Graph 3D program ,demo, and instructions
by Ravi Prasad

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                             GRAPH 3D FEATURES

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1)    Left and right handed coordinate systems
2)    Cartesian, spherical, and cylindrical coordinate systems
3)    all equations in 2 may be entered as Z squred, Rho squared,...
4)    Zoom sqr, Zoom fit, Zoom in, Zoom out options included
5)    Tilt X or Y axis at -135, -45, +45, -90, or user input custom tilt
6)    Rotate the image about the XY plane at any specified rotation angle.
7)    Program automatically detects and adjusts for cylinders &
      planes if any variables are missing in the equation.
8)    Totally menu drive
9)    View the graph with new option or zoom options without re-
      keying in the equation over and over again.
10)   Accuracy and speed (resolution) controlled by setting
      appropriate axis size and increments.
11)   All angular values entered are in radians unless otherwise
      stated by program.
12)   Standard (default) increment or custom increment for
      specified range values included.
13)   Requires 4.4K for entire program will complete features. 
      Any one module may be written in about 400 byes.






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                             GRAPH 3D FILES

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      1) D1, D2, D3..., D20
         These are the demo picture files used by the DEMO program
         These files need to be loaded only if you wish to run
         the DEMO program.

      2) DEMO.85P
         This is the DEMO program that uses the above picture files.

      3) GR3D.85P
         This is the full featured graph 3D program.

      4) GR3DPROG.ASC
         This is an ASCII listing of the graph 3d program source code.
         To print this on an ibm printer, simply type "COPY GR3DPROG.ASC PRN"
         at the DOS prompt or load it into a word processor on an IBM, MAC,
         or anyother system that accepts ASCII data input.

      5) GR3DPROG.PS
         This is a true typeset of the graph 3D program and instructions.
         This typeset will print to any postscript printer such as the 
         apple laser writer.  To print this file from an IBM attached 
         to a laserwriter, simply type "COPY GR3DPRG.PS PRN" at the DOS prompt.

      6) GR3DEMO.PS
         This is a postscript typeset file that shows all the equations
         plotted in the DEMO program with complete instructions.


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                          RUNNING THE PROGRAM

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1) Type "GR3D" and "ENTER" or press the "PRGM" key followed by
   the "F1" key and then selecting the appropriate menu function key
   designating the "GR3D" program.

2) If you wish to continue with the previous range settings from
   an earlier session, select "NO" at the "NEW CONFIGURATION"
   prompt.  For a new session with new range settings, select "YES"

3) Press "F1" key for a right handed coordinate setup of "F5" for
   a left handed coordinate setup.

4) If a right handed coordinate setup is selected (F1), you are
   prompted to select a tilt angle for the X axis.  If a left handed
   coordinate setup is selected (F5), a tilt for the Y axis is to be
   selected.  The tilt angle is customarily -135 degrees (zero
   degrees representing due east), although any tilt angle may be
   selected by the appropriate menu function keys.  The CUSTM key
   lets you enter any desired tilt angle.

5) Select a scaling option.  "SQR" is the standard scaling option
   which provides a one to one ratio for all axis.  The "FIT" option
   is more time consuming but gives a best view (enlarged and
   stretched) of the graph to fit on the screen.

6) Select "YES" or "NO" by pressing the appropriate menu function
   keys at the option to display the coordinate axis.  Note however,
   in the "FIT" option, the axis will be tilted with respect to the
   best fit view and may not APPEAR to be accurate.  The graph and
   axis displayed are however, accurately shown.

7) Select a working coordinate system at the "COORDINATE SYSTEM"
   prompt.  Valid choices are "F1" for cartesian coordinates, "F3"
   for spherical coordinates, and "F5" for cylindrical coordinates.

8) Select the minimum and maximum values for the variables to be
   used in graphing the equation.  The increment may be defaulted by
   entering the number ZERO for this option.  By carefully
   incrementing the variables, speed and accuracy may be controlled.
   Incrementing a variable allows the program to successively choose
   new values for the variables and compute the values for the
   defined equation.  The default increment results in a total of 20
   traces to be plotted.

9) Enter the equation as you would normally write them.  Keep in
   mind however, that the variables X Y Z must be in uppercase.  The
   option "Z..." will the plot the function Z as is.  The function
   "Z=+-" will plot the functions Z and -Z.  This way, if you have a
   function such as Z=+- sqrt (X^2+y^2), you need not enter them as
   two seperate equations.

10) Select an image rotation angle.  By selecting a rotation
    angle other than zero means to spin the image by actually
    spinning the Z axis the angle desired.  By rotating an image, you
    can examine parts of a graph that may not be visible in the tilt
    axis given.  For example, a paraboloid opening on the positive X
    axis in a right handed coordinate system (X axis tilted at -135
    degrees) rotated 90 degrees would now open on the positive Y
    axis.  Enter zero for no rotation.

11) Select the XYZ axis size.  The equation will not be plotted
    beyond the XYZ axis size unless a FIT graph was chosen.

12) After the equation is graphed, you may Zoom In, Zoom Out,
    perform a Zoom Fit or Zoom Sqr function.  The "Menu" option
    always returns to the main menu shown at the end of graphing an
    equation.  The "View" option simply eliminates the menu
    temporarily.  Press "ENTER", to return to the menu options.  The
    "REcfg" option lets you re-plot the equation with new range
    values along with other appropriate settings.  The "Graph" option
    will restart another graphing session.  The "Exit" option
    terminates the graphing session.

Note:  At the end of a graphing session, any equation plotted
       remains in view and may be stored to memory for later retrieval
       by pressing the "GRAPH" key, followed by the "STPic" menu
       function key and an appropriate file name.  Also, greek symbols
       may be incorporated into equations for cylindrical and spherical
       formats by pressing "2nd" followed by the "CHAR" key, followed in
       turn by the "GREEK" menu key.  The program is case sensitive and
       thus requires the usage of "XYZ" versus "xyz".



