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author | KatolaZ <katolaz@freaknet.org> | 2017-09-27 15:06:31 +0100 |
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committer | KatolaZ <katolaz@freaknet.org> | 2017-09-27 15:06:31 +0100 |
commit | 3aee2fd43e3059a699af2b63c6f2395e5a55e515 (patch) | |
tree | 58c95505a0906ed9cfa694f9dbd319403fd8f01d /doc/strong_conn.md |
First commit on github -- NetBunch 1.0
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diff --git a/doc/strong_conn.md b/doc/strong_conn.md new file mode 100644 index 0000000..fd2abb7 --- /dev/null +++ b/doc/strong_conn.md @@ -0,0 +1,104 @@ +strong_conn(1) -- Find the strongly connected components of a directed graph +====== + +## SYNOPSIS + +`strong_conn` <graph_in> [SHOW] + +## DESCRIPTION + +`strong_conn` finds the strongly connected components of the directed +graph given as input using the Kosaraju-Sharir algorithm, and prints +the size of each of them. If the optional second parameter `SHOW` is +provided, the program dumps on output also the list of nodes belonging +to each component. + +## PARAMETERS + +* <graph_in>: + input graph (edge list) if equal to `-` (dash), read the edge list + from STDIN. + + +* SHOW: + If the (optional) second parameter is equal to `SHOW`, the program + will dump on output the list of all the nodes belonging to each + strongly connected component. + +## OUTPUT + +`strong_conn` prints on the standard output the size of all the +strongly connected components of the directed graph given as input, +one per line: + + size_1 + size_2 + size_3 + ..... + +where `size_1` is the size of the first component, `size_2` is the +size of the second component, and so on. Notice that the sizes are not +sorted. If `SHOW` is given, the program shows the list of nodes +belonging to each strongly connected component, in the format: + + size_1: node_1 node_2 node_3 ... + size_2: node_1 node_2 node_3 ... + +## EXAMPLES + +The following command: + + $ strong_conn web-NotreDame.net + 53968 + 1 + 1 + 1 + 1 + 1 + 1 + .... + $ + +shows on output the size of the strongly connected component of the +graph `web-NotreDame.net` (the NotreDame WWW data set), in no particular +order. In this case the graph has 203609 strongly connected +components, most of them containing only 1 isolated node. If we want +to know who are the nodes belonging to each connected component, we +run: + + $ strong_conn web-NotreDame.net SHOW + 53968: 0 1 3 4 5 6 7 8..... + ..... 325727 325728 + 1: 351 + 1: 350 + 1: 2209 + 1: 2208 + 1: 2206 + 1: 10609 + .... + $ + +It is better to save the output of `strong_conn` into a file, e.g. by +using: + + $ strong_conn web-NotreDame.net SHOW > web-NotreDame.net_scc + +## SEE ALSO + +components(1), node\_components(1), largest_component(1) + + +## REFERENCES + +* V\. Latora, V. Nicosia, G. Russo, "Complex Networks: Principles, + Methods and Applications", Chapter 6, Cambridge University Press + (2017) + +* V\. Latora, V. Nicosia, G. Russo, "Complex Networks: Principles, + Methods and Applications", Appendix 8, Cambridge University Press + (2017) + + +## AUTHORS + +(c) Vincenzo 'KatolaZ' Nicosia 2009-2017 `<v.nicosia@qmul.ac.uk>`. |