Graph
=====

by Martin Budden
martinjb@cix

Graph plots 2D and 3D mathematical functions.

To install it put it in the \OPO directory on any drive.

Functions should be entered in standard OPL notation.  Note that the
variables x, y and z should be entered in lower case, this is so that
they are not confused with X, Y and Z that occur in function names
(eg EXP).

Any ideas for an icon would be appreciated.

All the fuctions are seeded, any ideas for more interesting fuctions
(especially the for 3D surface) would also be appreciated.

Settings Menu
-------------

Axes origin

Ploting intervals
Sets various plotting intervals.  More intervals generally give a
smoother plot, but take longer.

Surface hatch
Sets the density of the hatch for 3D surface plots.

Viewing angle
Sets the viewing angle for 3D plots.

Preferences
3 settings:
Use normalised axes: the axes limits are adjusted to be round numbers
(ie nEx, where n is 1, 2 or 5).
Use Function graphics update: if set the screen is updated more
frequently when plotting functions (so the plot is slower).
Use Surface graphics update: if set the screen is updated more
frequently when plotting surfaces (so the plot is slower).

Plot Menu
---------

The screen is not cleared between plots (as long as the dimension is
not changed) this allows functions to be superimposed on each other.

Function
Plots y as a function of x

Curve
Plots x,y as a function of t

3D curve
Plots x,y,z as a function of t

Surface
Plots z as a function of x,y.  The surface can be plotted as either
as a hatch, or as contours (or a combination of the two).

Special Menu
------------

Clear screen

Cursor
Displays a line cursor, so that values can be read off a plot (only
works is the most recently plotted function was y as a function of x.

View normalised axes
View the normalised axes settings.

View normalised origin
View the normalised origin settings.

Exit

===
END
===