java.lang.Object
- HAL.GridsAndAgents.PDEGrid2D

All Implemented Interfaces:

Grid2D, java.io.Serializable
```
public class PDEGrid2D
extends java.lang.Object
implements Grid2D, java.io.Serializable
```
PDEGrid2D class facilitates 2D diffusion with two arrays of doubles called fields the intended usage is that during a diffusion tick, the current values will be read, and the prev values will be written to after updates, Update is called to set the prev field as the current field.

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type Field Description

int length

boolean wrapX

boolean wrapY

int xDim

int yDim

Constructor Summary

Constructors
Constructor Description

PDEGrid2D(int xDim, int yDim)

PDEGrid2D(int xDim, int yDim, boolean wrapX, boolean wrapY)

Method Summary

Modifier and Type	Method	Description
`void`	`Add(double x, double y, double val)`
`void`	`Add(int i, double val)`	adds to the prev field value at the specified index
`void`	`Add(int x, int y, double val)`	sets the prev field value at the specified coordinates
`void`	`AddAll(double val)`	adds specified value to all entries of the delta field
`void`	`Advection(double[] xVels, double[] yVels)`	runs discontinuous advection
`void`	`Advection(double[] xVels, double[] yVels, Coords2DDouble BoundaryyConditionFn, Coords2DDouble BoundaryXvels, Coords2DDouble BoundaryYvels)`	runs discontinuous advection
`void`	`Advection(double xVel, double yVel)`
`void`	`Advection(double xVel, double yVel, double boundaryValue)`	runs advection as described above with a boundary value, meaning that the boundary value will advect in from the upwind direction, and the concentration will disappear in the downwind direction.
`void`	`Advection(double xVel, double yVel, Coords2DDouble BoundaryConditionFn)`	runs advection as described above with a boundary condition function, which will be evaluated with the out of bounds coordinates as arguments whenever a boundary value is needed, and should return the boundary value
`void`	`Advection(Grid2Ddouble xVels, Grid2Ddouble yVels)`	runs discontinuous advection
`void`	`Advection(Grid2Ddouble xVels, Grid2Ddouble yVels, Coords2DDouble BoundaryyConditionFn, Coords2DDouble BoundaryXvels, Coords2DDouble BoundaryYvels)`	runs discontinuous advection
`void`	`Diffusion(double diffCoef)`	runs diffusion on the current field, adding the deltas to the delta field.
`void`	`Diffusion(double[] diffRatesX, double[] diffRatesY)`	runs diffusion with discontinuous diffusion rates
`void`	`Diffusion(double[] diffRatesX, double[] diffRatesY, Coords2DDouble BoundaryConditionFn, Coords2DDouble BoundaryDiffusionRatesX, Coords2DDouble BoundaryDiffusionRatesY)`	runs diffusion with discontinuous diffusion rates
`void`	`Diffusion(double diffCoef, double boundaryValue)`	has the same effect as the above diffusion function without the boundary value argument, except rather than assuming zero flux, the boundary condition is set to either the boundaryValue, or wrap around
`void`	`Diffusion(double diffCoef, Coords2DDouble BoundaryConditionFn)`	has the same effect as the above diffusion function with a boundary condition function, which will be evaluated with the out of bounds coordinates as arguments whenever a boundary value is needed, and should return the boundary value
`void`	`Diffusion(Grid2Ddouble diffRatesX, Grid2Ddouble diffRatesY)`	runs diffusion with discontinuous diffusion rates
`void`	`Diffusion(Grid2Ddouble diffRatesX, Grid2Ddouble diffRatesY, Coords2DDouble BoundaryConditionFn, Coords2DDouble BoundaryDiffusionRatesX, Coords2DDouble BoundaryDiffusionRatesY)`	runs diffusion with discontinuous diffusion rates
`static void`	`Diffusion2DADIBetweenAction(double[] field, double[] scratch, double[] deltas, double diffRate, int xDim, int yDim, boolean wrapX, boolean wrapY, Coords2DDouble BC, TdmaSolver tdma, DoubleArrayToVoid BetweenAction)`
`void`	`DiffusionADI(double diffCoef)`
`void`	`DiffusionADI(double diffCoef, double boundaryCond)`
`void`	`DiffusionADI(double diffCoef, double boundaryCond, DoubleArrayToVoid BetweenAction)`
`double`	`Get(double x, double y)`
`double`	`Get(int i)`	gets the prev field value at the specified index
`double`	`Get(int x, int y)`	gets the prev field value at the specified coordinates
`double`	`GetAvg()`	gets the average value of all squares in the current field
`double[]`	`GetDeltas()`
`double[]`	`GetField()`
`double`	`GetMax()`	returns the max value in the grid
`double`	`GetMin()`	returns the min value in the grid
`double`	`GradientX(double x, double y)`
`double`	`GradientX(double x, double y, double boundaryCond)`
`double`	`GradientX(int x, int y)`	returns the gradient of the diffusible in the X direction at the coordinates specified
`double`	`GradientX(int x, int y, double boundaryCond)`	returns the gradient of the diffusible in the X direction at the coordinates specified, will use the boundary condition value if computing the gradient next to the boundary
`double`	`GradientY(double x, double y)`
`double`	`GradientY(double x, double y, double boundaryCond)`
`double`	`GradientY(int x, int y)`	returns the gradient of the diffusible in the Y direction at the coordinates specified
`double`	`GradientY(int x, int y, double boundaryCond)`	returns the gradient of the diffusible in the Y direction at the coordinates specified, will use the boundary condition value if computing the gradient next to the boundary
`boolean`	`IsWrapX()`
`boolean`	`IsWrapY()`
`int`	`Length()`
`double`	`MaxDelta()`	returns the maximum difference as stored on the delta field, call right before calling Update()
`double`	`MaxDeltaScaled(double denomOffset)`	like MaxDelta only the differences are scaled relative to the value in the current field.
`void`	`Mul(double x, double y, double val)`
`void`	`Mul(int i, double val)`	multiplies a value in the “current field” and adds the change to the “delta field”
`void`	`Mul(int x, int y, double val)`	multiplies a value in the “current field” and adds the change to the “delta field”
`void`	`MulAll(double val)`	multiplies all values in the “current field” and puts the results into the “delta field”
`void`	`Set(double x, double y, double val)`
`void`	`Set(int i, double val)`	sets the prev field value at the specified index
`void`	`Set(int x, int y, double val)`	sets the prev field value at the specified coordinates
`void`	`SetAll(double val)`	sets all squares in the delta field to the specified value
`void`	`SetAll(double[] vals)`	sets all squares in the delta field using the vals array
`void`	`SetNonNegative()`	ensures that all values will be non-negative on the next timestep, call before Update
`void`	`Update()`	adds the delta field into the current field
`int`	`UpdateCt()`
`int`	`Xdim()`
`int`	`Ydim()`

