Examples of a MATLAB Automation Server :: Calling MATLAB COM Automation Server (MATLAB®)

Examples of a MATLAB Automation Server

On this page…
Example — Running MATLAB Function from Visual Basic .NET Program Example — Viewing Methods from a Visual Basic .NET Client Example — Calling MATLAB Software from a Web Application Example — Calling MATLAB Software from a C# Client

On this page…

Example — Running MATLAB Function from Visual Basic .NET Program

Example — Viewing Methods from a Visual Basic .NET Client

Example — Calling MATLAB Software from a Web Application

Example — Calling MATLAB Software from a C# Client

Example — Running MATLAB Function from Visual Basic .NET Program

This example calls a user-defined MATLAB function named solve_bvp from a Microsoft Visual Basic client application through a COM interface. It also plots a graph in a new MATLAB window and performs a simple computation:

Dim MatLab As Object
Dim Result As String
Dim MReal(1, 3) As Double
Dim MImag(1, 3) As Double

MatLab = CreateObject("Matlab.Application")

'Calling MATLAB function from VB
'Assuming solve_bvp exists at specified location
Result = MatLab.Execute("cd d:\matlab\work\bvp")
Result = MatLab.Execute("solve_bvp")

'Executing other MATLAB commands
Result = MatLab.Execute("surf(peaks)")
Result = MatLab.Execute("a = [1 2 3 4; 5 6 7 8]")
Result = MatLab.Execute("b = a + a ")
'Bring matrix b into VB program
MatLab.GetFullMatrix("b", "base", MReal, MImag)

Example — Viewing Methods from a Visual Basic .NET Client

You can find out what methods are available from a MATLAB Automation server using the Object Browser of your Microsoft Visual Basic client application. To do this, follow this procedure in the client application to reference the MATLAB Application Type Library:

Select the Project menu.
Select Reference from the subsequent menu.
Check the box next to the MATLAB Application Type Library.
Click OK.

This enables you to view MATLAB Automation methods from the Visual Basic Object Browser under the Library called MLAPP. You can also see a list of MATLAB Automation methods when you use the term Matlab followed by a period. For example:

Dim Matlab As MLApp.MLApp
Private Sub View_Methods()
Matlab = New MLApp.MLApp
'The next line shows a list of MATLAB Automation methods 
Matlab.
End Sub

Example — Calling MATLAB Software from a Web Application

This example shows you how to create a Web page that uses a MATLAB application as an Automation server. Run this example from a local system; you cannot deploy it from a Web server. For another example using ASP.NET, see Technical Support solution 1–3JJZWN.

You can invoke MATLAB as an Automation server from any language that supports COM, so for Web applications, you can use VBScript and JavaScript. While this example is simple, it illustrates techniques for passing commands to MATLAB and writing data to and retrieving data from the MATLAB workspace. See Exchanging Data with the Server for related functions.

VBScript and HTML forms are combined in this example to create an interface that enables the user to select a MATLAB plot type from a pull-down menu, click a button, and create the plot in a MATLAB figure window. To accomplish this, the HTML file contains code that:

Starts MATLAB as an Automation server via a VBScript.
When users click a button on the HTML page, a VBScript executes that:
1. Determines the type of plot selected.
2. Forms a command string to create the type of plot selected.
3. Forms a string describing the type of plot selected, which passes to the MATLAB base workspace in a variable.
4. Executes the MATLAB command.
5. Retrieves the descriptive string from the MATLAB workspace.
6. Updates the text box on the HTML page.

