Learn more about MATLAB Builder NE

Matrix Math Example (Visual Basic)

To create the component for this example, see the first few steps in Matrix Math Example. Then create a Microsoft Visual Basic application as follows.

1. Review the sample application for this example in:

   matlabroot\toolbox\dotnetbuilder\Examples\VS8\NET\MatrixMathExample
   \MatrixMathVBApp\MatrixMathApp.vb.

   The program listing is shown here.

    MatrixMathApp.vb

   ' *******************************************************************************
   '
   ' MatrixMathApp.vb
   '
   ' This example demonstrates how to use MATLAB Builder NE to build a component 
   ' that returns multiple results and optionally uses sparse matrices for 
   ' arguments.  
   ' Copyright 2001-2009 The MathWorks, Inc.
   '
   ' *******************************************************************************
   
   Imports System
   
   Imports MathWorks.MATLAB.NET.Utility
   Imports MathWorks.MATLAB.NET.Arrays
   
   Imports MatrixMathComp
   
   
   Namespace MathWorks.Demo.MatrixMathApp
   
       ' <summary>
       ' This application computes cholesky, LU, and QR factorizations of a finite difference matrix of order N.
       ' The order is passed into the application on the command line.   
       ' </summary>
       ' <remarks>
       ' Command Line Arguments:
       ' <newpara></newpara>
       ' args[0] - Matrix order(N)
       ' <newpara></newpara>
       ' args[1] - (optional) sparse; Use a sparse matrix
       ' </remarks>
       Class MatrixMathDemoApp
   
   #Region " MAIN "
   
           ' <summary>
           ' The main entry point for the application.
           ' </summary>
           Shared Sub Main(ByVal args() As String)
   
               Dim makeSparse As Boolean = True
               Dim matrixOrder As Integer = 4
   
               Dim matrix As MWNumericArray = Nothing ' The matrix to factor
   
               Dim argOut As MWArray = Nothing   ' Stores single factorization result
               Dim argsOut() As MWArray = Nothing  ' Stores multiple factorization results
   
               Try
                   ' If no argument specified, use defaults
                   If (0 <> args.Length) Then
                       'Convert matrix order
                       matrixOrder = Int32.Parse(args(0))
   
                       If (0 > matrixOrder) Then
                           Throw New ArgumentOutOfRangeException("matrixOrder", matrixOrder, _
                                                                 "Must enter a positive integer for the matrix order(N)")
                       End If
   
                       makeSparse = ((1 < args.Length) AndAlso (args(1).Equals("sparse")))
                   End If
   
                   ' Create the test matrix.  If the second argument is "sparse", create a sparse matrix.
                   matrix = IIf(makeSparse, _
                   MWNumericArray.MakeSparse(matrixOrder, matrixOrder, MWArrayComplexity.Real, (matrixOrder + (2 * (matrixOrder - 1)))), _
                   New MWNumericArray(MWArrayComplexity.Real, MWNumericType.Double, matrixOrder, matrixOrder))
   
                   ' Initialize the test matrix
                   For rowIdx As Integer = 1 To matrixOrder
                       For colIdx As Integer = 1 To matrixOrder
                           If rowIdx = colIdx Then
                               matrix(rowIdx, colIdx) = New MWNumericArray(2.0)
                           ElseIf colIdx = rowIdx + 1 Or colIdx = rowIdx - 1 Then
                               matrix(rowIdx, colIdx) = New MWNumericArray(-1.0)
                           End If
                       Next colIdx
                   Next rowIdx
   
                   ' Create a new factor object
                   Dim factor As Factor = New Factor
   
                   ' Print the test matrix
                   Console.WriteLine("Test Matrix:{0}{1}{2}", Chr(10), matrix, Chr(10))
   
                   ' Compute and print the cholesky factorization using the single output syntax
                   argOut = factor.cholesky(matrix)
   
                   Console.WriteLine("Cholesky Factorization:{0}{1}{2}", Chr(10), argOut, Chr(10))
   
                   ' Compute and print the LU factorization using the multiple output syntax
                   argsOut = factor.ludecomp(2, matrix)
   
                   Console.WriteLine("LU Factorization:{0}L Matrix:{1}{2}{3}U Matrix:{4}{5}{6}", Chr(10), Chr(10), argsOut(0), Chr(10), Chr(10), argsOut(1), Chr(10))
   
                   MWNumericArray.DisposeArray(argsOut)
   
                   ' Compute and print the QR factorization 
                   argsOut = factor.qrdecomp(2, matrix)
   
                   Console.WriteLine("QR Factorization:{0}Q Matrix:{1}{2}{3}R Matrix:{4}{5}{6}", Chr(10), Chr(10), argsOut(0), Chr(10), Chr(10), argsOut(1), Chr(10))
   
                   Console.ReadLine()
   
               Catch exception As Exception
   
                   Console.WriteLine("Error: {0}", exception)
   
               Finally
   
                   ' Free native resources
                   If Not (matrix Is Nothing) Then
                       matrix.Dispose()
                   End If
                   If Not (argOut Is Nothing) Then
                       argOut.Dispose()
                   End If
   
                   MWNumericArray.DisposeArray(argsOut)
               End Try
           End Sub
   #End Region
       End Class
   End Namespace
   

   The statement

   Dim factor As Factor = New Factor

   creates an instance of the class Factor.

   The following statements call the methods that encapsulate the MATLAB functions:

   argOut = factor.cholesky(matrix)
   
      
   argsOut = factor.ludecomp(2, matrix)
   
   ...
   argsOut = factor.qrdecomp(2, matrix)

   Note   See Understanding the MatrixMath Program for more details about the structure of this program.

2. Build the MatrixMathApp application using Visual Studio .NET.

   1. The MatrixMathVBApp folder contains a Visual Studio .NET project file for this example. Open the project in Visual Studio .NET by double-clicking MatrixMathVBApp.vbproj in Windows Explorer. You can also open it from the MATLAB desktop by right-clicking MatrixMathVBApp.vbproj > Open Outside MATLAB.

   2. Add a reference to the MWArray component, which is matlabroot\toolbox\dotnetbuilder\bin\architecture\framework_version
      \mwarray.dll.

   3. If necessary, add (or update the location of) a reference to the MatrixMathComp component which you built in a previous step. (The component, MatrixMathComp.dll, is in the \MatrixMathExample\MatrixMathComp\x86\V2.0\Debug\distrib subfolder of your work area.)

3. Build and run the application in Visual Studio .NET.

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