboring criteria during minimization (min.cpp:167)

Setting up minimization ...

Memory usage per processor = 11.236 Mbytes

Step Temp E_pair E_mol TotEng Press Volume

0 0 -3298761.6 0 -3298761.6 -2513.4624

5017793.7

(THE JOB IS STILL RUNNING)****************************

Case 1: boundary p p s

OUTPUT:

****************************

LAMMPS (6 Feb 2012)

Lattice spacing in x,y,z = 4.28 4.28 4.28

Created orthogonal box = (0 0 0) to (171.2 171.2 171.2)

3 by 2 by 4 MPI processor grid

Created 515200 atoms

WARNING: Resetting reneighboring criteria during minimization (min.cpp:167)

Setting up minimization ...

Memory usage per processor = 13.1259 Mbytes

Step Temp E_pair E_mol TotEng Press Volume

0 0 -3295684.2 0 -3295684.2

-1287.7371 5017782

2242 0 -3295904.8 0 -3295904.8

687.1991 5017782

Loop time of 14446.9 on 24 procs for 2242 steps with 515200 atomsFor 3 different boundary condition, I got 3 different values of the number

of atoms.

Case 1: boundary p p p ==> 512000

Case 2: boundary s s s ==> 521721

Case 3: boundary p p s ==> 515200Does initial value of the NUMBER OF ATOM in a simulation box depend on the

boundary condition?

yes. if you place your atoms *exactly* on the box boundary.

with "s" boundary lammps should accept the atom on both

sides, with "p" boundary only from one side.

axel.