Command line

Installing the package also installs the spheropack command.

# 1000 spheres of diameter 1 in a periodic box of edge 10, packed until jammed
spheropack pack -n 1000 --box 10 --density max --seed 1 -o packing.csv

# a slab with walls in z, target density 0.55, polydisperse radii from a file
spheropack pack --radii-file radii.txt --box 10,10,20 --walls z --density 0.55 -o slab.csv

# 2D, 500 disks in a channel with walls in y
spheropack pack -n 500 --dim 2 --box 30,20 --walls y --density max -o disks.csv

The output is CSV with one sphere per line, x,y,z,r (x,y,r in 2D), with a header line; --format plain omits the header, --format legacy writes z,x,y,r without header. A summary of the run goes to standard error. The exit status is 1 when the target was not reached. spheropack pack --help lists all options, including the stopping criteria (--jammed-pressure, --max-pressure, --max-collisions, --timeout) and --growth-rate (see The growth rate).

Legacy tool

spheropack legacy-periodic replaces the legacy generate_periodic_packing: same options, same output format (z,x,y,r), and --growth_rate with its legacy meaning (a rate in 1/time, converted to the dimensionless growth rate as \(\Gamma = g\,d/2\)). It uses the legacy collision rule, so existing scripts give statistically the same packings, and like the legacy tool it does not stop on the pressure (only after \(10^5\) collisions per sphere). spheropack legacy-tube does the same for generate_packed_tube (tube axis in the first output column). Both accept --collision-rule elastic_growing, which never gets stuck and is faster, at the price of a slightly different structure next to walls.

spheropack legacy-tube --num_part=725 --part_diam=3e-3 --tube_diam=21e-3 \
    --tube_length=0.0599 --growth_rate=106.67 --seed=1 --file=tube.dat
spheropack legacy-periodic --num_part=50 --part_diam=3e-3 --box_size=0.0153 \
    --growth_rate=106.67 --seed=1 --file=periodic.dat --copy_periodic