Sorting names of nodes after graphtopoorder

Hello community! I'm quite successful with my Matlab skills I earnes within the last four days. After using graphtopoorder I'm missing the sorting of the Node-Names too. First I make a sparse from my adjaceny, then using the topo order.

order = graphtopoorder(S)

My node names are "nNodes".

How is it possible to sort the names in the order of the topo order? fgh=sort(nNames,j) didn't work...

Thank you!

Answer 1

[Kristen Amaddio]

You can use array indexing in order to sort the 'nNodes' in terms of the topological order generated by 'graphtopoorder'. I set up a simple example to reproduce your workflow:

% Simple DAG example
s = [1 1 1 2 2 3];
t = [2 3 4 5 6 7];
G = digraph(s,t);

% Define nNodes
nNodes = {'First' 'Second' 'Third' 'Fourth' 'Fifth' 'Sixth' 'Seventh'}';
G.Nodes.Name = nNodes;

% Create the adjacency matrix based on the DAG
% Then use this to create a sparse matrix
A = adjacency(G);
S = sparse(A);

% Get the topological sort of the DAG
order = graphtopoorder(S);

% Use indexing to sort the node names in terms of the topological order
sortedNames = nNodes(order);

Here you will see that the 'sortedNames' correspond to the sorted node order specified by 'order':

order =
     1     4     3     7     2     6     5
sortedNames =
 7×1 cell array
   'First'
   'Fourth'
   'Third'
   'Seventh'
   'Second'
   'Sixth'
   'Fifth'

Answer 2

[Moritz Geiger]

Thank you! It works! Fantastic!

I do not understand this line:

sortedNames = nNodes(order);

What is the background of this? Is the vector inside the brackets the attribute for sorting? I couldn't find it in the docu.

Thank you for your help!