Integrating a Simple MATLAB Function

The purpose of these examples is to highlight main steps required for integrating a MATLAB^® function.

Simple Plot

To create the component for this example, see Integrating a Simple MATLAB Function. Then create a Visual Basic^® application as follows:

Review the sample application for this example in matlabroot\toolbox\dotnetbuilder\Examples\VSVersion\NET\PlotExample\PlotVBApp\PlotApp.vb.

The program listing is shown here.

PlotApp.vb

The program does the following:

Creates two arrays of double values
Creates a Plotter object
Calls the drawgraph method to plot the equation using the MATLAB plot function
Uses MWNumericArray to handle the data needed by the drawgraph method to plot the equation
Note
For information about these data conversion classes, see the MATLAB MWArray Class Library Reference, available in the matlabroot\help\dotnetbuilder\MWArrayAPI folder, where matlabroot represents your MATLAB installation folder
Uses a try-catch block to catch and handle any exceptions

The statement

Dim plotter As Plotter = New Plotter

creates an instance of the Plotter class, and the statement

plotter.drawgraph(coords)

calls the method drawgraph.

Build the PlotApp application using Visual Studio^® .NET.
1. The PlotVBApp folder contains a Visual Studio .NET project file for this example. Open the project in Visual Studio .NET by double-clicking PlotVBApp.vbproj in Windows^® Explorer. You can also open it from the desktop by right-clicking PlotVBApp.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 fix the location of) a reference to the PlotComp component which you built in a previous step. (The component, PlotComp.dll, is in the \PlotExample\PlotComp\x86\V2.0\Debug\distrib subfolder of your work area.)
Build and run the application in Visual Studio .NET.

Phone Book

makephone Function

The makephone function takes a structure array as an input, modifies it, and supplies the modified array as an output.

Note

For complete reference information about the MWArray class hierarchy, see the MWArray API documentation.

Procedure

If you have not already done so, copy the files for this example as follows:
1. Copy the following folder that ships with MATLAB to your work folder:
```
matlabroot\toolbox\dotnetbuilder\Examples\VSVersion\NET\PhoneBookExample
```
2. At the MATLAB command prompt, cd to the new PhoneBookExample subfolder in your work folder.
Write the makephone function as you would any MATLAB function.
The following code defines the makephone function:
```
function book = makephone(friends)

book = friends;
for i = 1:numel(friends)
    numberStr = num2str(book(i).phone);
    book(i).external = ['(508) 555-' numberStr];
end
```
This code is already in your work folder in PhoneBookExample\PhoneBookComp\makephone.m.
From the MATLAB apps gallery, open the Library Compiler app.
Build the .NET component. See the instructions in Generate a .NET Assembly and Build a .NET Application for more details. Use the following information:

Project Name PhoneBookComp
Class Name phonebook
File to compile makephone.m

Write source code for an application that accesses the component.

The sample application for this example is in matlabroot\toolbox\dotnetbuilder\Examples\VSVersion\NETPhoneBookExample\PhoneBookVBApp\PhoneBookApp.vb.

The program defines a structure array containing names and phone numbers, modifies it using a MATLAB function, and displays the resulting structure array.

The program listing is shown here.

PhoneBookApp.vb

' Necessary package imports

Imports MathWorks.MATLAB.NET.Arrays
Imports PhoneBookComp

'
' getphone class demonstrates the use of the MWStructArray class
'
Public Module PhoneBookVBApp
    Public Sub Main()
        Dim thePhonebook As phonebook   'Stores deployment class instance
        Dim friends As MWStructArray    'Sample input data
        Dim result As Object()          'Stores the result
        Dim book As MWStructArray       'Output data extracted from result

        ' Create the new deployment object 
        thePhonebook = New phonebook()

        ' Create an MWStructArray with two fields 
        Dim myFieldNames As String() = {"name", "phone"}
        friends = New MWStructArray(2, 2, myFieldNames)

        ' Populate struct with some sample data --- friends and phone numbers 
        friends("name", 1) = New MWCharArray("Jordan Robert")
        friends("phone", 1) = 3386
        friends("name", 2) = New MWCharArray("Mary Smith")
        friends("phone", 2) = 3912
        friends("name", 3) = New MWCharArray("Stacy Flora")
        friends("phone", 3) = 3238
        friends("name", 4) = New MWCharArray("Harry Alpert")
        friends("phone", 4) = 3077

