jas.space
Class DblDiffuseGrid

java.lang.Object
  java.util.AbstractCollection
      jas.space.Grid
          jas.space.DblGrid
              jas.space.DblDiffuseGrid

All Implemented Interfaces:

ISimEventListener, java.lang.Iterable, java.util.Collection

public class DblDiffuseGrid
extends DblGrid
implements ISimEventListener

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 DblDiffuseTorusGrid space see the heatBugs example. See diffuse for a brief explanation of the diffusion algorithm. Note that this space doesn't seem to work correctly when run with hotspot 1.01

Version:

$Revision: 1.2 $ $Date: 2004/08/11 09:05:30 $

Author:

Nick Collier

Field Summary

static int	EVENT_DIFFUSE
static long	MAX
static int	MOORE
static int	VON_NEUMANN

Constructor Summary

DblDiffuseGrid(int xSize, int ySize)
Constructs a DblDiffuseTorusGrid space with the specificed dimensions

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

Method Summary

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.
double[]	getMatrix() Return the matrix of values representing the grid.
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.
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	performAction(int actionType) The object implementing this interface is able to receive an event notify.
void	print(double[] mtr)
void	setDiffusionConstant(double diffusionConstant) Sets the diffusion constant for this DblDiffuseTorusGrid space
void	setEvaporationRate(double rate) Sets the evaporation rate for this DblDiffuseTorusGrid space
void	update() Copies the writeLattice to the readLattice

Methods inherited from class jas.space.DblGrid

add, clear, copyGridTo, copyGridTo, countObjectsAt, get, getDbl, max, mean, min, multiply, resetTo, set, setDbl, size, sum, swapPositions, variance

Methods inherited from class jas.space.Grid

boundX, boundY, equals, getMooreNeighborsPositions, getVonNeumannNeighborsPositions, getXSize, getYSize, gridIterator, iterator, reflectX, reflectY, torusX, torusY, toString

Methods inherited from class java.util.AbstractCollection

add, addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

hashCode

Field Detail

EVENT_DIFFUSE

public static final int EVENT_DIFFUSE

See Also:

Constant Field Values

MAX

public static final long MAX

See Also:

Constant Field Values

MOORE

public static final int MOORE

See Also:

Constant Field Values

VON_NEUMANN

public static final int VON_NEUMANN

See Also:

Constant Field Values

Constructor Detail

DblDiffuseGrid

public DblDiffuseGrid(int xSize,
                      int ySize)

Constructs a DblDiffuseTorusGrid space with the specificed dimensions

Parameters:

xSize - size of the x dimension

ySize - size of the y dimension

DblDiffuseGrid

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

Constructs a DblDiffuseTorusGrid 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

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.

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.

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.

getMatrix

public double[] getMatrix()

Description copied from class: DblGrid

Return the matrix of values representing the grid.

Overrides:

getMatrix in class DblGrid

Returns:

A matrix of double with the same dimensions of the grid.

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."

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.

performAction

public void performAction(int actionType)

Description copied from interface: ISimEventListener

The object implementing this interface is able to receive an event notify.

Specified by:

performAction in interface ISimEventListener

Parameters:

actionType - The switch id to select the right action to perform. It might be an Sim.EVENT_* or a custom defined constant.

print

public void print(double[] mtr)

setDiffusionConstant

public void setDiffusionConstant(double diffusionConstant)

Sets the diffusion constant for this DblDiffuseTorusGrid space

setEvaporationRate

public void setEvaporationRate(double rate)

Sets the evaporation rate for this DblDiffuseTorusGrid space

update

public void update()

Copies the writeLattice to the readLattice