Integrating a Simple MATLAB Function

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

Simple Plot

Purpose

The drawgraph function displays a plot of input parameters x and y. The purpose of the example is to show you how to:

Use the MATLAB Compiler SDK™ product to convert a MATLAB function (drawgraph) to a method of a .NET class (Plotter) and wrap the class in a .NET assembly (PlotComp).
Access the component in a C# application (PlotApp.cs) by instantiating the Plotter class and using the MWArray class library to handle data conversion.
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
Build and run the PlotCSApp application, using the Visual Studio^® .NET development environment.

Procedure

If you have not already done so, copy the files for this example as follows:
1. Copy the following folder that ships with the MATLAB product to your work folder:
```
matlabroot\toolbox\dotnetbuilder\Examples\VSVersion\NET\PlotExample
```
2. At the MATLAB command prompt, change folder to the new PlotExample\PlotComp subfolder in your work folder.
Write the drawgraph function as you would any MATLAB function.
This code is already in your work folder in PlotExample\PlotComp\drawgraph.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 PlotComp
Class Name Plotter
File to compile drawgraph.m

Write source code for a C# application that accesses the component.

The sample application for this example is in matlabroot\toolbox\dotnetbuilder\Examples\VSVersion\PlotExample \PlotCSApp\PlotApp.cs.

The program listing is shown here.

PlotApp.cs

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 represent the data needed by the drawgraph method to plot the equation.
Uses a try-catch block to catch and handle any exceptions.

The statement

 Plotter plotter= new Plotter();

creates an instance of the Plotter class, and the statement

plotter.drawgraph((MWNumericArray)plotValues);

explicitly casts the native plotValues to MWNumericArray and then calls the method drawgraph.

Build the PlotCSApp application using Visual Studio .NET.
1. The PlotCSApp folder contains a Visual Studio .NET project file for this example. Open the project in Visual Studio .NET by double-clicking PlotCSApp.csproj in Windows^® Explorer. You can also open it from the desktop by right-clicking PlotCSApp.csproj > Open Outside MATLAB.
2. Add a reference to the MWArray component, which is matlabroot\toolbox\dotnetbuilder\bin\architecture\framework_version\mwarray.dll.
3. Add or, if necessary, 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

Purpose

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

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

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)
%MAKEPHONE Add a structure to a phonebook structure
%   BOOK = MAKEPHONE(FRIENDS) adds a field to its input structure.
%   The new field EXTERNAL is based on the PHONE field of the original.
%   Copyright 2006-2012 The MathWorks, Inc.

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

Write source code for an application that accesses the component.

The sample application for this example is in matlabroot\toolbox\dotnetbuilder\Examples\VSVersion\NET\ PhoneBookExample\PhoneBookCSApp\PhoneBookApp.cs.

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.cs

/* Necessary package imports */
using System;
using System.Collections.Generic;
using System.Text;
using MathWorks.MATLAB.NET.Arrays;
using PhoneBookComp;

namespace MathWorks.Examples.PhoneBookApp
{
  //
  // This class demonstrates the use of the MWStructArray class
  //
  class PhoneBookApp
    {
      static void Main(string[] args)
        {
          PhoneBook thePhonebook = null;  /* Stores deployment class instance */
          MWStructArray friends= null;   /* Sample input data */
          MWArray[] result= null;        /* Stores the result */
          MWStructArray book= null;      /* Output data extracted from result */

          /* Create the new deployment object */
          thePhonebook= new PhoneBook();

          /* Create an MWStructArray with two fields */
          String[] myFieldNames= { "name", "phone" };
          friends= new MWStructArray(2, 2, myFieldNames);

          /* Populate struct with some sample data --- friends and phone */
          /*  number extensions */
          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= (MWStructArray)result[0];
 
          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);

          Console.ReadLine();
        }

      public static void DispStruct(MWStructArray arr)
        {
          Console.WriteLine("Number of Elements: " + arr.NumberOfElements);
            
          int[] dims= arr.Dimensions;

          Console.Write("Dimensions: " + dims[0]);

          for (int idx= 1; idx < dims.Length; idx++)
            {
              Console.WriteLine("-by-" + dims[idx]);
            }
            
          Console.WriteLine("\nNumber of Fields: " + arr.NumberOfFields);
          Console.WriteLine("Standard MATLAB view:");
          Console.WriteLine(arr.ToString());

          Console.WriteLine("Walking structure:");

          string[] fieldNames= arr.FieldNames;

          for (int element= 1; element <= arr.NumberOfElements; element++)
            {
              Console.WriteLine("Element " + element);

              for (int field= 0; field < arr.NumberOfFields; field++)
                {
                  MWArray fieldVal= arr[arr.FieldNames[field], element];
                    
                  /* Recursively print substructures, */
                  /*  give string display of other classes */
                  if (fieldVal.GetType() == typeof(MWStructArray))
                    {
                      Console.WriteLine("   " + fieldNames[field] + ": 
                          nested structure:");
                      Console.WriteLine("+++ Begin of \"" + fieldNames[field] + "\" 
                          nested structure");
                      DispStruct((MWStructArray)fieldVal);
                      Console.WriteLine("+++ End of \"" + fieldNames[field] + 
                          "\" nested structure");
                    }

                  else
                    {
                      Console.Write("   " + fieldNames[field] + ": ");
                      Console.WriteLine(fieldVal.ToString());
                    }
                }
            }
        }
    }
}

The program does the following:

Creates a structure array, using MWStructArray to represent the example phonebook data.
Instantiates the Phonebook 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 thePhoneBookCSApp application using Visual Studio .NET.
1. The PhoneBookCSApp folder contains a Visual Studio .NET project file for this example. Open the project in Visual Studio .NET by double-clicking PhoneBookCSApp.csproj in Windows Explorer. You can also open it from the desktop by right-clicking PhoneBookCSApp.csproj > 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 PhoneBookComp component which you built in a previous step. (The component, PhoneBookComp.dll, is in the \PhoneBookExample\PhoneBookComp\x86\V2.0\Debug\distrib subfolder of your work area.)

Build and run the application in Visual Studio .NET.

The PhoneBookApp 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