org.geotoolkit.referencing.operation.transform
Class ExponentialTransform1D

Object
  FormattableObject
      AbstractMathTransform
          AbstractMathTransform1D
              ExponentialTransform1D

All Implemented Interfaces:

Serializable, Formattable, Parameterized, LenientComparable, MathTransform, MathTransform1D

@Immutable
public class ExponentialTransform1D
extends AbstractMathTransform1D
implements Serializable

A one dimensional exponential transform. Input values x are converted into output values y using the following equation:

y = scale · base^x

See any of the following providers for a list of programmatic parameters:

• Exponential

Tip: If a linear transform is applied before this exponential transform, then the equation can be rewritten as:

scale · base^{a + b·x} = scale · base^a · (base^b)^x

It is possible to find back the coefficients of the original linear transform by pre-concatenating a logarithmic transform before the exponential one, as below:

LinearTransform1D linear = (LinearTransform1D) ConcatenatedTransform.create(exponentialTransform,
        LogarithmicTransform1D.create(base, -Math.log(scale) / Math.log(base)));

Since:

2.0

Version:

3.18

Author:

Martin Desruisseaux (IRD, Geomatys)

See Also:

LogarithmicTransform1D, LinearTransform1D, Serialized Form

Module:

referencing/geotk-referencing (download)

View source code for this class

Nested Class Summary

Nested classes/interfaces inherited from class AbstractMathTransform

AbstractMathTransform.Inverse

Field Summary

double	base The base to be raised to a power.
double	scale The scale value to be multiplied.

Fields inherited from class FormattableObject

EPSG, GEOTIFF, INTERNAL, OGC, SINGLE_LINE

Constructor Summary

protected

ExponentialTransform1D(double base, double scale) Constructs a new exponential transform.

Method Summary

protected int	computeHashCode() Computes a hash value for this transform.
static MathTransform1D	create(double base) Constructs a new exponential transform with no scale.
static MathTransform1D	create(double base, double scale) Constructs a new exponential transform which include the given scale factor applied after the exponentiation.
double	derivative(double value) Gets the derivative of this function at a value.
boolean	equals(Object object, ComparisonMode mode) Compares the specified object with this math transform for equality.
ParameterDescriptorGroup	getParameterDescriptors() Returns the parameter descriptors for this math transform.
ParameterValueGroup	getParameterValues() Returns the parameter values for this math transform.
MathTransform1D	inverse() Creates the inverse transform of this object.
double	transform(double value) Transforms the specified value.
protected void	transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff) Transforms a single coordinate in a list of ordinal values.
void	transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) Transforms many coordinates in a list of ordinal values.
void	transform(double[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts) Transforms many coordinates in a list of ordinal values.
void	transform(float[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) Transforms many coordinates in a list of ordinal values.
void	transform(float[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts) Transforms many coordinates in a list of ordinal values.

Methods inherited from class AbstractMathTransform1D

derivative, getSourceDimensions, getTargetDimensions

Methods inherited from class AbstractMathTransform

createTransformedShape, derivative, ensureNonNull, equals, formatWKT, getName, hashCode, isIdentity, rollLongitude, transform, transform

Methods inherited from class FormattableObject

getDefaultIndentation, print, setDefaultIndentation, toString, toWKT, toWKT, toWKT

Methods inherited from class Object

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

Methods inherited from interface MathTransform

isIdentity, toWKT, transform

Field Detail

base

public final double base

The base to be raised to a power.

scale

public final double scale

The scale value to be multiplied.

Note: The scale could be handled by a concatenation with LinearTransform1D instead than an explicit field in this class. However the scale · base^x formula is extensively used as a transfer function in grid coverages. Consequently we keep this explicit field for performance reasons.

Constructor Detail

ExponentialTransform1D

protected ExponentialTransform1D(double base,
                                 double scale)

Constructs a new exponential transform. This constructor is provided for subclasses only. Instances should be created using the factory method, which may returns optimized implementations for some particular argument values.

Parameters:

base - The base to be raised to a power.

scale - The scale value to be multiplied.

Method Detail

create

public static MathTransform1D create(double base)

Constructs a new exponential transform with no scale.

Parameters:

base - The base to be raised to a power.

Returns:

The math transform.

