Which cycle detection within a directed graph are more efficient than O(n^2)? [closed]
Tarjan’s strongly connected components algorithm has O(|E| + |V|) time complexity. For other algorithms, see Strongly connected components on Wikipedia.
directed-graph
What options are available for the layout of directed or undirected graphs in .NET?
Graph# is also another option. I haven’t used it personally, but I’ve been meaning to get around to looking over it.
Tarjan cycle detection help C#
The above is actually correct, I did not understand what a strongly connected component was. I was expecting the function to return an empty List of strongly connected components, yet it was returning a list of single nodes. I believe the above is working. Feel free to use if you need it!
Getting the root (head) of a DiGraph in networkx (Python)
If by having “one root element” you mean your directed graph is a rooted tree, then the root will be the only node with zero in-degree. You can find that node in linear time (in the number of nodes) with: In [1]: import networkx as nx In [2]: G=nx.balanced_tree(2,3,create_using=nx.DiGraph()) # tree rooted at 0 In … Read more
How to detect if adding an edge to a directed graph results in a cycle?
If I understood your question correctly, then a new edge (u,v) is only inserted if there was no path from v to u before (i.e., if (u,v) does not create a cycle). Thus, your graph is always a DAG (directed acyclic graph). Using Tarjan’s Algorithm to detect strongly connected components (http://en.wikipedia.org/wiki/Tarjan%27s_strongly_connected_components_algorithm) sounds like an overkill … Read more
Graph serialization
Topological Sort (From Wikipedia): In graph theory, a topological sort or topological ordering of a directed acyclic graph (DAG) is a linear ordering of its nodes in which each node comes before all nodes to which it has outbound edges. Every DAG has one or more topological sorts. Pseudo code: L ← Empty list where … Read more
How do I check if a directed graph is acyclic?
I would try to sort the graph topologically, and if you can’t, then it has cycles.
how to draw directed graphs using networkx in python?
Fully fleshed out example with arrows for only the red edges: import networkx as nx import matplotlib.pyplot as plt G = nx.DiGraph() G.add_edges_from( [(‘A’, ‘B’), (‘A’, ‘C’), (‘D’, ‘B’), (‘E’, ‘C’), (‘E’, ‘F’), (‘B’, ‘H’), (‘B’, ‘G’), (‘B’, ‘F’), (‘C’, ‘G’)]) val_map = {‘A’: 1.0, ‘D’: 0.5714285714285714, ‘H’: 0.0} values = [val_map.get(node, 0.25) for node … Read more
GraphViz – How to connect subgraphs?
The DOT user manual gives the following example of a graph with clusters with edges between clusters: IMPORTANT: The initial compound=true statement is required. digraph G { compound=true; subgraph cluster0 { a -> b; a -> c; b -> d; c -> d; } subgraph cluster1 { e -> g; e -> f; } b … Read more
Best algorithm for detecting cycles in a directed graph [closed]
Tarjan’s strongly connected components algorithm has O(|E| + |V|) time complexity. For other algorithms, see Strongly connected components on Wikipedia.