isdag.m.svn-base

bayesian network structrue learning matlab program

function b = isdag(G)
b = sum(sum(G.*G'));        % How many undirected arcs ? (x2)
b=~b & ~isempty(G);
if b
  M = expm(full(G)) - eye(length(G)); M = (M>0);
  b = b & find(sum(sum(eye(length(G)).*M))); % is there no cycle ?
end