Hello MKS,
It seems you want to rewire an adjacency matrix by removing two random edges and adding two new ones.
Here are the steps to achieve this:
- Use the 'triu' function to obtain the upper triangular part of the matrix. For more information on 'triu' function, refer to this documentation: https://www.mathworks.com/help/matlab/ref/triu.html .
- Use the 'find' function to locate the indexes of non-zero elements. This will assign indexes to each edge in the adjacency matrix. For more information on 'find' function, refer to this documentation: https://www.mathworks.com/help/matlab/ref/find.html .
numEdgesToRewire = 2;
[existingEdgesRow, existingEdgesCol] = find(triu(B));
- Then, use the 'randperm' function to select two edges randomly. More information on this function, is in the documentation: https://www.mathworks.com/help/matlab/ref/randperm.html .
indicesToRemove = randperm(length(existingEdgesRow), numEdgesToRewire);
- The following code snippet can be used to remove the selected edges:
for k = 1:numEdgesToRewire
node1 = existingEdgesRow(indicesToRemove(k));
node2 = existingEdgesCol(indicesToRemove(k));
B(node1, node2) = 0;
B(node2, node1) = 0;
disp(['Removed edge between nodes ' num2str(node1) ' and ' num2str(node2)]);
end
- Use a while loop to find nodes and add new edges, as demonstrated in the code snippet below:
for k = 1:numEdgesToRewire
node1 = randi(n);
node2 = randi(n);
% Check for self-loops or existing edges
while node1 == node2 || B(node1, node2) == 1
node1 = randi(n);
node2 = randi(n);
end
disp(['Adding new edge between nodes ' num2str(node1) ' and ' num2str(node2)]);
B(node1, node2) = 1;
B(node2, node1) = 1;
end
