Package net.algart.math.functions

Class LogFunc

java.lang.Object

net.algart.math.functions.LogFunc

All Implemented Interfaces:

Func

public abstract class LogFunc
extends Object
implements Func

Logarithm function: f(x₀) = log_b(x₀) (b is the base of the logarithm). More precisely, the result of this function is Math.log(x[0])*(1.0/Math.log(b)) for the instance returned by getInstance(b) method or StrictMath.log(x[0])*(1.0/Math.log(b)) for the instance returned by getStrictInstance(b) method. The get(double...) method of the instance of this class requires at least 1 argument and throws IndexOutOfBoundsException if the number of arguments is 0.

This class is immutable and thread-safe: there are no ways to modify settings of the created instance.

Author:

Daniel Alievsky

Nested Class Summary

Nested classes/interfaces inherited from interface net.algart.math.functions.Func

Func.Updatable

Field Summary

Fields inherited from interface net.algart.math.functions.Func

ABS, ABS_DIFF, HALF_X_MINUS_Y, HALF_X_PLUS_Y, HALF_Y_MINUS_X, IDENTITY, MAX, MIN, POSITIVE_DIFF, REVERSE, SELECT, SELECT_FROM_8_DIRECTIONS_2D, SELECT_IF_GREATER, SELECT_IF_GREATER_OR_EQUAL, SHIFTS_ALONG_8_DIRECTIONS_2D, UPDATABLE_IDENTITY, X_MINUS_Y, X_PLUS_Y, Y_MINUS_X

Method Summary

Modifier and Type	Method	Description
double	get()	Equivalent to get(new double[0]).
abstract double	get(double x0)	Equivalent to get(new double[] {x0}).
abstract double	get(double... x)	Returns the result of this function for the given arguments: f(x0, x1, ..., xx.length-1).
abstract double	get(double x0, double x1)	Equivalent to get(new double[] {x0, x1}).
abstract double	get(double x0, double x1, double x2)	Equivalent to get(new double[] {x0, x1, x2}).
abstract double	get(double x0, double x1, double x2, double x3)	Equivalent to get(new double[] {x0, x1, x2, x3}).
static LogFunc	getInstance(double b)	Returns an instance of this class for the given logarithm base b using Math.log method.
static LogFunc	getStrictInstance(double b)	Returns an instance of this class for the given logarithm base b using StrictMath.log method.
String	toString()	Returns a brief string description of this object.

Methods inherited from class java.lang.Object

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

Method Details

getInstance

public static LogFunc getInstance(double b)

Returns an instance of this class for the given logarithm base b using Math.log method.

This method returns special optimized versions of this class for base=Math.E and base=10.0.

Parameters:

b - the base of the logarithm.

Returns:

an instance of this class using Math.log method.

getStrictInstance

public static LogFunc getStrictInstance(double b)

Returns an instance of this class for the given logarithm base b using StrictMath.log method.

This method returns special optimized versions of this class for base=Math.E and base=10.0.

Parameters:

b - the base of the logarithm.

Returns:

an instance of this class using StrictMath.log method.

get

public abstract double get(double... x)

Description copied from interface: Func

Returns the result of this function for the given arguments: f(x₀, x₁, ..., x_x.length-1).

This method must not change the values of x elements!

Specified by:

get in interface Func

Parameters:

x - the function arguments.

Returns:

the function result.

get

public double get()

Description copied from interface: Func

Equivalent to get(new double[0]). Provides better performance because it does not require Java array creation.

Specified by:

get in interface Func

Returns:

the function result.

get

public abstract double get(double x0)

Description copied from interface: Func

Equivalent to get(new double[] {x0}). Provides better performance because it does not require Java array creation.

Specified by:

get in interface Func

Parameters:

x0 - the function argument.

Returns:

the function result.

get

public abstract double get(double x0,
 double x1)

Description copied from interface: Func

Equivalent to get(new double[] {x0, x1}). Provides better performance because it does not require Java array creation.

Specified by:

get in interface Func

Parameters:

x0 - the first function argument.

x1 - the second function argument.

Returns:

the function result.

get

public abstract double get(double x0,
 double x1,
 double x2)

Description copied from interface: Func

Equivalent to get(new double[] {x0, x1, x2}). Provides better performance because it does not require Java array creation.

Specified by:

get in interface Func

Parameters:

x0 - the first function argument.

x1 - the second function argument.

x2 - the third function argument.

Returns:

the function result.

get

public abstract double get(double x0,
 double x1,
 double x2,
 double x3)

Description copied from interface: Func

Equivalent to get(new double[] {x0, x1, x2, x3}). Provides better performance because it does not require Java array creation.

Specified by:

get in interface Func

Parameters:

x0 - the first function argument.

x1 - the second function argument.

x2 - the third function argument.

x3 - the fourth function argument.

Returns:

the function result.

toString

public String toString()

Returns a brief string description of this object.

Overrides:

toString in class Object

Returns:

a brief string description of this object.