FunctionMath.ForwardDerivative Method

Definition

Namespace: Numerics.NET
Assembly: Numerics.NET (in Numerics.NET.dll) Version: 9.0.3

Overload List

ForwardDerivative(Func<Double, Double>, Double) Returns an approximation to the derivative of a function by using only function values at x and and values greater than x.
ForwardDerivative(Func<Double, Double>, Double, Double) Returns an approximation to the derivative of a function by using only function values at x and and values greater than x.
ForwardDerivative(Func<Double, Double>, Double, Double, Int32) Returns an approximation to the derivative of a function by using only function values at x and and values greater than x.
ForwardDerivative(Func<Double, Double>, Double, Int32, Int32, Boolean, Double, Double, Double) Returns an approximation to the derivative of the specified order of a function using forward finite differences.

ForwardDerivative(Func<Double, Double>, Double)

Returns an approximation to the derivative of a function by using only function values at x and and values greater than x.
C#
public static double ForwardDerivative(
	this Func<double, double> targetFunction,
	double x
)

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

Double
A numerical approximation to the derivative of targetFunction at x.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type Func<Double, Double>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

Exceptions

ArgumentNullException

targetFunction is null.

ForwardDerivative(Func<Double, Double>, Double, Double)

Returns an approximation to the derivative of a function by using only function values at x and and values greater than x.
C#
public static double ForwardDerivative(
	this Func<double, double> targetFunction,
	double x,
	out double estimatedError
)

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.
estimatedError  Double
On exit, this parameter contains an estimate of the absolute error of the approximation.

Return Value

Double
A numerical approximation to the derivative of targetFunction at x.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type Func<Double, Double>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

Exceptions

ArgumentNullException

targetFunction is null.

ForwardDerivative(Func<Double, Double>, Double, Double, Int32)

Returns an approximation to the derivative of a function by using only function values at x and and values greater than x.
C#
public static double ForwardDerivative(
	this Func<double, double> targetFunction,
	double x,
	out double estimatedError,
	out int evaluationsNeeded
)

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.
estimatedError  Double
On exit, this parameter contains an estimate of the absolute error of the approximation.
evaluationsNeeded  Int32
On exit, this parameter contains the number of function evaluations needed to calculate the numerical derivative.

Return Value

Double
A numerical approximation to the derivative of targetFunction at x.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type Func<Double, Double>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

Exceptions

ArgumentNullException

targetFunction is null.

ForwardDerivative(Func<Double, Double>, Double, Int32, Int32, Boolean, Double, Double, Double)

Returns an approximation to the derivative of the specified order of a function using forward finite differences.
C#
public static double ForwardDerivative(
	this Func<double, double> targetFunction,
	double x,
	int order = 1,
	int accuracyOrder = 2,
	bool adaptive = false,
	double xMin = -1.79769313486232E+308,
	double xMax = 1.79769313486232E+308,
	double noiseFactor = 10
)

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.
order  Int32  (Optional)
Optional. The order of the derivative. The default is 1.
accuracyOrder  Int32  (Optional)
Optional. The accuracy order of the finite difference method. The default is 2.
adaptive  Boolean  (Optional)
Optional. If true, the step size is computed based on the function values around the points where the function's derivative is requested. If false (the default), a default step size is used.
xMin  Double  (Optional)
Optional. The smallest value for which the function may be evaluated. The default is MinValue.
xMax  Double  (Optional)
Optional. The largest value for which the function may be evaluated. The default is MaxValue.
noiseFactor  Double  (Optional)
Optional. An estimate for the noise in the function values relative to the machine precision. The default is 10.

Return Value

Double
A numerical approximation to the derivative of targetFunction at x.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type Func<Double, Double>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

Exceptions

ArgumentNullException

targetFunction is null.

ArgumentOutOfRangeException

order is less than zero.

See Also