uchicago.src.sim.space
Class Diffuse2D

java.lang.Object
  uchicago.src.sim.space.Diffuse2D

All Implemented Interfaces:

Discrete2DSpace, Torus

Direct Known Subclasses:

Diffuse2DHexagonal, HeatSpace

public class Diffuse2D
extends java.lang.Object
implements Discrete2DSpace, Torus

Discrete 2nd order approximation of 2d diffusion with evaporation. Essentialy a java implementation of Diffuse2d in the Swarm simulation toolkit. Toroidal in shape and works with number values. This space simulates concurency through the use of a read and write matrix. Any writes to the space, write to the write matrix, and any reads to the read matrix. The diffuse() method then diffuses the write matrix and copies the new values into the read matrix.

For an example of a Diffuse2d space see the heatBugs example. See diffuse for a brief explanation of the diffusion algorithm.

Version:

$Revision: 1.5 $ $Date: 2004/11/03 19:50:57 $

Author:

Nick Collier

Field Summary

protected double	diffCon
protected double	evapRate
static long	MAX
static long	MIN
protected int	nextX
protected int	nextY
protected int	prevX
protected int	prevY
protected DoubleMatrix	readMatrix
protected DoubleMatrix	writeMatrix
protected int	x
protected int	xSize
protected int	y
protected int	ySize

Fields inherited from interface uchicago.src.sim.space.Discrete2DSpace

MOORE, VON_NEUMANN

Constructor Summary

Diffuse2D(double diffusionConstant, double evaporationRate, int xSize, int ySize)
Constructs a Diffuse2d space with the specified diffusion constant, evaporation rate, and dimensions

Diffuse2D(int xSize, int ySize)
Constructs a Diffuse2d space with the specificed dimensions

Method Summary

protected double[]	compareMax(double[] array)
protected double[]	compareMin(double[] array)
void	diffuse() Runs the diffusion with the current rates and values.
double[]	findMaximum(int x, int y, int range, boolean includeOrigin, int neighborhoodType) Finds the maximum grid cell value within a specified range from the specified origin coordinate.
double[]	findMinimum(int x, int y, int range, boolean includeOrigin, int neighborhoodType) Finds the minimum grid cell value within a specified range from the specified origin coordinate.
BaseMatrix	getMatrix() Gets the matrix collection class that contains all the values.
double[]	getMooreNeighbors(int x, int y) Gets the Moore neighbors of the specified coordinate. doubles are returned by row starting with the "NW corner" and ending with the "SE corner."
double[]	getMooreNeighbors(int x, int y, int xExtent, int yExtent) Gets the extended Moore neighbors of the specified coordinate.
java.lang.Object	getObjectAt(int x, int y) Gets the object (a Long) at the specified coordinate.
java.awt.Dimension	getSize() Gets the dimension of the space
int	getSizeX() Gets the size of the x dimension
int	getSizeY() Gets the size of the y dimension
double	getValueAt(int x, int y) Gets the value at the specified coordinate.
double[]	getVonNeumannNeighbors(int x, int y) Gets the von Neumann neighbors of the specified coordinate.
double[]	getVonNeumannNeighbors(int x, int y, int xExtent, int yExtent) Gets the extended von Neumann neighbors of the specified coordinate.
void	putObjectAt(int x, int y, java.lang.Object object) Puts the specified Object at the specified coordinate.
void	putValueAt(int x, int y, double value) Puts the specified value at the specified coordinate.
void	setDiffusionConstant(double diffusionConstant) Sets the diffusion constant for this Diffuse2d space
void	setEvaporationRate(double rate) Sets the evaporation rate for this Diffuse2d space
void	update() Copies the writeLattice to the readLattice
protected int	xnorm(int x) Normalize the x value to the toroidal coordinates
protected int	ynorm(int y) Normalize the y value to the toroidal coordinates

Methods inherited from class java.lang.Object

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

Field Detail

MAX

public static final long MAX

See Also:

Constant Field Values

MIN

public static final long MIN

See Also:

Constant Field Values

diffCon

protected double diffCon

evapRate

protected double evapRate

readMatrix

protected DoubleMatrix readMatrix

writeMatrix

protected DoubleMatrix writeMatrix

xSize

protected int xSize

ySize

protected int ySize

x

protected int x

prevX

protected int prevX

nextX

protected int nextX

y

protected int y

prevY

protected int prevY

nextY

protected int nextY

Constructor Detail

Diffuse2D

public Diffuse2D(int xSize,
                 int ySize)

Constructs a Diffuse2d space with the specificed dimensions

Parameters:

xSize - size of the x dimension

ySize - size of the y dimension

Diffuse2D

public Diffuse2D(double diffusionConstant,
                 double evaporationRate,
                 int xSize,
                 int ySize)

Constructs a Diffuse2d space with the specified diffusion constant, evaporation rate, and dimensions

Parameters:

diffusionConstant - the diffusion constant

evaporationRate - the evaporation rate

xSize - size of the x dimension

ySize - size of the y dimension

Method Detail

setDiffusionConstant

public void setDiffusionConstant(double diffusionConstant)

Sets the diffusion constant for this Diffuse2d space

setEvaporationRate

public void setEvaporationRate(double rate)

Sets the evaporation rate for this Diffuse2d space

diffuse

public void diffuse()

Runs the diffusion with the current rates and values. Following the Swarm class, it is roughly newValue = evap(ownValue + diffusionConstant * (nghAvg - ownValue)) where nghAvg is the weighted average of a cells eight neighbors, and ownValue is the current value for the current cell.

