30 lines
1.2 KiB
Matlab
30 lines
1.2 KiB
Matlab
% Return the list of nodes for varying graph representation types
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% Inputs: graph structure (matrix or cell or struct) and type of structure (string)
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% 'type' can be: 'adjacency','edgelist','adjlist' (neighbor list),'incidence' (incidence matrix)
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% Note 1: only the edge list allows/returns non-consecutive node indexing
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% Note 2: no build-in error check for graph structure
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%
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% Example representations of a directed 3-cycle: 1->2->3->1
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% 'adj' - [0 1 0; 0 0 1; 1 0 0]
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% 'adjlist' - {1: [2], 2: [3], 3: [1]}
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% 'edgelist' - [1 2; 2 3; 3 1] or [1 2 1; 2 3 1; 3 1 1] (1 is the edge weight)
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% 'inc' - [-1 0 1
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% 1 -1 0
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% 0 1 -1]
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%
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% GB: last updated, Jul 12 2014
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function nodes = getNodes(graph,type)
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if strcmp(type,'adjacency') || strcmp(type,'adjlist')
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nodes=[1:max([size(graph,1) size(graph,2)])];
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elseif strcmp(type,'edgelist')
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nodes=unique([graph(:,1)' graph(:,2)']);
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elseif strcmp(type,'incidence')
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nodes=[1:size(graph,1)];
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else
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printf('getNodes(): "type" input can only be\n "adj" (adjacency, nxn matrix)\n, "edgelist" (mx2 or mx3 matrix)\n, "adjlist" (list, nx1 cell)\n or "inc" incidence (nxm matrix)\n')
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nodes = 'invalid graph type';
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end |