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface HAL.Interfaces.Grid2D
AlongLineIs, ApplyHood, ApplyHood, ApplyHoodMapped, ApplyRectangle, BoundaryIs, ContainsValidI, ContainsValidI, DispX, DispY, Dist, DistSquared, GetHoodI, I, I, In, In, InWrap, ItoX, ItoY, MapHood, MapHood, MapHood, MapHood, MapI, MapXpt, MapXsq, MapYpt, MapYsq, RandomHoodI, WrapI

Field Detail

xDim
```
public final int xDim
```

yDim
```
public final int yDim
```

length
```
public final int length
```

wrapX
```
public boolean wrapX
```

wrapY
```
public boolean wrapY
```

Constructor Detail

PDEGrid2D

public PDEGrid2D(int xDim,
                 int yDim)

PDEGrid2D

public PDEGrid2D(int xDim,
                 int yDim,
                 boolean wrapX,
                 boolean wrapY)

Method Detail

UpdateCt
```
public int UpdateCt()
```

GetField
```
public double[] GetField()
```

GetDeltas
```
public double[] GetDeltas()
```

DiffusionADI

public void DiffusionADI(double diffCoef)

DiffusionADI

public void DiffusionADI(double diffCoef,
                         double boundaryCond)

DiffusionADI

public void DiffusionADI(double diffCoef,
                         double boundaryCond,
                         DoubleArrayToVoid BetweenAction)

