
XPRISM2(INPUT_FUNCTION)      Khoros       XPRISM2(INPUT_FUNCTION)

     KEYBOARD FUNCTION INPUT

     Xprism2 has a built-in function parser that can be used to
     generate 2D data points from a function automatically.  Fill
     in the function, the X minimum and maximum points, and the
     total number of X points. All functions are entered in
     cartesian coordinates.  An example of a 2D function is
     3*cos(x).  Note that when entering a 2D function, the ONLY
     accepted variable is "x".  Attempting to use any variable
     other than "x" will cause an error message.

     When providing a function to xprism2, one must make sure
     that the maximum and minimum X points (the bounds of the
     plot), are specified correctly in the parameters labeled "X
     Minimum", "X 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 vier the given
     interval, 2 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, xprism2 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
          Xprism2 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 2D 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 labeled "Points to be Displayed" allows the
          user to window on a specified portion of the data. In
          addition to windowing, the user may also subsample the
          data to be displayed. All data is read in when the
          "Plot File" button is clicked with the mouse; the
          "Points to be Displayed" option works on that data.
          Once plotted, the window and subsampling parameters may
          be changed for each currently displayed plot using 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; ie, every
               point is used.

          Begin Point
               The "Begin Point" specifies the first of the data
               points to plot. That is, which data point to begin
               with, the data points being numbered sequentially.
               For example, if the "Begin Point" is specified as
               5, the plot will start with the fifth data point.
               If the "Begin Point" is set to 0 (the default
               value), then the "end point" is ignored and all
               data points are used.

          End Point
               The "End Point" specifies the last of the data
               points to plot. That is, which data point to end
               with, the data points being numbered sequentially.
               For example, if the "End Point" is specified as
               25, the plot will end with the twenty-fifth data
               point. If the "End Point" is set to 0 (the default
               value), 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 five plot
          types may be displayed simultaneously in the graphics
          workspace.

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

Khoros                    Release: 1.0                          1

