Complex Math Library for C# and VB.NET

• Download DLL and source files - 57.3 KB

Introduction

Update: Things have changed since this article was written in 2002. (Thanks artcodingSB for the note) .NET now has complex types built in. If you are using an older version of .NET, this might still be helpful.

• https://msdn.microsoft.com/en-us/library/system.numerics.complex(v=vs.111).aspx

The .NET platform doesn't have complex numbers built in. If you do scientific calculations such as groundwater modeling, complex numbers are essential. This tip describes a full implementation of complex numbers for .NET, and how to use it with VB or C#.

Complex numbers have a real and imaginary part. Math operations are performed on complex numbers using special rules to keep track of the real and imaginary parts. Fortran and C++ have complex numbers built in.

C# Example (cs_complex.cs)

using System;
using KarlsTools;

class TestComplex{
   static void Main(string[] args)
    {
        Complex c1 = new Complex(3.0, 4.0);
        double d = Complex.Abs(c1);
        Console.WriteLine("Test Complex,  d = "+ d);
    }
}

Compile and run the above code with the following commands:

c:\>csc cs_complex.cs /r:complex.dll
C:\>cs_complex
Test Complex, d = 5

using System;
using KarlsTools;

VB .NET Example (vb_complex.vb)

Imports System
Imports KarlsTools

Module Module1

    Sub Main()
        Dim c1 As Complex = New Complex(3.0, 4.0)
        dim d as Double = Complex.Abs(c1)
        Console.WriteLine("Test Complex,  d = "& d.ToString())
    End Sub
End Module

Compile and run the above code with the following commands:

c:\>vbc vb_complex.vb /r:complex.dll /r:System.dll
c:\>vb_complex.exe
Test Complex, d = 5

Imports KarlsTools

Implementation

This class is implemented using Managed C++. It duplicates the capabilities of the Fortran complex*16 type, and is a value type class with static (shared) math functions. This is how the .NET Math class is designed. Non-trivial methods are wrappers around the Standard Template Library (STL) <complex> class. The library has been tested with C# against all C++ STL <complex> sample output on Microsoft's web site.

Use either Visual Studio or the make file to compile the library (complex.dll). If you have Visual C++, open complex.vcproj and build. An alternate way to compile is by typing 'nmake' from a command prompt. A make file is included with the download.

Issues When Wrapping a C++ STL Class for Use with VB and C#

An easy way to provide complete functionality is to wrap the C++ STL <complex> class using Managed C++. This works well but wrapped methods run twice as slow as a method written from scratch. This is because the MSIL code generated by the C++ compiler has calls to the System.Runtime.CompilerServices to access the STL. I compromised by writing trivial methods from scratch and relied on the STL implementation otherwise.

This class duplicates the FORTRAN complex*16 type. Eight bytes for the real part, and 8 bytes for the imaginary part, by using std::complex<double>. This is not as flexible as the C++ STL class which allows double, float, or int to be used.

Extra code was added to provide VB functionality. The C++/C# operators !=, ==, +, -, * and / didn't directly work in VB. I added methods: NotEqual, Equals, Add, Subtract, Multiply and Divide to provide complete functionality in VB. I do not understand why I needed to do this - please comment.