Table of contents
RANDSP - random sphere generator
randsp
< parameter-file >sphere-file
randsp
is a generator of spheres with random positions,
and optionally, random radii, which can be
processed by the
spheres
program to produce a list of visible arcs, which
sphplt
in turn can plot to make a hidden-sphere image.
Input to
randsp
consists of one Fortran namelist group, $DATA
... $END, specifying option parameters.
When preparing namelist input, recall that Fortran
requires that the dollar sign prefixing the
namelist name must be placed in column 2, and
column 1 is ignored.
Within the namelist group, variable assignments
may occur in any order, separated by commas, with
arbitrary whitespace between tokens. Variable
assignments are done in order, so that in the
event of multiple assignments to the same
variable, the last one applies.
Defaults are always provided for all namelist
variables, so that an empty namelist group is
often sufficient.
The namelist variables are:
-
DSEED
-
Random number seed in the range 1 ... 2**31-2.
-
NSPHER
-
Number of spheres desired.
-
MODE
-
Set to 1 for uniform radii (default 0.05),
to 2 for random radii (default 0.05),
or 3 for uniform radii (default 0.05) scaled by perspective.
-
EYEDST
-
Distance of eye in front of screen (default 1.0).
-
RMIN, RMAX
-
Range of sphere radii.
-
XMIN, XMAX, YMIN, YMAX, ZMIN, ZMAX
-
Range of coordinates into which
sphere centers must fall in order to
be saved. Normally, these are
0.0, 1.0, 0.0, 1.0, but a smaller range
may be desirable for debugging
purposes.
The random number generator is invoked the same
number of times in each MODE selection, so that
the same set of
(x,y,z,r)
values will be generated in each mode. The same
starting seed is used so that successively larger
values of
NSPHER
will have common initial spheres; this can be
overridden by specifying different seed values in
the input.
This input file will generate 5 spheres of
uniform radii 0.2, with initial random number seed
5.
$DATA DSEED=5, NSPHER=5, RMIN=0.2, RMAX=0.2 $END
This input file creates 10000 spheres in an
origin-centered cube 20 units on edge, with radii
randomly varying from 0.1 to 1.0.
$DATA
MODE = 2,
NSPHER = 10000,
XMIN = -10, XMAX = 10,
YMIN = -10, YMAX = 10,
ZMIN = -10, ZMAX = 10,
RMIN = 0.1, RMAX = 1.0,
$END
plot79(1L),
plot79-intro(1L),
spheres(1L),
sphplt(1L).
Nelson H. F. Beebe, Ph.D.
Center for Scientific Computing
Department of Mathematics
220 South Physics Building
University of Utah
Salt Lake City, UT 84112
Tel: (801) 581-5254
FAX: (801) 581-4148
E-mail: <beebe@math.utah.edu>