Since:

3.17

create

public static MathTransform1D create(double base,
                                     double scale)

Constructs a new exponential transform which include the given scale factor applied after the exponentiation.

Parameters:

base - The base to be raised to a power.

scale - The scale value to be multiplied.

Returns:

The math transform.

getParameterDescriptors

public ParameterDescriptorGroup getParameterDescriptors()

Returns the parameter descriptors for this math transform.

Specified by:

getParameterDescriptors in interface Parameterized

Overrides:

getParameterDescriptors in class AbstractMathTransform

Returns:

The parameter descriptors for this math transform, or null.

See Also:

OperationMethod.getParameters()

getParameterValues

public ParameterValueGroup getParameterValues()

Returns the parameter values for this math transform.

Specified by:

getParameterValues in interface Parameterized

Overrides:

getParameterValues in class AbstractMathTransform

Returns:

A copy of the parameter values for this math transform.

See Also:

SingleOperation.getParameterValues()

inverse

public MathTransform1D inverse()

Creates the inverse transform of this object.

Specified by:

inverse in interface MathTransform

Specified by:

inverse in interface MathTransform1D

Overrides:

inverse in class AbstractMathTransform1D

derivative

public double derivative(double value)

Gets the derivative of this function at a value.

Specified by:

derivative in interface MathTransform1D

transform

public double transform(double value)

Transforms the specified value.

Specified by:

transform in interface MathTransform1D

transform

protected void transform(double[] srcPts,
                         int srcOff,
                         double[] dstPts,
                         int dstOff)

Transforms a single coordinate in a list of ordinal values.

Overrides:

transform in class AbstractMathTransform1D

Parameters:

srcPts - The array containing the source point coordinates.

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

dstPts - the array into which the transformed point coordinate are returned. May be the same than srcPts.

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

transform

public void transform(double[] srcPts,
                      int srcOff,
                      double[] dstPts,
                      int dstOff,
                      int numPts)

Transforms many coordinates in a list of ordinal values.

Specified by:

transform in interface MathTransform

Overrides:

transform in class AbstractMathTransform

Parameters:

srcPts - The array containing the source point coordinates.

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

dstPts - The array into which the transformed point coordinates are returned. May be the same than srcPts.

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

numPts - The number of point objects to be transformed.

transform

public void transform(float[] srcPts,
                      int srcOff,
                      float[] dstPts,
                      int dstOff,
                      int numPts)

Transforms many coordinates in a list of ordinal values.

Specified by:

transform in interface MathTransform

Overrides:

transform in class AbstractMathTransform

Parameters:

srcPts - The array containing the source point coordinates.

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

dstPts - The array into which the transformed point coordinates are returned. May be the same than srcPts.

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

numPts - The number of point objects to be transformed.

transform

public void transform(double[] srcPts,
                      int srcOff,
                      float[] dstPts,
                      int dstOff,
                      int numPts)

Transforms many coordinates in a list of ordinal values.

Specified by:

transform in interface MathTransform

Overrides:

transform in class AbstractMathTransform

Parameters:

srcPts - The array containing the source point coordinates.

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

dstPts - The array into which the transformed point coordinates are returned.

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

numPts - The number of point objects to be transformed.

transform

public void transform(float[] srcPts,
                      int srcOff,
                      double[] dstPts,
                      int dstOff,
                      int numPts)

Transforms many coordinates in a list of ordinal values.

Specified by:

transform in interface MathTransform

Overrides:

transform in class AbstractMathTransform

Parameters:

srcPts - The array containing the source point coordinates.

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

dstPts - The array into which the transformed point coordinates are returned.

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

numPts - The number of point objects to be transformed.

computeHashCode

protected int computeHashCode()

Computes a hash value for this transform. This method is invoked by AbstractMathTransform.hashCode() when first needed.

Overrides:

computeHashCode in class AbstractMathTransform

Returns:

The hash code value. This value may change between different execution of the Geotk library.

equals

public boolean equals(Object object,
                      ComparisonMode mode)

Compares the specified object with this math transform for equality.

Specified by:

equals in interface LenientComparable

Overrides:

equals in class AbstractMathTransform

Parameters:

object - The object to compare with this transform.

mode - The strictness level of the comparison. Default to STRICT.

Returns:

true if the given object is a transform of the same class and if, given identical source position, the transformed position would be the equals.