Class CROperatorGridBilinearWeights

java.lang.Object

org.ddogleg.chainrule.ops.CROperatorGridBilinearWeights

All Implemented Interfaces:

CROperatorBackwardsJac<double[]>, CROperatorForward<double[]>

public class CROperatorGridBilinearWeights
extends Object
implements CROperatorBackwardsJac<double[]>

Turns a pixel into the 4 bilinear weights of the cell it lands in, ready to be blended by CROperatorBilinearPolyND. This is the half that knows how an image maps onto a grid.

The cell is worked out from the pixel. Whatever needs to fetch the matching knots reads it back through col and row, which is what the pre-forward hook does. A pixel outside the grid is not an error: the cell clamps to the nearest real one, the fractions leave [0,1], and the weights extrapolate.

The knots are ordered (col,row), (col+1,row), (col,row+1), (col+1,row+1)

See Also:

• ConfigGridCoefND

Field Summary

Fields

Modifier and Type	Field	Description
static final int	IN_PIXEL

Constructor Summary

Constructors

Constructor	Description
CROperatorGridBilinearWeights()

Method Summary

Modifier and Type	Method	Description
CROperatorGridBilinearWeights	configure(int width, int height, ConfigGridCoefND grid)
void	forward(CRArray<double[]> output)	Performs forward pass of the function.
Class<double[]>	getArrayType()	Primitive data type for the array
int	getInputCount()	Number of inputs
int	getInputSize(int which)	Returns the specified input's vector size
int	getOutputSize()	Returns the output vector's size
Map<String,String>	getSettings()	Retrieve a serialized description of the settings
void	jacobian(CRMatrix<double[]> dout, List<CRMatrix<double[]>> jacobianInputs)	The cell is fixed, so a weight only moves through the fractions, and those are linear in the pixel
void	setInput(int which, CRArray<double[]> input)	Specifies the value of an input's vector.
void	setSettings(Map<String,String> settings)	Reconfigures the block using the specified settings

Methods inherited from class Object

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

Methods inherited from interface CROperatorForward

normalizeAfterStep

Field Details

IN_PIXEL

public static final int IN_PIXEL

See Also:

• Constant Field Values

Constructor Details

CROperatorGridBilinearWeights

public CROperatorGridBilinearWeights()

Method Details

configure

public CROperatorGridBilinearWeights configure(int width,
 int height,
 ConfigGridCoefND grid)

forward

public void forward(CRArray<double[]> output)

Description copied from interface: CROperatorForward

Performs forward pass of the function. Must have already updated CROperatorForward.setInput(int, CRArray).

Specified by:

forward in interface CROperatorForward<double[]>

Parameters:

output - (Output) Output vector. Modified.

jacobian

public void jacobian(CRMatrix<double[]> dout,
 List<CRMatrix<double[]>> jacobianInputs)

The cell is fixed, so a weight only moves through the fractions, and those are linear in the pixel

Specified by:

jacobian in interface CROperatorBackwardsJac<double[]>

Parameters:

dout - (Input) Jacobian of output conditional on this function, computed from next layer.

jacobianInputs - (Output) Storage for all the Jacobian inputs. All matrices must be pre-declared and included in the list. If a matrix is marked as invalid, then the jacobian is skipped for that input.

setInput

public void setInput(int which,
 CRArray<double[]> input)

Description copied from interface: CROperatorForward

Specifies the value of an input's vector.

The implementation can safely save the array input points at along with its offset. Neither the values at that offset nor the array itself will change until after CROperatorForward.forward(CRArray) or a derived function such as CROperatorBackwardsJac.jacobian(CRMatrix, List) has been called. The input reference itself cannot be saved: the caller is free to recycle the CRArray the moment the call returns, including pointing it at another offset.

Specified by:

setInput in interface CROperatorForward<double[]>

Parameters:

which - Which input

input - The input's value. This reference can't be saved internally but the array and offset can be.

getInputSize

public int getInputSize(int which)

Description copied from interface: CROperatorForward

Returns the specified input's vector size

Specified by:

getInputSize in interface CROperatorForward<double[]>

getSettings

public Map<String,String> getSettings()

Description copied from interface: CROperatorForward

Retrieve a serialized description of the settings

Specified by:

getSettings in interface CROperatorForward<double[]>

setSettings

public void setSettings(Map<String,String> settings)

Description copied from interface: CROperatorForward

Reconfigures the block using the specified settings

Specified by:

setSettings in interface CROperatorForward<double[]>

getInputCount

public int getInputCount()

Description copied from interface: CROperatorForward

Number of inputs

Specified by:

getInputCount in interface CROperatorForward<double[]>

getOutputSize

public int getOutputSize()

Description copied from interface: CROperatorForward

Returns the output vector's size

Specified by:

getOutputSize in interface CROperatorForward<double[]>

getArrayType

public Class<double[]> getArrayType()

Description copied from interface: CROperatorForward

Primitive data type for the array

Specified by:

getArrayType in interface CROperatorForward<double[]>