com.numericalmethod.suanshu.analysis.function

Class SubFunction<R>

java.lang.Object

com.numericalmethod.suanshu.analysis.function.SubFunction<R>

Type Parameters:

R - the range of a function

All Implemented Interfaces:

Function<Vector,R>, java.io.Serializable

Direct Known Subclasses:

RealScalarSubFunction, RealVectorSubFunction

public abstract class SubFunction<R>
extends java.lang.Object
implements Function<Vector,R>

A sub-function, g, is defined over a subset of the domain of another (original) function, f. g(x) = f(x) when they are both defined. This implementation constructs a sub-function by restricting/fixing the values of a subset of variables of another function.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface com.numericalmethod.suanshu.analysis.function.Function

Function.EvaluationException

Field Summary

Fields

Modifier and Type	Field and Description
protected Function<Vector,R>	f the original, unrestricted function
protected java.util.Map<java.lang.Integer,java.lang.Double>	fixing the restrictions or fixed values

Constructor Summary

Constructors

Constructor and Description
SubFunction(Function<Vector,R> f, java.util.Map<java.lang.Integer,java.lang.Double> fixing) Construct a sub-function.

Method Summary

Modifier and Type	Method and Description
int	dimensionOfDomain() Get the number of variables the function has.
int	dimensionOfRange() Get the dimension of the range space of the function.
static Vector	getAllParts(Vector variables, java.util.Map<java.lang.Integer,java.lang.Double> fixed) Combine the variable and fixed values to form an input to the original function.
double[]	getVariablePart(double[] z) Given an input to the original function, this extracts the variable parts (excluding the fixed values).
boolean	isFixedIndex(int i) Check whether a particular index corresponds a fixed variable/value.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.numericalmethod.suanshu.analysis.function.Function

evaluate

Field Detail

f

protected final Function<Vector,R> f

the original, unrestricted function

fixing

protected final java.util.Map<java.lang.Integer,java.lang.Double> fixing

the restrictions or fixed values

Constructor Detail

SubFunction

public SubFunction(Function<Vector,R> f,
                   java.util.Map<java.lang.Integer,java.lang.Double> fixing)

Construct a sub-function.

Parameters:

f - the original, unrestricted function

fixing - the values held fixed for a subset of variables

Method Detail

dimensionOfDomain

public int dimensionOfDomain()

Description copied from interface: Function

Get the number of variables the function has. For example, for a univariate function, the domain dimension is 1; for a bivariate function, the domain dimension is 2.

Specified by:

dimensionOfDomain in interface Function<Vector,R>

Returns:

the number of variables

dimensionOfRange

public int dimensionOfRange()

Description copied from interface: Function

Get the dimension of the range space of the function. For example, for a Rⁿ->R^m function, the dimension of the range is m.

Specified by:

dimensionOfRange in interface Function<Vector,R>

Returns:

the dimension of the range

isFixedIndex

public boolean isFixedIndex(int i)

Check whether a particular index corresponds a fixed variable/value.

Parameters:

i - an index, counting from 1

Returns:

true if x_i is fixed to some value

getVariablePart

public double[] getVariablePart(double[] z)

Given an input to the original function, this extracts the variable parts (excluding the fixed values).

Parameters:

z - an input to the original function

Returns:

the variable part in z

getAllParts

public static Vector getAllParts(Vector variables,
                                 java.util.Map<java.lang.Integer,java.lang.Double> fixed)

Combine the variable and fixed values to form an input to the original function.

Parameters:

variables - the non-fixed variables/values to the restricted function

fixed - the fixed values to the original function

Returns:

an input to the original function