57 lines
1.6 KiB
Matlab
57 lines
1.6 KiB
Matlab
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% Degree-preserving random rewiring.
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% Note 1: Assume unweighted undirected graph.
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%
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% INPUTS: edge list, el (mx3) and number of rewirings, k (integer)
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% OUTPUTS: rewired edge list
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%
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% GB: last updated, Sep 26, 2012
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function el = rewire(el,k)
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rew=0;
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while rew<k
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% pick two random edges
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ind = randi(length(el),1,2);
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edge1=el(ind(1),:); edge2=el(ind(2),:);
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if length(intersect(edge1(1:2),edge2(1:2)))>0; continue; end % the two edges cannot overlap
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% else: rewire
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if not(ismember([edge1(1),edge2(2),1],el,'rows')) && not(ismember([edge1(2),edge2(1),1],el,'rows'))
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% first possibility: (e11,e22) & (e12,e21)
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el(ind(1),:)=[edge1(1),edge2(2),1];
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el(ind(2),:)=[edge1(2),edge2(1),1];
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% add the symmetric equivalents
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[~,inds1] = ismember([edge1(2),edge1(1),1],el,'rows');
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el(inds1,:)=[edge2(2),edge1(1),1];
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[~,inds2] = ismember([edge2(2),edge2(1),1],el,'rows');
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el(inds2,:)=[edge2(1),edge1(2),1];
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rew = rew + 1;
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elseif not(ismember([edge1(1),edge2(1),1],el,'rows')) && not(ismember([edge1(2),edge2(2),1],el,'rows'))
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% second possibility: (e11,e21) & (e12,e22)
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el(ind(1),:)=[edge1(1),edge2(1),1];
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el(ind(2),:)=[edge1(2),edge2(2),1];
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% add the symmetric equivalents
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[~,inds1] = ismember([edge1(2),edge1(1),1],el,'rows');
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el(inds1,:)=[edge2(1),edge1(1),1];
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[~,inds2] = ismember([edge2(2),edge2(1),1],el,'rows');
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el(inds2,:)=[edge2(2),edge1(2),1];
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rew = rew + 1;
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else
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'rewire(): creates a double edge'
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continue
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end
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end
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