comparison toolboxes/FullBNT-1.0.7/graph/mk_nbrs_of_digraph_not_vectorized.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function [Gs, op, nodes] = mk_nbrs_of_digraph2(G0)
+% MK_NBRS_OF_DIGRAPH Make all digraphs that differ from G0 by a single edge deletion, addition or reversal
+% [Gs, op, nodes] = mk_nbrs_of_digraph(G0)
+% op{i} = 'add', 'del', or 'rev' is the operation used to create the i'th neighbor.
+% nodes(i,1:2) are the head and tail of the operated-on arc.
+
+[I,J] = find(G0);
+G0bar = setdiag(~G0, 0); % exclude self loops in graph complement
+[Ibar,Jbar] = find(G0bar);
+nnbrs = 2*length(I) + length(Ibar);
+Gs = cell(1, nnbrs);
+op = cell(1, nnbrs);
+nodes = zeros(nnbrs, 2);
+
+nbr = 1;
+% all single edge deletions
+for e=1:length(I)
+  i = I(e); j = J(e);
+  G = G0;
+  G(i,j) = 0;
+  Gs{nbr} = G;
+  op{nbr} = 'del';
+  nodes(nbr, :) = [i j];
+  nbr = nbr + 1;
+end
+
+% all single edge reversals
+for e=1:length(I)
+  i = I(e); j = J(e);
+  G = G0;
+  G(i,j) = 0;
+  G(j,i) = 1;
+  Gs{nbr} = G;
+  op{nbr} = 'rev';
+  nodes(nbr, :) = [i j];
+  nbr = nbr + 1;
+end
+
+[I,J] = find(~G0);
+% all single edge additions
+for e=1:length(I)
+  i = I(e); j = J(e);
+  G = G0;
+  if i ~= j % don't add self loops
+    G(i,j) = 1;
+    Gs{nbr} = G;
+    op{nbr} = 'add';
+    nodes(nbr, :) = [i j];
+    nbr = nbr + 1;
+  end
+end
+
+assert(nnbrs == nbr-1);