com.opengamma.strata.math.impl.minimization

Class NullTransform

java.lang.Object

com.opengamma.strata.math.impl.minimization.NullTransform

All Implemented Interfaces:

ParameterLimitsTransform

public class NullTransform
extends Object
implements ParameterLimitsTransform

Provides a null implementation of parameter transformation; the functions return unchanged values.

Nested Class Summary

Nested classes/interfaces inherited from interface com.opengamma.strata.math.impl.minimization.ParameterLimitsTransform

ParameterLimitsTransform.LimitType

Constructor Summary

Constructors

Constructor and Description
NullTransform()

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj)
int	hashCode()
double	inverseTransform(double y) Performs the null inverse transform {y -> y}.
double	inverseTransformGradient(double y) The gradient of a null transform is one.
double	transform(double x) Performs the null transform {x -> x}.
double	transformGradient(double x) The gradient of a null transform is one.

Methods inherited from class java.lang.Object

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

Constructor Detail

NullTransform

public NullTransform()

Method Detail

inverseTransform

public double inverseTransform(double y)

Performs the null inverse transform {y -> y}. A function to transform an unconstrained fitting parameter (y*) to a constrained model parameter (y) - i.e. y = f^-1(y*)

Specified by:

inverseTransform in interface ParameterLimitsTransform

Parameters:

y - Fitting parameter

Returns:

Model parameter

inverseTransformGradient

public double inverseTransformGradient(double y)

The gradient of a null transform is one. The gradient of the function used to transform from a fitting parameter that can take any value, to a model parameter that is only allows to take certain values.

Specified by:

inverseTransformGradient in interface ParameterLimitsTransform

Parameters:

y - fitting parameter

Returns:

the gradient

transform

public double transform(double x)

Performs the null transform {x -> x}. A function to transform a constrained model parameter (y) to an unconstrained fitting parameter (y*) - i.e. y* = f(y)

Specified by:

transform in interface ParameterLimitsTransform

Parameters:

x - Model parameter

Returns:

Fitting parameter

transformGradient

public double transformGradient(double x)

The gradient of a null transform is one. The gradient of the function used to transform from a model parameter that is only allows to take certain values, to a fitting parameter that can take any value.

Specified by:

transformGradient in interface ParameterLimitsTransform

Parameters:

x - Model parameter

Returns:

the gradient

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object