

   xxggvviiss:: iinntteerraaccttiivvee mmuullttiiddiimmeennssiioonnaall ssccaalliinngg uussiinngg xxggoobbii ffoorr
   ddiissppllaayy

        xgvis(matrx,
        edges=NULL, pos=NULL, rowlab=NULL, colors=NULL, glyphs=NULL,
        erase=NULL, lines=NULL, linecolors=NULL, resources=NULL,
        display=NULL)

   AArrgguummeennttss::

      matrx: An nxn distance matrix

      edges: Line segments: specifications for the pattern of
             line segments which connect pairs of points.  The
             file must contain at least two numbers per line.
             The first two numbers represent the row numbers of
             the two points that should be connected.  (This is
             exactly like the structure of a fname.lines file
             in xgobi.)  In addition, if a third number is pre
             sent, it is taken to be an edge weight.  If this
             line is present and the distance matrix is absent,
             then the distance matrix is computed from it, with
             each edge representing a distance of one.

        pos: Starting positions:  an n x p matrix, with entries
             separated by white space and one row per line.  If
             this file is present and a distance file is
             absent, the distance matrix is computed from it.

     rowlab: Optional character vector of row labels; the
             default is `dimnames(matrx)[[1]]'.  If no default
             exists, xgobi constructs its own defaults.

     colors: Optional character vector, used to supply initial
             point colors to be used; the default is that all
             points are the same color.

     glyphs: Optional integer vector, used to supply glyphs to
             be used on startup; the default is that all points
             are drawn with the same glyph.

      erase: Optional integer vector of length equal to the
             number of rows in the data and composed of 1s and
             0s.  A 1 in position i specifies that point i
             should be erased.  The default is a vector of 0s.

      lines: Optional integer matrix, n by 2, which specifies
             by row number pairs of points to be connected by
             line segments.  If this file is present, then the
             edges file is used to create the distance matrix
             but the lines file is used to draw the edges.

   linecolors: Optional integer vector, of length n where n is
             the number of lines specified by the 'lines' argu
             ment.  It is used to supply line colors to be used
             on startup; the default is for all the lines to be
             drawn in the standard foreground color.

   resources: Optional character vector created by clicking on
             the "Save Resources" button in XGobi (if this
             XGvis was initiated during an S session).

    display: Optional character string, identifying the monitor
             on which to display the xgvis window.  The default
             is `"machine:0.0"' where `machine' is the name of
             the user's workstation.  See documentation for X.

   DDeessccrriippttiioonn::

        an interactive multidimensional scaling (MDS) program
        that consists of a control panel to manipulate the
        parameters of the MDS stress function and an xgobi win
        dow for data display.  It can be used either for visu
        alization of dissimilarity data, for dimension reduc
        tion, or for graph layout.  Graph layout is usually
        done in 2D, but xgvis allows layouts in arbitrary
        dimensions, 3D being the default.  It permits missing
        values, which can be used to implement multidimensional
        unfolding.

   VVaalluuee::

        The UNIX `status' upon completion, i.e. `0' if ok.

   SSiiddee EEffffeeccttss::

        The xgvis S function executes a call to the C program
        of the same name, and returns control of the S shell to
        the user.

   CCOONNTTAACCTT::

        D. F. Swayne dfs@research.att.com

   RReeffeerreenncceess::

        http://www.research.att.com/areas/stat/xgobi/
        http://www.public.iastate.edu/~dicook/

   EExxaammpplleess::

        ## The following examples use sample data files from the data_xgvis
        ## directory in the xgobi and xgvis distribution directory.

        data(morsecodes)
        xgvis(dmat = morsecodes.dist,
              pos = morsecodes.pos,
              row = morsecodes.row,
              colors = morsecodes.colors,
              glyphs = morsecodes.glyphs,
              lines = morsecodes.lines,
              linecolors = morsecodes.linecolors)

        data(perm4)
        xgvis(edges = perm4.edges)
        xgvis(edges = perm4.edges,
              linecolors = perm4.linecolors)

