Scilab function

graph_sum - sum of two graphs

### Calling Sequence

g2 = graph_sum(g,g1)

### Parameters

• g : graph list
• g1 : graph list
• g2 : graph list of the new graph

### Description

graph_sum creates a graph g2 with an adjacency matrix equal to the sum of the adjacency matrices of the two graphs g and g1. g and g1 are supposed to be simple graphs (use graph_simp before calling graph_complement if necessary) and to have the same number of nodes.

### Examples

```ta=[1 1 2 2 2 3 4 5 5 7 8 8 9 10 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 13 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];
g('edge_color')=modulo([1:(edge_number(g))],15)+1;
g('edge_width')=ones(1,(edge_number(g)));
g('node_diam')=[1:(g('node_number'))]+20;
g('node_name')=['A' 'B' 'C' 'D' 'E' 'F' 'G' 'H' 'I' 'J' 'K' 'L' 'M' 'N' 'O' 'P' 'Q'];
show_graph(g);
ta=[2 3 4 5 11 12 1];
he=[10 5 6 7 15 17 7];
g1=make_graph('foo',1,17,ta,he);
g1('node_x')=[283 163 63 57 164 164 273 271 339 384 504 513 439 623 631 757 642];
g1('node_y')=[59 133 223 318 227 319 221 324 432 141 209 319 428 443 187 151 301];
g1('edge_color')=modulo([1:(edge_number(g1))],15)+1;
g1('edge_width')=10*ones(1,(edge_number(g1)));
g1('node_diam')=[1:(g1('node_number'))]+20;
g1('node_name')=['A' 'B' 'C' 'D' 'E' 'F' 'G' 'H' 'I' 'J' 'K' 'L' 'M' 'N' 'O' 'P' 'Q'];
show_graph(g1,'new');
g2=graph_sum(g,g1);
show_graph(g2,'new');
```