FunctionMath.Derivative Method

public static double Derivative(
	this Func<double, double> targetFunction,
	double x
)

<ExtensionAttribute>
Public Shared Function Derivative ( 
	targetFunction As Func(Of Double, Double),
	x As Double
) As Double

public:
[ExtensionAttribute]
static double Derivative(
	Func<double, double>^ targetFunction, 
	double x
)

[<ExtensionAttribute>]
static member Derivative : 
        targetFunction : Func<float, float> * 
        x : float -> float 

Parameters

targetFunction  Func<Double, Double>

A delegate that represents a function of one variable that specifies the function to differentiate.

x  Double

The point at which to evaluate the derivative.

Return Value

Usage Note

public static double Derivative(
	this Func<double, double> targetFunction,
	double x,
	DifferencesDirection direction
)

<ExtensionAttribute>
Public Shared Function Derivative ( 
	targetFunction As Func(Of Double, Double),
	x As Double,
	direction As DifferencesDirection
) As Double

public:
[ExtensionAttribute]
static double Derivative(
	Func<double, double>^ targetFunction, 
	double x, 
	DifferencesDirection direction
)

[<ExtensionAttribute>]
static member Derivative : 
        targetFunction : Func<float, float> * 
        x : float * 
        direction : DifferencesDirection -> float 

Parameters

targetFunction  Func<Double, Double>

A delegate that represents a function of one variable that specifies the function to differentiate.

x  Double

The point at which to evaluate the derivative.

direction  DifferencesDirection

A DifferencesDirection that specifies the interval to be used for differentiation.

Return Value

Usage Note

This method is useful when the targetFunction is not defined or is discontinuous on either side of x.

If the function is badly behaved on the left, you can set direction to Forward, and the function will only be evaluated at x and to the right of x. Passing Forward causes the function to be evaluated at x and points to the left of x.

If the function is well-behaved on both sides, you should use Central, since that will, in general, yield better results. This is also the default when the direction parameter is omitted.

public static double Derivative(
	this Func<double, double> targetFunction,
	double x,
	out double error
)

<ExtensionAttribute>
Public Shared Function Derivative ( 
	targetFunction As Func(Of Double, Double),
	x As Double,
	<OutAttribute> ByRef error As Double
) As Double

public:
[ExtensionAttribute]
static double Derivative(
	Func<double, double>^ targetFunction, 
	double x, 
	[OutAttribute] double% error
)

[<ExtensionAttribute>]
static member Derivative : 
        targetFunction : Func<float, float> * 
        x : float * 
        error : float byref -> float 

Parameters

targetFunction  Func<Double, Double>

A delegate that represents a function of one variable that specifies the function to differentiate.

x  Double

The point at which to evaluate the derivative.

error  Double

On return, an estimate for the error in the derivative.

Return Value

Usage Note

public static double Derivative(
	this Func<double, double> targetFunction,
	double x,
	DifferencesDirection direction,
	out int evaluationsNeeded
)

<ExtensionAttribute>
Public Shared Function Derivative ( 
	targetFunction As Func(Of Double, Double),
	x As Double,
	direction As DifferencesDirection,
	<OutAttribute> ByRef evaluationsNeeded As Integer
) As Double

public:
[ExtensionAttribute]
static double Derivative(
	Func<double, double>^ targetFunction, 
	double x, 
	DifferencesDirection direction, 
	[OutAttribute] int% evaluationsNeeded
)

[<ExtensionAttribute>]
static member Derivative : 
        targetFunction : Func<float, float> * 
        x : float * 
        direction : DifferencesDirection * 
        evaluationsNeeded : int byref -> float 

Parameters

targetFunction  Func<Double, Double>

A delegate that represents a function of one variable that specifies the function to differentiate.

x  Double

The point at which to evaluate the derivative.

direction  DifferencesDirection

A DifferencesDirection that specifies the interval to be used for differentiation.

evaluationsNeeded  Int32

On exit, contains the number of function evaluations needed to evaluate the derivative.

Return Value

Usage Note

This method is useful when the targetFunction is not defined or is discontinuous on either side of x.

If the function is badly behaved on the left, you can set direction to Forward, and the function will only be evaluated at x and to the right of x. Passing Forward causes the function to be evaluated at x and points to the left of x.

If the function is well-behaved on both sides, you should use Central, since that will, in general, yield better results. This is also the default when the direction parameter is omitted.

Reference