Values from the readMatrix are used to calculate diffusion. This value is then written to the writeMatrix. When this has been done for every cell in the grid, the writeMatrix is copied to the readMatrix.

update

public void update()

Copies the writeLattice to the readLattice

getVonNeumannNeighbors

public double[] getVonNeumannNeighbors(int x,
                                       int y)

Gets the von Neumann neighbors of the specified coordinate. doubles are returned in west, east, north, south order. The double at x, y is not returned.

Parameters:

x - the x coordinate of the object

y - the y coordinate of the object

Returns:

an array of doubles in west, east, north, south order

getVonNeumannNeighbors

public double[] getVonNeumannNeighbors(int x,
                                       int y,
                                       int xExtent,
                                       int yExtent)

Gets the extended von Neumann neighbors of the specified coordinate. The extension in the x and y direction are specified by xExtent and yExtent. doubles are returned in west, east, north, south order with the most distant object first. The double at x,y is not returned.

Parameters:

x - the x coordinate of the object

y - the y coordinate of the object

xExtent - the extension of the neighborhood in the x direction

yExtent - the extension of the neighborhood in the y direction

Returns:

an array of doubles in west, east, north, south order with the most distant object first.

getMooreNeighbors

public double[] getMooreNeighbors(int x,
                                  int y)

Gets the Moore neighbors of the specified coordinate. doubles are returned by row starting with the "NW corner" and ending with the "SE corner." The double at x, y is not returned.

Parameters:

x - the x coordinate of the object

y - the y coordinate of the object

Returns:

an array of doubles ordered by row starting with the "NW corner" and ending with the "SE corner."

getMooreNeighbors

public double[] getMooreNeighbors(int x,
                                  int y,
                                  int xExtent,
                                  int yExtent)

Gets the extended Moore neighbors of the specified coordinate. The extension in the x and y direction are specified by xExtent and yExtent. doubles are returned by row starting with the "NW corner" and ending with the "SE corner." The double at x,y is not returned.

Parameters:

x - the x coordinate of the object

y - the y coordinate of the object

xExtent - the extension of the neighborhood in the x direction

yExtent - the extension of the neighborhood in the y direction

Returns:

an array of doubles ordered by row starting with the "NW corner" and ending with the "SE corner."

findMaximum

public double[] findMaximum(int x,
                            int y,
                            int range,
                            boolean includeOrigin,
                            int neighborhoodType)

Finds the maximum grid cell value within a specified range from the specified origin coordinate.

Parameters:

x - the x origin coordinate

y - the y origin coordinate

range - the range out from the coordinate to search

includeOrigin - include object at origin in search

neighborhoodType - the type of neighborhood to search. Can be one of Discrete2DSpace.VON_NEUMANN or Discrete2DSpace.MOORE.

Returns:

the Objects determined to be the maximum.

compareMax

protected double[] compareMax(double[] array)

findMinimum

public double[] findMinimum(int x,
                            int y,
                            int range,
                            boolean includeOrigin,
                            int neighborhoodType)

Finds the minimum grid cell value within a specified range from the specified origin coordinate.

Parameters:

x - the x origin coordinate

y - the y origin coordinate

range - the range out from the coordinate to search

includeOrigin - include object at origin in search

neighborhoodType - the type of neighborhood to search. Can be one of Discrete2DSpace.VON_NEUMANN or Discrete2DSpace.MOORE.

Returns:

the Objects determined to be the maximum.

compareMin

protected double[] compareMin(double[] array)

getSizeX

public int getSizeX()

Gets the size of the x dimension

Specified by:

getSizeX in interface Discrete2DSpace

getSizeY

public int getSizeY()

Gets the size of the y dimension

Specified by:

getSizeY in interface Discrete2DSpace

getSize

public java.awt.Dimension getSize()

Gets the dimension of the space

Specified by:

getSize in interface Discrete2DSpace

getObjectAt

public java.lang.Object getObjectAt(int x,
                                    int y)

Gets the object (a Long) at the specified coordinate.

Specified by:

getObjectAt in interface Discrete2DSpace

Parameters:

x - the x coordinate

y - the y coordinate

Returns:

the Object at x,y

getValueAt

public double getValueAt(int x,
                         int y)

Gets the value at the specified coordinate.

Specified by:

getValueAt in interface Discrete2DSpace

Parameters:

x - the x coordinate

y - the y coordinate

Returns:

the value at x, y

putObjectAt

public void putObjectAt(int x,
                        int y,
                        java.lang.Object object)

Puts the specified Object at the specified coordinate.

Specified by:

putObjectAt in interface Discrete2DSpace

Parameters:

x - the x coordinate

y - the y coordinate

object - the object to put

Throws:

java.lang.IllegalArgumentException - if object is not an instance of Number

putValueAt

public void putValueAt(int x,
                       int y,
                       double value)

Puts the specified value at the specified coordinate.

Specified by:

putValueAt in interface Discrete2DSpace

Parameters:

x - the x coordinate

y - the y coordinate

value - the value to put

getMatrix

public BaseMatrix getMatrix()

Gets the matrix collection class that contains all the values. In this case the readMatrix is returned.

Specified by:

getMatrix in interface Discrete2DSpace

Returns:

the write matrix.

xnorm

protected int xnorm(int x)

Normalize the x value to the toroidal coordinates

Parameters:

x - the value to normalize

Returns:

the normalized value

ynorm

protected int ynorm(int y)

Normalize the y value to the toroidal coordinates

Parameters:

y - the value to normalize

Returns:

the normalized value