
INPUT FILES:

One of these three is required: 
- a file of dissimilarities (NxN),
- a file of multivariate data (Nxp),
- a file of edges describing a discrete graph.

USAGE:

- Input based on file extensions:

    xgvis xyz

  If one of the following files is present, it will be read
  and interpreted as a dissimilarity matrix, a graph, or a
  multivariate dataset:

    xyz.dist
    xyz.edges
    xyz.pos, xyz.dat

  If files of more than one type are present, they have descending 
  prority in this order: dist, edges, pos

  In the presence of a dist or edges file, the pos file will be used
  for starting positions.

- Input based on flags:

    xgvis -dist  xyz
    xgvis -edges xyz
    xgvis -pos   xyz
        
  The file "xyz" will be read and interpreted accordingly.


FORMAT:

- dissimilarity file: 
    N lines 
    N dissimilarity values per line (separated by white space)

  example: N=3
    0 3 4
    3 0 5
    4 5 0

- edges file: let K be the number of edges of the graph
    K lines
    2 integers between 1 and N per line (separated by white space)
    optionally: a third (real) value on each line for edge weights

  examples: K=3, N=3                K=2, N=3 with weights
    1 2                             1 2 1.5
    2 3                             2 3 4.5
    3 1

- multivariate data file:
    N lines
    p values per line (separated by white space)

  example: p=2, N=3
    0.0 1.0 
    0.5 2.0
    1.0 1.0

The dissimilarity file can contain missing values, represented by the
strings "na" or "NA" or "."  By making use of specific missing value
patterns, XGvis can be used to perform "Multidimensional Unfolding."


ADDITIONAL OPTIONAL FILES:

- file extensions:

  point labels: either of xyz.label, xyz.row, xyz.case
  point glyphs: xyz.glyphs
  point colors: xyz.colors
  line (edge) colors:  xyz.linecolors

- flags: 

  -labels labelfile
  -glyphs glyphfile
  -pointcolors colorfile
  -linecolors colorfile

- Another method for reading in these files is after startup by using
  the "Read" function from "File" in the XGobi window of XGvis.


