graph-list

Scilab type
Last update : September 1996

graph-list - description of graph list

### Description

A graph in Scilab is represented by a Scilab typed list. We call it a graph list.

You will find below the complete description of the list. Each element is described by one or more lines. The first line gives the name of the element and its definition. Additional informations, such as the default for elements that can have one, are given in the other lines. Indeed, only the 5 first elements must have a value in the list, all the others can be given the empty vector `[]` as a value, and then the default is used when it is needed by functions or by the Metanet window. For instance, you can define a graph list by

    g=make_graph('min',1,1,[1],[1]);

which is the simplest graph you can create in Metanet (it is directed, has one node and one loop arc on this node).

The name of the element in the list is very important because it is used to access the elements of the list. For instance, if `g` is a graph list, to get the name of the graph, you only have to do:

    g('name')

or

    g.name

and if you want to change the name of the graph to `'toto'`, you have to do:

    g('name')='toto';

or

    g.name='toto';

Moreover, you can get the number of edges and the number of arcs of the graph by using `edge_number(g)` and `arc_number(g)` (these names do not correspond to elements of the list). For compatibility, `node_number(g)` can also be used instead of `g('node_number')` or `g.node_number`.

A graph list can be syntactically correct but not represent a good graph. You can use the function `check_graph` to check it. Moreover it is a good idea to give nodes different names. In fact, this does not give errors in Scilab, but strange behaviour can appear when using the Metanet window. This is not checked by `check_graph` because it is time consuming. It is only checked when loading, saving or showing a graph.

The elements of a graph list are given below:

  name:- the name of the graph
  -it is a string with a maximum of 80 characters
  directed:- flag giving the type of the graph
  -it is equal to 1 (graph directed) or equal to 0 (graph undirected)
  node_number:- number of nodes
  tail:- row vector of the tail node numbers
  head:- row vector of the head node numbers
  node_name:- row vector of node names
  -the names of the nodes must be different
  -default is the node numbers as node names
  node_type:- row vector of the node types
  -the type is an integer from 0 to 2, default is 0 (plain node):
  -0 = plain node
  -1 = sink node
  -2 = source node
  node_x:- row vector of the x coordinate of the nodes
  -default is computed
  node_y:- row vector of the y coordinate of the nodes
  -default is computed
  node_color:- row vector of the node colors
  -the color is an integer from 0 to 16, default is 0 (default foreground):
  -0 = default foreground
  -1 = navyblue
  -2 = blue
  -3 = skyblue
  -4 = aquamarine
  -5 = forestgreen
  -6 = green
  -7 = lightcyan
  -8 = cyan
  -9 = orange
  -10 = red
  -11 = magenta
  -12 = violet
  -13 = yellow
  -14 = gold
  -15 = beige
  -16 = background
  node_diam:- row vector of the size of the node diameters in pixels
  -a node is drawn as a circle
  -default is the value of element `default_node_diam`
  node_border:- row vector of the size of the node borders in pixels
  -a node is drawn as a circle
  -default is the value of element `default_node_border`
  node_font_size:- row vector of the size of the font used to draw the name of the node
  -you can choose 8, 10, 12, 14, 18 or 24
  -default is the value of element `default_font_size`
  node_demand:- row vector of the node demands
  -default is 0
  edge_name:- row vector of the edge names
  -it is better that the names of the edges are different, but this is not an error
  -default is the edge numbers as edge names
  edge_color:- row vector of the edge colors
  -the color is an integer from 0 to 16 (see `node_color`)
  -default is 0 (default foreground)
  edge_width:- row vector of the size of the edge widths in pixels
  -default is the value of element `default_edge_width`
  edge_hi_width:- row vector of the size of the highlighted edge widths in pixels
  -default is the value of element `default_edge_hi_width`
  edge_font_size:- row vector of the size of the fonts used to draw the name of the edge
  -you can choose 8, 10, 12, 14, 18 or 24
  -default is the value of element `default_font_size`
  edge_length:- row vector of the edge lengths
  -default is 0
  edge_cost:- row vector of the edge costs
  -default is 0
  edge_min_cap:- row vector of the edge minimum capacities
  -default is 0
  edge_max_cap:- row vector of the edge maximum capacities
  -default is 0
  edge_q_weight:- row vector of the edge quadratic weights
  -default is 0
  edge_q_orig:- row vector of the edge quadratic origins
  -default is 0
  edge_weight:- row vector of the edge weights
  -default is 0
  default_node_diam:- default size of the node diameters of the graph
  -default is 20 pixels
  default_node_border:- default size of the node borders of the graph
  -default is 2 pixels
  default_edge_width:- default size of the edge widths of the graph
  -default is 1 pixel
  default_edge_hi_width:- default size of the highlighted edge widths of the graph
  -default is 3 pixels
  default_font_size:- default size of the font used to draw the names of nodes and edges
  -default is 12
  node_label:- row vector of node labels
  edge_label:- row vector of edge labels

### Examples

    g=load_graph(SCI+'/demos/metanet/mesh100');
    g('node_color')=int(rand(1:g('node_number'))*16);
    g('edge_color')=int(rand(1:edge_number(g))*16);
    show_graph(g)

### See Also

`arc_number`, `check_graph`, `edge_number`, `glist`, `make_graph`, `node_number`,