xFunctions, by  David Eck                                         27 October 1999
                Department of Mathematics and Computer Science
                Hobart and William Smith Colleges
                Geneva, NY 14456, USA
                Email:  eck@hws.edu
                WWW:    http://math.hws.edu/eck/


This README file accompanies the download of xFunctions, an educational Java
applet/application that covers some aspects of calculus and pre-calculus
mathematics.  xFunctions can be freely distributed for non-commercial use.
(If you find a commercial use for it, please get my permission first.)
xFunctions can be found on the Web at http://math.hws.edu/xFunctions/
While I do not expect to further develop xFunctions, I will try to fix bugs 
and interface problems.  Please send comments to me at the above email address.

The use of xFunctions is explained in the file index.html.  The file
using_examples.html tells you how to write examples that xFunctions will
load them when it starts up.  The file example_file.txt contains some
examples of this sort.


TO POST xFunctions ON YOUR WEB SITE:

    Just place the entire xFunctions folder from the download where
    it can be read by your Web server.  It is not necessary (or advisable)
    to unzip the file named xFunctions.zip.  This file contains the
    compiled code for the xFunctions applet.
    
    You are certainly welcome to use xFunctions on your own Web pages.
    For instructional Web pages, I suggest using the "Launcher" version,
    so that students can resize the xFunctions window and can move back
    and forth easily between the xFunctions window and the Web page.
    It's a good idea to use only one copy of xFunctions.zip on your
    site (so that Web browsers will only have to download it once even
    when it is used on more than one page).  If your pages are not
    all in the same directory, use a relative path to the xFunctions.zip
    file.  For example, if xFunctions.zip is in the directory above
    the Web page, you could use
           <applet archive="../xFunctions.zip" code="xFunctionsLauncher"
                                                        width=200 height=30>


TO RUN xFunctions AS A STANDALONE APPLICATION:

    If you have a Java interpreter, such as the one in Sun Microsystem's
    Java Development Kit (JDK) or Java Runtime Environment (JRE), you
    can run xFunctions as a standalone applications, instead of in a
    Web browser.  The application version is named xFunctionsFrame,
    and it is one of the classes in the xFunctions.zip file.
    
    One way to run xFunctionsFrame is to unzip the xFunctions.zip file.
    Then you can simply apply the Java interpreter by typing a command
    such as:
    
            java  xFunctionsFrame
            
    (If you have Internet Explorer on your Windows computer, you might be
    able to use the command "jview" instead of "java" to invoke the
    Microsoft Java interpreter.)
 
    If you have a file of examples for xFunctions to load, you can specify
    the file name as a command line parameter.  For example, to load the
    file of examples that came with the xFunctions downlaod, use:
    
             java  xFunctionsFrame  example_file.txt
    
    It is not really necessary to unzip the xFunctions.zip file, if you know
    how to use the "classpath" option of your Java interpreter.  You have
    to specify a classpath that includes both xFunctions.zip and the standard
    Java classes.  Unfortunately, this leads to a long command.  On my Linux
    computer, for example, I would say:
    
             java  -classpath  xFunctions.zip:/usr/lib/java/lib/classes.zip  xFunctionsFrame
             
    (In practice, I would actually do something like this in an alias or
    shell script.)
    
    
OTHER NOTES:

    xFunctions is written in Java 1.0, so in theory it should run
    under any version of Java.  However, it really needs a modern, stable
    version on a fast machine to work well.  (It's in Java 1.0 because
    I started it a while ago, and left it half done for a long time.)
    
    I have tried xFunctions using several versions of Java, including:
    Netscape 4.5 or better on Linux, Windows, and Macintosh;
    Internet Explorer 4 and 5 on Windows, and the Apple Applet Runner 2.1.4.
    I've noticed a few problems on many of these platforms that seem to
    be bugs in the Java implementation rather than xFunctions.  I've worked
    around a few of them, but others remain.  For example:  In Internet
    Explorer 4, functions are graphed as if undefined values are equal to
    one.  This problem doesn't occur in Internet Explorer 5, so I haven't
    tried to work around it.  Sometimes when the applet starts up in
    Apple Applet Runner, the pop-up menu and buttons are disabled.  Using
    the "Reload' command makes them work.  Netscape has a few problems 
    with using the mouse.
    
    I welcome comments on xFunctions and information about how people
    are using it.