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

first hg version after svn

+function Gs = mk_all_dags(N, order)
+% MK_ALL_DAGS generate all DAGs on N variables
+% G = mk_all_dags(N)
+%
+% G = mk_all_dags(N, order) only generates DAGs in which node i has parents from 
+% nodes in order(1:i-1). Default: order=[] (no constraints).
+%
+% G{i} is the i'th dag
+%
+% Note: the number of DAGs is super-exponential in N, so don't call this with N > 4.
+
+if nargin < 2, order = []; end
+
+use_file = 0;
+
+global BNT_HOME
+fname = sprintf('%s/DAGS%d.mat', BNT_HOME, N);
+if use_file & exist(fname, 'file')
+  S = load(fname, '-mat');
+  fprintf('loading %s\n', fname);
+  Gs = S.Gs;
+  return;
+end
+
+m = 2^(N*N);
+ind = ind2subv(2*ones(1,N^2), 1:m);
+Gs = {};
+j = 1;
+directed = 1;
+for i=1:m
+  dag = reshape(ind(i,:)-1, N, N);
+  if acyclic(dag, directed)
+    out_of_order = 0;
+    if ~isempty(order)
+      for k=1:N-1
+	if any(dag(order(k+1:end), k))
+	  out_of_order = 1;
+	  break;
+	end
+      end
+    end
+    if ~out_of_order
+      Gs{j} = dag;
+      j = j + 1;
+    end
+  end
+end
+
+if use_file
+  disp(['mk_all_dags: saving to ' fname '!']);
+  save(fname, 'Gs');
+end