Diffusion2DADIBetweenAction

public static void Diffusion2DADIBetweenAction(double[] field,
                                               double[] scratch,
                                               double[] deltas,
                                               double diffRate,
                                               int xDim,
                                               int yDim,
                                               boolean wrapX,
                                               boolean wrapY,
                                               Coords2DDouble BC,
                                               TdmaSolver tdma,
                                               DoubleArrayToVoid BetweenAction)

Get
```
public double Get(int x,
                  int y)
```
gets the prev field value at the specified coordinates

Get

public double Get(double x,
                  double y)

Get
```
public double Get(int i)
```
gets the prev field value at the specified index

Set

public void Set(int x,
                int y,
                double val)

sets the prev field value at the specified coordinates

Set

public void Set(double x,
                double y,
                double val)

Set

public void Set(int i,
                double val)

sets the prev field value at the specified index

Add

public void Add(int x,
                int y,
                double val)

sets the prev field value at the specified coordinates

Add

public void Add(double x,
                double y,
                double val)

Add

public void Add(int i,
                double val)

adds to the prev field value at the specified index

Mul
```
public void Mul(int x,
                int y,
                double val)
```
multiplies a value in the “current field” and adds the change to the “delta field”

Mul

public void Mul(double x,
                double y,
                double val)

Mul
```
public void Mul(int i,
                double val)
```
multiplies a value in the “current field” and adds the change to the “delta field”

GetMax
```
public double GetMax()
```
returns the max value in the grid

GetMin
```
public double GetMin()
```
returns the min value in the grid

Update
```
public void Update()
```
adds the delta field into the current field

Advection

public void Advection(double xVel,
                      double yVel)

Advection
```
public void Advection(double xVel,
                      double yVel,
                      double boundaryValue)
```
runs advection as described above with a boundary value, meaning that the boundary value will advect in from the upwind direction, and the concentration will disappear in the downwind direction.

Advection
```
public void Advection(double xVel,
                      double yVel,
                      Coords2DDouble BoundaryConditionFn)
```
runs advection as described above with a boundary condition function, which will be evaluated with the out of bounds coordinates as arguments whenever a boundary value is needed, and should return the boundary value

Advection

public void Advection(double[] xVels,
                      double[] yVels)

runs discontinuous advection

Advection

public void Advection(Grid2Ddouble xVels,
                      Grid2Ddouble yVels)

runs discontinuous advection

Advection

public void Advection(double[] xVels,
                      double[] yVels,
                      Coords2DDouble BoundaryyConditionFn,
                      Coords2DDouble BoundaryXvels,
                      Coords2DDouble BoundaryYvels)

runs discontinuous advection

Advection

public void Advection(Grid2Ddouble xVels,
                      Grid2Ddouble yVels,
                      Coords2DDouble BoundaryyConditionFn,
                      Coords2DDouble BoundaryXvels,
                      Coords2DDouble BoundaryYvels)

runs discontinuous advection

Diffusion
```
public void Diffusion(double diffCoef)
```
runs diffusion on the current field, adding the deltas to the delta field. This form of the function assumes either a reflective or wrapping boundary (depending on how the PDEGrid was specified). the diffCoef variable is the nondimensionalized diffusion conefficient. If the dimensionalized diffusion coefficient is x then diffCoef can be found by computing (x*SpaceStep)/TimeStep^2 Note that if the diffCoef exceeds 0.25, this diffusion method will become numerically unstable.

Diffusion
```
public void Diffusion(double diffCoef,
                      double boundaryValue)
```
has the same effect as the above diffusion function without the boundary value argument, except rather than assuming zero flux, the boundary condition is set to either the boundaryValue, or wrap around

Diffusion
```
public void Diffusion(double diffCoef,
                      Coords2DDouble BoundaryConditionFn)
```
has the same effect as the above diffusion function with a boundary condition function, which will be evaluated with the out of bounds coordinates as arguments whenever a boundary value is needed, and should return the boundary value

