Geometry
Class Topology

java.lang.Object
  |
  +--Geometry.Topology

public class Topology

extends java.lang.Object

Builds the positions that can be randomly selected within the region it is associated with. The random distribution is based on the shape of the region; currently only wedges and toroids are supported. A bell curve with adjustable decay rate is applied to make positions nearer the center more probable than those at the edges.

Version:

Created 12 August 2003

Author:

Dan Tappan

See Also:

Region

Field Summary

private static float	CELL_BASE
static float	DEFAULT_DECAY_RATE
private int	GENERATION_BASE
private java.util.ArrayList	m_cell_list
private float[][]	m_generation_count
private float	m_max_generation_count
private Region	m_region
static int	NUM_CELL_SUBDIVISIONS
static int	NUM_RINGS
static int	NUM_SECTORS

Constructor Summary

protected	Topology(Region parent_region, float decay_rate) Creates a new topology for distributing random coordinates over a region.
protected	Topology(Region parent_region, Topology topology1, Topology topology2) Creates a new topology for distributing random coordinates over a region.

Method Summary

private void	createDistribution(float decay_rate) Creates a distribution of random coordinates over a region based on its shape.
private void	createToroidDistribution(int sector_start, int sector_end, int sector_center, int ring_start, int ring_end, int ring_center, float decay_rate) Creates a random distribution over a toroid-shaped region.
private void	createWedgeDistribution(int sector_start, int sector_end, int sector_center, int ring_start, int ring_end, int ring_center, float decay_rate) Creates a random distribution over a wedge-shaped region.
void	dumpActualDistribution(int sample_size) Dumps to stdout a list of actual random coordinates over a sample to show how an actual distribution corresponds to the predicted one.
void	dumpPredictedDistribution(boolean is_histogram_otherwise_gnuplot) Dumps to stdout a list of predicted random coordinates to show how an actual distribution should look.
private void	generateRandomList() Generates a list of random coordinates based on the distribution.
java.util.ArrayList	getCellMesh(int geometry_ring, int geometry_sector) Returns a list RegionCoordinates corresponding to the corners of all topology cells within a region cell.
protected float	getGenerationCount(int ring, int sector) Returns the number of random coordinates to generate for a topology cell.
static int	getNextSector(int sector) Returns the next topology sector number.
static int	getPreviousSector(int sector) Returns the previous topology sector number.
RegionCoordinate	getRandomCoordinate() Returns a random coordinate distributed over the topology.
int	getRandomPoolSize() Returns the number of random coordinates available.
static float	getRegionRing(int topology_ring) Returns the Region ring (or fraction thereof) corresponding to a Topology ring.
static float	getRegionSector(int topology_sector) Returns the Region sector (or fraction thereof) corresponding to a Topology sector.
static int	getTopologyRingLowerBound(int region_ring) Returns the smallest Topology ring corresponding to a Region ring.
static int	getTopologyRingUpperBound(int region_ring) Returns the largest Topology ring corresponding to a Region ring.
static int	getTopologySectorLowerBound(int region_sector) Returns the smallest Topology sector corresponding to a Region sector.
static int	getTopologySectorUpperBound(int region_sector) Returns the largest Topology sector corresponding to a Region sector.
private void	initialize() Initializes the topology.
private void	joinDistributions(Topology topology1, Topology topology2) Builds a new topology as the sum of two existing topologies.
java.lang.String	toString() Returns a string representation of this object.
java.lang.String	toString(boolean list_cells) Returns a string representation of this object.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

NUM_CELL_SUBDIVISIONS

public static final int NUM_CELL_SUBDIVISIONS

See Also:

Constant Field Values

CELL_BASE

private static final float CELL_BASE

See Also:

Constant Field Values

GENERATION_BASE

private int GENERATION_BASE

NUM_RINGS

public static final int NUM_RINGS

See Also:

Constant Field Values

NUM_SECTORS

public static final int NUM_SECTORS

See Also:

