

 
Manual Reference Pages  RBOX (1)
NAME
rbox  generate point distributions for qhull
CONTENTS
Synopsis
Description
Examples
Options
Bugs
See Also
Author
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 dimension 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 origin.

rbox 10 s D2
 
10 random points on a 2d circle.

rbox 100 W0
 
100 random points on the surface of a cube.

rbox 1000 s D4
 
1000 random points on a 4d sphere.

rbox c D5 O0.5
 
a 5d hypercube with one corner at the origin.

rbox d D10
 
a 10d diamond.

rbox x 1000 r W0
 
100 random points on the surface of a fixed simplex

rbox y D12
 
a 12d 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 coordinates +3/3.

rbox 64 M3,4 z
 
a rotated, {0,1,2,3} x {0,1,2,3} x {0,1,2,3} lattice (Mesh) of integer points.

rbox P0 P0 P0 P0 P0
 
5 copies of the origin in 3d. Try ’rbox P0 P0 P0 P0 P0  qhull QJ’.

r 100 s Z1 G0.1
 
two cospherical 100gons plus another cospherical point.

100 s Z1
 
a cone of points.

100 s Z1e7
 
a narrow cone of points with many precision errors.


OPTIONS
n

number of points

Dn

dimension nd (default 3d)

Bn

bounding box coordinates (default 0.5)

l

spiral distribution, available only in 3d

Ln

lens distribution of radius n. May be used with ’s’, ’r’, ’G’, and ’W’.

Mn,m,r

lattice (Mesh) rotated by {[n,m,0], [m,n,0], [0,0,r], ...}.
Use ’Mm,n’ for a rigid rotation with r = sqrt(n^2+m^2). ’M1,0’ is an
orthogonal lattice. For example, ’27 M1,0’ is {0,1,2} x {0,1,2} x {0,1,2}.

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 sixdigit coordinates. In R^4, sevendigit
coordinates will overflow hyperplane normalization.

Zn s

restrict points to a disk about the z+ axis and the sphere (default Z1.0).
Includes the opposite pole. ’Z1e6’ generates degenerate points under
single precision.

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@qhull.org, other correspondence to qhull@qhull.org
SEE ALSO
qhull(1)
AUTHOR
C. Bradford Barber
c/o The Geometry Center
400 Lind Hall
207 Church Street S.E.
Minneapolis, MN 55455
Geometry Center  RBOX (1)  August 10, 1998 
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