Diffusion

public void Diffusion(double[] diffRatesX,
                      double[] diffRatesY)

runs diffusion with discontinuous diffusion rates

Diffusion

public void Diffusion(Grid2Ddouble diffRatesX,
                      Grid2Ddouble diffRatesY)

runs diffusion with discontinuous diffusion rates

Diffusion

public void Diffusion(double[] diffRatesX,
                      double[] diffRatesY,
                      Coords2DDouble BoundaryConditionFn,
                      Coords2DDouble BoundaryDiffusionRatesX,
                      Coords2DDouble BoundaryDiffusionRatesY)

runs diffusion with discontinuous diffusion rates

Diffusion

public void Diffusion(Grid2Ddouble diffRatesX,
                      Grid2Ddouble diffRatesY,
                      Coords2DDouble BoundaryConditionFn,
                      Coords2DDouble BoundaryDiffusionRatesX,
                      Coords2DDouble BoundaryDiffusionRatesY)

runs diffusion with discontinuous diffusion rates

SetAll
```
public void SetAll(double val)
```
sets all squares in the delta field to the specified value

MulAll
```
public void MulAll(double val)
```
multiplies all values in the “current field” and puts the results into the “delta field”

SetAll
```
public void SetAll(double[] vals)
```
sets all squares in the delta field using the vals array

AddAll
```
public void AddAll(double val)
```
adds specified value to all entries of the delta field

GetAvg
```
public double GetAvg()
```
gets the average value of all squares in the current field

MaxDelta
```
public double MaxDelta()
```
returns the maximum difference as stored on the delta field, call right before calling Update()

MaxDeltaScaled
```
public double MaxDeltaScaled(double denomOffset)
```
like MaxDelta only the differences are scaled relative to the value in the current field. the denomOffset is used to prevent a division by zero

GradientX
```
public double GradientX(int x,
                        int y)
```
returns the gradient of the diffusible in the X direction at the coordinates specified

GradientX

public double GradientX(double x,
                        double y)

GradientY
```
public double GradientY(int x,
                        int y)
```
returns the gradient of the diffusible in the Y direction at the coordinates specified

GradientY

public double GradientY(double x,
                        double y)

GradientX
```
public double GradientX(int x,
                        int y,
                        double boundaryCond)
```
returns the gradient of the diffusible in the X direction at the coordinates specified, will use the boundary condition value if computing the gradient next to the boundary

GradientX

public double GradientX(double x,
                        double y,
                        double boundaryCond)

GradientY
```
public double GradientY(int x,
                        int y,
                        double boundaryCond)
```
returns the gradient of the diffusible in the Y direction at the coordinates specified, will use the boundary condition value if computing the gradient next to the boundary

GradientY

public double GradientY(double x,
                        double y,
                        double boundaryCond)

SetNonNegative
```
public void SetNonNegative()
```
ensures that all values will be non-negative on the next timestep, call before Update

Xdim
```
public int Xdim()
```
Specified by:

Xdim in interface Grid2D

Ydim
```
public int Ydim()
```
Specified by:

Ydim in interface Grid2D

Length
```
public int Length()
```
Specified by:

Length in interface Grid2D

IsWrapX
```
public boolean IsWrapX()
```
Specified by:

IsWrapX in interface Grid2D

IsWrapY
```
public boolean IsWrapY()
```
Specified by:

IsWrapY in interface Grid2D

Modifier and Type	Field	Description
`int`	`length`
`boolean`	`wrapX`
`boolean`	`wrapY`
`int`	`xDim`
`int`	`yDim`

Constructor	Description
`PDEGrid2D(int xDim, int yDim)`
`PDEGrid2D(int xDim, int yDim, boolean wrapX, boolean wrapY)`

Class PDEGrid2D

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface HAL.Interfaces.Grid2D

Field Detail

xDim

yDim

length

wrapX

wrapY

Constructor Detail

PDEGrid2D

PDEGrid2D

Method Detail

UpdateCt

GetField

GetDeltas

DiffusionADI

DiffusionADI

DiffusionADI

Diffusion2DADIBetweenAction

Get

Get

Get

Set

Set

Set

Add

Add

Add

Mul

Mul

Mul

GetMax

GetMin

Update

Advection

Advection

Advection

Advection

Advection

Advection

Advection

Diffusion

Diffusion

Diffusion

Diffusion

Diffusion

Diffusion

Diffusion

SetAll

MulAll

SetAll

AddAll

GetAvg

MaxDelta

MaxDeltaScaled

GradientX

GradientX

GradientY

GradientY

GradientX

GradientX

GradientY

GradientY

SetNonNegative

Xdim

Ydim

Length

IsWrapX

IsWrapY