com.numericalmethod.suanshu.analysis.differentiation.multivariate
Class GradientFunction

java.lang.Object
  com.numericalmethod.suanshu.analysis.differentiation.multivariate.GradientFunction

All Implemented Interfaces:

Function, RealVectorFunction

public class GradientFunction
extends java.lang.Object
implements RealVectorFunction

Compute the gradient function, g(x), for a real scalar function f(x).

The gradient function evaluates the gradient at a point using a numerical method, e.g., finite difference. g(x) has the same domain as f(x). Its range dimension is the same as the domain dimension.

Nested Class Summary

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

Function.EvaluationException

Field Summary

RealScalarFunction

f the real scalar function to compute the gradient for

Constructor Summary

GradientFunction(RealScalarFunction f)
Construct a GradientFunction to compute the gradient numerically.

Method Summary

int	dimension4Domain() Get the number of variables of the function.
int	dimension4Range() Get the dimension of the range space the function.
Vector	evaluate(double... x) Compute g(x).

Methods inherited from class java.lang.Object

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

Field Detail

f

public final RealScalarFunction f

the real scalar function to compute the gradient for

Constructor Detail

GradientFunction

public GradientFunction(RealScalarFunction f)

Construct a GradientFunction to compute the gradient numerically.

Parameters:

f - a real scalar function

Method Detail

evaluate

public Vector evaluate(double... x)

Compute g(x). A real function, f, takes a double array double[],

{x0, x1, ..., xn}

and maps it to a Vector,

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

Specified by:

evaluate in interface RealVectorFunction

Parameters:

x - a point x

Returns:

g(x)

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