Constant Field Values

DEFAULT_DECAY_RATE

public static final float DEFAULT_DECAY_RATE

See Also:

Constant Field Values

m_generation_count

private float[][] m_generation_count

m_max_generation_count

private float m_max_generation_count

m_cell_list

private java.util.ArrayList m_cell_list

m_region

private Region m_region

Constructor Detail

Topology

protected Topology(Region parent_region,
                   float decay_rate)

Creates a new topology for distributing random coordinates over a region. The central tendency of the distribution is evenly down the center of a wedge or evenly riding around the high point of a ring. The measure of variability is normally defined as a bell curve (without standard-deviation constraints), but other distributions are possible.

Parameters:

parent_region - - the region this topology is associated with

decay_rate - - the decay rate of the distribution curve: 0=uniform, 1=concave, 2+=bell (larger produces a wider bell), negative=bimodal

Topology

protected Topology(Region parent_region,
                   Topology topology1,
                   Topology topology2)

Creates a new topology for distributing random coordinates over a region. This constructor is called only to build the topology for the result of the logical join of two regions.

Parameters:

parent_region - - the region this topology is associated with

topology1 - - the topology of the first region contributing to the join

topology2 - - the topology of the second region contributing to the join

Method Detail

createDistribution

private void createDistribution(float decay_rate)

Creates a distribution of random coordinates over a region based on its shape. Only wedges and toroids are currently supported.

Parameters:

decay_rate - - the decay rate of the distribution curve, as defined in the constructor

See Also:

Topology(Geometry.Region, Geometry.Topology, Geometry.Topology)

createToroidDistribution

private void createToroidDistribution(int sector_start,
                                      int sector_end,
                                      int sector_center,
                                      int ring_start,
                                      int ring_end,
                                      int ring_center,
                                      float decay_rate)

Creates a random distribution over a toroid-shaped region. The most likely coordinates appear through the center of the ring and taper outward to the least likely.

The distribution is based on the following equation (formatted for GnuPlot):

   plot [0:1] 100**-x**decay_rate * GENERATION_BASE + 1
 

Parameters:

sector_start - - the start sector

sector_end - - the end sector

sector_center - - the best-fitting center sector

ring_start - - the start ring

ring_end - - the end ring

ring_center - - the best-fitting center ring

decay_rate - - the decay rate of the distribution curve, as defined in the constructor

See Also:

Topology(Geometry.Region, Geometry.Topology, Geometry.Topology)

createWedgeDistribution

private void createWedgeDistribution(int sector_start,
                                     int sector_end,
                                     int sector_center,
                                     int ring_start,
                                     int ring_end,
                                     int ring_center,
                                     float decay_rate)

Creates a random distribution over a wedge-shaped region. The most likely coordinates appear down the center of the wedge and taper outward to the least likely.

The distribution is based on the following equation (formatted for GnuPlot):

   plot [0:1] 100**-x**decay_rate * GENERATION_BASE + 1
 

Parameters:

sector_start - - the start sector

sector_end - - the end sector

sector_center - - the best-fitting center sector

ring_start - - the start ring

ring_end - - the end ring

ring_center - - the best-fitting center ring

decay_rate - - the decay rate of the distribution curve, as defined in the constructor

See Also:

Topology(Geometry.Region, Geometry.Topology, Geometry.Topology)

dumpActualDistribution

public void dumpActualDistribution(int sample_size)

Dumps to stdout a list of actual random coordinates over a sample to show how an actual distribution corresponds to the predicted one.

This is for development use only.

Parameters:

sample_size - - the sample size

dumpPredictedDistribution

public void dumpPredictedDistribution(boolean is_histogram_otherwise_gnuplot)

Dumps to stdout a list of predicted random coordinates to show how an actual distribution should look.

This is for development use only.

getGenerationCount

protected float getGenerationCount(int ring,
                                   int sector)

Returns the number of random coordinates to generate for a topology cell.