Here is the HTML used to create this example:

<HTML>
<HEAD>
<TITLE>Example of calling MATLAB from VBScript</TITLE>
</HEAD>
<BODY>
<FONT FACE = "Arial, Helvetica, Geneva" SIZE = "+1" COLOR = "maroon">
Example of calling MATLAB from VBScript
</FONT>
<FONT FACE = "Arial, Helvetica, Geneva" SIZE = "-1">

<!-- %%%%%%%%%%%%%%%%%%%% BEGIN SCRIPT %%%%%%%%%%%%%%%%%%%% -->
<SCRIPT LANGUAGE="VBScript">
<!-- Invoke MATLAB as a COM Automation server upon loading page
' Initialize global variables
Dim MatLab	'COM Automation server variable
Dim MLcmd	'string to send to MATLAB for execution
' Invoke COM Automation server
Set MatLab = CreateObject("Matlab.Application")
' End initialization script -->	
</SCRIPT>

<!-- %%%%%%%%%%%%%%%%%%%% END SCRIPT %%%%%%%%%%%%%%%%%%%% -->
<!-- Create form to contain controls -->
<FORM NAME="Form">
<!-- Create pulldown menu to select which plot to view -->
<P>Select type of plot:
<SELECT NAME=plot_choice>
	<OPTION SELECTED VALUE=first>Line</OPTION>
	<OPTION VALUE=second>Peaks</OPTION>
	<OPTION VALUE=third>Logo</OPTION>
</SELECT>
<!-- Create button to create plot and fill text area -->
<P>Create figure:
<INPUT TYPE="button" NAME="plot_but" VALUE="Plot">

<!-- %%%%%%%%%%%%%%%%%%%% BEGIN SCRIPT %%%%%%%%%%%%%%%%%%%% -->
<SCRIPT FOR="plot_but" EVENT="onClick" LANGUAGE="VBScript">
<!-- Start script 
Dim plot_choice
Dim text_str  	'string to display in text area
Dim form_var	'form object variable
Set form_var = Document.Form
plot_choice = form_var.plot_choice.value
' Condition MATLAB command to execute based on plot choice
If plot_choice = "first"	Then
   MLcmd = "figure; plot(1:10);" 
   text_str = "Simple line plot of 1 to 10"
   Call MatLab.PutCharArray("text","base",text_str)
Elseif plot_choice = "second" Then
   MLcmd = "figure; mesh(peaks);" 
   text_str = "Mesh plot of peaks"
   Call MatLab.PutCharArray("text","base",text_str)
Elseif plot_choice = "third" Then
   MLcmd = "figure; logo;" 
   text_str = "MATLAB logo"
   Call MatLab.PutCharArray("text","base",text_str)
End If
' Execute command in MATLAB
MatLab.execute(MLcmd)
' Get variable from MATLAB into VBScript
Call MatLab.GetWorkspaceData("text","base","text_str")
' Update text area	
form_var.plottext.value = text_str
' End script -->
</SCRIPT>

<!-- %%%%%%%%%%%%%%%%%%%% END SCRIPT %%%%%%%%%%%%%%%%%%%% -->
<!-- Create text area to show text -->
<P><TEXTAREA NAME="plottext" ROWS="1" COLS="50" 
CONTENTEDITABLE="false"></TEXTAREA> 
</FONT>
</FORM>
</BODY>
</HTML>

Example — Calling MATLAB Software from a C# Client

This example creates data in the client C# program and passes it to MATLAB. The matrix (containing complex data) is then passed back to the C# program.

The reference to the MATLAB Type Library for C# is:

MLApp.MLAppClass matlab = new MLApp.MLAppClass();

From your C# client program, add a reference to your project to the MATLAB COM object. For example, in Microsoft Visual Studio, open your project. From the Project menu, select Add Reference. Select the COM tab in the Add Reference dialog box. Select the MATLAB application.

Here is the complete example:

using System;
namespace ConsoleApplication4
{
class Class1
{
[STAThread]
static void Main(string[] args)
{
MLApp.MLAppClass matlab = new MLApp.MLAppClass();

System.Array pr = new double[4];
pr.SetValue(11,0);
pr.SetValue(12,1);
pr.SetValue(13,2);
pr.SetValue(14,3);

System.Array pi = new double[4];
pi.SetValue(1,0);
pi.SetValue(2,1);
pi.SetValue(3,2);
pi.SetValue(4,3);

matlab.PutFullMatrix("a", "base", pr, pi);

System.Array prresult = new double[4];
System.Array piresult = new double[4];

matlab.GetFullMatrix("a", "base", ref prresult, ref piresult);
}
}
}