Module org.apache.sis.referencing

Package org.apache.sis.referencing.operation.transform

Class AbstractMathTransform1D

Object

FormattableObject

AbstractMathTransform

AbstractMathTransform1D

All Implemented Interfaces:

Parameterized, Lenient­Comparable, Math­Transform, Math­Transform1D

public abstract class AbstractMathTransform1D
extends AbstractMathTransform
implements MathTransform1D

Base class for math transforms that are known to be one-dimensional in all cases. One-dimensional math transforms are not required to extend this class, however doing so may simplify their implementation.

The simplest way to implement this abstract class is to provide an implementation for the following methods only:

• transform(double)
• derivative(double)

Immutability and thread safety

All Apache SIS implementations of Math­Transform1D are immutable and thread-safe. It is highly recommended that third-party implementations be immutable and thread-safe too. This means that unless otherwise noted in the javadoc, Math­Transform1D instances can be shared by many objects and passed between threads without synchronization.

Serialization

Math­Transform1D may or may not be serializable, at implementation choices. Most Apache SIS implementations are serializable, but the serialized objects are not guaranteed to be compatible with future SIS versions. Serialization should be used only for short term storage or RMI between applications running the same SIS version.

Since:

0.5

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	Abstract­Math­Transform1D.Inverse	Base class for implementation of inverse math transforms.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Abstract­Math­Transform1D()	Constructor for subclasses.

Method Summary

Modifier and Type	Method	Description
abstract double	derivative(double value)	Gets the derivative of this function at a value.
Matrix	derivative(Direct­Position point)	Gets the derivative of this transform at a point.
final int	get­Source­Dimensions()	Returns the dimension of input points, which is always 1.
final int	get­Target­Dimensions()	Returns the dimension of output points, which is always 1.
Math­Transform1D	inverse()	Returns the inverse transform of this object.
abstract double	transform(double value)	Transforms the specified value.
Matrix	transform(double[] src­Pts, int src­Off, double[] dst­Pts, int dst­Off, boolean derivate)	Transforms a single point in the given array and opportunistically computes its derivative if requested.

Methods inherited from class AbstractMathTransform

compute­Hash­Code, equals, equals, format­To, get­Contextual­Parameters, get­Domain, get­Parameter­Descriptors, get­Parameter­Values, hash­Code, is­Identity, transform, transform, transform, transform, transform, try­Concatenate

Methods inherited from class FormattableObject

print, to­String, to­String, to­WKT

Methods inherited from class Object

clone, finalize, get­Class, notify, notify­All, wait, wait, wait

Methods inherited from interface MathTransform

is­Identity, to­WKT, transform, transform, transform, transform, transform

Constructor Details

AbstractMathTransform1D

protected AbstractMathTransform1D()

Constructor for subclasses.

Method Details

getSourceDimensions

public final int getSourceDimensions()

Returns the dimension of input points, which is always 1.

Specified by:

get­Source­Dimensions in interface Math­Transform

Specified by:

get­Source­Dimensions in class Abstract­Math­Transform

Returns:

the number of dimensions of input points.

See Also:

• Default­Operation­Method.get­Source­Dimensions()

getTargetDimensions

public final int getTargetDimensions()

Returns the dimension of output points, which is always 1.

Specified by:

get­Target­Dimensions in interface Math­Transform

Specified by:

get­Target­Dimensions in class Abstract­Math­Transform

Returns:

the number of dimensions of output points.

See Also:

• Default­Operation­Method.get­Target­Dimensions()

transform

public abstract double transform(double value)
                          throws TransformException

Transforms the specified value.

Specified by:

transform in interface Math­Transform1D

Parameters:

value - the value to transform.

Returns:

the transformed value.

Throws:

Transform­Exception - if the value cannot be transformed.

transform

public Matrix transform(double[] srcPts,
 int srcOff,
 double[] dstPts,
 int dstOff,
 boolean derivate)
                 throws TransformException

Transforms a single point in the given array and opportunistically computes its derivative if requested. The default implementation delegates to transform(double) and potentially to derivative(double). Subclasses may override this method for performance reason.

Specified by:

transform in class Abstract­Math­Transform

Parameters:

src­Pts - the array containing the source coordinates (cannot be null).

src­Off - the offset to the point to be transformed in the source array.

dst­Pts - the array into which the transformed coordinates is returned. May be the same than src­Pts. May be null if only the derivative matrix is desired.

dst­Off - the offset to the location of the transformed point that is stored in the destination array.

derivate - true for computing the derivative, or false if not needed.

Returns:

the matrix of the transform derivative at the given source position, or null if the derivate argument is false.

Throws:

Transform­Exception - if the point cannot be transformed or if a problem occurred while calculating the derivative.

See Also:

• Abstract­Math­Transform.derivative(Direct­Position)
• Abstract­Math­Transform.transform(Direct­Position, Direct­Position)
• Math­Transforms.derivative­And­Transform(Math­Transform, double[], int, double[], int)

derivative

public abstract double derivative(double value)
                           throws TransformException

Gets the derivative of this function at a value. The derivative is the 1×1 matrix of the non-translating portion of the approximate affine map at the value.

Specified by:

derivative in interface Math­Transform1D

Parameters:

value - the value where to evaluate the derivative.

Returns:

the derivative at the specified point.

Throws:

Transform­Exception - if the derivative cannot be evaluated at the specified point.

derivative

public Matrix derivative(DirectPosition point)
                  throws TransformException

Gets the derivative of this transform at a point. The default implementation ensures that point is one-dimensional, then delegates to derivative(double).

Specified by:

derivative in interface Math­Transform

Overrides:

derivative in class Abstract­Math­Transform

Parameters:

point - the position where to evaluate the derivative, or null.

Returns:

the derivative at the specified point (never null).

Throws:

Mismatched­Dimension­Exception - if point does not have the expected dimension.

Transform­Exception - if the derivative cannot be evaluated at the specified point.

inverse

public MathTransform1D inverse()
                        throws NoninvertibleTransformException

Returns the inverse transform of this object. The default implementation returns this if this transform is an identity transform, or throws an exception otherwise. Subclasses should override this method.

Specified by:

inverse in interface Math­Transform

Specified by:

inverse in interface Math­Transform1D

Overrides:

inverse in class Abstract­Math­Transform

Throws:

Noninvertible­Transform­Exception