1. kruskal(1)
  2. www.complex-networks.net
  3. kruskal(1)


kruskal - Find the minimum/maximum spanning tree of a graph


kruskal graph_in [MAX]


kruskal computes the minimum (or maximum) spanning tree of graph_in, using the Kruskal's algorithm. If grahp_in is unweighted, kruskal computes one of the spanning trees of the graph. The program prints on output the (weighted) edge list of the spanning tree.



undirected input graph (edge list). It must be an existing file.


If the second (optional) parameter is equal to MAX, compute the maximum spanning tree. Otherwise, compute the minimum spanning tree.


The program prints on STDOUT the edge list of the minimum (maximum) spannig tree of graph_in, in the format:

    i_1 j_1 w_ij_1
    i_2 j_2 w_ij_2


To find the minimum spanning tree of the graph stocks_62_weight.net (the network of stocks in the New York Exchange market) we use the command:

    $ kruskal stocks_62_weight.net
    52 53 0.72577357
    43 53 0.72838212
    2 53 0.72907212
    36 53 0.7973488
    53 58 0.79931683
    26 27 0.8029602

which prints on output the edge list of the minimum spanning tree. However, since the weight of each edge in that graph indicates the similarity in the behaviour of two stocks, the maximum spanning tree contains information about the backbone of similarities among stocks. To obtain the maximum spannin tree, we just specify MAX as second parameter:

    $ kruskal stocks_62_weight.net MAX
    56 58 1.523483
    2 52 1.3826744
    32 51 1.3812241
    33 55 0.86880272
    7 28 0.8631584
    1 53 0.81876166


clust_w(1), dijkstra(1), largest_component(1)



(c) Vincenzo 'KatolaZ' Nicosia 2009-2017 <v.nicosia@qmul.ac.uk>.

  1. www.complex-networks.net
  2. September 2017
  3. kruskal(1)