From 3aee2fd43e3059a699af2b63c6f2395e5a55e515 Mon Sep 17 00:00:00 2001 From: KatolaZ Date: Wed, 27 Sep 2017 15:06:31 +0100 Subject: First commit on github -- NetBunch 1.0 --- doc/components.md | 130 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 130 insertions(+) create mode 100644 doc/components.md (limited to 'doc/components.md') diff --git a/doc/components.md b/doc/components.md new file mode 100644 index 0000000..24e4f8b --- /dev/null +++ b/doc/components.md @@ -0,0 +1,130 @@ +components(1) -- Find the connected components of a graph +====== + +## SYNOPSIS + +`components` [SHOW] + +## DESCRIPTION + +`components` finds the connected components of the undirected graph +given as input using the Depth-First Search 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 + +* : + 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 + connected component. + +## OUTPUT + +`components` prints on the standard output the size of all the +connected components of the undirected 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 component, in the format: + + size_1: node_1 node_2 node_3 ... + size_2: node_1 node_2 node_3 ... + +## EXAMPLES + +The following command: + + $ components er_1000_5000.txt + 1000 + $ + +shows on output the size of the only connected component of the graph +`er_1000_5000.txt`. In this case the graph has only one connected +component (it is a super-critical Erdos-Renyi random graph with 1000 +nodes and 5000 edges). A more interesting example can be obtained +using the graph `er_1000_2000.txt`: + + $ components er_1000_2000.txt + 985 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + $ + +In this case, the graph has 16 connected components: one of those +components contains 985 nodes, while the other 15 components consist +of isolated nodes. If we want to know who are the nodes belonging to +each connected component, we run: + + $ components er_1000_2000.txt SHOW + 985: 0 1 2 3 4 5 6 7 8 9 10 11 12..... + ... + 1: 63 + 1: 75 + 1: 218 + 1: 222 + 1: 368 + 1: 398 + 1: 441 + 1: 566 + 1: 572 + 1: 663 + 1: 715 + 1: 756 + 1: 863 + 1: 883 + 1: 917 + $ + +If we run: + + $ components er_1000_2000.txt SHOW > er_1000_2000.txt_components + +the result of `components` will be saved in the file +`er_1000_2000.txt_components`. + +## SEE ALSO + +strong_conn(1), node_components(1), largest_component(1) + + +## REFERENCES + +* V\. Latora, V. Nicosia, G. Russo, "Complex Networks: Principles, + Methods and Applications", Chapter 3, 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 ``. -- cgit v1.2.3