Parameters:

ring - - the ring

sector - - the sector

Returns:

the number of coordinates. This is a float because it also serves as the elevation for generating a cell mesh

getNextSector

public static int getNextSector(int sector)

Returns the next topology sector number. This adds 1 to the current sector except when the last sector needs to wrap around to the first.

Parameters:

sector - - the sector

Returns:

the next sector number

getPreviousSector

public static int getPreviousSector(int sector)

Returns the previous topology sector number. This substract 1 to the current sector except when the first sector needs to wrap around to the last.

Parameters:

sector - - the sector

Returns:

the previous sector number

generateRandomList

private void generateRandomList()

Generates a list of random coordinates based on the distribution.

getCellMesh

public java.util.ArrayList getCellMesh(int geometry_ring,
                                       int geometry_sector)

Returns a list RegionCoordinates corresponding to the corners of all topology cells within a region cell.

Parameters:

geometry_ring - - the region ring

geometry_sector - - the region sector

Returns:

the list, which can feed into a Java3D QuadArray after coordinate manipulation

See Also:

RegionCoordinate

getRandomCoordinate

public RegionCoordinate getRandomCoordinate()

Returns a random coordinate distributed over the topology.

Returns:

the coordinate

getRandomPoolSize

public int getRandomPoolSize()

Returns the number of random coordinates available. If this is considered too small, increase GENERATION_BASE.

Returns:

the size

getRegionRing

public static float getRegionRing(int topology_ring)

Returns the Region ring (or fraction thereof) corresponding to a Topology ring. Since multiple topology cells exists within a single geometry cell, a fractional value is possible.

Parameters:

topology_ring - - the topology ring

Returns:

the region ring

getRegionSector

public static float getRegionSector(int topology_sector)

Returns the Region sector (or fraction thereof) corresponding to a Topology sector. Since multiple topology cells exists within a single geometry cell, a fractional value is possible.

Parameters:

topology_sector - - the topology sector

Returns:

the region sector

getTopologyRingLowerBound

public static int getTopologyRingLowerBound(int region_ring)

Returns the smallest Topology ring corresponding to a Region ring. Since multiple topology cells exists within a single geometry cell, there is no one-to-one correspondence in this conversion direction.

Parameters:

region_ring - - the region ring

Returns:

the lower-bounded topology ring

getTopologyRingUpperBound

public static int getTopologyRingUpperBound(int region_ring)

Returns the largest Topology ring corresponding to a Region ring. Since multiple topology cells exists within a single geometry cell, there is no one-to-one correspondence in this conversion direction.

Parameters:

region_ring - - the region ring

Returns:

the upper-bounded topology ring

getTopologySectorLowerBound

public static int getTopologySectorLowerBound(int region_sector)

Returns the smallest Topology sector corresponding to a Region sector. Since multiple topology cells exists within a single geometry cell, there is no one-to-one correspondence in this conversion direction.

Returns:

the lower-bounded topology ring

getTopologySectorUpperBound

public static int getTopologySectorUpperBound(int region_sector)

Returns the largest Topology sector corresponding to a Region sector. Since multiple topology cells exists within a single geometry cell, there is no one-to-one correspondence in this conversion direction.

Returns:

the upper-bounded topology ring

initialize

private void initialize()

Initializes the topology.

joinDistributions

private void joinDistributions(Topology topology1,
                               Topology topology2)

Builds a new topology as the sum of two existing topologies. This is used after logically joining two regions.

Parameters:

topology1 - - the topology of the first region contributing to the join

topology2 - - the topology of the second region contributing to the join

toString

public java.lang.String toString()

Returns a string representation of this object. Individual cells are not listed; to do so, use the other variant of this method.

Overrides:

toString in class java.lang.Object

Returns:

the String representation

See Also:

Support.toPrettyString(java.lang.String), toString(boolean)

toString

public java.lang.String toString(boolean list_cells)

Returns a string representation of this object.

Parameters:

list_cells - - whether the contents of each cell should be listed

Returns:

the String representation

See Also:

Support.toPrettyString(java.lang.String)