24 lines
751 B
Matlab
24 lines
751 B
Matlab
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% Count the number of multiple edges in the graph.
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%
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% INPUT: adjacency matrix, nxn
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% OUTPUT: integer, number of multiple edges
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%
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% Examples: multiEdges([0 2; 2 0])=1, and multiEdges([0 0 1; 2 0 0; 0 1 0])=1
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%
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% Note 1: The definition of number of multi-arcs/edges (node pairs
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% that have multiple edges across them) here is:
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% mA = length(find(adj>1)); (normalized by 2 if the graph is directed).
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%
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% Note 2: This creates a natural difference in counting for
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% undirected and directed graphs.
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%
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% Other routines used: isSymmetric.m
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% GB: last updated, Sep 26 2014
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function mE=multiEdges(adj)
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if isSymmetric(adj) % here use "is symmetric" as surrogate for "is directed"
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mE=length(find(adj>1))/2;
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else
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mE=length(find(adj>1));
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end
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