Count Loops in a Graph

Calculates the number of loops in a graph consisting of nodes and edges

Description

The code contained in these files counts the number of loops (cycles) in a network (graph) that consists of nodes and edges. The user can:
 - Obtain a network (from a file or randomly generated)
 - View the network (optional)
 - Reduce the network (optional)
 - View the reduced network (optional)
 - Start the counting algorithm
 - Save the network to a file (optional)
 - Save the loops to a file (optional)
 - View the loop length distribution (optional)

There are two ways to execute the code:
1. GUI (loops_gui.m) opens an interface with buttons
2. M-FILE (run_loops.m) runs all the code without the GUI interface

The algorithm used to count the loops is an iterative process I developed that I call the ILCA (Iterative Loop Counting Algorithm). It transforms the network into a tree and does a *depth first* search on the tree for loops. This is a *brute force* technique as there are no known (to my knowledge anyway) algorithms for providing a good estimation of the number of loops/cycles in a network/graph.

• MATLAB release: MATLAB 8.0 (R2012b)

[Zi Sue]

It is very nice but is there anyone can solve any problems for me？

[Ben Petschel]

Nice code and very well documented.

Another idea uses the theory of cycle subspaces (e.g. chapter 5 of Wallis's book on graph theory) - use a spanning tree to construct the (e-v+1) fundamental cycles and then check all 2^(e-v+1) combinations to eliminate disjoint unions and figure-8's. Does this algorithm compare favourably with your tree method?

[zahra shahbazi]

it is awesome!

[hamza drid]

Added more example
i want know some detail about this work

[Simone Severini]

Excellent!

[ed churchill]

this is really neat!