constantcurve.vb

这里是用VB写的数学库。以前用C、C++写的比较多。内容有：复数运算、矩阵运算、解方程、积分微分等。非常有用。

' The Constant class resides in the Extreme.Mathematics.Curves namespace.
Imports Extreme.Mathematics.Curves

Namespace Extreme.Mathematics.QuickStart.VB

    ' Illustrates the use of the DoubleComplex class in the
    ' Extreme Optimization Mathematics Library for .NET.
    Module ConstantCurve

        Sub Main()
            ' All curves inherit from the Curve abstract base
            ' class. It cannot be instantiated. This class 
            ' defines methods and properties that are available
            ' to all derived types, including Constant, Line,
            ' Quadratic, Polynomial, ChebyshevSeries and
            ' LinearFunction.
            '
            ' This QuickStart sample illustrates the Constant
            ' class.

            ' 
            ' Creating Constant curves.
            '

            ' Let's start by creating a Constant curve and some 
            ' Line curves.
            ' A Constant curve has the same value everywhere.
            Dim constant1 As Constant = New Constant(3)
            ' There is one predefined Constant curve, which is
            ' zero everywhere:
            Dim constant2 As Constant = Constant.Zero

            '
            ' Curve Parameters
            '

            ' The shape of any curve is determined by a set of parameters.
            ' These parameters can be retrieved and set through the
            ' Parameters collection. The number of parameters for a curve 
            ' is given by this collection's Count property.
            '
            ' Constants have one parameter: the y value.
            Console.WriteLine("constant1.ParameterCount = {0}", _
                constant1.Parameters.Count)
            ' Parameters can easily be retrieved:
            Console.WriteLine("constant1.Parameters(0) = {0}", _
                constant1.Parameters(0))
            ' Parameters can also be set:
            constant1.Parameters(0) = 3

            '
            ' Curve Methods
            '

            ' The ValueAt method returns the y value of the
            ' curve at the specified x value:
            Console.WriteLine("constant1.ValueAt(2) = {0}", _
                constant1.ValueAt(2))

            ' The SlopeAt method returns the slope of the curve
            ' a the specified x value:
            Console.WriteLine("constant1.SlopeAt(2) = {0}", _
                constant1.SlopeAt(2))

            ' You can also create a new curve that is the 
            ' derivative of the original:
            Dim derivative As Curve = constant1.GetDerivative()
            Console.WriteLine("Slope at 2 (derivative) = {0}", _
                derivative.ValueAt(2))

            ' You can get a Line that is the tangent to a curve
            ' at a specified x value using the TangentAt method:
            Dim tangent As Line = constant1.TangentAt(2)
            Console.WriteLine("Slope of tangent line at 2 = {0}", _
                tangent.Slope)

            ' For many curves, you can evaluate a definite
            ' integral exactly:
            Console.WriteLine("Integral between 0 and 1 = {0}", _
                constant1.Integral(0, 1))

            ' You can find the zeroes or roots of the curve
            ' by calling the FindRoots method:
            Dim roots As Double() = constant1.FindRoots()
            Console.WriteLine("constant1 curve has {0} roots.", _
                roots.Length)

            Console.Write("Press Enter key to exit...")
            Console.ReadLine()
        End Sub

    End Module

End Namespace