../images/grain_growth.0.png ../images/grain_growth.3.png ../images/grain_growth.28.png

Commands & Concepts

  • Create lattice [1]
  • Initialize spin values
    • set (random or simple conditionals)
    • read sites (read file, e.g. DREAM3D)
  • Select app style: potts (a model for grain growth)
  • Select solve style: tree (stores event probabilities in binary tree)
  • Set kT: temperature/energy relevant to potts model
  • Request output text/images for analysis
  • Choose diag style
    • energy (running energy tally for entire lattice)
    • cluster (very useful: compute cluster volumes, centroids)

spparks input file

  • Run spparks:

    #!/bin/bash
let N=128, 256
let Q=2048
kT="0.85"
spk_flame.gnu -var kT $kT -var N $N -var Q $Q < grain_growth.in

  • Download 'grain_growth.in'

    # SPPARKS 'potts' model for modeling 'grain' growth
# let N=128, 256
# let Q=2048
# kT="0.85"
# spk_flame.gnu -var kT $kT -var N $N -var Q $Q < grain_growth.in

seed		 56897

# Use 'Potts' app to simulate grain growth;
# Site 'spins' can assume values of its nearest neighbors.
app_style	 potts/neighonly ${Q}

# 2d lattice; Each site has 8 neighbors
dimension	 2
lattice		 sq/8n 1.0

# Define lattice extent called 'square'; 
region		 square block 0 ${N} 0 ${N} -1.0 1.0

# Define 'axis' aligned simulation domain on 'square'
create_box	 square

# Creates sites on lattice defined above; 
# Also creates neighborhood list for each site
create_sites     box

# Initializes sites randomly with values between 1 and {Q}
set site range 1 ${Q}

# Simulation temperature; Units of energy
temperature	 ${kT}

# KMC solver
solve_style      tree
# sectors are required to run 'tree' kmc in parallel
sector yes

# Diagnostic style energy computes the total energy for all sites
diag_style       energy

# Print diagnostic information to screen 50 steps 
stats            50.0

# Write snapshot of site values 
#   to 'grain_growth.dump' every 50 steps
dump  1 text  50.0 grain_growth.dump
# Write 'cluster/grain' diagnostics
diag_style       cluster stats no delt 50.0 filename grain_growth.cluster

# Write 'image'; see 'dump' documentation
dump grain_growth_image image 50 grain_growth.*.jpg site site crange 1 ${Q} drange 1 1 view 0.0 0.0 boundary site 1 shape cube box no 1 zoom 1.95 size 512 512
dump_modify grain_growth_image boundcolor black backcolor white pad 4 

# Run for 1400 *spparks* steps
run              1400.0
[1]../images/cubic_lattice_bcc1.gif

https://www.uwgb.edu/dutchs/symmetry/bravais.htm