Adding weights to a graph

Hi All,

I have the following graph.

NNode = 11;
tail = 1:NNode-1;
head = 2:NNode;
Graph = graph(tail,head);
Graph.Edges.Weight1 = randn(height(Graph.Edges),1) 
Graph.Edges.Weight2 = randn(height(Graph.Edges),1) 
H = Graph
H = addedge(H,1,2,Graph.Edges.Weight1(1))
H = addedge(H,3,2,Graph.Edges.Weight1(1))
plot(Graph);

When I try to add new nodes, edges and assign weights, the following error is obtained

Error using graph/addedge (line 139)
Unable to add weighted edges to an unweighted graph.

Error in Untitled (line 9)
H = addedge(H,1,2,Graph.Edges.Weight1(1))
 

In line 9, a weighted graph is assigned to a variable H. I am adding new edges and weights to H. I am not sure why

Unable to add weighted edges to an unweighted graph.

error appears.

Could someone look into this?

Answer 1

[Walter Roberson]

Graph = graph(tail,head);

Graph creates an undirected graph without weights, using a slightly different data structure than a graph that has weights. You need to either create the graph with weights, graph(tail,head,appropriate_weights) or else you need to assign to the Weight property of the graph, such as Graph.Weight = randn(10,1) . Once the Weight structure is there, then you can use addedge() to add edges with weights.