Scilab function

add_node - adds a disconnected node to a graph

### Calling Sequence

  `g1 = add_node(g,[xy,name])`

### Parameters

- `g` : graph list
- `xy` : optional row vector of coordinates of new node
- `name` : optional name of the added node
- `g1` : graph list of the new graph with the added node

### Description

`add_node` adds a disconnected node to graph `g` and returns the new graph `g1`.

The coordinates of the new node can be given as a row vector of coordinates in `xy`. If the nodes of graph `g` have no coordinates (elements `node_x` and `node_y` are `[]`), to give `xy` has no effect. If the nodes of graph `g` have coordinates and `xy` is not given, the new node has `(0,0)` as coordinates.

If `name` is given, it is the name of the new node, otherwise the number of nodes plus 1 is taken as the name of the new node.

### Examples

    ta=[1 1 2 2 2 3 4 5 5 7 8 8 9 10 10 10 11 12 13 13 13 14 15 16 16 17 17];
    he=[2 10 3 5 7 4 2 4 6 8 6 9 7 7 11 15 12 13 9 10 14 11 16 1 17 14 15];
    g=make_graph('foo',1,17,ta,he);
    g('node_x')=[283 163 63 57 164 164 273 271 339 384 504 513 439 623 631 757 642];
    g('node_y')=[59 133 223 318 227 319 221 324 432 141 209 319 428 443 187 151 301];
    show_graph(g);
    n=g('node_number');
    g1=add_node(g,[270 140]);
    g1('node_color')=[ones(1,n) 11];
    show_graph(g1);

### See Also

`add_edge` `delete_arcs` `delete_nodes`