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Rbox manual
NAME
rbox - generate point distributions for qhull
SYNOPSIS
Command "rbox" (w/o arguments) lists the options.
DESCRIPTION
rbox generates random or regular points according to the
options given, and outputs the points to stdout. The points
are generated in a cube, unless 's' or given. The format of
the output is the following: first line contains the dimen-
sion and a comment, second line contains the number of
points, and the following lines contain the points, one
point per line. Points are represented by their coordinate
values.
EXAMPLES
rbox 10
10 random points in the unit cube centered at the ori-
gin.
rbox 10 s D2
10 random points on a 2-d circle.
rbox 100 W0
100 random points on the surface of a cube.
rbox 1000 s D4
1000 random points on a 4-d sphere.
rbox c D5 O0.5
a 5-d hypercube with one corner at the origin.
rbox d D10
a 10-d diamond.
rbox x 1000 r W0
100 random points on the surface of a fixed simplex
rbox y D12
a 12-d simplex.
rbox l 10
10 random points along a spiral
rbox l 10 r
10 regular points along a spiral plus two end points
rbox 1000 L10000 D4 s
1000 random points on the surface of a narrow lens.
rbox c G2 d G3
a cube with coordinates +2/-2 and a diamond with coor-
dinates +3/-3.
rbox P0 P0 P0 P0 P0
5 copies of the origin in 3-d. Try 'rbox P0 P0 P0 P0
P0 | qhull QJ'.
r 100 s Z1 G0.1
two cospherical 100-gons plus another cospherical
point.
100 s Z1
a cone of points.
100 s Z1e-7
a narrow cone of points with many precision errors.
OPTIONS
n number of points
Dn dimension n-d (default 3-d)
Bn bounding box coordinates (default 0.5)
l spiral distribution, available only in 3-d
Ln lens distribution of radius n. May be used with 's',
'r', 'G', and 'W'.
s cospherical points randomly generated in a cube and
projected to the unit sphere
x simplicial distribution. It is fixed for option 'r'.
May be used with 'W'.
y simplicial distribution plus a simplex. Both 'x' and
'y' generate the same points.
Wn restrict points to distance n of the surface of a
sphere or a cube
c add a unit cube to the output
c Gm add a cube with all combinations of +m and -m to the
output
d add a unit diamond to the output.
d Gm add a diamond made of 0, +m and -m to the output
Pn,m,r
add point [n,m,r] to the output first. Pad coordinates
with 0.0.
n Remove the command line from the first line of output.
On offset the data by adding n to each coordinate.
t use time in seconds as the random number seed (default
is command line).
tn set the random number seed to n.
z generate integer coordinates. Use 'Bn' to change the
range. The default is 'B1e6' for six-digit coordinates.
In R^4, seven-digit coordinates will overflow hyper-
plane normalization.
Zn s restrict points to a disk about the z+ axis and the
sphere (default Z1.0). Includes the opposite pole.
'Z1e-6' generates degenerate points under single preci-
sion.
Zn Gm s
same as Zn with an empty center (default G0.5).
r s D2
generate a regular polygon
r s Z1 G0.1
generate a regular cone
BUGS
Some combinations of arguments generate odd results.
Report bugs to qhull_bug@geom.umn.edu, other correspondence
to qhull@geom.umn.edu
SEE ALSO
qhull(1)
AUTHOR
C. Bradford Barber
c/o The Geometry Center
400 Lind Hall
207 Church Street S.E.
Minneapolis, MN 55455
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Comments to: qhull@geom.umn.edu
Created: Sept. 25, 1995 --- Last modified: Jan. 8, 1998