com.numericalmethod.suanshu.analysis.function.rn2r1
Class Projection

java.lang.Object
  com.numericalmethod.suanshu.analysis.function.rn2r1.Projection

All Implemented Interfaces:

Function, RealScalarFunction

public class Projection
extends java.lang.Object
implements RealScalarFunction

This class creates a real-valued function RealScalarFunction from a vector-valued function RealVectorFunction by taking only one of its coordinate components in the vector output. This is essentially projecting a high dimensional output to only 1 dimension.

For example, suppose we have a Rⁿ → R^m RealVectorFunction

 f1 = [y1, y2, y3]'
 

We can create a Rⁿ → R¹ RealScalarFunction by taking its second coordinate. That is

 f2 = y2
 

Nested Class Summary

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

Function.EvaluationException

Field Summary

int	dimension the dimension/coordinate to take from the output of f It counts from 1.
RealVectorFunction	f the original Rn → Rm function

Constructor Summary

Projection(RealVectorFunction f, int dimension)
Construct a Rⁿ → R¹ projection from the Rⁿ → R^m function f.

Method Summary

int	dimension4Domain() Get the number of variables of the function.
int	dimension4Range() Get the dimension of the range space the function.
double	evaluate(double... x) A real function, f, takes a double array double[], {x0, x1, ..., xn} and maps it to a double, f(x0, x1, ..., xn)

Methods inherited from class java.lang.Object

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

Field Detail

f

public final RealVectorFunction f

the original Rⁿ → R^m function

dimension

public final int dimension

the dimension/coordinate to take from the output of f

It counts from 1.

Constructor Detail

Projection

public Projection(RealVectorFunction f,
                  int dimension)

Construct a Rⁿ → R¹ projection from the Rⁿ → R^m function f.

Parameters:

f - a vector-valued function

dimension - the dimension/coordinate of the f value to output

Method Detail

evaluate

public double evaluate(double... x)

Description copied from interface: RealScalarFunction

A real function, f, takes a double array double[],

{x0, x1, ..., xn}

and maps it to a double,

f(x0, x1, ..., xn)

Specified by:

evaluate in interface RealScalarFunction

Parameters:

x - {x} = {x0, x1, ... xn}

Returns:

f({x}) as output

dimension4Domain

public int dimension4Domain()

Description copied from interface: Function

Get the number of variables of the function.

For example, for a univariate function, the domain dimension is 1. For a bivariate function, the domain dimension is 2.

Specified by:

dimension4Domain in interface Function

Returns:

the number of variables

dimension4Range

public int dimension4Range()

Description copied from interface: Function

Get the dimension of the range space the function.

For example, for a Rn->Rm function, the dimension of the range is m.

Specified by:

dimension4Range in interface Function

Returns:

the dimension of the range