The MathWizards Java Package

The MathWizards Java^TM package is a set of Java classes that provide matlab-compatible interpretation capabilities to Java applets and applications running on Windows NT/95. This document describes the contents of the package and provides instructions for running the included demonstrations.

NOTE: The MathWizards package is compatible with Java 1.1. Using it with Java 1.0 will not work!

• Security Warning
• Contents of this directory
• Additional software you may need to obtain
• How to run the demos
• Troubleshooting

Security Warning

The MathXplorer/J, MathViews interpreter class does not currently abide by the security limitations imposed by applet-running environments. In fact, the MathViews interpreter has full access to the host on which it runs. It can invoke external commands, traverse the host's file system, even create and delete commands, even if the applet which includes it does not have those permissions. You should bear this openness in mind when writing or running applets/applications.

Contents of this directory

• MathWizards package jar files, containing classes loaded dynamically during the execution of an applet or application.
• The graph package distribution, including java source, demos, and documentation. This package provides 2D plotting functionality. It is licensed by Leigh Brookshaw, its author, under the terms of the GNU General Public License.
• graph package jar file.
• Java source files for the MathWizards.demo package, which includes demonstration applets and applications.
• Documentation for the MathWizards class API.
• MathViews' script file (M-files) used by some of the demonstration applets.
• batch files that illustrate the necessary steps to run the demos. You will need to modify bin/setpath.bat to match your installation. Run hindex.bat for the master list of MathXplorer/J demos.

Additional software you may need to obtain

• If you are going to develop applets or applications that incorporate any of the MathWizards classes, you must use development tools found in any JDK 1.1-compatible development environment. Sun Microsystem's own JDK 1.1, found at the JavaSoft site, will do. The JDK 1.1 distribution includes appletviewer which runs applets, and java and jre, which run stand-alone Java applications.
• If you are not developing applets or applications, all you need is a Java SDK 1.1-compatible runtime environment. Again, Sun's own JRE will work nicely.
• If you want to view MathWizards-based applets in a Web browser, you are currently limited to Sun's HotJava 1.0, which is the only browser that fully implements Java SDK 1.1. According to Netscape, full support in Navigator/Communicator is imminent...

How to run the demos

• Install MathViews. The installation does two things that are relevant to the Java package:
  • It places the libraries mathsrv1.dll and mwjni11.dll in appropriate system directories where they will be seen by Java. If you've moved these DLL's to other directories, make sure you add those directories to the PATH environment variable. Otherwise, "UnsatisfiedLinkError" will surely appear.

  • It defines the MVPATH environment variable. Like the PATH and CLASSPATH variables, this variable consists of list of directories. The MathViews interpreter searches these directories for scripts with an "m" suffix. Several scripts needed by MathWizards demos are in the mfiles subdirectory mentioned above. If you've deleted this environment variable by accident, you can always restore it: suppose the MathViews installation is on E:\MathViews. Then to make the MathViews interpreter aware of both the general-purpose mfiles and those used by the Java package demos, invoke the following at command at the DOS prompt:

    set MVPATH=E:\MathViews\mv;E:\MathViews\java\demos\mfiles
    
    
    

• Define (or prepend) the CLASSPATH environment variable with the location of the MathWizards and graph class files. This allows java to find and access the MathWizards and graph packages. For example, suppose you are using JDK 1.1, and the core Java classes (file classes.zip) are found in C:\JDK\lib. Further suppose that the MathWizards and graph class files are installed in E:\MathViews\Java\class. Then the CLASSPATH can be set with the following DOS command:

  set CLASSPATH=E:\MathViews\Java\class;C:\JDK\lib
  
  
  

  You can also permanently add the CLASSPATH variable to you environment.

• Now, to run the stand-alone demo application Simple, invoke the following commands at the DOS prompt:

  java MathWizards.demo.Simple
  
  
  

• To run an applet demonstration, you need to point your browser to the HTML document which instantiates the applet(s). For example, using HotJava, you would invoke the following at the DOS prompt:

  cd E:\MathViews\java\demo
  
  
  hotjava ASimple.html
  
  
  

  Of course, you could use the JDK's appletviewer instead of hotjava. You will be able use Netscape Navigator once it has full Java SDK 1.1 support.

Troubleshooting

Simple is stand-alone application useful for debugging your MathWizards Java package installation. You may observe the following two errors on running Simple by invoking the command

java MathWizards.demo.Simple

at the DOS prompt:

• Can't find class MathWizards.demo.Simple

  The CLASSPATH environment variable does not include the directory in which the MathWizards subdirectory resides. As described above, you must do this first.

• java.lang.UnsatisfiedLinkError: no mwjni11 in shared library path
  
  
          at java.lang.Runtime.loadLibrary(Runtime.java:440)
  
  
          at java.lang.System.loadLibrary(System.java:569)
  
  
          at
  
  
          at MathWizards.demo.MVFrame. (Simple.java:16)
  
  
          at MathWizards.demo.Simple.main(Simple.java:139)
  
  
  

  Java is unable to find the DLL mwjni11.dll. The file must be in one of the directories which constitute the PATH environment variables. Alternatively, it can be in the system subdirectory, where it can be accessed without modifying PATH (this is where the installation procedure places it). To fix this, find the file and make PATH point to it. Instead, you move mwjni11.dll to one of the directories that are already in the PATH.

Once you have Simple running, type

x = rand(4)

at the prmopt, followed by enter. The prompt is the yellow text box at the bottom of the window. Then, try invoking

x = paraboloid(10)

If you get the following error message in the top text box:

while executing 'Submatrix'


paraboloid :  


Undefined variable or function 

Then, your MVPATH environment variable either does not exist or does not include the directory which contains the mfiles used by the demo applets. You must define or modify it first. Remeber that you can find out what your MVPATH is by typing

_MVPATH

at the MathViews prompt.