# Input file for part3d

# maximum number of particles to place (fewer will be used if they don't fit)
particles	1000000
# all particles have this radius and mass
rad		0.001
mass		0.0001

# to create a volume of particles: number, xstart, xend, ystart, yend, zstart, zend
#block		10000  0.8 1.0  0.0 1.0  0.0 1.0
# same block, but force particles to be non-intersecting
#niblock	10000  0.8 1.0  0.0 1.0  0.0 1.0
# or, a block in 2D
#block		10000  0.8 1.0  0.0 1.0
#niblock	10000  0.8 1.0  0.0 1.0

# or, create a block of randomly-placed particles in a sphere (num, center, radius)
#sphere		10000  0.5 0.5 0.5  0.2
# or, same but force non-intersecting
#nisphere	10000  0.5 0.5 0.5  0.2
# the same in 2D
sphere		1000000  0.0 0.0 0.0  0.7
#nisphere	5000  3.0 3.0  0.2

#galaxy 		10000  0 0 0  0 0 0

# to read in a list of particle positions from a file: filename,
#    translate x, y, z, and velocity add u, v, w
#read_part	output100.part	0.0 0.0 0.0  -1.0 0.0 0.0
# or in 2D (make sure to read in a file that was written in 2D mode, too!
#read_part	output100.part	0.0 0.0  -1.0 0.0

# to create a strand of spaghetti/cable/rope: length per particle, number of particles, E, xstart, xend, ystart, yend, zstart, zend
#strand 0.0025 1000 3.0e+10 0.45330993288 0.5406039187 0.0025  0.42679000056 0.55287886642 0.95
# we'd also reccommend a small dt for this contact sim:
# dt		0.000001

# set simulation dt lower for higher rk, E
# changed coeff. of friction, from 
dt		0.02
end_time	200.0
#end_time	0.2
output_dt	0.02		write output files this often

# octree parameters (20, 20 are decent settings for most 3D sims)
max_ppc		32		maximum number of particles per level
max_levels	20		maximum number of levels in octree, root=1

# apply r^-2 attraction force between all particles
use_self_grav	yes
G		0.00001		gravitation constant
# good to keep delta about the same as particle radius
delta		0.001		gravitation anti-discontinuity addend
# 1.5 gives about 1-2% accuracy, > is more accurate, do not use <0.75
theta		2.0		Barnes and Hut's theta parameter
direct		no		compare to direct method, compute errors

# apply earth-like, constant-vector gravity
use_uniform_grav no
g		0.0	0.0	-1.0
# or, in 2D
#g		0.0	-1.0

# use contact forces? set stiffness (rk) and damping (rc)
use_contact	no
rk		1.0e+5
rc		1.0e+3
contact_per_grav	1
# for strands, part3d will compute rk and b(ending) from E and r

# the outer bounds of the computational domain, particles outside of
#   this bound will be removed from the simulation
#comp_domain	-10.0 10.0  -10.0 10.0  -10.0 10.0
# or in 2D
comp_domain	-1.0 1.0  -1.0 1.0  -1.0 1.0

# some options on the output
#outfile_root	output_		add extra prefix to all output file names
#start_frame	1000		start output numbering at 1000
image_size	1024		resolution of all output images
image_depth	8		8 or 16 bits per pixel
density				create a density image
write_pgm	no		write in ASCII PGM
write_png	yes		call libpng to write png file
write_rad	no
write_part	no		can restart using these files