
XPRISM3(INPUT_FUNCTION)      Khoros       XPRISM3(INPUT_FUNCTION)

     KEYBOARD FUNCTION INPUT

     Xprism3 has a built-in function parser that can be used to
     generate 3D data points from a function automatically.  Fill
     in the function, the X and Y minimum and maximum points, and
     the total number of X and Y points. All functions are
     entered in cartesian coordinates.  An example of a 3D func-
     tion is 3*cos(x)+sin(y).  Note that when entering a 3D func-
     tion, the ONLY accepted variables are "x" and "y".  Attempt-
     ing to use any variables other than "x" and "y" will cause
     an error message.

     When providing a function to xprism3, one must make sure
     that the maximum and minimum X and Y points (the bounds of
     the plot), are specified correctly in the parameters labeled
     "Minimum", "Maximum" and "Number of Points", respectively.
     The defaults are -1 to 1 with a total of 30 points. Be sure
     that the function is defined over the interval specified.
     If the function provided is not defined over the given
     interval, 3 things may occur:

     (1)  The built-in parser will generate an error message

     (2)  Round-off error may cause the parser to compute points
          that are NOT EXACTLY at the point where the function is
          UNDEFINED.  In this case, xprism3 will go ahead and
          plot the function to the best of its ability, in spite
          of the fact that it is undefined over the specified
          interval.  Results may or may not be close to the
          correct graph of the function.

     (3)  If there is an error that the signal handlers in
          Xprism3 cannot handle, the package will core dump.

     The function "minimun", "maximum", and "number of points"
     fields are string fields. Therefore, for any of these fields
     a constant such as "pi", or an expression such as
     tan(0.9923) can be entered. The only restriction is that the
     expression can not be a function of x or y.

     To plot the 3D function, make sure that all parameters are
     filled out correctly, and click on the "PLOT FUNCTION"
     action button.  The function will be evaluated as indicated
     and displayed accroding to the current value of the "plot
     type" toggle.

     Points to Be Displayed

          The option, "points to be displayed", allows the user
          to window on a specified portion of the data. Along
          with windowing the user can subsample the data to be
          displayed. Note, All data is read in when the "Plot
          File" button is clicked with the mouse. The "points to
          be displayed" works on the data read in. The window and
          subsampling parameter may be changed for each plot on
          the "Attributes" subform. The "points to be displayed"
          option has three items that can be changed. The follow-
          ing explains these options:

          Step Size
               This "Step Size" option specifies how the data
               should be subsampled between the begin point and
               the end point. The default value is 1, every
               point.

          Begin Point
               The "Begin Point" specifies the begin point of the
               data to plot. That is what data point number to
               begin with. If the "Begin Point" is set to 0, then
               the "end point" is ignored and all data points are
               used.

          End Point
               The "End Point" specifies the end point of the
               data to plot. That is what data point number to
               end with. If the "End Point" is set to 0, then the
               last data point in the file is used as the end
               point.

     Plot Type

          Each plot that is input will be displayed as the plot
          type that is indicated by the "plot type" toggle in the
          "Input File" pane.  Thus, by changing the plot type
          before each new plot is displayed, any of the nine plot
          types may be displayed simultaneously in the graphics
          workspace.

          Copyright 1991, University of New Mexico. All rights
          reserved.

Khoros                    Release: 1.0                          1