        ' Show some of the sample data 
        Console.WriteLine("Friends: ")
        Console.WriteLine(friends.ToString())

        ' Pass it to a MATLAB function that determines external phone number 
        result = thePhonebook.makephone(1, friends)
        book = CType(result(0), MWStructArray)
        Console.WriteLine("Result: ")
        Console.WriteLine(book.ToString())

        ' Extract some data from the returned structure '
        Console.WriteLine("Result record 2:")

        Console.WriteLine(book("name", 2))
        Console.WriteLine(book("phone", 2))
        Console.WriteLine(book("external", 2))

        ' Print the entire result structure using the helper function below 
        Console.WriteLine("")
        Console.WriteLine("Entire structure:")
        dispStruct(book)
    End Sub


    Sub dispStruct(ByVal arr As MWStructArray)
        Console.WriteLine("Number of Elements: " + arr.NumberOfElements.ToString())
        'int numDims = arr.NumberofDimensions
        Dim dims As Integer() = arr.Dimensions
        Console.Write("Dimensions: " + dims(0).ToString())

        Dim i As Integer
        For i = 1 To dims.Length
            Console.WriteLine("-by-" + dims(i - 1).ToString())
        Next i
        Console.WriteLine("")
        Console.WriteLine("Number of Fields: " + arr.NumberOfFields.ToString())
        Console.WriteLine("Standard MATLAB view:")
        Console.WriteLine(arr.ToString())
        Console.WriteLine("Walking structure:")

        Dim fieldNames As String() = arr.FieldNames

        Dim element As Integer
        For element = 1 To arr.NumberOfElements
            Console.WriteLine("Element " + element.ToString())
            Dim field As Integer
            For field = 0 To arr.NumberOfFields - 1
                Dim fieldVal As MWArray = arr(arr.FieldNames(field), element)
                ' Recursively print substructures, give string display of other classes 
                If (TypeOf fieldVal Is MWStructArray) Then
                    Console.WriteLine("   " + fieldNames(field) + ": nested structure:")
                    Console.WriteLine("+++ Begin of \"" + fieldNames[field] + 
                                                      " \ " nested structure")

                    dispStruct(CType(fieldVal, MWStructArray))
                    Console.WriteLine("+++ End of \"" + fieldNames[field] + 
                                                      " \ " nested structure")
                Else
                    Console.Write("   " + fieldNames(field) + ": ")
                    Console.WriteLine(fieldVal.ToString())
                End If
            Next field
        Next element
    End Sub
End Module

The program does the following:

Creates a structure array, using MWStructArray to represent the example phonebook data.
Instantiates the plotter class as thePhonebook object, as shown: thePhonebook = new phonebook();
Calls the makephone method to create a modified copy of the structure by adding an additional field, as shown: result = thePhonebook.makephone(1, friends);

Build thePhoneBookVBApp application using Visual Studio .NET.
1. The PhoneBookVBApp folder contains a Visual Studio .NET project file for this example. Open the project in Visual Studio .NET by double-clicking PhoneBookVBApp.vbproj in Windows Explorer. You can also open it from the desktop by right-clicking PhoneBookVBApp.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 fix the location of) a reference to the PhoneBookVBComp component which you built in a previous step. (The component, PhoneBookComp.dll, is in the \PhoneBookExample\PhoneBookVBApp\x86\V2.0\Debug\distrib subfolder of your work area.)

Build and run the application in Visual Studio .NET.

The getphone program should display the output:

Friends: 
2x2 struct array with fields:
    name
    phone
Result: 
2x2 struct array with fields:
    name
    phone
    external
Result record 2:
Mary Smith
3912
(508) 555-3912

Entire structure:
Number of Elements: 4
Dimensions: 2-by-2
Number of Fields: 3
Standard MATLAB view:
2x2 struct array with fields:
    name
    phone
    external
Walking structure:
Element 1
   name: Jordan Robert
   phone: 3386
   external: (508) 555-3386
Element 2
   name: Mary Smith
   phone: 3912
   external: (508) 555-3912
Element 3
   name: Stacy Flora
   phone: 3238
   external: (508) 555-3238
Element 4
   name: Harry Alpert
   phone: 3077
   external: (508) 555-3077

Documentation