62 lines
1.3 KiB
Plaintext
62 lines
1.3 KiB
Plaintext
# Demonstrate pair style base on sna/grid
|
|
# Check numerical forces
|
|
|
|
variable nrep index 3
|
|
variable a index 3.0
|
|
variable ngrid index 2
|
|
variable del index 0.1
|
|
variable fdelta index 0.0001
|
|
|
|
units metal
|
|
|
|
atom_modify map yes
|
|
|
|
# generate the box and atom positions using a BCC lattice
|
|
|
|
variable nx equal ${nrep}
|
|
variable ny equal ${nrep}
|
|
variable nz equal ${nrep}
|
|
|
|
boundary p p p
|
|
|
|
lattice custom $a &
|
|
a1 1 0 0 &
|
|
a2 0 1 0 &
|
|
a3 0 0 1 &
|
|
basis 0 0 0 &
|
|
basis 0.5 0.5 0.5 &
|
|
# origin 0.25 0.25 0.25
|
|
# origin 0.25e-3 0.25e-3 0.25e-3
|
|
|
|
region box block 0 ${nx} 0 ${ny} 0 ${nz}
|
|
create_box 1 box
|
|
create_atoms 1 box
|
|
mass 1 180.88
|
|
displace_atoms all random ${del} ${del} ${del} 12345
|
|
|
|
# define grid compute and atom compute
|
|
|
|
group snapgroup type 1
|
|
variable twojmax equal 2
|
|
variable rcutfac equal 4.67637
|
|
variable rfac0 equal 0.99363
|
|
variable rmin0 equal 0
|
|
variable wj equal 1
|
|
variable radelem equal 0.5
|
|
variable bzero equal 0
|
|
variable quad equal 0
|
|
variable switch equal 1
|
|
|
|
pair_style sna/grid grid ${ngrid} ${ngrid} ${ngrid} &
|
|
${rcutfac} ${rfac0} ${twojmax} ${radelem} &
|
|
${wj} rmin0 ${rmin0} bzeroflag ${bzero} &
|
|
quadraticflag ${quad} switchflag ${switch}
|
|
pair_coeff * * Al
|
|
|
|
fix fnum all numdiff 1 ${fdelta}
|
|
variable ferrsq atom (fx-f_fnum[1])^2+(fy-f_fnum[2])^2+(fz-f_fnum[3])^2
|
|
compute faverrsq all reduce ave v_ferrsq
|
|
thermo_style custom c_faverrsq
|
|
|
|
run 0
|